Search

The 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme converts cortisone to cortisol and participates in the regulation of glucocorticoid levels in tissues. 11β-HSD1 is expressed in the liver, kidney, adipose tissue, placenta, and brain. 11β-HSD1 is a target for treatment of depression, anxiety, posttraumatic stress disorder, and also against age-related cognitive function and memory loss. In this study, we evaluated the radiotracer 11C-AS2471907 (3-(2-chlorophenyl)-4-(methyl-11 C)-5-[2-[2,4,6-trifluorophenoxy]propan-2-yl]-4H-1,2,4-triazole) to image 11β-HSD1 availability in the human brain with PET. Methods: Fifteen subjects were included in the study. All subjects underwent one 2-h scan after a bolus administration of 11C-AS2471907. Two subjects underwent an additional scan after blockade with the selective and high-affinity 11β-HSD1 inhibitor ASP3662 to evaluate 11C-AS2471907 nondisplaceable distribution volume. Five subjects also underwent an additional scan to evaluate the within-day test-retest variability of 11C-AS2471907 volumes of distribution (V T). Results: 11C-AS2471907 time-activity curves were best fitted by the 2-tissue-compartment (2TC) model. 11C-AS2471907 exhibited a regionally varying pattern of uptake throughout the brain. The V T of 11C-AS2471907 ranged from 3.7 ± 1.5 mL/cm3 in the caudate nucleus to 14.5 ± 5.3 mL/cm3 in the occipital cortex, with intermediate values in the amygdala, white matter, cingulum, insula, frontal cortex, putamen, temporal and parietal cortices, cerebellum, and thalamus (from lowest to highest V T). From the blocking scans, nondisplaceable distribution volume was determined to be 0.16 ± 0.04 mL/cm3 for 11C-AS2471907. Thus, nearly all uptake was specific and the binding potential ranged from 22 in the caudate to 90 in the occipital cortex. Test-retest variability of 2TC V T values was less than 10% in most large cortical regions (14% in parietal cortex) and ranged from 14% (cerebellum) to 51% (amygdala) in other regions. The intraclass correlation coefficient of 2TC V T values ranged from 0.55 in the white matter to 0.98 in the cerebellum. Conclusion: 11C-AS2471907 has a high fraction of specific binding in vivo in humans and reasonable within-day reproducibility of binding parameters.

Layer V pyramidal neurons constitute principle output neurons of the medial prefrontal cortex (mPFC)/neocortex to subcortical regions including the intralaminar/midline thalamic nuclei, amygdala, basal ganglia, brainstem nuclei and the spinal cord. The effects of 5-hydroxytryptamine (5-HT) on layer V pyramidal cells primarily reflect a range of excitatory influences through 5-HT2A receptors and inhibitory influences through non-5-HT2A receptors, including 5-HT1A receptors. While the 5-HT2A receptor is primarily a postsynaptic receptor on throughout the apical dendritic field of 5-HT2A receptors, activation of a minority of 5-HT2A receptors also appears to increase spontaneous excitatory postsynaptic currents/potentials (EPSCs/EPSPs) via a presynaptic effect on thalamocortical terminals arising from the midline and intralaminar thalamic nuclei. Activation of 5-HT2A receptors by the phenethylamine hallucinogen also appears to increase asynchronous release of glutamate upon the layer V pyramidal dendritic field, an effect that is suppressed by 5-HT itself through non-5-HT2A receptors. Serotonergic hallucinogens acting on 5-HT2A receptors also appears to increase gene expression of immediate early genes (iEG) and other receptors appearing to induce an iEG-like response like BDNF. Psychedelic hallucinogens acting on 5-HT2A receptors also induce head twitches in rodents that appear related to induction of glutamate release. These electrophysiological, biochemical and behavioral effects of serotonergic hallucinogens appear to be related to modulating glutamatergic thalamocortical neurotransmission and/or shifting the balance toward 5-HT2A receptor activation and away from non-5-HT2A receptor activation. These 5-HT2A receptor induced responses are modulated by feedback homeostatic mechanisms through mGlu2, mGlu4, and mGlu8 presynaptic receptors on thalamocortical terminals. These 5-HT2A receptor and glutamatergic interactions also appear to play a role on higher cortical functions of the mPFC such as motoric impulsivity and antidepressant-like behavioral responses on the differential-reinforcement-of low rate 72-s (DRL 72-s schedule). These mutually opposing effects between 5-HT2A receptor and mGlu autoreceptor activation (e.g., blocking 5-HT2A receptors and enhancing activity at mGlu2 receptors) may play a clinical role with respect to currently prescribed or novel antidepressant drugs. Thus, there is an important balance between 5-HT2A receptor activation and activation of mGlu autoreceptors on prefrontal cortical layer V pyramidal cells with respect to the electrophysiological, biochemical and behavioral effects serotonergic hallucinogenic drugs.

A new type of DNA metal complex hybrid catalyst, which is based on single-stranded DNA oligonucleotides, is described. It was shown that oligonucleotides as short as 14 nucleotides that fold into hairpin structures are suitable as nucleic acid components for DNA hybrid catalysts. With these catalysts, excellent enantioinduction in asymmetric Diels-Alder reactions with selectivity values as high as 96 % enantiomeric excess (ee) can be achieved. Molecular dynamics simulations indicate that a rather flexible loop combined with a rigid stem region provides DNA scaffolds with these high selectivity values.

There is a need for simple, fast, efficient and sensitive methods of analysis for glyphosate and its degradate aminomethylphosphonic acid (AMPA) in diverse matrices such as water, plant materials and soil to facilitate environmental research needed to address the continuing concerns related to increasing glyphosate use. A variety of water-based solutions have been used to extract the chemicals from different matrices. Many methods require extensive sample preparation, including derivatization and clean-up, prior to analysis by a variety of detection techniques. This review summarizes methods used during the past 15 years for analysis of glyphosate and AMPA in water, plant materials and soil. The simplest methods use aqueous extraction of glyphosate and AMPA from plant materials and soil, no derivatization, solid-phase extraction (SPE) columns for clean-up, guard columns for separation and confirmation of the analytes by mass spectrometry and quantitation using isotope-labeled internal standards. They have levels of detection (LODs) below the regulatory limits in North America. These methods are discussed in more detail in the review.

There is substantial evidence that glutamate can modulate the effects of 5-hydroxytryptamine2A (5-HT2A) receptor activation through stimulation of metabotropic glutamate2/3 (mGlu2/3) receptors in the prefrontal cortex. Here we show that constitutive deletion of the mGlu2 gene profoundly attenuates an effect of 5-HT2A receptor activation using the mouse head twitch response (HTR). MGlu2 and mGlu3 receptor knockout (KO) as well as age-matched ICR (CD-1) wild type (WT) mice were administered (±)1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and observed for head twitch activity. DOI failed to produce significant head twitches in mGlu2 receptor KO mice at a dose 10-fold higher than the peak effective dose in WT or mGlu3 receptor KO mice. In addition, the mGlu2/3 receptor agonist LY379268, and the mGlu2 receptor positive allosteric modulator (PAM) CBiPES, potently blocked the HTR to DOI in WT and mGlu3 receptor KO mice. Conversely, the mGlu2/3 receptor antagonist LY341495 (10 mg/kg) increased the HTR produced by DOI (3 mg/kg) in mGlu3 receptor KO mice. Finally, the mGlu2 receptor potentiator CBiPES was able to attenuate the increase in the HTR produced by LY341495 in mGlu3 receptor KO mice. Taken together, all of these results are consistent with the hypothesis that that DOI-induced head twitches are modulated by mGlu2 receptor activation. These results also are in keeping with a critical autoreceptor function for mGlu2 receptors in the prefrontal cortex with differential effects of acute vs. chronic perturbation (e.g., constitutive mGlu2 receptor KO mice). The robust attenuation of DOI-induced head twitches in the mGlu2 receptor KO mice appears to reflect the critical role of glutamate in ongoing regulation of 5-HT2A receptors in the prefrontal cortex. Future experiments with inducible knockouts for the mGlu2 receptor and/or selective mGlu3 receptor agonists/PAMs/antagonists could provide an important tools in understanding glutamatergic modulation of prefrontal cortical 5-HT2A receptor function.

5-Hydroxytryptamine2A (5-HT2A) receptors are enriched in layers I and Va of the rat prefrontal cortex and neocortex and their activation increases the frequency of glutamatergic excitatory post-synaptic potentials/currents (EPSP/Cs) onto layer V pyramidal cells. A number of other G-protein coupled receptors (GPCRs) are also enriched in cortical layers I and Va and either induce (α1-adrenergic and orexin2) or suppress (metabotropic glutamate2 [mGlu2], adenosine A1, μ-opioid) both 5-HT-induced EPSCs and head twitches or head shakes induced by the phenethylamine hallucinogen 2,5-dimethoxy-4-iodoamphetamine (DOI). Another neurotransmitter receptor also localized to apparent thalamocortical afferents to layers I and Va of the rat prefrontal cortex and neocortex is the β2-adrenergic receptor. Therefore, we conducted preliminary electrophysiological experiments with rat brain slices examining the effects of epinephrine on electrically-evoked EPSPs following bath application of DOI (3 μM). Epinephrine (0.3–10 μM) suppressed the late EPSPs produced by electrical stimulation and DOI. The selective β2-adrenergic receptor antagonist ICI-118,551 (300 nM) resulted in a rightward shift of the epinephrine concentration-response relationship. We also tested the selective β2-adrenergic receptor agonist clenbuterol and the antagonist ICI-118,551 on DOI-induced head twitches. Clenbuterol (0.3–3 mg/kg, i.p.) suppressed DOI (1.25 mg/kg, i.p.)-induced head twitches. This clenbuterol effect appeared to be at least partially reversed by the selective β2-adrenergic receptor antagonist ICI-118,553 (0.01–1 mg/kg, i.p.), with significant reversal at doses of 0.1 and 1 mg/kg. Thus, β2-adrenergic receptor activation reverses the effects of phenethylamine hallucinogens in the rat prefrontal cortex. While Gi/Go-coupled GPCRs have previously been shown to suppress both the electrophysiological and behavioral effects of 5-HT2A receptor activation in the mPFC, the present work appears to extend this suppressant action to a Gs-coupled GPCR. Furthermore, the modulation of 5-HT2A receptor activation-induced glutamate release onto mPFC layer V pyramidal neurons apical dendrites by a range GPCRs in rat brain slices appears to results in behaviorally salient effects of relevance when screening for novel CNS therapeutic drugs.

ObjectiveTo evaluate the efficacy and safety of coadministered lanreotide Autogel (LA; 120 mg/month) and pegvisomant (40–120 mg/week) in acromegaly.DesignThis is a 28-week, multicenter, open-label, single-arm sequential study.MethodsPatients (n=92) biochemically uncontrolled, on somatostatin analogs (SSAs) or using pegvisomant monotherapy entered a 4-month run-in taking LA (120 mg/month). Patients uncontrolled after the run-in period (n=57) entered a 28-week coadministration period, receiving LA 120 mg/month plus pegvisomant (60 mg once weekly, adapted every 8 weeks based on IGF1 levels to 40–80 mg once weekly or 40 or 60 mg twice weekly).ResultsIn total, 33 (57.9%) patients had normalized IGF1 following coadministration (PP5×upper limit of normal with normalization after withdrawal).ConclusionsIn patients partially controlled by SSAs, LA (120 mg/month) plus pegvisomant normalized IGF1 in 57.9% of patients after 7 months, at a median effective pegvisomant dose of 60 mg/week, and 78.9% at any time. In these patients, results suggest a pegvisomant-sparing effect versus daily pegvisomant monotherapy.

Recordings made from layer V (L5) pyramidal cells of the prefrontal cortex (PFC) and neocortex in rodent slice preparations have shown that serotonin (5-hydroxytryptamine, 5-HT) and serotonergic hallucinogens induce an increase in the frequency of spontaneous excitatory postsynaptic currents (EPSCs) in the apical dendritic field by activating 5-HT2A receptors. Serotonergic hallucinogens induce late EPSCs and increase recurrent network activity when subcortical or mid-cortical regions are stimulated at low frequencies (e.g., 0.1 Hz). A range of agonists or positive allosteric modulators (PAMs) for mostly Gi/o-coupled receptors, including metabotropic glutamate2 (mGlu2), adenosine A1, or μ-opioid receptors, suppress these effects of 5-HT2A receptor stimulation. Furthermore, a range of mostly Gq/11-coupled receptors (including orexin2 [OX2]; α1-adrenergic, and mGlu5 receptors) similarly induce glutamate (Glu) release onto L5 pyramidal cells. Evidence implicates a number of brain regions in mediating these effects of serotonergic hallucinogens and Gq/11-coupled receptors including the midline and intralaminar thalamic nuclei, claustrum, and neurons in deep PFC. These effects on 5-HT2A receptors and related GPCRs appear to play a major role in the behavioral effects of serotonergic hallucinogens, such as head twitches in rodents and higher order behaviors such as rodent lever pressing on the differential-reinforcement-of-low rate 72-s (DRL 72-s) schedule. This implies that the effects of 5-HT2A receptor activation on the activity of L5 pyramidal cells may be responsible for mediating a range of behaviors linked to limbic circuitry with connectivity between the PFC, striatum, thalamus, claustrum, striatum, amygdala, and the hippocampal formation.

Nucleic acids can form efficient hybrid catalysts for asymmetric catalysis upon binding of low-molecular-weight metal complexes. Up to now DNA has been the preferred nucleic acid component, while RNA was largely ignored. It is shown that despite RNA's successful use in ribozymes, RNA is less suited for use in hybrid catalysts for asymmetric catalysis. A common dimethyl bipyridine copper complex does not form highly active and enantioselective hybrid catalysts with RNA due to the absence of synergistic effects between the copper complex and dsRNA.

BACKGROUND There is a need for a simple, fast, efficient and sensitive method for analysis of glyphosate and its degradate aminomethylphosphonic acid (AMPA) in diverse matrices such as water, vegetation and soil. RESULTS Aqueous extracts from water, vegetation and soil were passed through reverse-phase and cation-exchange columns and directly injected into a tandem mass spectrometer using only a guard column for separation. Extraction efficiencies from the three matrices were >80% for both glyphosate and AMPA. The method reporting levels (MRLs) for glyphosate in water, vegetation and soil were 3.04 µg L−1, 0.05 mg kg−1 and 0.37 mg kg−1 respectively. AMPA MRLs were 5.06 µg L−1 for water, 0.08 mg kg−1 for vegetation and 0.61 mg kg−1 for soil. CONCLUSIONS A validated, simple and efficient liquid chromatography–tandem mass spectrometry (LC-MS/MS) method for routine analysis of glyphosate and AMPA in water, vegetation and soil that uses minimal sample handling and clean-up will facilitate the additional environmental research needed to address the continuing concerns related to increasing glyphosate use. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Important functional interactions between the metabotropic glutamate 2 (mGlu2) and 5-hydroxytryptamine2A (5-HT₂A) neurotransmitter receptors have been established based on electrophysiological, biochemical and behavioral evidence. Over the last several years, dimerization between 5-HT₂A and mGlu2 receptors has been proposed to account for the functional cross-talk between these two receptors in the prefrontal cortex. The pros and cons for the existence of a heteromeric complex between 5-HT₂A and mGlu2 receptors will be reviewed here. First, the fundamental criteria needing to establish evidence for heteromeric complexes will be reviewed. Then, the in vitro evidence for and against heteromeric complexes between 5-HT₂A and mGlu2 receptors will be discussed in regard to physical and functional interactions. Finally, the data with native in situ mGlu2 and 5-HT₂A receptors will be discussed with respect to whether heteromeric complexes or a simple functional interaction between two distinct GPCRs based on brain network activity is the more simple explanation for a range of in vivo data.

Group II metabotropic glutamate (mGlu) receptor agonists were efficacious in randomized clinical research trials for schizophrenia and generalized anxiety disorder. The regional quantification of mGlu(2) and mGlu(3) receptors remains unknown. A selective and structurally novel mGlu(2/3) receptor agonist, 2-amino-4-fluorobicyclo[3.1.0]hexane-2,6-dicarboxylic acid (LY459477) was tritiated and the distribution of mGlu(2) and mGlu(3) receptors was studied in transgenic mice lacking either mGlu(2), mGlu(3) or both receptors. LY459477 is an agonist with 1-2 nM potency for rodent and human mGlu(2) and mGlu(3) receptors. The functional selectivity of LY459477 was demonstrated by over 640-fold selectivity and the displacement binding selectivity was greater than 320-fold for all glutamate receptors except mGlu(6) (∼230-fold). More than 1000-fold selectivity was demonstrated for all non-glutamate receptors known to be targeted by antipsychotic drugs. Like atypical antipsychotic drugs, LY459477 reversed in vitro electrophysiological effects of a serotonergic hallucinogen and behavioral effects of phencyclidine or amphetamine. There was virtually no binding of [(3)H]LY459477 to any brain region in mice with a deletion of both mGlu(2) and mGlu(3) receptors. Regions enriched in mGlu(2) receptors included the medial prefrontal cortex, select hippocampal regions, the medial mammillary nucleus, the medial habenula, and the cerebellar granular cell layer. Regions enriched in mGlu(3) receptors were the dorsolateral entorhinal cortex, the hippocampal CA1 field, the piriform cortex, the substantia nigra, the thalamic reticular nucleus, and primary sensory thalamic nuclei. These findings suggest [(3)H]LY459477 should be a useful tool to further define the role of mGlu(2) and mGlu(3) receptors throughout the brain with respect to major neuropsychiatric syndromes. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.

In vivo translational imaging techniques, such as positron emission tomography and single-photon emission-computed tomography, are the only ways to adequately determine that a drug engages its target. Unfortunately, there are far more experimental mechanisms being tested in the clinic than there are radioligands, impeding the use of this risk-mitigating approach in modern drug discovery and development. Pharmacological magnetic resonance imaging (phMRI) offers an approach for developing new biomarkers with the potential to determine central activity and dose selection in animals and humans. Using phMRI, we characterized the effects of xanomeline on ketamine-induced activation on blood oxygen level-dependent (BOLD) signal. In the present studies, xanomeline alone dose-dependently increased the BOLD signal across several regions of interest, including association and motor and sensory cortical regions. It is noteworthy that xanomeline dose-dependently attenuated ketamine-induced brain activation patterns, effects that were antagonized by atropine. In conclusion, the muscarinic 1/4-preferring receptor agonist xanomeline suppressed the effects of the N-methyl-D-aspartate channel blocker ketamine in a number of brain regions, including the association cortex, motor cortex, and primary sensory cortices. The region-specific brain activation observed in this ketamine challenge phMRI study may provide a method of confirming central activity and dose selection for novel antipsychotic drugs in early clinical trials for schizophrenia, if the data obtained in animals can be recapitulated in humans.

Some recently published in vitro studies with two metabotropic glutamate 2/3 receptor (mGluR(2/3)) agonists [(-)-2-oxa-4-aminobicyclo[3.1.0] hexane-4,6-dicarboxylic acid (LY379268) and 1S,2S,5R,6S-2-aminobicyclo[3.1.0]hexane-2,6-bicaroxylate monohydrate (LY354740)] suggest that these compounds may also directly interact with dopamine (DA) D(2) receptors. The current in vitro and in vivo studies were undertaken to further explore this potential interaction with D(2) receptors. LY379268 and LY354740 failed to inhibit D(2) binding in both native striatal tissue homogenates and cloned receptors at concentrations up to 10 microM. LY379268 and LY354740 (up to 10 microM) also failed to stimulate [(35)S]GTPgammaS binding in D(2L)- and D(2S)-expressing clones in the presence of NaCl or N-methyl-d-glucamine. In an in vivo striatal D(2) receptor occupancy assay, LY379268 (3-30 mg/kg) or LY354740 (1-10 mg/kg) failed to displace raclopride (3 microg/kg i.v.), whereas aripiprazole (10-60 mg/kg) showed up to 90% striatal D(2) receptor occupancy. LY379268 (10 mg/kg) and raclopride (3 mg/kg) blocked d-amphetamine and phencyclidine (PCP)-induced hyperactivity in wild-type mice. However, the effects of LY379268 were lost in mGlu(2/3) receptor knockout mice. In DA D(2) receptor-deficient mice, LY379268 but not raclopride blocked both PCP and d-amphetamine-evoked hyperactivity. In the striatum and nucleus accumbens, LY379268 (3 and 10 mg/kg) was without effect on the DA synthesis rate in reserpinized rats and also failed to prevent S-(-)-3-(3-hydroxyphenyl)-N-propylpiperidine-induced reductions in DA synthesis rate. Taken together, the current data fail to show evidence of direct DA D(2) receptor interactions of LY379268 and LY354740 in vitro or in vivo. Instead, these results provide further evidence for a novel antipsychotic mechanism of action for mGluR(2/3) agonists.

Down-regulation of 5-hydroxytryptamine 2A (5-HT 2A ) receptors has been a consistent effect induced by most antidepressant drugs. The evidence for down-regulation of 5-HT 2A receptor binding following subchronic treatment with fluoxetine and other selective serotonin reuptake inhibitors (SSRIs) is mixed. The question of 5-HT 2A receptor sensitivity during chronic administration of antidepressants is important since activation of 5-HT 2A receptors is associated with impulsivity. Continued activation of 5-HT 2A receptors may functionally oppose activation of other non-5-HT 2A receptors in the prefrontal cortex associated with the clinical efficacy of SSRI treatment. Therefore, the effects of repeated daily administration of fluoxetine (10 mg/kg, i.p. ×3 weeks) on pharmacologically characterized electrophysiological response mediated by 5-HT 2A receptor activation, 5-HT-induced excitatory postsynaptic currents (EPSCs), in rat prefrontal cortical slices was examined. The concentration–response curve for 5-HT-induced EPSCs was unchanged following subchronic fluoxetine treatment. This subchronic fluoxetine treatment failed to modify electrophysiological responses to AMPA in layer V pyramidal cells as well. These findings would be consistent with the hypothesis that blockade of 5-HT 2A receptors may enhance the effects of SSRIs or serotonin/norepinephrine reuptake inhibitors (SNRIs).

Glutamate plays an important role in the psychotomimetic effects of both channel blocking N-methyl d -aspartate (NMDA) receptor antagonists and hallucinogenic drugs which activate 5-hydroxytryptamine2A (5-HT2A) receptors. Previous work suggested that activation of non-NMDA ionotropic glutamate receptors mediates the effects of 5-HT-induced excitatory post-synaptic potentials/currents (EPSPs/EPSCs) when recording from layer V pyramidal cells in the rat medial pre-frontal cortex (mPFC). However, those effects are mediated by either α-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) or kainate receptors of the iGluk5 subtype. To test whether activation of AMPA receptors is sufficient to mediate 5-HT-induced EPSCs, a 2,3-benzodiazepine that selectively blocks AMPA receptors was assessed. This selective AMPA receptor antagonist potently suppressed 5-HT-induced EPSCs. Since phenethylamine hallucinogens induce head shakes by activating 5-HT2A receptors in the mPFC and this action is modulated by glutamate, we also examined whether selective blockade of AMPA receptors would suppress DOI-induced head shakes. As predicted, we found that selective blockade of AMPA receptors suppressed DOI-induced head shakes. Given evidence that activation of AMPA receptors is an important downstream effect for both channel blocking NMDA receptor antagonists and phenethylamine hallucinogens, we also tested multiple doses of DOI with a sub-anesthetic dose of MK-801. Synergistic action between these two classes of psychotomimetic drugs was demonstrated by MK-801 enhancing DOI-induced head shakes and locomotor activity. These findings expand the dependence of both channel blocking NMDA receptor antagonists and phenethylamine hallucinogens on enhancing extracellular glutamate.

Pomaglumetad methionil (LY2140023) is a mGlu2/3 receptor agonist prodrug reported in 2007 to possess antipsychotic efficacy based on results of a phase 2 trial conducted entirely in Russia using in-patients with schizophrenia. Since that time, pomaglumetad methionil failed to demonstrate antipsychotic efficacy compared to placebo in three phase 2 or phase 3 trials, despite risperidone separating from placebo in one phase 3 trial. While there was some evidence of an antipsychotic effect in these studies on an a priori specified genetically-defined subpopulation based on single nucleotide polymorphisms of the 5-hydroxytryptamine2A receptor gene (HTR2A) , these effects were modest when compared to very limited effects in the overall population of schizophrenic patients responding to SOC second generation antipsychotic drugs. Post-hoc analyses also suggested antipsychotic efficacy for pomaglumetad methionil in subjects with a disease duration equal/less than 3 years or subjects previously treated with antipsychotic drugs predominantly acting at dopamine D2 receptors compared to 5-HT2A receptors. Orthogonal to these results with the mGlu2/3 receptor agonist prodrug, a 5-HT2A receptor inverse agonist pimavanserin demonstrated antipsychotic efficacy in subjects with Parkinson's disease (PD) psychosis despite limited and at best modest evidence of antipsychotic efficacy for a number of selective 5-HT2A receptor antagonists in subjects with schizophrenia. Based on the precedent for pimavanserin in PD psychosis, the known overlapping preclinical profile of mGlu2/3 receptor agonists and 5-HT2A receptor antagonists/inverse agonists and the neurobiology of other psychosis associated with neurodegenerative illness, there remains open a hypothesis that mGlu2/3 receptor agonists may exert clinically significant antipsychotic effects in PD psychosis, dementia with Lewy Bodies, and Alzheimer's disease psychosis.

5-Hydroxytryptamine2A (5-HT2A) receptor regulation is atypical compared to most other monoaminergic receptors in that chronic administration of both antagonists and agonists results in down-regulation of cortical 5-HT2A receptor number and the functional in vitro and in vivo effects. We have recently found that midline thalamic lesions, which appeared to block glutamate release induced by activation of 5-HT2A receptors, also increased 5-HT2A receptor binding in layers I and Va of the medial prefrontal cortex (mPFC). These layers contain the highest density of both 5-HT2A receptors and thalamocortical terminals from the midline and intralaminar thalamic nuclei. These findings suggest the hypothesis that excitatory amino acid release plays a role in regulation of postsynaptic 5-HT2A receptors, and that down-regulation of 5-HT2A receptors by 5-HT2A agonists may not be attributed only to simple occupancy of the receptor by direct agonists. Therefore, we examined the effect of a single 30 min pretreatment with the metabotropic glutamate2/3 (mGlu2/3) receptor agonist (1S,2S,5R,6S)-2-aminobicyclo[3.1.0] hexane-2,6-dicarboxylate monohydrate (LY354740; 10 mg/kg, i.p.) on the second of three consecutive days of 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCl (DOI) treatment (1.25 mg/kg, i.p.). The subchronic DOI administration significantly decreased binding of [125I]DOI to 5-HT2A receptors in layers I and Va of the mPFC by approximately 25%. In contrast, a single dose of LY354740 on Day 2 of this regimen completely blocked the DOI-induced down-regulation. Thus, a presumed hypoglutamatergic state secondary to thalamic lesions and increased glutamate release induced by a subchronic regimen of a 5-HT2A agonist (and hallucinogenic drug) differentially regulate prefrontal cortical 5-HT2A receptor binding.

Background & Aims: The activated pregnane X receptor is antifibrogenic in rodent chronic liver injury in vivo models. The aim of this study was to determine the effects of human pregnane X receptor activators on human hepatic stellate cell transdifferentiation to a profibrogenic phenotype in vitro. Methods: Hepatic stellate cells were isolated from resected human liver and cultured under conditions in which they trans-differentiate into profibrogenic myofibroblasts. Results: The pregnane X receptor was expressed in primary cultures at the level of messenger RNA and protein and was activated by the ligand rifampicin as judged by increases in binding of proteins to the pregnane X receptor ER6 DNA response element and by increases in ER6-dependent reporter gene expression. Short-term treatment of hepatic stellate cells with rifampicin inhibited the expression of selected fibrosis-related genes (transforming growth factor β1, α–smooth muscle actin), proliferation-related genes, and WNT signaling-associated genes. There was also an increase in interleukin-6 secretion and an inhibition in DNA synthesis. Long-term treatment with rifampicin over several weeks reduced the proliferation and transdifferentiation of hepatic stellate cells. Small interfering RNA knockdown of the pregnane X receptor in a hepatic stellate cell line reduced the binding of proteins to the ER6 DNA response element and abrogated pregnane X receptor activator-dependent changes in transforming growth factor β1 expression, interleukin-6 secretion, and proliferation. Conclusions: The pregnane X receptor is transcriptionally functional in human hepatic stellate cells and activators inhibit transdifferentiation and proliferation. The pregnane X receptor may therefore be an effective target for antifibrotic therapy.

Both a 5-hydroxytryptamine2A (5-HT2A) agonist and immobilization stress previously have been shown to differentially alter brain-derived neurotrophic factor (BDNF) mRNA expression in the neocortex and hippocampus. Both 5-HT2A receptor activation and immobilization stress also increase glutamate release in the rat prefrontal cortex. Given that the metabotropic glutamate2/3 receptor (mGluR2/3) agonist (1S,2S,5R,6S)-2-aminobicyclo[3.1.0] hexane-2,6-dicarboxylate monohydrate (LY354740) suppressed electrophysiological, behavioral and biochemical effects of 5-HT2A receptor activation in the medial prefrontal cortex (mPFC), we assessed the efficacy of the mGluR2/3 agonist in suppressing the stress-induced increase in BDNF mRNA expression. LY35740 (10 mg/kg, i.p.) attenuated the immobilization stress-induced increase in BDNF mRNA expression in the rat mPFC. This result is consistent with the hypothesis that mGlu2/3 agonists may be an efficacious treatment for stress-induced neuropsychiatric syndromes.

Background In the past few years, computer-based analysis of atomic-force microscopic images has acquired increasing importance for studying biomolecules such as DNA. On the one hand, fully automated methods do not allow analysis of complex shapes; on the other hand, manual methods are usually time consuming and inaccurate. The semiautomated approach presented in this report overcomes the drawbacks of both methods. Methods Two kinds of images were analyzed: computer-generated filaments that modeled circular DNA molecules on a surface and real atomic-force microscopic images of DNA molecules adsorbed on an appropriate substrate surface. Results The algorithm was tested on a group of 140 simulated and 189 real plasmids with a nominal length of 913 nm. The accuracy of the length measurement was statistically evaluated on the ensemble of molecules, with particular attention to the influence of the noise. Mean contour lengths of 912 ± 5 nm and 910 ± 47 nm were found for simulated and real plasmids, respectively. The measured end-to-end distance of λ-DNA molecules as a function of their contour length is reported, from which it is possible to estimate the stiffness of the DNA molecules adsorbed onto a surface; the value obtained for the DNA persistence length (42 ± 5 nm) is consistent with values measured by other imaging techniques. Conclusions An interactive algorithm for DNA molecule measurements based on the detection of the filament ridge line in a digitized image is presented. The simulation of artificial filaments combined with the experimental data demonstrates that the proposed method can be a valuable tool for the DNA contour length evaluation, especially in the case of complex shapes where the use of automatic methods is not possible. © 2005 Wiley-Liss, Inc.

Ultra-cold neutrons (UCN), neutrons with energies low enough to be confined by the Fermi potential in material bottles, are playing an increasing role in measurements of fundamental properties of the neutron. The ability to manipulate UCN with material guides and bottles, magnetic fields, and gravity can lead to experiments with lower systematic errors than have been obtained in experiments with cold neutron beams. The UCN densities provided by existing reactor sources limit these experiments. The promise of much higher densities from solid deuterium sources has led to proposed facilities coupled to both reactor and spallation neutron sources. In this Letter we report on the performance of a prototype spallation neutron-driven solid deuterium source. This source produced bottled UCN densities of 145±7 UCN/cm 3 , about three times greater than the largest bottled UCN densities previously reported. These results indicate that a production UCN source with substantially higher densities should be possible.

A theoretical model for computing the basic hydrodynamic parameters of macromolecules in a water environment is presented. Starting from the 3D structure of the molecule, taking into account the hydration shell, the following parameters are calculated: translation friction coefficient, diffusion coefficient and intrinsic viscosity. The novel Monte Carlo algorithms also work effectively in the case of large molecules. The consumption of CPU time is proportional to Nq, where N is the number of atoms in the molecule and q a coefficient of 1.6–1.7, respectively.

Chemical solution deposition method (CSD) method was used to prepare PbTiO 3 (PT), Pb 1-x Ca x TiO 3 (PCT), PbTiO 3 -Al 2 O 3 (PT-AL) and Pb 1-x Ca x TiO 3 -Al 2 O 3 (PCT-AL) thin films on amorphous (soda-lime glass, SiO 2 glass) substrates. The films were examined by XRD methods to describe the phase composition, cell parameters, type and degree of texture. In dependence on the molar ratio of Ti:Al, the different extent of crystallographic ordering was observed ranging from randomly oriented to strongly textured crystallites of PT. (100) preferred orientation growth of PT grains was identified.

Recent electrophysiological studies in our laboratory have demonstrated a physiological interaction between 5-HT(2A) and metabotropic glutamate2/3 (mGlu2/3) receptors in the medial prefrontal cortex. Several behavioral studies have found that phenethylamine hallucinogens with partial agonist activity at 5-HT(2A) receptors induce head shakes when directly administered into the medial prefrontal cortex. The purpose of the present experiments was to examine whether an interaction occurs between mGlu2/3 and 5-HT(2A) receptors on a behavioral level using head shakes induced by phenethylamine hallucinogens as a model of 5-HT(2A) receptor activation. Administration of the mGlu2/3 agonist LY354740 (0.3-10 mg/kg, ip) suppressed head shakes induced by the phenethylamine hallucinogen 1-(2, 5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI). Conversely, administration of the mGlu2/3 antagonist LY341495 (1 mg/kg, ip) enhanced the frequency of DOI-induced head shakes. Taken together, these results raise the possibility that the psychomimetic properties of hallucinogenic drugs may be mediated in part, via increased glutamate release following activation of 5-HT(2A) receptors.

We investigated the effects of stepwise thermal treatment of [100]-CZ- and FZ-silicon on the crystal defects and the etching behavior in KOH solutions. The anisotropy (the quotient of the vertical etch rate and the underetching of the mask), formed crystal defects as well as the surface roughness of the exposed {100}- and {111}-planes are examined. Thermal treatment of the silicon substrate can result in a precipitation of the interstitial oxygen. The precipitated oxygen causes elastic stress in the crystal which can be relieved by a generation of defects [1] , [2] . We found out that the evolution of these defects accelerates the lateral etch rate considerably. For the reference, the samples without thermal treatment the anisotropy has a value of 120 for FZ-silicon and 70 for CZ-silicon, respectively. However, with rising temperature and process time the anisotropy decreases to 30 for FZ-silicon and 15 for CZ-silicon. At the same time, the surface quality of the {100}- and {111}-planes degrades with increasing temperature. The roughness value Ra rises from 5 nm to approximately 30 nm. Along with the variation of the etching behavior during thermal treatment, we further present a suitable model for the oxygen-dependence of the etch rate.

Integrated petrological and geochemical examination of metasedimentary assemblages associated with mesothermal lode gold mineralization in five major centers of past and present production (Ballarat, Percydale, Tarnagulla, Maldon, Fosterville) in central Victoria, Australia, reveal that hydrothermal alteration in the hosting Cambro-Ordovician turbidites is much more pronounced and extensive than has previously been recognized. Characteristically, the auriferous reef structures are surrounded by bleached zones up to several tens of meters wide. Sericitization, carbonatization and carbonate spotting, and pyrite and arsenopyrite porphyroblasts—within and beyond zones of visible bleaching—are the most obvious features of alteration. Quantitative XRD analysis illustrates that these marked bleached halos are due to the replacement of albitized plagioclase clasts by white mica and the breakdown of metamorphic chlorite to form secondary carbonates, and to a lesser extent, kaolin. The negative correlation between metamorphic chlorite and hydrothermal carbonate phases provides a reliable mineralogical alteration index useful to exploration. Geochemical reconnaissance profiles also indicate the development of systematic trends in response to hydrothermal alteration involving mainly SiO2, K2O, Na2O, CO2, As, Au, and S at constant bulk rock volume. Calculation of a geochemical alteration index given by the ratio K2O + CO2 / K2O + CO2 + Na2O + Al2O3 suggests that this can be a reliable indicator of alteration, in particular where concentrations of individual invariable oxides such as Al2O3 vary too much in response to lithological variations. Saturation indices that are based on ratios of 3K/Al and CO2/(Mg + Fe + Ca) are less reliable, because muscovite and carbonate are not always the dominant alteration mineral species of relevance. The alteration assemblages, as well as mineralogical and geochemical trends at the five ore systems investigated herein, are common to many slate belt-hosted gold deposits. The results of this investigation show that, although the detection of such systematic spatial variations relative to mineralization can be complicated, for example by postore modification of the wall rocks due to contact metamorphism (e.g., at Maldon) or where mineralization is not associated with massive to laminated quartz veins (e.g., at Fosterville), recognition of extensive, though not always conspicuous, alteration halos around mesothermal lode gold mineralization represents a potentially powerful tool for exploration in slate belts.

A prototype of a solid deuterium (SD 2 ) source of Ultra-Cold Neutrons (UCN) is currently being tested at LANSCE. The source is contained within an assembly consisting of a 4 K polyethylene moderator surrounded by a 77 K beryllium flux trap in which is embedded a spallation target. Time-of-flight measurements have been made of the cold neutron spectrum emerging directly from the flux trap assembly. A comparison is presented of these measurements with results of Monte Carlo (LAHET/MCNP) calculations of the cold neutron fluxes produced in the prototype assembly by a beam of 800 MeV protons incident on the tungsten target. A UCN detector was coupled to the assembly through a guide system with a critical velocity of 8 m/s ( 58 Ni). The rates and time-of-flight data from this detector are compared with calculated values. Measurements of UCN production as a function of SD 2 volume (thickness) are compared with predicted values. The dependence of UCN production on SD 2 temperature and proton beam intensity are also presented.

The dynamic behaviour of biofilters intended to remove toluene and xylene from air was studied during transient states. Laboratory scale biofilters were filled with a mixture of peat, bark and wood and inoculated with a mixed microbial population. Toluene and xylene were applied both as single pollutants and as mixtures. Attention was focused on the evaluation of the following transients: the response of biofilters to step changes and peaks in pollutant concentrations, the effect of changes between single and multiple pollutant loadings and the response to shutdown periods. The biofilters demonstrated a good dynamic stability during transient states induced by change in inlet pollutant concentrations. Their time periods did not exceed three hours. No interaction between xylene and toluene degradation was observed during changes in loading with single pollutants or their mixture. The performance interruptions lasting less than 24 hours were found to have no significant influence on the removal efficiency of biofilters. When the biofilters were reacclimated after longer starvation periods, a short temporary decrease in efficiency whose minimum and duration were proportional to the length of a preceding shutdown period was observed. The longest starvation period (7 days) resulted in a reacclimation lasting 7 hours only. Adaptations of a microbial population to new operating conditions as well as sorption/desorption processes were suggested as the main factors influencing the dynamic reponse characteristics.

Interest in the role of serotonin (5-HT) in the therapeutic effects of atypical antipsychotic drugs originated from the observations that: (1) clozapine and other atypical drugs have a high affinity for 5-HT2A relative to D2 receptors; and (2) 5-HT2A receptors mediate the central effects of psychedelic hallucinogens. Recently, we found that 5-HT evokes a focal release of glutamate in the apical dendritic field of layer V pyramidal cells in prefrontal cortex, measured electrophysiologically by an increased frequency of spontaneous excitatory postsynaptic potentials/currents (EPSPs/EPSCs). An atypical mode of transmitter release (termed asynchronous release) seems to be involved because EPSC induction is tetrodotoxin (TTX)-sensitive but is not dependent on impulse flow and is supported by Sr2+ in the absence of external Ca2+. The 5-HT-induced increase in spontaneous EPSCs is blocked completely by the selective 5-HT2A antagonist M100907 (MDL 100,907). M100907 also blocks the enhancement by hallucinogens of a late, asynchronous component of electrically evoked EPSPs/EPSCs. Group II/III metabotropic glutamate agonists, which act downstream from 5-HT2A receptors at presynaptic inhibitory autoreceptors, markedly suppress the 5-HT-induced release of glutamate. Subtype-selective group II/III agonists, such as the group II metabotropic agonist LY354740, are particularly interesting in terms of therapeutic potential, because they are able to suppress the 5-HT2A-induced EPSCs while sparing overall glutamatergic transmission. An analysis of the mechanisms by which 5-HT2A receptors induce glutamate release suggests new targets for the design of novel treatments for schizophrenia.

Residual macrostresses are measured on samples having a surface layer composed of a steel substrate and a thin TiN coating. The surface of machine components can be covered by a TiN layer for the purpose of increasing hardness and wear resistance. Various methods are used for the deposition of this layer. Among them there are: physical vapour deposition (PVD), like-ion plating, sputter ion plating, magnetron sputtering (MS), and chemical vapour deposition. This article deals with the layers of TiN deposited on steel 12050 using PVD-MS. The TiN layer is studied in connection with residual stress distribution and the machining of the substrate surface. The substrate is machined by milling and then coated with a TiN layer.

Previously, serotonin (5-HT) was found to induce a marked increase in glutamatergic spontaneous excitatory postsynaptic currents (EPSCs) in apical dendrites of layer V pyramidal cells of prefrontal cortex; this effect was mediated by 5-HT2A receptors, a proposed site of action of hallucinogenic and atypical antipsychotic drugs. Unexpectedly, although the effect of 5-HT was Ca2+-dependent and tetrodotoxin-sensitive, it did not appear to involve the activation of excitatory afferent impulse flow. This paradox prompted us to investigate (in rat brain slices) whether 5-HT was acting through an atypical mode of excitatory transmitter release. We found that the frequency of 5-HT-induced spontaneous EPSCs was fully supported by Sr2+ in the absence of added Ca2+, implicating the mechanism of asynchronous transmitter release which has been linked to the high-affinity Ca2+-sensor synaptotagmin III. Although the early, synchronous component of electrically evoked EPSCs was reduced while 5-HT was being applied, late, nonsynchronous components were enhanced during 5-HT washout and also by the 5-HT2 partial agonist 1-(2,5-dimethoxy-4-iodophenyl-2-aminopropane (DOI); the effect of DOI was blocked by a selective 5-HT2A antagonist (MDL 100,907). This late, nonsynchronous component was distinct from conventional polysynaptic EPSCs evoked in the presence of the GABAA antagonist bicuculline, but resembled asynchronous glutamatergic excitatory postsynaptic potentials (EPSPs) evoked in the presence of Sr2+. An enhancement of asynchronous EPSCs by a specific neurotransmitter receptor has not been reported previously. The possible role of excessive asynchronous transmission in the cerebral cortex in mediating the hallucinogenic effects of 5-HT2A agonists such as DOI is discussed.

Conditions are described for the preparation of 188Re-RC-160, a radiolabeled synthetic peptide derived from an analogue of somatostatin, using a lyophilized labeling kit containing RC-160 (200 μg) and stannous tartrate to which is added carrier-free 188 Re (β, E max , 2,12 MeV ; γ, 155 KeV , 10%, T 1 2 = 16.7 h ) . The 3its have been radiolabeled with > 2960 Mbq (80 mCi) with a high labeling efficiency and no need for subsequent purification. Radiolabeling results in one major peak when analyzed by reverse-phase (RP) HPLC. Presumptive radiolysis was detected at 2.5 h post-labeling; however, a convenient method is described for stabilizing the kits against radiolysis by the post-labeling addition of ascorbic acid.

Pharmacological techniques have defined the existence of two different alpha 1-adrenoceptors, the alpha 1A- and alpha 1B-adrenoceptor subtypes and both of these receptors have been cloned in addition to a cloned alpha 1d-adrenoceptor. A subpopulation of interneurons in layer III of the rat piriform cortex that are excited by 5-hydroxytryptamine (5-HT) via 5-HT2A receptors are also excited by norepinephrine via alpha 1-adrenoceptors. In the present study we determined the pA2 values against the norepinephrine-mediated excitation of piriform cortical interneurons for a number of antagonists that are (1) not selective for alpha 1A- or alpha 1B-adrenoceptors (prazosin), (2) selective for alpha 1A-adrenoceptors (5-methyl urapidil, 2-(2,6-dimethoxy-phenoxyethyl)- aminomethyl-1,4-benzodioxane hydrochloride (WB 4101), benoxathian, phentolamine) and (3) selective for alpha 1B-adrenoceptors (spiperone and risperidone). The pA2 values for the antagonist blockade of norepinephrine-mediated interneuron excitation were significantly correlated to literature values for the pKi values of antagonist binding to the alpha 1B-adrenoceptor (r = 0.919) and the cloned alpha 1b-adrenoceptor (r = 0.849) but were not correlated to the pKi values of antagonist binding to the alpha 1A-adrenoceptor or the cloned alpha 1a- and alpha 1d-adrenoceptor. Thus, we conclude that this population of piriform cortical interneurons is excited by norepinephrine via alpha 1B-adrenoceptors.

A multiresidue method for the determination of chlorsulfuron, metsulfuron-methyl, thifensulfuron-methyl, and triasulfuron in soil by high-performance liquid chromatography/electrospray/mass spectrometry (LC/ES/MS) is reported. A clay loam soil, spiked at 6.0 μg kg-1 with all four herbicides, was extracted with 0.1 M ammonium carbonate, and the extract was cleaned up by C18-SPE. The herbicides were quantified using selected ion monitoring. The percent recoveries were as follows: chlorsulfuron, 80.1 ± 7.9%; metsulfuron-methyl, 99.4 ± 8.6%; thifensulfuron-methyl, 95.9 ± 5.9%; and triasulfuron 100.5 ± 24.3%. We have shown that we can analyze and confirm four 4-methoxy-6-methyl-1,3,5-triazin-2-yl-containing sulfonylurea herbicides in soil by LC/ES/MS. This multiresidue method should also be appropriate for other sulfonylurea and polar herbicides. Keywords: Chlorsulfuron; metsulfuron-methyl; thifensulfuron-methyl; triasulfuron; LC/MS; electrospray; soil

Monoclonal antibodies can be directly labelled with 188Re using a simple one-step radiolabelling kit. Using B72.3 as a model antibody, the formulation was optimized and kits were made and tested and compared to data previously reported for the same antibody labelled with other radioisotopes. Labelling with Re-188 was carried out with the eluate of a W-188/Re-188 generator from Oak Ridge National Laboratory. Fresh generator eluate was added to the pre-reduced lyophilized antibody and the mixture allowed to incubate overnight at room temperature. The radiochemical purity, immunoreactive fraction, and biodistribution in normal and LS174T tumor bearing nude mice was determined. The radiochemical purity was 88 ± 7%, the immunoreactive fraction was 68.46 ± 3.8%. The immunoreactive fraction was higher than any previously reported for this antibody when labelled with other radioisotopes. At 48 h, 7.9 ± 2.4% of the injected dose per gram was found in the tumor. The biodistribution and tumor uptake of Re-188 labelled B72.3 was similar to that previously reported for Re-186 and In-111 labelled B72.3.

The effects of four serotonin (5-HT)-1A compounds (buspirone, gepirone, ipsapirone and zalospirone) were compared with 5-hydroxytryptophan (5-HTP) [a 5-HT precursor with antidepressant (AD) efficacy], and diazepam (a benzodiazepine anxiolytic), on a differential-reinforcement-of-low-rate 72-s (DRL 72-s) schedule. Past research has shown that AD and anxiolytic compounds each have distinct effects on the DRL 72-s interresponse time (IRT) distribution profile. In the present paper, the profile of the IRT distribution was quantitatively characterized by three metrics: burst ratio, peak location and peak area. 5-HTP shifted the IRT distribution peak toward longer IRT durations, increased reinforcement rate and decreased response rate. The profile of the IRT distribution was not disrupted by 5-HTP. Diazepam disrupted the IRT distribution and increased bursting. In general, the arylpiperazine, 5-HT1A compounds increased reinforcement rate, decreased response rate and disrupted the profile of the IRT distribution. The effects of the four arylpiperazine 5-HT1A compounds on the IRT distribution profile were different from the AD profile of 5-HTP and the benzodiazepine anxiolytic profile of diazepam. Disruption of the IRT distribution by buspirone, gepirone, ipsapirone and zalospirone may result from decreased 5-HT transmission mediated by the presynaptic, somatodendritic 5-HT1A receptor.

The normalization of excessive glutamatergic neurotransmission through the activation of metabotropic glutamate 2 (mGlu2) receptors may have therapeutic potential in a variety of psychiatric disorders, including anxiety/depression and schizophrenia. Here, we characterize the pharmacological properties of N-(4-((2-(trifluoromethyl)-3-hydroxy-4-(isobutyryl)phenoxy)methyl)benzyl)-1-methyl-1H-imidazole-4-carboxamide (THIIC), a structurally novel, potent, and selective allosteric potentiator of human and rat mGlu2 receptors (EC(50) = 23 and 13 nM, respectively). THIIC produced anxiolytic-like efficacy in the rat stress-induced hyperthermia assay and the mouse stress-induced elevation of cerebellar cGMP and marble-burying assays. THIIC also produced robust activity in three assays that detect antidepressant-like activity, including the mouse forced-swim test, the rat differential reinforcement of low rate 72-s assay, and the rat dominant-submissive test, with a maximal response similar to that of imipramine. Effects of THIIC in the forced-swim test and marble burying were deleted in mGlu2 receptor null mice. Analysis of sleep electroencephalogram (EEG) showed that THIIC had a sleep-promoting profile with increased non-rapid eye movement (REM) and decreased REM sleep. THIIC also decreased the dark phase increase in extracellular histamine in the medial prefrontal cortex and decreased levels of the histamine metabolite tele-methylhistamine (t-MeHA) in rat cerebrospinal fluid. Collectively, these results indicate that the novel mGlu2-positive allosteric modulator THIIC has robust activity in models used to predict anxiolytic/antidepressant efficacy, substantiating, at least with this molecule, differentiation in the biological impact of mGlu2 potentiation versus mGlu2/3 orthosteric agonism. In addition, we provide evidence that sleep EEG and CSF t-MeHA might function as viable biomarker approaches to facilitate the translational development of THIIC and other mGlu2 potentiators.

The 14 different serotonin or 5-hydroxytryptamine (5-HT) receptors are widely distributed throughout the central nervous system. Of these 14 serotonin receptors, 13 mediate the slow modulatory action of 5-HT upon fast excitatory or inhibitory effects of glutamate/aspartate and γ-aminobutyric acid (GABA)/glycine, respectively. The presence of different 5-HT receptors in discrete cellular compartments through the neuroaxis allows for an integrated effect of serotonergic neurotransmission on sleep and arousal processes, executive functions of the prefrontal cortex, affective behavior, aggression, learning and memory, and modulation of pain. This is accomplished though specific 5-HT receptors controlling the pacemaker functions of midbrain and brainstem 5-HT-containing neurons which project throughout the neuroaxis, as discussed elsewhere. Different 5-HT receptors are localized on local or projection GABAergic neurons in addition to the different compartments (axons, axon terminals, dendrites, cell bodies) of glutamatergic local or output cells. 5-HT receptors are also present either on other biogenic amine-containing cells or on cells modulating the other biogenic amine-containing cells to modulate the electrophysiological action of norepinephrine, dopamine and acetylcholine throughout the neuroaxis.

Kits for direct labeling of IgG with 99mTc were used without modification for the preparation of [67Cu]IgG. The IgG was pre-treated to generate thiolate groups which would bind 67Cu. The direct labeling of reduced IgG with 67Cu was highly efficient, resulting in approx. 95% 67Cu binding. Non-reduced IgG (negative control) had labeling efficiencies of less than 10%. IgG pre-exposed to Cu(II) had reduced amounts of 99mTc bound to it. The results demonstrate a direct relationship between copper- and 99mTc-binding sites in IgG.

Modulation of glutamatergic neurotransmission by metabotropic glutamate2/3 (mGlu2/3) receptor agonists effectively treats seemingly diverse neuropsychiatric illness such as generalized anxiety disorder and schizophrenia. Activation of adenosine A 1 heteroceptors, like mGlu2 autoreceptors, decreases glutamate release in the medial prefrontal cortex (mPFC) and other limbic brain regions. Previously, we have reported electrophysiological, neurochemical and behavioral evidence for interactions between the 5-hydroxytryptamine 2A (5-HT 2A ) and mGlu2/3 receptors in the mPFC. The present studies were designed to investigate the effects in rats of adenosine A 1 receptor activation/blockade on a behavior modulated by 5-HT 2A receptor activation/blockade in the mPFC: head shakes induced in the rat by phenethylamine hallucinogens. An adenosine A 1 receptor agonist, N 6 -cyclohexyladenosine (CHA) suppressed head shakes induced by activation of 5-HT 2A receptors with the phenethylamine hallucinogen (±)-2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI). An adenosine A1 receptor antagonist, 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), enhanced DOI-induced head shakes and blocked the suppressant action of an adenosine A 1 receptor agonist on DOI-induced head shakes. Thus, the pattern of activity for an agonist and antagonist at the adenosine A1 receptor with respect to modulating DOI-induced head shakes is similar to the pattern observed with mGlu2/3 receptor agonists and antagonists. These novel observations with an adenosine A 1 receptor agonist suggest that this pharmacological action could contribute to antipsychotic effects in addition to thymoleptic effects.

Monoamine uptake inhibitors block the neurotoxic effects of methamphetamine (MA) upon dopaminergic and serotonergic neurons in the rat. The neurotoxic effects of MA upon dopaminergic neurons have previously been suggested to be mediated via formation of 6-hydroxydopamine (6-OHDA) from endogenous stores of dopamine (DA). In the present experiments, administration of the DA uptake inhibitor amfonelic acid (AFA, 10 mg/kg, i.p.) did not block the formation of 6-OHDA in rats treated with a single s.c. 100 mg/kg dose of MA. Consistent with the lack of effect by AFA on MA-induced 6-OHDA formation, neither AFA (10 mg/kg, i.p.) nor the DA and 5-hydroxytryptamine (5-HT) uptake inhibitor mazindol (40 mg/kg, i.p., MAZ) blocked the depletion seen in neostriatal DA levels 1, 2 or 8 h following administration of a single 100 mg/kg dose of MA. In fact, AFA enhanced the DA depletions 2 and 8 h following MA administration. AFA also enhanced the MA-induced increase in locomotor activity in rats and this effect was blocked by lesions of dopaminergic neurons with i.v.t. (intraventricular) 6-OHDA in desipramine-pretreated rats. These results suggest that DA uptake inhibitors do not prevent the neurotoxic effect of MA on DA neurons by either preventing entry of MA into the cell or blocking the efflux of DA out of the cell. Instead, the DA uptake inhibitors appear to prevent the neurotoxic effect of MA upon dopaminergic neurons by blocking entry of 6-OHDA into the cell.

Neostriatal 6-hydroxydopamine (6-OHDA) was detected in 6 of 13 rats pretreated 2 or 4 hr earlier with methamphetamine (MA; 100 mg/kg, SC) and pargyline (25 mg/kg, IP, 30 min before MA injection). Neostriatal 6-OHDA was detected in 2 of 16 rats treated 2 or 4 hr earlier with MA. These results suggest that pargyline pretreatment may enhance formation of 6-OHDA from endogenous stores of dopamine (DA) following MA administration. Alternatively, these results suggest that pargyline pretreatment may protect endogenously formed 6-OHDA from oxidative deamination by monoamine oxidase. Enhancement of MA-induced neostriatal 6-OHDA levels may be the mechanism by which pargyline enhances the long-term neurotoxic effects of MA upon dopaminergic nerve terminals. These observations support the hypothesis that MA toxicity to DA-containing fibers is caused by the conversion of released DA into 6-OHDA.

Mice and rat populations are commonly controlled by two classes of rodenticide anticoagulants, coumarins and indandiones. However, poisoning of nontarget animals also often occurs. For cases such as these, a rapid, multiresidue method, which provides positive confirmation for both classes of anticoagulant rodenticides, is needed by diagnostic laboratories. A method was developed for the determination of seven anticoagulant rodenticides, coumafuryl, pindone, warfarin, diphacinone, chlorophacinone, bromadiolone, and brodifacoum, in diverse matrices, animal feed, cooked beef, and fruit-flavored beverages using high-performance liquid chromatography/electrospray/mass spectrometry. Detection was by MS/MS with electrospray ionization in negative mode. Confirmation was by retention time, m/z of molecular ion, and two parent-daughter transitions. Recoveries from selected the matrices ranged from 61 to 117%. Limits of quantitation were as low as 1.5-4.5 ng g -1 . The developed method was rapid and provided the simultaneous confirmation and quantification of the seven anticoagulant rodenticides.

The two endcaps of the PHENIX multiplicity/vertex detector are comprised of 24 wedge-shaped silicon pad detectors. The performance of a double-metal pad detector designed for these endcaps is described.

Activation and blockade of prefrontal cortical 5-hydroxytryptamine2A (5-HT2A) receptors have been linked to the action of hallucinogenic and antidepressant/antipsychotic drugs; these effects may involve modulation of glutamate release from thalamocortical afferents. Although activation of metabotropic glutamate 2 (mGlu2) receptors may suppress 5-HT-induced excitatory postsynaptic currents (EPSCs), group III mGlu receptors (mGlu4/7/8) also are expressed in the thalamus and may suppress 5-HT-induced EPSCs. We have found by intracellular recordings from layer V pyramidal cells of the medial prefrontal cortex (mPFC) that group III mGlu receptor agonists (R,S)-4-phosphonophenylglycine (PPG), L-4-phosphono-2-aminobutyric acid (L-AP4), L-serine-O-phosphate (L-SOP), and (S)-2-amino-2-methyl-4-phosphonobutanoic acid (MAP4) preferentially suppress 5-HT-induced EPSCs compared with excitatory postsynaptic potentials evoked by electrical stimulation of the white matter. A number of pharmacological features [e.g., the rank order of agonist potency; MAP4 partial agonist action; differential potency for the group III mGlu receptor antagonist (R,S)-alpha-cyclopropyl-4-phosphonophenylglycine (CPPG) in blocking the suppressant action of PPG or MAP4; and a relatively low potency of 2S-2-amino-2-(1S,2S-2-carboxycycloprop-1-yl)-3(xanthy-9-yl)propanoic acid (LY341495) in blocking the suppressant action of PPG or L-SOP] suggest that activation of both mGlu4 and mGlu8 receptors may play a role in suppressing 5-HT-induced EPSCs. Furthermore, L-SOP did not alter the synaptic currents or steady-state inward current induced by alpha-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid. Thus, although both group III and group II mGlu receptor agonists suppress the frequency of 5-HT-induced EPSCs in the mPFC, they differ in that the group III mGlu receptor agonists appear to have relatively minimal effects on glutamate released by sources other than thalamocortical afferents.