84 results on '"Serotonin Receptor Binding"'
Search Results
2. In silico decryption of serotonin–receptor binding: local non-covalent interactions and long-range conformational changes
- Author
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Padmabati Mondal
- Subjects
chemistry.chemical_classification ,0303 health sciences ,Hydrogen bond ,Chemistry ,General Chemical Engineering ,Stacking ,General Chemistry ,Interaction energy ,010402 general chemistry ,01 natural sciences ,Serotonin Receptor Binding ,0104 chemical sciences ,03 medical and health sciences ,Molecular dynamics ,Serotonin binding ,Biophysics ,Non-covalent interactions ,Binding site ,030304 developmental biology - Abstract
Serotonin–receptor binding is the key step in the process behind serotonin functionality, including several psychological and physiological behaviours. This study is focused on identifying the main non-covalent interactions controlling the stability of serotonin–receptor complexes as well as the main conformational changes in the receptor due to serotonin–receptor binding using classical molecular dynamics simulations and quantum chemical calculations. A qualitative analysis based on two order parameters ((i) the centre of mass distance and (ii) the angle between the surface normals of each aromatic residue and serotonin in the binding site) on the serotonin–receptor complex trajectory suggests that the T-type stacking interaction is predominant in the binding site. Quantum chemical calculations of the stacking interaction energy provide the quantitative contributions of important aromatic residues to the stabilization of the complex. Furthermore, a three body stacking interaction (named ‘L’-type) was observed and likely contributes to the stability of the complex. Direct and water-mediated hydrogen bonding between the residues in the binding site and serotonin contributes to the complex stability. Principal component analysis of the molecular dynamics simulation trajectory of the serotonin–receptor complex and the apo-receptor in water indicates that the whole receptor is significantly stabilized due to serotonin binding. An analysis based on the dynamic cross correlation function reflects the strong correlation between trans-membrane (TM)3, TM5, TM6 (containing residues responsible for the stacking interaction and hydrogen bonding) and mini-G0 which may participate in signal transduction leading to the functionality of serotonin.
- Published
- 2020
3. Serotonin Receptor Binding Characteristics of Geissoschizine Methyl Ether, an Indole Alkaloid in Uncaria Hook
- Author
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Yasushi Ikarashi, Kazushige Mizoguchi, and Kyoji Sekiguchi
- Subjects
0301 basic medicine ,Agonist ,medicine.drug_class ,pharmacological aspect ,Yokukansan ,yokukansan ,Biology ,Pharmacology ,Serotonergic ,Biochemistry ,Serotonin Receptor Binding ,Binding, Competitive ,Article ,Indole Alkaloids ,03 medical and health sciences ,0302 clinical medicine ,Drug Discovery ,medicine ,Animals ,Humans ,BPSD ,Receptor ,5-HT receptor ,Alkaloid ,Organic Chemistry ,Brain ,Geissoschizine methyl ether ,Rats ,030104 developmental biology ,Uncaria ,Receptors, Serotonin ,Molecular Medicine ,Serotonin ,pharmacokinetics ,030217 neurology & neurosurgery ,dementia ,Drugs, Chinese Herbal ,Protein Binding - Abstract
Background: Geissoschizine methyl ether (GM) is one of the indole alkaloids in Uncaria hook, and an active ingredient of yokukansan (YKS) that improves behavioral and psychological symptoms of dementia (BPSD) in patients with several types of dementia. The pharmacological action of GM has been related to various serotonin (5-HT) receptor subtypes. Objective: The aim of this article is to review the binding characteristics of GM to the 5-HT receptor subtypes in the brains using our own data and previous findings. Method: Competitive receptor-binding and agonist/antagonist activity assays for several 5-HT receptor subtypes were performed. Moreover, the articles describing pharmacokinetics and brain distribution of GM were searched in PubMed. Results: GM bound the following 5-HT receptor subtypes: 5-HT1A, 5-HT1B, 5-HT2A, 5-HT2B, 5-HT2C, 5- HT4, 5-HT5A, 5-HT6, and 5-HT7. Among these receptors, GM had partial agonistic activity for 5-HT1A receptors and antagonistic activity for 5-HT2A, 5-HT2B, 5-HT2C, and 5-HT7 receptors. Also, GM was metabolized by various CYP isoforms, mainly CYP3A4. Parent/unchanged GM was detected in both the blood and brain of rats after oral administration of YKS. In the brains, GM was presumed to bind to 5- HT1A, 5-HT2A, 5-HT2B, 5-HT2C, and 5-HT7 receptors on neuron-like large cells mainly in the frontal cortex. Conclusion: These results suggest that GM is a pharmacologically important alkaloid that regulates various serotonergic activities or functions by binding to multiple 5-HT receptor subtypes. Thus, this review provides recent 5-HT receptor-related evidence that GM is partly responsible for pharmacological effects of YKS.
- Published
- 2018
4. Recognition of repulsive and attractive regions of selected serotonin receptor binding site using FMO-EDA approach
- Author
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Rafał Kafel, Anna K. Drabczyk, Rafał Kurczab, Jolanta Jaśkowska, and Paweł Śliwa
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ONIOM ,Models, Molecular ,Serotonin 5-HT1 Receptor Antagonists ,010402 general chemistry ,Ligands ,01 natural sciences ,Serotonin Receptor Binding ,Molecular mechanics ,Catalysis ,Piperazines ,Inorganic Chemistry ,0103 physical sciences ,Humans ,Molecular orbital ,Physical and Theoretical Chemistry ,Binding site ,G protein-coupled receptor ,Binding Sites ,010304 chemical physics ,Chemistry ,Organic Chemistry ,0104 chemical sciences ,Computer Science Applications ,Crystallography ,Molecular geometry ,Computational Theory and Mathematics ,Receptors, Serotonin ,Helix ,Serotonin 5-HT2 Receptor Antagonists ,Serotonin Antagonists ,Protein Binding - Abstract
The complexes of selected long-chain arylpiperazines with homology models of 5-HT1A, 5-HT2A, and 5-HT7 receptors were investigated using quantum mechanical methods. The molecular geometries of the ligand-receptor complexes were firstly optimized with the Our own N-layered Integrated molecular Orbital and molecular Mechanics (ONIOM) method. Next, the fragment molecular orbitals method with an energy decomposition analysis scheme (FMO-EDA) was employed to estimate the interaction energies in binding sites. The results clearly showed that orthosteric binding sites of studied serotonin receptors have both attractive and repulsive regions. In the case of 5-HT1A and 5-HT2A two repulsive areas, located in the lower part of the binding pocket, and one large area of attraction engaging many residues at the top of all helices were identified. Additionally, for the 5-HT7 receptor, the third area of destabilization located at the extracellular end of the helix 6 was found.
- Published
- 2018
5. Les relations entre le bisphénol A et les troubles du spectre autistique se précisent : la sérotonine est-elle le lien manquant ?
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C. Dejean and D. Sarrouilhe
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0301 basic medicine ,endocrine system ,medicine.medical_specialty ,Breast milk ,Serotonergic ,Serotonin Receptor Binding ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Arts and Humanities (miscellaneous) ,Internal medicine ,medicine ,Serotonin transporter ,biology ,business.industry ,Neurotoxicity ,medicine.disease ,Psychiatry and Mental health ,030104 developmental biology ,Xenoestrogen ,Endocrinology ,chemistry ,biology.protein ,Autism ,Serotonin ,business ,030217 neurology & neurosurgery - Abstract
The etiology of autism spectrum disorders (ASD) is believed to be multifactorial and to involve genetic and environmental components. Environmental chemical exposures are increasingly understood to be important in causing neurotoxicity in fetuses and newborns. Recent data from the Centers for Disease Control and Prevention in the United States suggest a substantial increase in ASD prevalence, only partly explicable by factors such as diagnostic substitution. Bisphenol A (BPA) is an ubiquitous xenoestrogen widely employed in a variety of consumer products including plastic and metal food and beverage containers, dental sealants and fillings, medical equipment and thermal receipts. Therefore, most people are exposed almost continuously to BPA in industrialized countries. Sources of BPA exposure are predominantly diet, but also through inhalation or dermal absorption. BPA can be measured in many human fluids and tissues including saliva, serum, urine, amniotic fluid, follicular fluid, placental tissue and breast milk. There is concern that BPA exposure may influence human brain development and may contribute to the increasing prevalence of neurodevelopmental and behavioural problems. Epigenetic mechanisms are suggested by a mouse study that demonstrated that BPA exposure during gestation had long lasting, transgenerational effects on social recognition. Previous epidemiological studies suggested a relationship between maternal BPA exposure and ASD. A recent study of 46 children with ASD and 52 controls found for the first time a direct association between children with ASD and BPA exposure and demonstrated that BPA is not metabolized well in children with ASD. The metabolomic analyses showed a correlation between ASD and essential amino acid metabolism pathways. Essential amino acids are precursors of neurotransmitters, for example tryptophan for serotonin. Fetal and prenatal BPA exposure was suggested to perturb the serotonergic system in rat and mice models. On the other hand, hyperserotonemia was reported in approximately one-third of autistic patients and also in relatives. Moreover, neuroimaging studies revealed two fundamentally different types of serotonin synthesis abnormality in children with autism compared to age-matched nonautistic children, a difference in whole-brain capacity and focal abnormalities. Finally, decreased serotonin transporter and serotonin receptor binding have been reported in both children and adults with autism. So, the link between BPA and autism could be a defect of the normal in utero or perinatal serotonergic system development. In France, BPA was banned in baby bottles in 2010 and in any food or beverage packaging since January 2015. Therefore, there is an urgent need to find safe alternatives in the use of BPA in the manufacture of industrial products.
- Published
- 2017
6. Influence of B vitamins on binding properties of serotonin receptors in the CNS of rats.
- Author
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Dakshinamurti, K., Sharma, S., and Bonke, D.
- Abstract
Treatment of normal adult rats with pyridoxine or a B-vitamin mixture resembling Neurobion 1 led to an increase in serotonin content of various brain areas and to a decrease in the number of serotonin S receptors. The results indicate that the pyridoxal phosphate level in regions of the brain regulates the extent of decarboxylation of 5-hydroxytryptophan, the precursor of serotonin. The results also suggest a continuum from deficiency in pyridoxine to treatment of animals with a moderate excess of pyridoxine which is reflected in the synthesis and secretion into the synaptic cleft of the neurotransmitter serotonin. [ABSTRACT FROM AUTHOR]
- Published
- 1990
- Full Text
- View/download PDF
7. Comparison of the pharmacological characteristics of 5 HT and 5 HT binding sites with those of serotonin autoreceptors which modulate serotonin release.
- Author
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Martin, Louis and Sanders-Bush, Elaine
- Abstract
The abilities of various 5-hydroxytryptamine (5 HT) receptor agonists to inhibit the K-evoked release of H-5 HT from prelabelled synaptosomal preparations of rat hypothalamus were studied. In addition, the abilities of various 5 HT receptor agonists and antagonists to compete with H-5 HT and H-spiperone binding to 5 HT and 5 HT sites, respectively, were determined. The orders of potency of the agonists for inhibiting K-evoked H-5 HT release and for inhibiting H-5 HT and H-spiperone binding were then compared. Likewise, the abilities of the antagonists to block the inhibitory effect of 5 HT on its own K-evoked release (data from previous studies) were compared to the affinities of these compounds for the H-5 HT and H-spiperone binding sites. A significant correlation was obtained between the effects of the agonists on K-evoked H-5 HT release and H-5 HT binding but not H-spiperone binding. Furthermore, the antagonists which have been demonstrated to block the inhibitory effect of 5 HT on its own release (methiothepin, methysergide, metergoline and quipazine) had higher affinities for the H-5 HT binding site than the other antagonists. A similar correlation could not be made between antagonist activity at the 5 HT autoreceptor and affinity for the H-spiperone binding site. These results demonstrate that the 5 HT autoreceptor and the 5 HT binding site have similar pharmacological characteristics. On this basis, it is suggested that 5 HT autoreceptor and the 5 HT binding site may be related 5 HT receptor sites. [ABSTRACT FROM AUTHOR]
- Published
- 1982
- Full Text
- View/download PDF
8. Structural, Functional, and Molecular Neuroimaging in Depression
- Author
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Kai Zhang, Hong Zhang, Jing Huang, Mei Tian, and Jin Feng
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biology ,business.industry ,Dopaminergic ,Serotonergic ,Serotonin Receptor Binding ,Neurochemical ,Neuroimaging ,biology.protein ,Medicine ,business ,Prefrontal cortex ,Neuroscience ,Default mode network ,Dopamine transporter - Abstract
Depression is a globally prevalent psychiatric disorder which is associated with genetic, environmental, and psychological factors. Structural, functional, molecular neuroimaging approaches, particularly magnetic resonance imaging (MRI) and radionuclide imaging techniques, have been increasingly used to detect neurobiological changes, analyze neurochemical correlates, and parse pathophysiological mechanisms underlying depression. With the use of MRI, structural abnormalities in the prefrontal-subcortical regions involved in the cognitive control of affective state are discovered to be associated with aberrant neural activity. Besides, abnormal functional networks particularly default mode network, as revealed by functional MRI, are likely related to aberrant metabolism and dysfunctional serotonergic system detected by radionuclide imaging. Moreover, radionuclide imaging studies demonstrate that serotonin deficiency in the midbrain may play a critical role in the genesis of depression, and the incongruent reduction of serotonin receptor binding in the prefrontal cortex and midbrain may contribute to the action of suicide. Apart from serotonergic system, dysfunctional striatal dopaminergic system has been identified in depression, and a great dopamine transporter availability may be a state marker of a depressive episode as detected by radionuclide imaging. Future multimodal neuroimaging investigations carried out in multiple sites are essential to clarify the potential associations among these structural, functional, and molecular changes, as well as their implications for behavior and cognitive.
- Published
- 2017
9. Aging-induced changes in brain regional serotonin receptor binding: Effect of Carnosine
- Author
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Mrinal K. Poddar and S. Banerjee
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0301 basic medicine ,Male ,endocrine system ,medicine.medical_specialty ,Aging ,Serotonin ,Carnosine ,Hippocampus ,Serotonergic ,Serotonin Receptor Binding ,Antioxidants ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Internal medicine ,medicine ,Animals ,Rats, Wistar ,Receptor ,Chemistry ,General Neuroscience ,Brain ,Rats ,030104 developmental biology ,medicine.anatomical_structure ,Endocrinology ,Monoamine neurotransmitter ,nervous system ,Cerebral cortex ,Receptors, Serotonin ,030217 neurology & neurosurgery - Abstract
Monoamine neurotransmitter, serotonin (5-HT) has its own specific receptors in both pre- and post-synapse. In the present study the role of carnosine on aging-induced changes of [(3)H]-5-HT receptor binding in different brain regions in a rat model was studied. The results showed that during aging (18 and 24 months) the [(3)H]-5-HT receptor binding was reduced in hippocampus, hypothalamus and pons-medulla with a decrease in their both Bmax and KD but in cerebral cortex the [(3)H]-5-HT binding was increased with the increase of its only Bmax. The aging-induced changes in [(3)H]-5-HT receptor binding with carnosine (2.0 μg/kg/day, intrathecally, for 21 consecutive days) attenuated in (a) 24-month-aged rats irrespective of the brain regions with the attenuation of its Bmax except hypothalamus where both Bmax and KD were significantly attenuated, (b) hippocampus and hypothalamus of 18-month-aged rats with the attenuation of its Bmax, and restored toward the [(3)H]-5-HT receptor binding that observed in 4-month-young rats. The decrease in pons-medullary [(3)H]-5-HT binding including its Bmax of 18-month-aged rats was promoted with carnosine without any significant change in its cerebral cortex. The [(3)H]-5-HT receptor binding with the same dosages of carnosine in 4-month-young rats (a) increased in the cerebral cortex and hippocampus with the increase in their only Bmax whereas (b) decreased in hypothalamus and pons-medulla with a decrease in their both Bmax and KD. These results suggest that carnosine treatment may (a) play a preventive role in aging-induced brain region-specific changes in serotonergic activity (b) not be worthy in 4-month-young rats in relation to the brain regional serotonergic activity.
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- 2015
10. Neuron density and serotonin receptor binding in prefrontal cortex in suicide
- Author
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Hanga Galfalvy, Mihran J. Bakalian, J. John Mann, Mark D. Underwood, Suham Kassir, and Victoria Arango
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Adult ,Male ,Imipramine ,Ketanserin ,Adolescent ,Prefrontal Cortex ,Tritium ,Serotonergic ,Serotonin Receptor Binding ,Article ,Young Adult ,Serotonin Agents ,medicine ,Humans ,Pharmacology (medical) ,Prefrontal cortex ,Serotonin transporter ,5-HT receptor ,Aged ,Neurons ,Pharmacology ,8-Hydroxy-2-(di-n-propylamino)tetralin ,Depressive Disorder, Major ,biology ,Middle Aged ,Up-Regulation ,Suicide ,Psychiatry and Mental health ,medicine.anatomical_structure ,nervous system ,Case-Control Studies ,Postmortem Changes ,Receptors, Serotonin ,biology.protein ,Autoradiography ,Female ,Serotonin ,Neuron ,Psychology ,Neuroscience ,Protein Binding ,medicine.drug - Abstract
Although serotonin receptor and cytoarchitectonic alterations are reported in prefrontal cortex (PFC) in suicide and depression, no study has considered binding relative to neuron density. Therefore, we measured neuron density and serotonin transporter (SERT), 5-HT1A and 5-HT2A binding in matched suicides and controls. Suicides and normal controls (n=15 matched pairs) were psychiatrically characterized. Neuron density and binding were determined in dorsal [Brodmann area (BA) 9] and ventral (BA 47) PFC by stereology and quantitative autoradiography in near-adjacent sections. Binding index was defined as the ratio of receptor binding to neuron density. Suicides had lower neuron density in the gyrus of both areas. The binding index was lower for SERT in BA 47 but not in BA9; the 5-HT1A binding index was higher in BA 9 but not in BA 47, while the 5-HT2A binding index was not different between groups. SERT binding was lower in suicides in BA 47 but not BA 9, while 5-HT1A binding was higher in BA 9 but not BA 47. SERT binding negatively correlated with 5-HT1A binding in BA 47 in suicides. Neuron density decreased with age. The 5-HT1A binding index was higher in females than males. We found lower neuron density and lower SERT binding index in both PFC regions in suicides. More 5-HT1A binding with less SERT binding and the negative correlation in depressed suicides suggests post-synaptic receptor up-regulation, and it is independent of the difference in neuron density. Thus, abnormalities in both cortical neurons and in their serotonergic innervation are present in suicides and future studies will need to determine whether cortical changes reflect the trophic effect of altered serotonin innervation.
- Published
- 2011
11. An approach for serotonin depletion in pigs: Effects on serotonin receptor binding
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Pia Weikop, Anders Ettrup, Birgitte Rahbek Kornum, and Gitte M. Knudsen
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Serotonin ,medicine.medical_specialty ,Swine ,Citalopram ,Biology ,Tritium ,Serotonergic ,Serotonin Receptor Binding ,Functional Laterality ,Cellular and Molecular Neuroscience ,Internal medicine ,Fenclonine ,medicine ,Animals ,Biogenic Monoamines ,Drug Interactions ,Tissue Distribution ,Serotonin Antagonists ,Serotonin Uptake Inhibitors ,Chromatography, High Pressure Liquid ,5-HT receptor ,Analysis of Variance ,Dose-Response Relationship, Drug ,Brain ,Endocrinology ,5-HT6 receptor ,Autoradiography ,Female ,Receptors, Serotonin, 5-HT4 ,Selective Serotonin Reuptake Inhibitors ,Protein Binding ,medicine.drug - Abstract
Depletion of central serotonin (5-HT) levels and dysfunction in serotonergic transmission are implicated in a variety of human CNS disorders. The mechanisms behind these serotonergic deficits have been widely studied using rodent models, but only to a limited extent in larger animal models. The pig is increasingly used as an experimental animal model especially in neuroscience research. Here, we present an approach for serotonin depletion in the pig brain. Central serotonin depletion in Danish Landrace pigs was achieved following 4 days treatment with para-chlorophenylalanine (pCPA). On day 5, tissue concentrations of 5-HT in seven distinct brain structures from one hemisphere: frontal and occipital cortex, striatum, hippocampus, cerebellum, rostral, and caudal brain stem, were determined. The other hemisphere was processed for receptor autoradiography. Treatments with 50 mg/kg and 100 mg/kg pCPA caused average decreases in 5-HT concentrations of 61% ± 14% and 66% ± 16%, respectively, and a substantial loss of 5-HT immunostaining was seen throughout the brain. The serotonin depletion significantly increased 5-HT₄ receptor binding in nucleus accumbens, but did not alter 5-HT(1A) and 5-HT(2A) receptor or serotonin transporter binding in any brain region. In conclusion, 4 days treatment with pCPA effectively reduces 5-HT levels in the pig brain. Further, whereas several 5-HT markers did not change after the pCPA treatment, 5-HT₄ receptors were consistently upregulated, indicating a greater susceptibility of this receptor to altered 5-HT levels. This porcine model of serotonin depletion will be useful in future studies of cerebral serotonergic dysfunction.
- Published
- 2010
12. Reduced midbrain-pons serotonin transporter binding in patients with obsessive?compulsive disorder
- Author
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Elsebeth S. Hansen, T. B. Jakobsen, J. H. Lønborg, Lars H. Pinborg, T. G. Bolwig, and Steen G. Hasselbalch
- Subjects
Adult ,Male ,Obsessive-Compulsive Disorder ,medicine.medical_specialty ,Statistics as Topic ,Serotonergic ,Serotonin Receptor Binding ,Iodine Radioisotopes ,chemistry.chemical_compound ,Cocaine ,Mesencephalon ,Reference Values ,Pons ,Internal medicine ,mental disorders ,medicine ,Humans ,Neurotransmitter ,Serotonin transporter ,Serotonin Plasma Membrane Transport Proteins ,Tomography, Emission-Computed, Single-Photon ,biology ,Binding potential ,Middle Aged ,medicine.disease ,Logan plot ,Frontal Lobe ,Psychiatry and Mental health ,Endocrinology ,chemistry ,biology.protein ,Female ,Serotonin ,Nerve Net ,Psychology ,Neuroscience ,Anxiety disorder - Abstract
Objective: To evaluate current hypothesis regarding the pathophysiology of obsessive–compulsive disorder (OCD) by studying the serotonin receptor binding in patients with OCD using single photon emission computerized tomography (SPECT). Method: We studied nine patients (four men and five women, age range 21–56 years) fulfilling the DMS-III-R criteria for OCD using SPECT and the serotonin transporter (SERT) tracer 123I-β-CIT. SERT binding potential (BP2) was determined by Logan plot derived from seven scans obtained during 10–400 min. Results: The binding of 123I-β-CIT in midbrain-pons was reduced in OCD patients when compared with controls (BP2 0.97 ± 0.07 vs. 0.84 ± 0.12, P = 0.011). There was no correlation between BP2 and any of the clinical variables (age at onset, disease duration, and Yale-Brown Obsessive–Compulsive Scale score). Conclusion: This study suggests a reduced serotonergic input into the fronto-subcortical circuits in OCD, thereby diminishing the inhibitory regulation of serotonin on these circuits.
- Published
- 2007
13. Fatty acids differentially affect serotonin receptor and transporter binding in the rat brain
- Author
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T.M. du Bois, W. Bell, Xu-Feng Huang, and Chao Deng
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Male ,medicine.medical_specialty ,Ketanserin ,Saturated fat ,Biology ,Serotonin Receptor Binding ,Rats, Sprague-Dawley ,Radioligand Assay ,Polyunsaturated fat ,Internal medicine ,Free fatty acid receptor 1 ,medicine ,Animals ,Ergolines ,5-HT receptor ,Serotonin Plasma Membrane Transport Proteins ,chemistry.chemical_classification ,Analysis of Variance ,General Neuroscience ,Fatty Acids ,Brain ,Fatty acid ,Rats ,Paroxetine ,Endocrinology ,chemistry ,Receptors, Serotonin ,Serotonin Antagonists ,Selective Serotonin Reuptake Inhibitors ,Protein Binding ,Polyunsaturated fatty acid ,medicine.drug - Abstract
The aim of this study was to examine the influence of different fat diets on serotonin receptor and transporter binding. Male Sprague-Dawley rats were fed a diet of either high saturated fat, omega-6 polyunsaturated fatty acid, omega-3 polyunsaturated fatty acid or low fat (control) for eight weeks. Using Beta-Imager quantification techniques, [(3)H]ketanserin, [(3)H]mesulergine and [(3)H]paroxetine binding to serotonin (5-HT)(2A), 5-HT(2C) receptors and 5-HT transporters (5-HTT) was measured throughout the brain in all four groups. All three high fatty acid diets influenced serotonin receptor binding, however the most pronounced effects were that compared with the low fat control group, i) 5-HT(2A) receptor binding was increased in the caudate putamen, but reduced in the mammillary nucleus in high saturated fat and high omega-6 polyunsaturated fatty acid diet groups; ii) 5-HT(2C) receptor binding was reduced in the mamillary nucleus of saturated fat group and reduced in prefrontal cortex of the omega-6 polyunsaturated fatty acid and omega-3 polyunsaturated fatty acid groups; and iii) 5-HTT binding was reduced in the hippocampus in the omega-6 polyunsaturated fatty acid group. Overall, the omega-6 polyunsaturated fatty acid diet exerted the most influence on serotonin receptor and transporter binding. These results may be of importance in relation to neuropsychiatric diseases such as schizophrenia, where associations between altered fatty acid levels and the serotonergic system have been made.
- Published
- 2006
14. Metabolism and Receptor Binding of Serotonin in Brain Structures During Performance of a Conditioned Passive Avoidance Response
- Author
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G. F. Molodtsova
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Male ,Serotonin ,medicine.medical_specialty ,Time Factors ,Monoamine oxidase ,Conditioning, Classical ,Striatum ,Tritium ,Serotonergic ,Serotonin Receptor Binding ,chemistry.chemical_compound ,Internal medicine ,Avoidance Learning ,medicine ,Animals ,Rats, Wistar ,Prefrontal cortex ,Neurotransmitter ,Monoamine Oxidase ,Brain Chemistry ,Behavior, Animal ,Chemistry ,General Neuroscience ,Brain ,Hydroxyindoleacetic Acid ,Rats ,Endocrinology ,nervous system ,Receptors, Serotonin ,5-HT6 receptor ,Neuroscience ,Protein Binding - Abstract
The levels of serotonin and its metabolite 5-hydroxyindoleacetic acid, monoamine oxidase activity, and the specific binding of the radioligand [3H]serotonin were measured in the prefrontal cortex, striatum, amygdaloid complex, hippocampus, and periacqueductal gray matter of the midbrain in rats at different time points after training to a conditioned passive avoidance reaction. Changes in serotoninergic activity were found to be characteristic only for the process of reproducing the conditioned reaction. The metabolism and serotonin receptor binding in these brain structures did not change immediately after the training period or one day after this, or in conditions of failure to reproduce the reaction because of amnesia, or in untrained animals. The involvement of the brain serotoninergic system in the process of performing the conditioned reaction was found to demonstrate a spatial-structural selectivity: the metabolism and receptor binding of serotonin changed in the amygdaloid complex, periacqueductal gray matter, and the striatum, while no changes were seen in the hippocampus or prefrontal cortex. All three brain structures showed decreases in [3H]serotonin receptor binding of. Serotonin levels did not change, though the amygdaloid complex and periacqueductal gray matter showed increases in oxidative deamination of serotonin and increases in the active transport of the metabolite, while the striatum showed decreases in serotonin catabolism. The differences in the catabolism of this neurotransmitter suggest that the decrease in serotonin receptor binding in these brain structures depends on different synaptic processes — presynaptic in the striatum and postsynaptic in the amygdaloid complex and periacqueductal gray matter. It is concluded that the decrease in the functional activity of serotoninergic transmission in the amygdaloid complex and periacqueductal gray matter is one of the mechanisms involved in activation of the emotiogenic system triggering the process of reproduction of the memory trace.
- Published
- 2005
15. Dopamine/serotonin receptor ligands. Part VIII[1]:the dopamine receptor antagonist LE300 - modelled and X-ray structure plus further pharmacological characterization, including serotonin receptor binding, biogenic amine transporter testing and in vivo testings
- Author
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Jochen Lehmann, Michael Decker, Martin Nieger, and Klaus-Jürgen Schleifer
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Pharmacology ,Chemistry ,Organic Chemistry ,General Medicine ,Serotonin Receptor Binding ,Dopamine receptor D3 ,Dopamine ,Dopamine receptor D2 ,Drug Discovery ,medicine ,Serotonin ,Serotonin Antagonists ,Receptor ,5-HT receptor ,medicine.drug - Abstract
LE300, a benz[d]indolo[2,3-g]azecine with nanomolar affinities to the hD1 receptor family, has been further pharmacologically characterized and its modelled structure was compared to its X-ray structure in order to explain NMR data, that was not in accordance to the X-ray structure. Moderate affinity at the hD3 receptor was determined, nanomolar affinities were found at the 5-HT2A and 5-HT2C receptors, micromolar affinity at the 5-HT1A receptor using binding assays. Functional studies indicate moderate antagonist activity at the 5-HT2A site . No activity was found at dopamine, serotonin and norepinephrine transporters. These results suggested the use of LE300 for cocaine addiction treatment. High activities were found using in vivo testing: LE300 suppressed spontanous locomotor activity with an ID50 of 1.24 mg/kg and attenuated locomotor activity induced by 20 mg/kg cocaine with an AD50 of 1.50 mg/kg. It failed to substitute for the discriminative stimulus effects produced by cocaine.
- Published
- 2004
16. Pteridines and affective disorders
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Durk Fekkes, R. Hoekstra, and Psychiatry
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medicine.medical_specialty ,Neopterin ,Biopterin ,Disease ,Tetrahydrobiopterin ,Serotonin Receptor Binding ,Psychiatry and Mental health ,chemistry.chemical_compound ,Endocrinology ,chemistry ,Dopamine ,Internal medicine ,medicine ,Serotonin ,Psychology ,Biological Psychiatry ,Pteridine ,medicine.drug - Abstract
The pteridine tetrahydrobiopterin (BH4) is an essential cofactor in the biosynthesis of dopamine, (nor)epinephrine, serotonin and nitric oxide (NO). Furthermore, BH4 has a direct influence on release mechanisms of these neurotransmitters and on serotonin receptor binding activityimmunology. The synthesis of BH4 is stimulated by interferon-gamma and hence there is a close relationship with the immune systemHPA-axis. In animal experiments it was also found that the hypothalamus–pituitary–adrenal axis influences the pteridine metabolism. In clinical studies, so far, no evidence has been found for this relationshipdiseases. A congenital biopterin deficiency results in atypical phenylketonuria with severe neuropsychiatric symptoms. In several neurological diseases, such as Parkinson's disease, decreased levels of BH4 are founddepression. Since 1984 there have been reports on decreased biopterin and increased neopterin levels in urine and plasma of depressed patients. Conflicting results have also been found, however, due probably to methodological problemstherapy. Until now, oral administration of BH4 to depressed patients has been performed by two investigators, which resulted in mainly temporal clinical improvementdiscussion. Understanding of biochemical mechanisms in which pteridines are involved may contribute to our knowledge of the pathogenesis and treatment of affective disorders. This paper aims to provide an overview of the relevant literature and warrant for further research on this intriguing compound.
- Published
- 2002
17. Developmental changes in brain serotonin synthesis capacity in autistic and nonautistic children
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Jennifer A. Lee, James Janisse, Michael E. Behen, Otto Muzik, Harry T. Chugani, Robert Rothermel, and Diane C. Chugani
- Subjects
medicine.medical_specialty ,Psychosis ,Serotonin uptake ,Central nervous system ,medicine.disease ,Serotonin Receptor Binding ,Developmental disorder ,Endocrinology ,medicine.anatomical_structure ,Neurology ,Internal medicine ,medicine ,Autism ,Neurology (clinical) ,Serotonin ,Sibling ,Psychology ,Neuroscience - Abstract
Serotonin content, serotonin uptake sites, and serotonin receptor binding measured in animal studies are all higher in the developing brain, compared with adult values, and decline before puberty. Furthermore, a disruption of synaptic connectivity in sensory cortical regions can result from experimental increase or decrease of brain serotonin before puberty. The purpose of the present study was to determine whether brain serotonin synthesis capacity is higher in children than in adults and whether there are differences in serotonin synthesis capacity between autistic and nonautistic children. Serotonin synthesis capacity was measured in autistic and nonautistic children at different ages, using alpha[11C]methyl-L-tryptophan and positron emission tomography. Global brain values for serotonin synthesis capacity (K complex) were obtained for autistic children (n = 30), their nonautistic siblings (n = 8), and epileptic children without autism (n = 16). K-complex values were plotted according to age and fitted to linear and five-parameter functions, to determine developmental changes and differences in serotonin synthesis between groups. For nonautistic children, serotonin synthesis capacity was more than 200% of adult values until the age of 5 years and then declined toward adult values. Serotonin synthesis capacity values declined at an earlier age in girls than in boys. In autistic children, serotonin synthesis capacity increased gradually between the ages of 2 years and 15 years to values 1.5 times adult normal values and showed no sex difference. Significant differences were detected between the autistic and epileptic groups and between the autistic and sibling groups for the change with age in the serotonin synthesis capacity. These data suggest that humans undergo a period of high brain serotonin synthesis capacity during childhood, and that this developmental process is disrupted in autistic children.
- Published
- 1999
18. Test-retest variability of serotonin 5-HT2A receptor binding measured with positron emission tomography and [18F]altanserin in the human brain
- Author
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Julie C. Price, Carolyn C. Meltzer, Yiyun Huang, N.S. Mason, R. A. Sweet, Daniel P. Holt, N. Simpson, Chet Mathis, Donald Sashin, Thomas E. Nichols, Brian J. Lopresti, and Gwenn S. Smith
- Subjects
medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Human brain ,Serotonin Receptor Binding ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,medicine.anatomical_structure ,Endocrinology ,chemistry ,Positron emission tomography ,Internal medicine ,Altanserin ,medicine ,Radioligand ,Serotonin ,Nuclear medicine ,business ,Receptor ,5-HT receptor - Abstract
The role of serotonin in CNS function and in many neuropsychiatric diseases (e.g., schizophrenia, affective disorders, degenerative dementias) support the development of a reliable measure of serotonin receptor binding in vivo in human subjects. To this end, the regional distribution and intrasubject test-retest variability of the binding of [18F]altanserin were measured as important steps in the further development of [18F]altanserin as a radiotracer for positron emission tomography (PET) studies of the serotonin 5-HT2A receptor. Two high specific activity [18F]altanserin PET studies were performed in normal control subjects (n = 8) on two separate days (2-16 days apart). Regional specific binding was assessed by distribution volume (DV), estimates that were derived using a conventional four compartment (4C) model, and the Logan graphical analysis method. For both analysis methods, levels of [18F]altanserin binding were highest in cortical areas, lower in the striatum and thalamus, and lowest in the cerebellum. Similar average differences of 13% or less were observed for the 4C model DV determined in regions with high receptor concentrations with greater variability in regions with low concentrations (16-20%). For all regions, the absolute value of the test-retest differences in the Logan DV values averaged 12% or less. The test-retest differences in the DV ratios (regional DV values normalized to the cerebellar DV) determined by both data analysis methods averaged less than 10%. The regional [18F]altanserin DV values using both of these methods were significantly correlated with literature-based values of the regional concentrations of 5-HT2A receptors determined by postmortem autoradiographic studies (r2 = 0.95, P < 0.001 for the 4C model and r2 = 0.96, P < 0.001 for the Logan method). Brain uptake studies in rats demonstrated that two different radiolabeled metabolites of [18F]altanserin (present at levels of 3-25% of the total radioactivity in human plasma 10-120 min postinjection) were able to penetrate the blood-brain barrier. However, neither of these radiolabeled metabolites bound specifically to the 5-HT2A receptor and did not interfere with the interpretation of regional [18F]altanserin-specific binding parameters obtained using either a conventional 4C model or the Logan graphical analysis method. In summary, these results demonstrate that the test-retest variability of [18F]altanserin-specific binding is comparable to that of other PET radiotracers and that the regional specific binding of [18F]altanserin in human brain was correlated with the known regional distribution of 5-HT2A receptors. These findings support the usefulness of [18F]altanserin as a radioligand for PET studies of 5-HT2A receptors.
- Published
- 1998
19. Structural modification of receptor-binding technetium-99m complexes in order to improve brain uptake
- Author
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Bernd Johannsen, Peter Brust, Hartmut Spies, Ralf Berger, R. Syhre, Sepp Seifert, Hans-Juergen Pietzsch, and Matthias Scheunemann
- Subjects
medicine.medical_specialty ,Chemistry ,Brain ,Technetium ,General Medicine ,Blood–brain barrier ,Serotonin Receptor Binding ,Rats ,Structure-Activity Relationship ,medicine.anatomical_structure ,Order (biology) ,Endocrinology ,Pharmacokinetics ,Receptors, Serotonin ,Internal medicine ,Lipophilicity ,medicine ,Biophysics ,Animals ,Structure–activity relationship ,Molecule ,Radiology, Nuclear Medicine and imaging ,Rats, Wistar ,Radionuclide Imaging ,Technetium-99m - Abstract
Low brain uptake is a generally accepted problem in developing technetium-99m brain receptor imaging agents. For a class of potential 5-HT2A receptor-binding agents we tried to improve the original low brain uptake of 0.4% injected dose (ID) in rats 5 min p.i. by modifying the lipophilic properties of the molecules. Because of the presence of a protonable nitrogen, which according to the pKa value leads to ionization of the molecule at blood pH, the pKa value was considered to be the parameter most suitable for adjustment of lipophilicity. Insertion of ether-oxygen in the molecule of five candidates lowers the apparent pKa value from 10.0 to 8.3 and dramatically increases the brain uptake to 1.3% ID at 5 min. The direct relationship between brain uptake and apparent pKa cannot be simply explained by the increase in the pKa-governed proportion of the neutral species.
- Published
- 1997
20. Click chemistry based synthesis of dopamine D4 selective receptor ligands for the selection of potential PET tracers
- Author
-
Harald Hübner, Ashutosh Banerjee, Peter Gmeiner, Olaf Prante, and Simone Maschauer
- Subjects
Hydrocarbons, Fluorinated ,Stereochemistry ,Clinical Biochemistry ,Triazole ,Pharmaceutical Science ,Ligands ,Biochemistry ,Serotonin Receptor Binding ,Piperazines ,chemistry.chemical_compound ,Radioligand Assay ,Structure-Activity Relationship ,Chemical Moiety ,Dopamine ,Drug Discovery ,medicine ,Humans ,Receptor ,Molecular Biology ,Molecular Structure ,Organic Chemistry ,Receptors, Dopamine D4 ,Triazoles ,chemistry ,Alkynes ,Positron-Emission Tomography ,Click chemistry ,Molecular Medicine ,Click Chemistry ,Selectivity ,Derivative (chemistry) ,medicine.drug - Abstract
Taking advantage of click chemistry, a library of N-arylpiperazinylmethyl triazoles bearing fluoro substituted appendages was synthesized and the target compounds were investigated for dopamine and serotonin receptor binding. With the aim to bias their hydrophilicity and to optimize their D4 receptor affinity and selectivity, a concise series of triazoles containing fluoroalkyl, fluoroalkoxy, fluoroalkoxyphenyl, and deoxyfluoroglucosyl substituents was studied. The D4 receptor affinity and selectivity could be tuned by altering the chemical moiety attached to the triazole unit. Among the test compounds, the fluoroethoxyphenyl derivative 15b showed weak partial agonism at D4 and a K(i) value of 14 nM, while its fluoropropoxyphenyl homologue 16a turned out to act as a neutral D4 antagonist (K(i)=5.1 nM). Both, 15b and 16a revealed an excellent balance between D4 receptor affinity and subtype selectivity, providing lead candidates for the development of (18)F-labeled radioligands for D4 receptor imaging studies by positron emission tomography (PET).
- Published
- 2013
21. Abnormalities in 5-HT1A and 5-HT1B receptor binding in severe-seizure genetically epilepsy-prone rats (GEPR-9s)
- Author
-
M.A. Statnick, Ronald A. Browning, P.C. Jobe, and J.W. Dailey
- Subjects
Male ,endocrine system ,medicine.medical_specialty ,Hippocampus ,Hippocampal formation ,Biology ,Serotonergic ,Corpora quadrigemina ,Binding, Competitive ,Serotonin Receptor Binding ,Cellular and Molecular Neuroscience ,Epilepsy ,Internal medicine ,medicine ,Animals ,heterocyclic compounds ,5-HT receptor ,Pharmacology ,8-Hydroxy-2-(di-n-propylamino)tetralin ,Dose-Response Relationship, Drug ,musculoskeletal, neural, and ocular physiology ,medicine.disease ,Rats ,Endocrinology ,nervous system ,Pindolol ,Receptors, Serotonin ,5-HT1A receptor ,Serotonin Antagonists - Abstract
The present study was designed to determine whether abnormalities in serotonin receptor binding co-exist with the presynaptic serotonergic deficits that have previously been identified in the genetically epilepsy-prone rat (GEPR) brain. In vitro binding of [3H]8-OH-DPAT (0.16-10.3 nM) to 5-HT1A receptor sites was found to be decreased in the hippocampus of severe seizure GEPRs (GEPR-9s) when compared to nonepileptic control rats, while no difference in [3H]8-OH-DPAT binding was observed in the GEPR-9 corpora quadrigemina or midbrain tegmentum. The decreased binding of [3H]8-OH-DPAT to hippocampal membranes was due to a decrease in Bmax (P0.001), rather than to a change in the Kd. Conversely, in vitro binding of [125I]cyanopindolol (2-400 pM) to 5-HT1B receptor sites was increased in the GEPR-9 hippocampus, corpora quadrigemina and midbrain tegmentum when compared to nonepileptic control rats. The increased binding of [125I]cyanopindolol in all three regions resulted from an increase in the Bmax (P0.05), rather than a change in the Kd. These finding suggest that in addition to the innate reduction in 5-HT presynaptic markers, GEPR-9s also exhibit abnormalities in the density of 5-HT1A and 5-HT1B receptors in some regions of the brain. Inasmuch as serotonin acts to attenuate audiogenic seizures in GEPRs, these abnormalities in 5-HT receptor binding may contribute to the seizure susceptibility exhibited by these animals.
- Published
- 1996
22. Synthesis and serotonin receptor binding properties of 5-substituted 3-(1′,2′,5′,6′-tetrahydropyridin-3′-yl) indoles
- Author
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Arnold R. Martin, L.A. Gharat, Torsten Dahlgren, Youhua Yang, A.M. Johansson, R.L. Dean, Georgina M. Lambert, D L Nelson, and H.B. Li
- Subjects
Indole test ,Agonist ,Chemistry ,Stereochemistry ,medicine.drug_class ,Organic Chemistry ,Clinical Biochemistry ,Pharmaceutical Science ,Biochemistry ,Serotonin Receptor Binding ,Dissociation constant ,Drug Discovery ,medicine ,Molecular Medicine ,Receptor ,Molecular Biology - Abstract
A semi-rigid 5-hydroxytryptamine (5-HT) analogue, RU28253 [5-methoxy-3-(1′,2′,5′,6′-tetrahydropyridin-3′-yl) indole], is a potent 5-HT 1 and 5-HT 2 agonist. It is isomeric to RU24969 [5-methoxy-3-(1′,2′,5′,6′-tetrahydropyridin-4′-yl) indole], a conformationally restricted 5-HT homologue, which has been extensively used in the study and classification of 5-HT receptors. A series of RU28253 derivatives with diverse substituents on indole 5-position were synthesized and their dissociation constants determined at the 5-HT 1 and 5-HT 2 receptors.
- Published
- 1995
23. Characterization of [3H]LSD binding to a serotonin-sensitive site in honeybee (Apis mellifera) brain
- Author
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Torsten May, Wolfgang Blenau, and Joachim Erber
- Subjects
Tryptamine ,GTP' ,Physiology ,5-HT2A receptor ,Methysergide ,Biology ,Pharmacology ,Biochemistry ,Serotonin Receptor Binding ,chemistry.chemical_compound ,chemistry ,medicine ,Serotonin ,Binding site ,Molecular Biology ,5-HT receptor ,medicine.drug - Abstract
The binding of [3H]lysergic acid diethylamide ([3H]LSD) to a putative serotonin receptor site (S-site) in membrane preparations of honeybee brain was analyzed. All experiments were performed in the presence of 10 μM dopamine to inhibit [3H]LSD binding to an additional site, which is dopamine-sensitive (D-site). [3H]LSD binds reversibly to the S-site with a KD value of 0.89 nM. The maximal concentration of binding sites is 790 fmol/mg protein. Serotonin, lisuride, methysergide, 5-methoxytryptamine and tryptamine are the most potent displacers of S-site binding. The displacement efficacy of several other potential serotonin receptor agonists and antagonists was analyzed. Addition of the stable GTP analogue GTPTS or high sodium concentrations reduced specific [3H]LSD binding to the putative serotonin receptor binding site.
- Published
- 1995
24. Structure-Activity Relationships in the 8-Amino-6,7,8,9-tetrahydro-3H-benz[e]indole Ring System. Part 2: Effect of 8-Amino Nitrogen Substitution on Serotonin Receptor Binding and Pharmacology
- Author
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Chiu-Hong Lin, Håkan Wikström, Ennis, Stjernlöf P, Nabil B. Ghazal, Kjell A. Svensson, Robert Louis Hoffman, M. W. Smith, Haadsma-Svensson, and Groningen Research Institute of Pharmacy
- Subjects
Male ,Agonist ,Indoles ,Intrinsic activity ,Nitrogen ,medicine.drug_class ,Stereochemistry ,DOPAMINE RECEPTOR ,Binding, Competitive ,Serotonin Receptor Binding ,CLONING ,Rats, Sprague-Dawley ,Structure-Activity Relationship ,Dopamine ,Drug Discovery ,medicine ,Animals ,Receptor ,SITES ,POTENT ,Chemistry ,8-HYDROXY-2-(DI-NORMAL-PROPYLAMINO)TETRALIN ,Ligand (biochemistry) ,Rats ,AGONIST ,5-HT1A RECEPTOR ,Biochemistry ,Dopamine receptor ,Receptors, Serotonin ,RAT ,Molecular Medicine ,5-HT1A receptor ,SUBTYPE ,medicine.drug - Abstract
A series of analogs of the potent and selective 5-HT1A agonist 8-(di-n-propylamino)-6,7,8,9-tetrahydro-3H-benz[e]indole-1-carbaldehyde (2b) (OSU191) was prepared in which the dipropylamino group was modified to bear a variety of substituents. These compounds were evaluated for both in vitro and in vivo effects, including the establishment of a receptor binding profile for these analogs at the 5-HT1A, dopamine D-2, dopamine D-3, 5-HT1D alpha, and 5-HT1D beta sites. Several of the analogs were evaluated for their biochemical effects in reserpinized rats, specifically with regard to in vivo changes in brain levels of 5-HTP and DOPA. Nearly all of the compounds prepared for this study were exceedingly potent at the 5-HT1A receptor, although most also displayed significant affinity for the dopamine D-2 receptor. A strong preference for the 5-HT1D alpha, over the 5-HT1D beta receptor was also apparent. An analog bearing a butylglutarimide side chain, S-7k, was extremely selective for the 5-HT1A receptor. Although this compound possessed a K-i of 0.6 nM, it elicited only modest changes in 5-HTP brain levels. However, this compound did not appear as an antagonist when tested in a cyclic-AMP-based intrinsic activity assay.
- Published
- 1995
25. Ketanserin Analogs: The Effect of Structural Modification on 5-HT2 Serotonin Receptor Binding
- Author
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Kim Arruda, Milt Teitler, Abd M. Ismaiel, and Richard A. Glennon
- Subjects
Male ,Magnetic Resonance Spectroscopy ,Ketanserin ,Chemical Phenomena ,Stereochemistry ,Substituent ,In Vitro Techniques ,Serotonin Receptor Binding ,Piperazines ,Rats, Sprague-Dawley ,Radioligand Assay ,Structure-Activity Relationship ,chemistry.chemical_compound ,Piperidines ,Drug Discovery ,medicine ,Animals ,Binding site ,Receptor ,Cerebral Cortex ,Binding Sites ,Molecular Structure ,Chemistry, Physical ,5-HT2 receptor ,Rats ,Piperazine ,chemistry ,Receptors, Serotonin ,Molecular Medicine ,Piperidine ,medicine.drug - Abstract
Ketanserin (1) is a fairly selective 5-HT2 antagonist that binds both at 5-HT2A and 5-HT2C receptors. A previous structure-affinity relationship study revealed that the structure of the piperidine-containing ketanserin molecule could be rather severely abbreviated with little effect on 5-HT2A affinity. The present investigation explores several inconsistencies identified in the earlier study and suggests that multiple modes of binding may be possible for ketanserin analogues. Perhaps the nature of the benzylic substituent is the most significant determinant of the manner in which these agents bind at 5-HT2A receptors, and it is possible that certain orientations may avail themselves of an auxiliary binding site. Depending upon the length of the piperidine N-alkyl chain, variation of the benzylic substituent from a carbonyl, to an alcohol, to a methylene group has a nonparallel influence on binding, and this may be further affected by the presence of a second ring nitrogen atom. The results of the present investigation provide evidence that although the structure of ketanserin can be abbreviated, and even modified by conversion of the piperidine ring to a piperazine, the resultant analogues may bind in more than one orientation at the receptors. A key structural feature that may play a prominent role in anchoring or orienting these compounds at 5-HT2A receptors is the benzylic carbonyl group.
- Published
- 1995
26. Synthesis, Pharmacological Investigation and Computational Studies on a Tricyclic Ergoline Analog with Selective Dopamine Autoreceptor Activity
- Author
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Joachim Mierau, Georg Höfner, Bernd Bollinger, and Peter Gmeiner
- Subjects
Tetrahydronaphthalenes ,Stereochemistry ,Pharmaceutical Science ,Antidepressive Agents, Tricyclic ,Motor Activity ,Binding, Competitive ,Chemical synthesis ,Serotonin Receptor Binding ,Receptors, Dopamine ,Structure-Activity Relationship ,chemistry.chemical_compound ,Dopamine ,Drug Discovery ,medicine ,Animals ,Autoreceptors ,8-Hydroxy-2-(di-n-propylamino)tetralin ,Molecular Structure ,Chemistry ,Rats, Inbred Strains ,Ligand (biochemistry) ,Rats ,Ergoline ,Electrophilic amination ,Dopamine Agonists ,Lactam ,Autoreceptor ,Haloperidol ,medicine.drug - Abstract
The novel aminobenzindolone 8 was prepared and evaluated as a potential antipsychotic agent. The target compound was synthesized in eight steps starting from the tetrahydrobenzindolone 9. The key step of the synthesis was an electrophilic amination of the aromatic ketone 11 followed by reductive degradation when the diethoxymethyl group was employed for protection of the lactam nitrogen and also for the benzylic position 2a. Dopamine and serotonin receptor binding studies revealed 8 to be a potent and selective ligand at the D-2 autoreceptor (ki = 4.0 nM). Further in vivo studies including the GBL-test and locomotor activity measurements indicated agonistic activity of 8 at the prejunctional binding sites. Comparison of ab initio based molecular electrostatic isopotential maps corroborates our hypothesis that the dopamine structure 6, containing an intramolecular hydrogen bond donating effect of the meta-HO-group, represents the conformation which is active at the dopamine D-2 autoreceptor.
- Published
- 1995
27. Structural modification of receptor-binding technetium-99m complexes in order to improve brain uptake
- Author
-
Johannsen, Bernd, Berger, Ralf, Brust, Peter, Pietzsch, Hans-Juergen, Scheunemann, Matthias, Seifert, Sepp, Spies, Hartmut, and Syhre, Rosemarie
- Published
- 1997
- Full Text
- View/download PDF
28. Influence of Amine Substituents on 5-HT2A versus 5-HT2C Binding of Phenylalkyl- and Indolylalkylamines
- Author
-
Joseph De. Los Angeles, Ho Law, Allison King, Katharine Herrick-Davis, Mohamed El-Bermawy, Richard A. Glennon, Malgorzata Dukat, and Milt Teitler
- Subjects
Binding Sites ,Indoles ,Stereochemistry ,Chemistry ,Transfection ,Serotonin Receptor Binding ,Cell Line ,Radioligand Assay ,Structure-Activity Relationship ,Receptors, Serotonin ,Phenethylamines ,Drug Discovery ,Ethylamines ,Humans ,Molecular Medicine ,Amine gas treating ,Ketanserin ,Selectivity ,Receptor - Abstract
The effect of 15 different amine substituents on 5-HT2A and 5-HT2C serotonin receptor binding was investigated for two series of compounds (i.e., phenylalkylamine and indolyalkylamine derivatives). In general, amine substitution decreases receptor affinity; however, N-(4-bromobenzyl) substitution results in compounds that bind at 5-HT2A receptors with high affinity (K i
- Published
- 1994
29. ChemInform Abstract: Structure-Activity Relationships in the 8-Amino-6,7,8,9-tetrahydro-3H- benz(e)indole Ring System. Part 2. Effect of 8-Amino Nitrogen Substitution on Serotonin Receptor Binding and Pharmacology
- Author
-
H. Wikstroem, Robert Louis Hoffman, Kjell A. Svensson, N. B. Ghazal, M. W. Smith, Chiu-Hong Lin, Susanne R. Haadsma-Svensson, P. Stjernloef, and Michael D. Ennis
- Subjects
Indole test ,Stereochemistry ,Chemistry ,Substitution (logic) ,chemistry.chemical_element ,General Medicine ,Ring (chemistry) ,Serotonin Receptor Binding ,Nitrogen - Published
- 2010
30. ChemInform Abstract: Nitrogen-Containing Heteroalicycles with Serotonin Receptor Binding Affinity: Development of Gastroprokinetic and Antiemetic Agents
- Author
-
Iwao Fujiwara, Naoyuki Yoshida, and Shiro Kato
- Subjects
Antiemetic Agent ,medicine.drug_class ,Carboxamide ,General Medicine ,Pharmacology ,Mosapride ,Serotonin Receptor Binding ,chemistry.chemical_compound ,chemistry ,Cisapride ,Dopamine receptor D3 ,Dopamine receptor D2 ,medicine ,Benzamide ,medicine.drug - Abstract
To obtain gastroprokinetic agents with more potent and selective activity than metoclopramide and cisapride, a series of N-(4-benzyl-2-morpholinylmethyl)benzamides were designed and prepared. Their synthesis and structure-activity relationships were described. As a result, mosapride was selected as a promising candidate for potent gastroprokinetic activity with selective 5-HT4 receptor agonistic activity. As an extension to this project, the novel benzamide and the carboxamide derivatives having 1-benzyl-4-methylhexahydro-1,4-diazepine ring in the amine moiety were prepared and evaluated for 5-HT3 receptor antagonistic activity. DAT-582 was identified as an antiemetic agent in cancer chemotherapy. The asymmetric synthesis of DAT-582 and the SAR studies were briefly reviewed. In further modifications of the N-(1-benzyl-4-methylhexahydro-1,4-diazepin-6-yl)benzamides, the novel nicotinamides with 1-ethyl-4-methylhexahydro-1,4-diazepin ring were found to have potent 5-HT3 and dopamine D2 and D3 receptor antagonistic activities and to show weak central nervous system depression and extrapyramidal syndrome. After extensive SARs, AS-8112 was selected as a broad antiemetic agent.
- Published
- 2010
31. Ketanserin analogs: structure-affinity relationships for 5-HT2 and 5-HT1C serotonin receptor binding
- Author
-
Jeff L. Herndon, Abd M. Ismaiel, Richard A. Glennon, Stacy P. Ingher, and Milt Teitler
- Subjects
Male ,Ketanserin ,Stereochemistry ,Binding, Competitive ,Serotonin Receptor Binding ,Rats, Sprague-Dawley ,Structure-Activity Relationship ,chemistry.chemical_compound ,Amide ,Drug Discovery ,medicine ,Animals ,Moiety ,heterocyclic compounds ,Receptor ,musculoskeletal, neural, and ocular physiology ,Antagonist ,musculoskeletal system ,Rats ,chemistry ,Receptors, Serotonin ,cardiovascular system ,Molecular Medicine ,Serotonin Antagonists ,Serotonin ,Piperidine ,medicine.drug - Abstract
Ketanserin is the prototypic 5-HT2 serotonin antagonist; although it has been an important tool for the study of serotonin pharmacology, it has had relatively little impact on drug design because remarkably little is known about its structure-affinity relationships. Furthermore, ketanserin also binds at 5-HT1C receptors and even less is known about the influence of its structural features on 5-HT1C receptor affinity. The present study reveals that the fluoro and carbonyl groups of the 4-fluorobenzoyl portion of ketanserin make small contributions to 5-HT2 binding and that the intact benzoylpiperidine moiety is an important feature. Ring-opening of the piperidine ring reduces affinity. Although the quinazoline-2,4-dione moiety also contributes to binding, it appears to play a smaller role and can be structurally simplified with retention of 5-HT2 affinity. N-(4-Phenylbutyl)-4-(4-fluorobenzoyl)piperidine (39), for example, binds with nearly the same affinity (Ki = 5.3 nM) as ketanserin (Ki = 3.5 nM). All of the compounds examined bind at 5-HT1C sites with lower affinity than ketanserin, and some of the simplified analogues bind with nearly 10 times the 5-HT2 versus 5-HT1C selectivity of ketanserin; however, none displays > 120-fold selectivity. Several of the compounds, such as the amide 32 and the urea 33 represent examples of new structural classes of 5-HT2 ligands.
- Published
- 1992
32. Long-term administration of m-chlorophenylpiperazine (mCPP) to rats induces changes in serotonin receptor binding, dopamine levels and locomotor activity without altering prolactin and corticosterone secretion
- Author
-
John S. Partilla, Elizabeth M. Dax, and Jakob Ulrichsen
- Subjects
Male ,Agonist ,medicine.medical_specialty ,Ketanserin ,medicine.drug_class ,Dopamine ,Motor Activity ,Biology ,Pharmacology ,Serotonin Receptor Binding ,Piperazines ,Radioligand Assay ,chemistry.chemical_compound ,Corticosterone ,Internal medicine ,medicine ,Animals ,Neurotransmitter Agents ,Brain ,Rats, Inbred Strains ,Prolactin ,Rats ,Endocrinology ,chemistry ,Hypothalamus ,Receptors, Serotonin ,Serotonin ,medicine.drug - Abstract
Meta-chlorophenylpiperazine (mCPP) is a serotonin (5-HT) agonist with antidepressant actions. In order to investigate the effects of chronic mCPP treatment the drug was administered to rats for 15 days (5 mg/kg twice daily). Controls were administered saline. Long-term mCPP treatment led to a 36% increase in [3H]8-hydroxy-2-(di-n-propylamino)tetralin ([3H]8-OH-DPAT) binding to 5-HT1a receptors in hippocampus and a 74% decrease in [3H]ketanserin binding to 5-HT2 receptors in cortex, while (-)[125I]iodocyanopindolol ([125I]CYP) binding to 5-HT1b receptors in hypothalamus and striatum was unchanged. In hypothalamus, chronic mCPP treatment decreased the levels of dopamine (DA) but not 5-HT. The usual suppression of locomotor activity induced by acute mCPP administration was less after long-term mCPP treatment. Brain and plasma levels of mCPP following an acute dose were not different between controls and rats previously administered mCPP, suggesting that altered rate of metabolism of the drug did not explain the tolerance to the mCPP-induced decrease in locomotor activity. mCPP-induced prolactin (PRL) and corticosterone release were not changed by previous long-term mCPP administration. Thus, chronic mCPP administration to rats induced alterations in density of 5-HT receptor subtypes, hypothalamic levels of DA and locomotor behavior.
- Published
- 1992
33. Elimination of Ascorbic Acid-Induced Membrane Lipid Peroxidation and Serotonin Receptor Loss by Trolox-c, A Water Soluble Analogue of Vitamin E
- Author
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Steven G. Britt, Vincent W. S. Chiu, Scott R. VandenBerg, and Gerard T. Redpath
- Subjects
Serotonin ,Antioxidant ,medicine.medical_treatment ,In Vitro Techniques ,Serotonin Receptor Binding ,Antioxidants ,Lipid peroxidation ,Membrane Lipids ,Radioligand Assay ,chemistry.chemical_compound ,medicine ,Animals ,Vitamin E ,Chromans ,Pharmacology ,Chemistry ,Biological membrane ,Ascorbic acid ,Membrane ,Solubility ,Biochemistry ,Receptors, Serotonin ,Cattle ,Female ,Lipid Peroxidation ,Trolox - Abstract
Ascorbic acid is commonly used as an antioxidant to prevent the decomposition of ligands in neurotransmitter receptor studies, but may alter biological membranes by initiating lipid peroxidation in the presence of physiologic metal ions. The aim of the present study was to characterize the effect of ascorbic acid-induced lipid peroxidation on an applicable membrane receptor and to examine an appropriate antioxidant system. Ascorbic acid generated significant lipid peroxidation (5.5 to 45 fold increase in malonaldehyde levels) in three diverse tissues having different membrane properties: bovine brain, mouse teratoma, and rat kidney. In membranes from bovine cerebral cortex, ascorbate-induced lipid peroxidation was associated with a 26% decrease in [3H]-serotonin receptor binding (Bmax = 159 +/- 11 from control of 216 +/- 10 fmol/mg protein), with no significant change in KD. Trolox-C, a water soluble analogue of vitamin E, completely blocked the ascorbate-induced loss of serotonin receptor binding in brain membranes, and the combination of Trolox-C and ascorbate prevented [3H]-serotonin decomposition in solution. Trolox-C also prevented ascorbate-induced lipid peroxidation in brain, teratoma, and kidney membranes. Lipid peroxidation may be a significant factor in the ascorbate-induced alteration of brain membranes as reflected by reduced binding to serotonin receptors. The combination of Trolox-C (200 microM) and ascorbic acid (1.0 mM) maintains a protective environment for oxygen sensitive neurotransmitters while blocking the deleterious effects of ascorbic acid on lipid membranes.
- Published
- 1992
34. Influence of B vitamins on binding properties of serotonin receptors in the CNS of rats
- Author
-
D. Bonke, K. Dakshinamurti, and S. K. Sharma
- Subjects
Serotonin ,medicine.medical_specialty ,Synaptic cleft ,Biology ,Pharmacology ,Synaptic Transmission ,Serotonin Receptor Binding ,chemistry.chemical_compound ,Internal medicine ,Drug Discovery ,medicine ,Animals ,Neurotransmitter ,Genetics (clinical) ,5-HT receptor ,Afferent Pathways ,Brain ,Nociceptors ,Pyridoxine ,General Medicine ,Rats ,B vitamins ,Endocrinology ,Spinal Cord ,chemistry ,Receptors, Serotonin ,Vitamin B Complex ,Molecular Medicine ,Endogenous agonist ,Synaptosomes ,medicine.drug - Abstract
Treatment of normal adult rats with pyridoxine or a B-vitamin mixture resembling Neurobion® 1 led to an increase in serotonin content of various brain areas and to a decrease in the number of serotonin S2 receptors. The results indicate that the pyridoxal phosphate level in regions of the brain regulates the extent of decarboxylation of 5-hydroxytryptophan, the precursor of serotonin. The results also suggest a continuum from deficiency in pyridoxine to treatment of animals with a moderate excess of pyridoxine which is reflected in the synthesis and secretion into the synaptic cleft of the neurotransmitter serotonin.
- Published
- 1990
35. Dopamine and serotonin receptor binding and antipsychotic efficacy
- Author
-
Jeffrey A. Welge, Aaron D Logue, Robert K. McNamara, Paul E. Keck, Neil M. Richtand, and Stephen M. Strakowski
- Subjects
medicine.medical_specialty ,Psychosis ,medicine.drug_class ,medicine.medical_treatment ,Atypical antipsychotic ,Pharmacology ,Serotonin Receptor Binding ,Statistics, Nonparametric ,Internal medicine ,Dopamine receptor D2 ,medicine ,Animals ,Humans ,Antipsychotic ,5-HT receptor ,Dose-Response Relationship, Drug ,business.industry ,Receptors, Dopamine D2 ,medicine.disease ,Typical antipsychotic ,Psychiatry and Mental health ,Endocrinology ,Dopamine receptor ,business ,Receptors, Serotonin, 5-HT2 ,Antipsychotic Agents ,Protein Binding - Abstract
The relationship between clinically effective antipsychotic drug dosage and binding affinity to cloned dopamine (DA) and serotonin receptor subtypes was analyzed in an effort to elucidate the contribution of individual receptor subtypes to medication response. Clinically effective dose and binding affinity to D(2) DA receptor were modestly correlated for typical antipsychotic medications (r=0.54, p=0.046), but surprisingly were not correlated for atypical antipsychotics (r=0.41, p=0.31). For typical antipsychotics, a more robust inverse relationship was observed between medication dose and 5-HT(2C) affinity (r=-0.68, p=0.021). The strongest correlation for typical antipsychotics was observed between drug dosage and 5-HT(2C)/D(2) binding affinity ratio (r=-0.81, p=0.003). For atypical antipsychotics, no significant correlations were identified between medication dosage and 5-HT(2C), 5-HT(2A), 5-HT(2C)/D(2), or 5-HT(2A)/D(2) receptor-binding affinities. In contrast, atypical antipsychotic medication dosage was highly correlated with the ratios of D(2) (5-HT(2A)/5-HT(1A)) (r=0.80, p=0.031), and D(2) (5-HT(2C)/5-HT(1A)) (r=0.78, p=0.038) binding affinities. These observations demonstrate an interaction between D(2) and 5-HT(2C) receptor effects contributing to positive symptom response for typical antipsychotic medications, suggesting that signaling through 5-HT(2C) receptors interacts with and improves antipsychotic effects achieved via D(2) receptor blockade. This analysis also demonstrates that, in contrast to typical antipsychotics, therapeutic effects of atypical antipsychotic medications are determined by opposing interactions among three different domains: (1) increasing D(2) DA receptor-binding affinity enhances antipsychotic potency. (2) Increasing 5-HT(2C) and 5-HT(2A) receptor-binding affinities also facilitate antipsychotic efficacy. (3) Increasing 5-HT(1A) receptor-binding affinity, in contrast, reduces antipsychotic efficacy.
- Published
- 2007
36. Synthesis and Biological Investigations of Dopaminergic Partial Agonists Preferentially Recognizing the D4 Receptor Subtype
- Author
-
Stefan Löber, Harald Hübner, and Peter Gmeiner
- Subjects
Stereochemistry ,Clinical Biochemistry ,GTPgammaS ,Pharmaceutical Science ,Pharmacology ,Biochemistry ,Serotonin Receptor Binding ,Partial agonist ,Receptor subtype ,chemistry.chemical_compound ,Structure-Activity Relationship ,Dopamine ,Drug Discovery ,medicine ,Structure–activity relationship ,Receptor ,Molecular Biology ,Molecular Structure ,Chemistry ,Organic Chemistry ,Receptors, Dopamine D4 ,Dopaminergic ,General Medicine ,Ligand (biochemistry) ,Molecular Medicine ,medicine.drug ,Protein Binding - Abstract
Aminomethyl-substituted biaryls bearing a pyrazole or triazole moiety were synthesized and investigated for dopamine and serotonin receptor binding. The N-arylpyrazoles 3b,f,g and 4 revealed Ki values in the subnanomolar range (0.28-0.70 nM) for the dopamine D4 receptor subtype. Employing both mitogenesis and GTPgammaS assays, ligand efficacy was evaluated indicating partial agonist properties. Interestingly, the tetrahydropyrimidine 4 (FAUC 2020) displayed significant intrinsic selectivity for D2(long) over D2(short).
- Published
- 2006
37. Serotonin receptor binding and mRNA expression in the hippocampus of fearful amygdala-kindled rats
- Author
-
Michael J. Meaney, Lisa E. Kalynchuk, and John P. J. Pinel
- Subjects
Male ,medicine.medical_specialty ,Serotonin ,Hippocampus ,Amygdala ,Serotonin Receptor Binding ,Binding, Competitive ,Open field ,chemistry.chemical_compound ,Radioligand Assay ,Internal medicine ,medicine ,Kindling, Neurologic ,Animals ,Rats, Long-Evans ,Receptor, Serotonin, 5-HT2A ,RNA, Messenger ,Neurotransmitter ,Serotonin Plasma Membrane Transport Proteins ,Kindling ,General Neuroscience ,Dentate gyrus ,Fear ,Anxiety Disorders ,Electric Stimulation ,Rats ,Up-Regulation ,Endocrinology ,medicine.anatomical_structure ,nervous system ,chemistry ,Epilepsy, Temporal Lobe ,Gene Expression Regulation ,Receptors, Serotonin ,Dentate Gyrus ,Receptor, Serotonin, 5-HT1A ,Psychology - Abstract
Amygdala kindling in rats increases fear behavior. The neural correlates of this fear are not well understood. In this experiment, we investigated the relation between serotonin receptor binding and mRNA expression and fearful behavior in amygdala-kindled rats. Rats received either 100 kindling stimulations or sham stimulations, and their fear behavior was subsequently assessed in an unfamiliar open field. Then, the rats were sacrificed and 5-HT transporter binding, 5-HT1A and 5-HT2A receptor binding, and 5-HT1A mRNA expression in several brain regions was assessed. The kindled rats were significantly more fearful in the open field than the sham-stimulated rats. They also had significantly more 5-HT1A receptor binding and mRNA expression in the dentate gyrus than the sham-simulated rats, and these increases in 5-HT1A receptor binding and mRNA expression were significantly correlated to the increases in fear. There were no significant differences between the kindled and sham-stimulated rats in 5-HT transporter binding or 5-HT2A receptor binding. These results suggest that alterations in 5-HT1A receptors in the dentate gyrus may play a role in the expression of kindled fear.
- Published
- 2005
38. Characterization of 5‐HT 1A,B and 5‐ <scp>HT</scp> 2A,C Serotonin Receptor Binding
- Author
-
Kelly A. Berg, Alan Frazer, William P. Clarke, and Georgianna G. Gould
- Subjects
Biochemistry ,5-HT2A receptor ,Chemistry ,Enzyme-linked receptor ,5-HT5A receptor ,General Medicine ,Serotonin ,Receptor ,Serotonin Receptor Binding ,Endogenous agonist ,5-HT receptor - Abstract
This unit describes assays for measuring the binding of radioligands to two major types of receptors for 5-hydroxytryptamine (5-HT or serotonin), 5-HT₁ and 5-HT₂ receptors, in homogenates of brain tissue or cloned into cells in culture. The specific receptor subtypes covered are 5-HT(₁A), 5-HT(₁B), 5-HT(₂A), and 5-HT(₂C). In addition, methodology for using quantitative autoradiography to measure radioligand binding to serotonin receptors in brain slices is described. Protocols are provided for characterization of both saturation and competition binding assays, and instructions for data analysis of these assays is also described. In addition, methodology is provided for the quantification (image analysis) of radioligand binding in brain tissue sections to determine receptor density, preparation of rat brain sections for quantitative autoradiography, and thionin staining of thaw-mounted tissue sections to define certain brain regions.
- Published
- 2001
39. Decreased serotonin 2A receptor densities in neuroleptic-naive patients with schizophrenia: A PET study using [(18)F]setoperone
- Author
-
Thomas J. Ruth, Lakshmi N. Yatham, Elton T.C. Ngan, and Peter F. Liddle
- Subjects
Adult ,Male ,medicine.medical_specialty ,Postmortem studies ,Fluorine Radioisotopes ,Adolescent ,Setoperone ,Pyrimidinones ,behavioral disciplines and activities ,Serotonin Receptor Binding ,chemistry.chemical_compound ,Internal medicine ,mental disorders ,medicine ,Humans ,Receptor, Serotonin, 5-HT2A ,Radionuclide Imaging ,5-HT receptor ,Binding potential ,Brain ,medicine.disease ,Frontal Lobe ,Psychiatry and Mental health ,Endocrinology ,chemistry ,Frontal lobe ,Schizophrenia ,Receptors, Serotonin ,Female ,Serotonin ,Psychology ,Antipsychotic Agents - Abstract
OBJECTIVE: The authors compared serotonin receptor binding in patients with schizophrenia and healthy comparison subjects.METHOD: They used positron emission tomography with [18F]setoperone to examine six patients with schizophrenia who had never been given neuroleptics and seven age-matched subjects who did not have schizophrenia.RESULTS: A nondirected voxel-based analysis of the subjects’ entire search volume found that serotonin 2A binding potential in the frontal cortex index was significantly smaller (by 16.3%) in patients with schizophrenia than in healthy subjects.CONCLUSIONS: The authors conclude that the decrease in serotonin receptor densities previously reported in postmortem studies of subjects with schizophrenia are present at the onset of the illness, before exposure to neuroleptics.
- Published
- 2000
40. Spiperone: influence of spiro ring substituents on 5-HT2A serotonin receptor binding
- Author
-
Katharine Herrick-Davis, Malgorzata Dukat, Kamel Metwally, Christina T. Egan, Richard A. Glennon, Ann DuPre, Colleen B. Gauthier, Carol Smith, and Milt Teitler
- Subjects
Spiperone ,Stereochemistry ,Serotonin Receptor Binding ,Mice ,Radioligand Assay ,Structure-Activity Relationship ,Dopamine receptor D2 ,Drug Discovery ,medicine ,Receptor, Serotonin, 5-HT2C ,Structure–activity relationship ,Animals ,Receptor, Serotonin, 5-HT2A ,Receptor ,Binding selectivity ,Chemistry ,Receptors, Dopamine D2 ,Antagonist ,3T3 Cells ,Recombinant Proteins ,Rats ,Dopamine D2 Receptor Antagonists ,Receptors, Serotonin ,Molecular Medicine ,Dopamine Antagonists ,Serotonin ,Serotonin Antagonists ,Receptors, Serotonin, 5-HT1 ,medicine.drug - Abstract
Spiperone (1) is a widely used pharmacological tool that acts as a potent dopamine D2, serotonin 5-HT1A, and serotonin 5-HT2A antagonist. Although spiperone also binds at 5-HT2C receptors, it is one of the very few agents that display some (ca. 1000-fold) binding selectivity for 5-HT2A versus 5-HT2C receptors and, hence, might serve as a useful template for the development of novel 5-HT2A antagonists if the impact of its various substituent groups on binding was known. In the present investigation we focused on the 1, 3,8-triazaspiro[4.5]decanone portion of spiperone and found that replacement of the N1-phenyl group with a methyl group only slightly decreased affinity for cloned rat 5-HT2A receptors. However, N1-methyl derivatives displayed significantly reduced affinity for 5-HT1A, 5-HT2C, and dopamine D2 receptors. Several representative examples were shown to behave as 5-HT2 antagonists. As such, N1-alkyl analogues of spiperone may afford entry into a novel series of 5-HT2A-selective antagonists.
- Published
- 1998
41. A study on the effect of deoxynivalenol on serotonin receptor binding in pig brain membranes
- Author
-
D.B. Prelusky
- Subjects
Male ,Binding Sites ,Swine ,Ligand binding assay ,Trichothecene ,Cell Membrane ,Brain ,General Medicine ,Biology ,Pollution ,Serotonin Receptor Binding ,Binding, Competitive ,Biochemistry ,Cell surface receptor ,Culture Techniques ,Receptors, Serotonin ,Radioligand ,Potency ,Animals ,Serotonin Antagonists ,Receptor ,Trichothecenes ,5-HT receptor ,Food Science - Abstract
Central serotoninergic (5-hydroxytryptamine, 5HT) pathways are believed to be involved in the mechanisms of anorexia and/or emesis evoked by the trichothecene mycotoxin deoxynivalenol (DON). Using an in vitro membrane receptor binding assay, the competitive potency of DON was investigated against several radioactive ligands that have a high affinity for selective 5HT receptor subgroups. Receptor site densities and displacement profiles in twelve selected regions of pig brain were investigated. Overall, DON possessed only minimal efficacy to competently block any of the 5HT-ligands tested. IC50 values (50% inhibitory concentration) of at least 5 mM DON were required to inhibit binding, and in certain regions concentrations of 100 mM were ineffective. In comparison, several standard 5HT-antagonists showed 10(3)-10(5) times greater capability than DON to displace binding of these ligands. Because these results indicated DON possesses only weak affinity for the 5HT-receptor subtypes investigated here, this suggested that in vivo, unless relatively high concentrations of the toxin are present, its pharmacological effects may be mediated by mechanisms other than a functional interaction with serotoninergic receptors at the central level.
- Published
- 1996
42. Technetium(V) and Rhenium(V) Complexes for 5-HT2A Serotonin Receptor Binding: Structure-Affinity Considerations
- Author
-
Matthias Scheunemann, Bernd Johannsen, R. Syhre, Jannette Wober, H.-J. Pietzsch, Peter Brust, and H Spies
- Subjects
Male ,Cancer Research ,Denticity ,Ketanserin ,Stereochemistry ,chemistry.chemical_element ,Serotonin Receptor Binding ,Binding, Competitive ,chemistry.chemical_compound ,Structure-Activity Relationship ,Thioether ,medicine ,Organometallic Compounds ,Moiety ,Animals ,Radiology, Nuclear Medicine and imaging ,Chelation ,Receptor, Serotonin, 5-HT2A ,Tissue Distribution ,Rats, Wistar ,Alkyl ,chemistry.chemical_classification ,Brain ,Organotechnetium Compounds ,Rhenium ,Rats ,chemistry ,Receptors, Serotonin ,Molecular Medicine ,medicine.drug - Abstract
Starting from the lead structure of ketanserin, a prototypic serotonin (5-HT) antagonist, new oxotechnetium(V) and oxorhenium(V) complexes were synthesized that are able to compete with [ 3 H]ketan-serin in receptor-binding assays. To imitate organic 5-HT 2 receptor ligands, fragments of ketanserin were combined with chelate moieties. Neutral compounds of the general formula [MOL 1 L 2 ] (M = Tc, Re; L 1 = HSCH 2 CH 2 CH 2 CH 2 SH, N -(2-mercaptophenyl)salicylideneimine, N -(2-mercaptoethyl)-salicylideneimine,3-(2-[ N,N -bis (2-mercapto- S -ethyl)]-aminolethyl)-2,4-(1H,3H)-quinazolinedione and L 2 = HSR with R=subst. alkyl) were prepared by common action of a Tc(V) or Re(V) precursor with a mixture of equimolar amounts of a tridentate ligand L 1 and a monodentate thiolate L 2 bearing fragments of the lead structure. Lipophilic complexes consisting of a small S 4 thiolate/thioether chelate unit, protonable nitrogen-containing spacer, and simple benzyl moiety significantly inhibited the specific binding of [ 3 H]ketan-serin with IC 50 values between 10 and 50 nM.
- Published
- 1996
43. Hyperammonemia increases serotonin 1A receptor expression in both rat hippocampus and a transfected hippocampal cell line, HN2-5
- Author
-
Jessy J. Alexander, Glyn Dawson, Probal Banerjee, and James H. Tonsgard
- Subjects
Male ,medicine.medical_specialty ,Transcription, Genetic ,Hippocampus ,Gene Expression ,Biology ,Acetates ,Tritium ,Serotonin Receptor Binding ,Cell Line ,Rats, Sprague-Dawley ,Cellular and Molecular Neuroscience ,Thalamus ,Ammonia ,Glutamine synthetase ,Internal medicine ,medicine ,Animals ,RNA, Messenger ,Receptor ,8-Hydroxy-2-(di-n-propylamino)tetralin ,Behavior, Animal ,Cell Membrane ,Hyperammonemia ,Transfection ,medicine.disease ,Rats ,Serotonin Receptor Agonists ,Glutamine ,Endocrinology ,nervous system ,Cell culture ,Receptors, Serotonin ,Indicators and Reagents - Abstract
Hyperammonemia is an important cause of cerebral dysfunction in liver failure. We used two well-established models to induce hyperammonemia in rats, injection of urease and injection of methionine sulfoximine (MSO). Urease gave a 10-fold increase in blood ammonia while MSO, a glutamine synthetase inhibitor, gave a 4-fold increase in blood ammonia with no increase in brain glutamine levels. We observed a 2-fold increase in 5-HT1A receptor (5-HT1A-R) expression ([3H] 8-OH-DPAT binding) in hippocampus, and little change elsewhere, including thalamus in both models, thus eliminating a role for increased glutamine in the receptor induction. In contrast, a 4 to 8-fold increase in 5-HT1A-R mRNA was observed both in hippocampus and thalamus, suggesting some post-transcriptional regulation. In the absence of glutamine, ammonium acetate treatment of a hippocampal cell line which had been engineered to stably express the 5-HT1A-R (HN2-5) gave a 1.5-fold increase in [3H] 8-OH-DPAT binding and a 4-fold increase in the mRNA levels for the 5-HT1A-R. We conclude that the cell line HN2-5 is a good model for studying some of the biochemical sequelae of hyperammonemia and that changes in brain function are not only at the metabolic level, as thought earlier, but can also occur at the transcriptional level.
- Published
- 1995
44. Serotonin receptor binding in a colony model of chronic social stress
- Author
-
Christina R. McKittrick, Robert J. Blanchard, Bruce S. McEwen, Randall R. Sakai, and D. Caroline Blanchard
- Subjects
Dominance-Subordination ,Male ,medicine.medical_specialty ,Serotonergic ,Social Environment ,Serotonin Receptor Binding ,chemistry.chemical_compound ,Corticosterone ,Internal medicine ,medicine ,Animals ,Iodocyanopindolol ,Biological Psychiatry ,5-HT receptor ,8-Hydroxy-2-(di-n-propylamino)tetralin ,musculoskeletal, neural, and ocular physiology ,5-HT2 receptor ,Dentate gyrus ,Brain ,Rats ,Endocrinology ,nervous system ,chemistry ,Pindolol ,Receptors, Serotonin ,5-HT1A receptor ,Autoradiography ,Female ,Serotonin ,Ketanserin ,Psychology ,Arousal ,Stress, Psychological - Abstract
Male rats housed in mixed-sex groups quickly established dominance hierarchies in which subordinates appeared severely stressed. Subordinate rats had elevated basal corticosterone (CORT) levels relative to dominants and individually housed controls. Several subordinates had blunted CORT responses to a novel stressor, leading to the classification of subordinates as either stress-responsive or nonresponsive. Binding to 5-HT1A receptors was reduced in stress-responsive subordinates compared to controls throughout hippocampus and dentate gyrus. Decreased binding was observed in nonresponsive subordinates only in CA3 of hippocampus. In addition, 5-HT1A binding was decreased in CA1, CA3, and CA4 in dominants compared to controls. Binding to 5-HT2 receptors was increased in parietal cortex in both responsive and nonresponsive subordinates compared to controls. No changes were observed in binding to 5-HT1B receptors. These results are discussed in the context of regulation of the serotonergic system by stress and glucocorticoids and possible relevance to the pathophysiology of depression.
- Published
- 1995
45. Effect of 5,7-dihydroxytryptamine, ovariectomy and gonadal steroids on serotonin receptor binding in rat brain
- Author
-
Maya Frankfurt, Scott D. Mendelson, Christina R. McKittrick, and Bruce S. McEwen
- Subjects
Male ,endocrine system ,medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,Ovariectomy ,5,7-Dihydroxytryptamine ,Nerve Tissue Proteins ,Biology ,Serotonin Receptor Binding ,Hippocampus ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,Endocrinology ,Internal medicine ,medicine ,Animals ,Iodocyanopindolol ,Neurotransmitter ,Gonadal Steroid Hormones ,Progesterone ,Denervation ,Brain Chemistry ,Serotonin Plasma Membrane Transport Proteins ,8-Hydroxy-2-(di-n-propylamino)tetralin ,Membrane Glycoproteins ,Endocrine and Autonomic Systems ,Membrane Transport Proteins ,Estrogens ,Rats ,Paroxetine ,nervous system ,chemistry ,Hypothalamus ,Ventromedial Hypothalamic Nucleus ,Pindolol ,Receptors, Serotonin ,Autoradiography ,Female ,Serotonin ,Carrier Proteins ,Orchiectomy ,hormones, hormone substitutes, and hormone antagonists - Abstract
Quantitative autoradiography was used to assess alterations in serotonin (5-HT) receptor binding in the hypothalamus and hippocampus following denervation with 5,7-dihydroxytryptamine (5,7-DHT), ovariectomy (OVX) and gonadal steroid manipulation. Seven days after 5,7-DHT injection, 5-HT1a receptor density was significantly increased in the ventromedial hypothalamic nucleus (VMN) of intact but not OVX female rats. Under these conditions 5-HT1b receptor density was unchanged in any brain region examined and 5-HT transporter binding was decreased in all 5,7-DHT injected animals. In addition, there was a significant interaction between OVX and 5,7-DHT for both the 5-HT1a receptor and the 5-HT transporter in the VMN, such that OVX inhibited the 5,7-DHT-induced increase in 5-HT1a receptors and attenuated the 5,7-DHT-induced decrease in 5-HT transporter binding. In a separate experiment the effect of gonadal steroid manipulation on 5-HT receptor binding was assessed. In female OVX rats, 5-HT1a receptor density was unchanged by estrogen or estrogen and progesterone administration. In male rats, castration significantly decreased 5-HT1a receptor density in the medial preoptic area. Estrogen and progesterone administration to female OVX rats increased the density of 5-HT1b receptors in the VMN, as compared to estrogen alone. The relationship of these results to the role of 5-HT in mediating lordosis behavior is discussed.
- Published
- 1994
46. Alterations of serotonin receptor binding in the hypothalamus following acute denervation
- Author
-
Scott D. Mendelson, Christina R. McKittrick, Maya Frankfurt, and Bruce S. McEwen
- Subjects
Male ,medicine.medical_specialty ,5,7-Dihydroxytryptamine ,Hypothalamus ,Hippocampus ,Dorsomedial Hypothalamic Nucleus ,Biology ,Serotonergic ,Ligands ,Serotonin Receptor Binding ,Injections ,chemistry.chemical_compound ,Internal medicine ,medicine ,Animals ,Receptor ,Molecular Biology ,Denervation ,General Neuroscience ,Axons ,Rats ,Paroxetine ,Endocrinology ,chemistry ,Ventromedial Hypothalamic Nucleus ,Hypothalamic Area, Lateral ,Receptors, Serotonin ,Neurology (clinical) ,Serotonin ,Developmental Biology - Abstract
Quantitative autoradiography was used to determine the effect of acute serotonergic denervation with 5,7-dihydroxytryptamine (5,7-DHT) on serotonin 5HT1a and 5-HT1b receptors in male rats. Seven days after intrahypothalamic 5,7-DHT injection there was a significant increase in the density of 5HT1a receptors in the ventromedial and dorsomedial hypothalamic nuclei (VMN and DMN) of male rats. In adjacent sections, 5-HT1b receptors were significantly increased only in the VMN. No changes in receptor density were observed in the lateral hypothalamic area or hippocampus even though binding of [3H]paroxetine, which labels the presynaptic transporter site, was significantly decreased in all evaluated brain regions in 5,7-DHT-treated animals. In addition to demonstrating that 5-HT1a and 5-HT1b receptors are differentially regulated in different brain areas, these results show that in the brain regions examined both 5-HT1a and 5-HT1b receptors are primarily post-synaptic.
- Published
- 1993
47. A preliminary study of cortical S2 serotonin receptors and cognitive performance following stroke
- Author
-
Dean Foster Wong, Philip Morris, H. S. Mayberg, R. G. Robinson, K. Bolla, S. E. Starkstein, and Robert F Dannals
- Subjects
Adult ,Male ,medicine.medical_specialty ,Neuropsychological Tests ,Serotonergic ,behavioral disciplines and activities ,Serotonin Receptor Binding ,Radioligand Assay ,Cognition ,Internal medicine ,medicine ,Humans ,Effects of sleep deprivation on cognitive performance ,Stroke ,5-HT receptor ,Aged ,Cerebral Cortex ,medicine.diagnostic_test ,business.industry ,Neuropsychological test ,Middle Aged ,medicine.disease ,Psychiatry and Mental health ,Cerebrovascular Disorders ,Serotonin binding ,Endocrinology ,medicine.anatomical_structure ,Cerebral cortex ,Receptors, Serotonin ,Female ,Neurology (clinical) ,business ,Neuroscience - Abstract
Cortical serotonin receptor binding was measured with positron-emission tomography (PET) in uninjured regions of cortex in 26 stroke patients. Cognitive function was assessed with the Mini-Mental State Exam (MMSE) and a neuropsychological test battery. Left frontal cortex serotonin binding was correlated positively with MMSE total score (r = 0.50, P = 0.01) and with the MMSE concentration, writing, and copying tasks (r = 0.42, 0.56, 0.53, respectively; P < 0.05). Tests of orientation and repetition of difficult phrases were significantly correlated with serotonin binding (r = 0.53 and 0.52, respectively; P < 0.05). These findings suggest that cognitive performance after stroke may be influenced by alterations in the serotonergic system.
- Published
- 1993
48. Prenatal protein malnutrition in rats enhances serotonin release from hippocampus
- Author
-
John Tonkiss, Janina R. Galler, Jin-Chung Chen, and Ladislav Volicer
- Subjects
Male ,medicine.medical_specialty ,Serotonin ,Medicine (miscellaneous) ,Hippocampus ,Hippocampal formation ,Serotonin Receptor Binding ,Protein-Energy Malnutrition ,Pregnancy ,Internal medicine ,Casein ,Culture Techniques ,medicine ,Animals ,Serotonin transporter ,Nutrition and Dietetics ,biology ,Tryptophan ,Caseins ,Hydroxyindoleacetic Acid ,Paroxetine ,Rats ,Pregnancy Complications ,Endocrinology ,Prenatal Exposure Delayed Effects ,Receptors, Serotonin ,biology.protein ,Female ,Dietary Proteins ,medicine.drug - Abstract
The effect of prenatal protein malnutrition on central serotonin metabolism was assessed in 220- to 240-d-old male rats. The malnourished rats (denoted 6,25 group) were males born to dams fed a 6% casein diet during pregnancy and fostered at birth to dams fed a control (25% casein) diet. They were compared with males born to dams fed 25% casein diet. Tissue concentrations of serotonin, 5-hydroxyindoleacetic acid, 5-hydroxytryptophan, L-tryptophan and catecholamines in the hippocampal formation in the 6,25 group were similar to those of well-fed controls (25,25 group). However, a twofold greater basal serotonin efflux from hippocampal slices of 6,25 rats compared with slices from 25,25 rats was observed during a 20-min incubation period. Hippocampal [3H]paroxetine binding indicated that there was no alteration of apparent maximal binding and affinity of the serotonin transporter in the 6,25 rats. In addition, there was no difference in serotonin receptor binding in hippocampal membranes from 6,25 and 25,25 rats. The results indicate that prenatal protein malnutrition causes selective changes in central serotonin metabolism.
- Published
- 1992
49. Platelet 5-HT2 serotonin receptor binding sites in autistic children and their first-degree relatives
- Author
-
Edwin H. Cook, Mark S. Wainwright, Daniel X. Freedman, Bruce D. Perry, and Bennett L. Leventhal
- Subjects
Blood Platelets ,Male ,medicine.medical_specialty ,Spiperone ,Adolescent ,Heterologous ,Serotonin Receptor Binding ,Iodine Radioisotopes ,Radioligand Assay ,Internal medicine ,medicine ,Humans ,Platelet ,First-degree relatives ,Autistic Disorder ,Receptor ,Child ,Biological Psychiatry ,Whole blood ,Endocrinology ,Child, Preschool ,Receptors, Serotonin ,Serotonin ,Psychology ,medicine.drug - Abstract
We examined platelet serotonin2 [5-hydroxytryptamine2 (5-HT2)] receptor binding sites, whole blood serotonin (5-HT), and plasma norepinephrine (NE) in male autistic children and their first-degree relatives. Saturation studies utilizing 125I-spiroperidol labeled the 5-HT2 sites with an affinity of 224.6 +/- 84.4 pmol/L (Kd). No group differences, i.e., autistic (n = 12), siblings (n = 6), parents (n = 22), control (adult; n = 7: child; n = 10), were seen for either the Kd or the total number of sites (Bmax: 14.3 +/- 10.9 fmol/mg protein). No correlations were found in any group between binding parameters (Kd or Bmax) and whole blood 5-HT. For the parental group, inverse correlations were found between NE and Bmax (standing NE, rs = -0.67, n = 21, p = 0.001; supine NE, rs = -0.49, n = 22, p = 0.021). In the autistic group, no correlation was seen between plasma NE and Bmax. A correlation between the autistic boys' Bmax and their fathers' Bmax was observed (rs = 0.79, n = 11, p = 0.004). These findings suggest (1) circulating NE may be involved in heterologous regulation of 5-HT2 receptors in the platelet and (2) genetic (paternal-filial) factors may play a role in the expression of 5-HT2 binding sites in the platelet. These preliminary findings are discussed in relation to heterologous receptor regulation. The relationships between these findings and either the pathophysiology of autism or hyperserotonemia in autism are unknown.
- Published
- 1991
50. Spontaneous remission of post-stroke depression and temporal changes in cortical S2-serotonin receptors
- Author
-
Philip Morris, Robert G. Robinson, R M Parikh, and Helen S. Mayberg
- Subjects
Temporal cortex ,Cerebral Cortex ,medicine.medical_specialty ,Spiperone ,business.industry ,Depression ,Remission, Spontaneous ,Spontaneous remission ,Middle Aged ,Placebo ,Serotonin Receptor Binding ,Psychiatry and Mental health ,Cerebrovascular Disorders ,Internal medicine ,Receptors, Serotonin ,Cardiology ,Medicine ,Post-stroke depression ,Humans ,Female ,Neurology (clinical) ,business ,5-HT receptor ,Depression (differential diagnoses) ,medicine.drug - Abstract
A patient with post-stroke depression following infarction of the left basal ganglia is described. The patient's depression remitted during a 6-week double-blind treatment trial while receiving placebo medication. Cortical S2-receptor binding that was measured using 11C-N methyl spiperone and positron emission tomography (PET), increased in the left temporal cortex by more than 25% during the treatment trial. The change in serotonin receptor binding and its relationship to the improvement in mood observed in this patient are consistent with previously published data demonstrating a correlation between serotonin receptor binding in the left temporal cortex and severity of symptoms of depression.
- Published
- 1991
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