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From early to later stages of Type I Diabetes Mellitus (TIDM), signalling molecules including brain indolamines and protein kinases are altered significantly, and that has been implicated in the Metabolic Disorders (MD) as well as impairment of retinal, renal, neuronal and cardiovascular systems. Considerable attention has been focused to the effects of diabetes on these signalling systems. However, the exact pathophysiological mechanisms of these signals are not completely understood in TIDM, but it is likely that hyperglycemia, acidosis, and insulin resistance play significant roles. Insulin maintains normal glycemic levels and it acts by binding to its receptor, so that it activates the receptor's tyrosine kinase activity, resulting in phosphorylation of several substrates. Those substrates provide binding/interaction sites for signalling molecules, including serine/threonine kinases and indolamines. For more than two decades, our research has been focused on the mechanisms of protein kinases, CaM Kinase and Serotonin transporter mediated alterations of indolamines in TIDM. In this review, we have also discussed how discrete areas of brain respond to insulin or some of the pharmacological agents that triggers or restores these signalling molecules, and it may be useful for the treatment of specific region wise changes/disorders of diabetic brain.

Brain glycogen could be considered as an energy store for neuronal activity, with high relevance in epilepsies. We selected two lines of mice based upon their latency to methionine sulfoximine (MSO) dependent-seizures: MSO-Fast and MSO-Slow, and their neurochemical characterization was attempted in order to look for the mechanisms of epileptogeny. We determined the MSO effect on brain glycogen in the two selected lines and their eight parental strains, and on indolamines and catecholamines. The increase in brain glycogen content induced by MSO is significantly lower in MSO-Fast than in MSO-Slow. At the onset of seizures the degradation of accumulated glycogen was higher in MSO-Slow mice than in MSO-Fast ones. Moreover, a positive correlation was observed between the magnitude of latency toward MSO-induced seizures and brain glycogen content in the eight parental strains used for selection. A striking proportionality between the content of glycogen and 5-hydroxytryptamine (5-HT) was observed in cerebral cortices of both selected lines. However, the cortical 5-HT level is higher in MSO-Fast than in MSO-Slow, and it is significantly decreased at the onset of seizures in both lines. Brain glycogen content is implicated in the developed model of mice with different latency to MSO-dependent seizures: The higher the brain glycogen content, the longer the latency; and 5-HT is involved in the control of latency to seizures-induced by MSO in these two lines. Our model of MSO "sensitive" (MSO-Fast) and "resistant" (MSO-Slow) mice could lead to a better understanding of MSO mechanisms of epileptogenesis, and the relationship between epileptogenic and glycogenic MSO effects.

In this study, we examined the relative efficacies of alpha-tocopherol, N-acetyl-serotonin, and melatonin in reducing ascorbate-Fe(2+) lipid peroxidation (LPO) of rat testicular microsomes and mitochondria. Special attention was paid to the changes produced on the highly polyunsaturated fatty acids (PUFAs) C20:4 n6 and C22:5 n6. The LPO of testicular microsomes or mitochondria produced a significant decrease of C20:4 n6 and C22:5 n6. Both long-chain PUFAs were protected when the antioxidants were incorporated either in microsomes or mitochondria. By comparison of the IC50 values obtained between alpha-tocopherol and both indolamines, it was observed that alpha-tocopherol was the most efficient antioxidant against the LPO induced by ascorbate-Fe(2+) under experimental conditions in vitro, IC50 values from the inhibition of alpha-tocopherol on the chemiluminescence were higher in microsomes (0.14 mM) than in mitochondria (0.08 mM). The protective effect observed by alpha-tocopherol in rat testis mitochondria was higher compared with microsomes, associated with the higher amount of [C20:4 n6] + [C22:5 n6] in microsomes than that in mitochondria. Melatonin and N-acetyl-serotonin were more effective in inhibiting the LPO in mitochondria than that in microsomes. Thus, a concentration of 1 mM of both indolamines was sufficient to inhibit in approximately 70% of the light emission in mitochondria, whereas a greater dosage of 10 times (10 mM) was necessary to produce the same effect in microsomes. It is proposed that the vulnerability to LPO of rat testicular microsomes and mitochondria in the presence of both indolamines is different because of the different proportion of PUFAs in these organelles.

Hyperglycemia and ketoacidosis are the two most serious factors in acute metabolic complications of both type 1 and type 2 diabetes. Dysfunction of the central nervous system is a well-documented complication of diabetes. We and others have previously reported that acute or chronic diabetes in animal's results in altered brain neurotransmitter levels. In this study, we investigated the effects of acute (7 days) glucose-induced hyperglycemia and sodium acetoacetate (NaAcAc) or ammonium chloride (NH4Cl) induced acidosis on the level of indolamines (5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA)) as well as PKC-alpha expression/activity in discrete areas of rat brain. Glucose-induced (500 mg/kg, bw) hyperglycemic ( approximately 249 mg%) rats showed significant (p

The purpose of the present study was to evaluate the effect of 4-pregnen-17-hydroxy-3-one (A) and two steroids homologues: 3beta-acetoxy-5,16-pregnadien-20-one (B) and 3beta-acetoxy-16alpha-17alpha-epoxy-4-pregnen-20-one (C). Male Wistar rats were treated with o-cresol combined (A, B or C) steroids. Lipid peroxidation status as result of measurement reactive substances to thiobarbituric acid (TBARS) as well as serotonin (5-HT) and its precursor 5-hydroxytryptophan (5-HTP) were measured. The prostate glands were weighed, the 5alpha-reductase activity was determined. The animals treated with A, B, and C steroids showed a slight increase in both 5alpha-reductase activity and prostate size. 5-HT and 5-HTP levels did not change significantly, and TBARS showed an increase in the group treated with B steroid and a decrease in the A steroid group with significant differences in both groups (p0.05) versus control group. Results suggest that A steroid reduces TBARS in rat brain, perhaps as a result of the interaction between the testosterone unsaturated carbons and OH(-) groups with free radicals.

Arylalkylamine N-acetyltransferase (NAT) from the female colleterial glands of Periplaneta americana showed activity peaks at pH 6.0 and 9.5 and the pH profile changed during oogenesis. The left gland contained higher activity than the right gland but the right gland also contained recognizable activity. The patterns in activity change depended on the substrate used, tryptamine (TN) or serotonin (5-HT). When TN was used as the substrate, the alkaline peak was higher than the acidic peak. In contrast, when 5-HT was used, the acidic peak was much higher than the alkaline peak. This suggests that at least two NATs are present in this species that are specific to pH and substrate species. Of the four combinations of the two pH ranges and two substrate indolamines, the enzyme activity that showed a similar change to the oocyte maturation was obtained in the combination of pH 6.0 and TN. TN was actually detected in the colleterial glands by fluorescent measurements according to Hess and Uderfriend [J. Pharmacol. Exp., 127 (1959) 175-177]. It peaked on the 6th day of emergence, which corresponded to the first rise of oocyte length and yolk accumulation, whereas a small peak appeared in the phase of the second rise. TN, or more likely N-acetyl TN, may therefore be involved in the regulation of oocyte maturation which could be a novel mechanism in oocyte maturation.

The serotonin system has been implicated in the modulation of endocrine and behavioral components of reproduction. In this study, we examined endogenous hypothalamic indolamines during sexual differentiation and long-term effects of exogenous steroids during this time. In Experiment 1, Japanese quail were studied during the last half of embryonic development and early post-hatch. Samples were taken at embryonic day 10 (E10), E12, E14, E16, hatch (day 0), and days 3 and 5, post-hatch. Hypothalamic indolamines, including serotonin (5-HT) and its metabolite, 5-hydroxy indole acetic acid (5-HIAA) were measured by HPLC-EC detection. Females had relatively higher hypothalamic 5-HT at E14 than males, with both sexes showing increasing levels thereafter. By day 5, post-hatch, hypothalamic 5-HT content was higher in males than in females. When turnover was estimated by comparing relative concentrations of 5-HT to 5-HIAA, males were significantly higher at E12 and E14 than females. These data suggest that there are stage specific changes in the serotonin system, as well as sexually dimorphic patterns in the ontogeny and activity of this system. In Experiment 2, we investigated the effects of embryonic steroid hormone treatment on the serotonin system and on male sexual behavior. Birds were treated with either estradiol benzoate (EB), testosterone propionate (TP) or sesame oil (vehicle control) at selected embryonic days (E10, E12, E14, E16, 0, D3, and D5). At 4 weeks post-hatch, birds were transferred to short photoperiod (16D:8L) for 3 weeks to prevent photostimulated reproductive development. At 7 weeks of age, males were implanted with a 20 mm silastic capsule filled with testosterone and sexual behavior was tested 1 week later. Brains were collected from both males and females, and preoptic area (POA) indolamines were measured. Steroid treatment at E10 or E12 resulted in the loss of male sexual behavior. Moreover, males treated with EB or TP on E12 also had increased POA 5-HT content as adults, compared to control males. Females treated with EB on either E10 or E 12 also had higher POA 5-HT content than control or TP treated females. These data provide evidence for sexual dimorphism in the hypothalamic 5-HT system at specific stages during embryonic development. Moreover, males were sensitive to exogenous EB and TP on E12, whereas females appeared to be affected by EB only and appeared to be sensitive to steroid effects over a longer period of time in development. Moreover, exogenous steroids at E12 in males also correlated with impaired sexual behavioral. These data suggest that long-term effects of embryonic steroid exposure may be mediated in part through effects on the serotonin neurotransmitter system.

We investigated innervation to body wall muscles as well as distribution of 5-HT (serotonin) and its effects on longitudinal muscles of body wall (LMBW) of the sea cucumber Apostichopus japonicus. With serial sections we found neural branches and fibers extending from hyponeural part of radial nerve towards LMBW and circular muscles of body wall. With the aqueous aldehyde (Faglu) method yellow fluorescence indicating indolamines was observed in LMBW and in the mesentery connecting LMBW to the body wall. With indirect immunohistochemistry 5-HT-like immunoreactivity was observed in LMBW and in mesentery. These results strongly suggested that both LMBW and mesentery contained 5-HT. The effects of monoamine neurotransmitters were studied in LMBW. Putative neurotransmitters tested were 5-HT, adrenaline, noradrenaline, dopamine, and DOPA at the concentration of 10(-6) M. The application of 5-HT caused no contraction or relaxation, but it inhibited the contraction induced by 10(-6)-10(-5) M acetylcholine (ACh). Catecholamines were ineffective by themselves and had no effects on the contraction induced by ACh. The present histological, histochemical, and pharmacological studies strongly suggested that holothurian LMBW was innervated by inhibitory serotonergic neurons of the hyponeural nervous system.

Quantitative analysis of signaling molecules from single cells and cellular materials requires careful validation of the analytical methods. Strategies have been investigated that enable single neurons and neuronal tissues to be stored before being assayed for many low-weight, biologically active molecules, such as serotonin, dopamine, and citrulline. Both metacerebral cell and pedal ganglia homogenates isolated from Pleiuohbrain-Chae californica have been studied by capillary electrophoresis with two complimentary laser-induced fluorescence detection methods. For homogenized ganglia samples, several cellular analytes (such as arginine and citrulline) are unaffected by standing at room temperature for days. Many other analytes in the biological matrix, including the catecholamines and indolamines, degrade by 20% within 10 h at room temperature. Rapidly freezing samples or preserving them with ascorbic acid preserves more than 80% of the dopamine and about 70% of the serotonin even after five days. In addition, serotonin and dopamine remain completely stable for at least five days by combining the ascorbic acid preservation and freezing at -20 degrees C. The timing of preservation is critical in maintaining the original composition of the biological samples. Using our optimum storage protocol of freezing the sample within 2 h after isolation, we can store frozen homogenate ganglia samples for more than four weeks before assay while still obtaining losses less than 10% of the original serotonin and dopamine. The nanoliter-volume single cell samples, however, must be analyzed within 4 h to obtain losses of less than 10% for serotonin related metabolites.

In an attempt to define the role of the pineal hormone melatonin and two analogues (5-methoxytryptamine, 5MT, and 6-hydroxymelatonin, 6HM) in limiting oxidative stress, the present study investigated the changes in glutathione, lipid peroxidation, and the activity of the antioxidant enzyme glutathione peroxidase after exercise (swimming for 60 min) with or without treatment with the indolamines mentioned. Lipid peroxidation was measured by estimating tissue levels of malondialdehyde and 4-hydroxyalkenals; the experimental animals in these studies were male Sprague-Dawley rats. In the liver, swimming exercise increased the levels of reduced glutathione (GSH) and also significantly increasing oxidized glutathione (GSSG), while decreasing the GSH/GSSG ratio, an index directly related to oxidative stress. When the animals were treated with melatonin, the concentrations of GSH and GSSG were also increased after swimming; however, no reduction in the GSH/GSSG ratio appeared. In the animals treated with 6HM the changes were the same as in those treated with melatonin. In muscle as well, the concentration of GSH and the GSH/GSSG ratio were decreased following 60 min of swimming. Pretreatment of the rats with melatonin prevented these effects. Pretreatment of the rats with both 5MT and 6HM also prevented the changes. Brain GSH/GSSG ratio was not affected by either exercise or indolamine administration. Swimming enhanced lipid peroxidation in the liver, muscle and brain; however, this was prevented in animals treated with melatonin or 6HM before swimming. Glutathione peroxidase was significantly elevated after exercise in the brain but not in the liver and muscle. It is concluded that swimming imposes a severe oxidative stress and suggests that melatonin and, to a lesser degree, 5MT and 6HM confer protection against the oxidative damage associated with swimming for 60 min. This mechanism may be reasonably attributed to their indole structure, which possibly allows these molecules to act as free-radical scavengers.

I. Introduction PAST studies of antidepressants have focused almost exclusively on their effects on the metabolism and receptors of monoamine neurotransmitters in various brain regions. These studies have been extended to the molecular effects of antidepressants and have led to a profoundly expanded understanding of their actions in the central nervous system. For example, long-term administration of antidepressants decreases the expression of tyrosine hydroxylase, down-regulates cAMP-dependent protein kinase, modulates the mRNA expression of central β-adrenoceptors and serotonin (5-HT) receptors, and alters the functional activity of specific G protein subunits and adenylyl cyclase (1). Taken together, these and many other recent observations clearly indicate that antidepressants interfere not only with the production and release of catecholamines and indolamines but also with the signal transduction of those neurotransmitters that have long been implicated in the pathogenesis and treatment of depression...

Neuroendocrine cells are present in virtually all organs of the vertebrate body; however, it is yet uncertain whether they exist in the ovaries. Previous reports of ovarian neurons and neuron-like cells in mammals and birds might have resulted from misidentification. The aim of the present work was to determine the identity of neuron-like cells in immature ovaries of the domestic fowl. Cells immunoreactive to neurofilaments, synaptophysin, and chromogranin-A, with small, dense-core secretory granules, were consistently observed throughout the sub-cortical ovarian medulla and cortical interfollicular stroma. These cells also displayed immunoreactivity for tyrosine, tryptophan and dopamine β-hydroxylases, as well as to aromatic L-DOPA decarboxylase, implying their ability to synthesize both catecholamines and indolamines. Our results support the argument that the ovarian cells previously reported as neuron-like in birds, are neuroendocrine cells.

Electrochemical detection is often used to detect catecholamines and indolamines in brain samples that have been separated by conventional reverse-phase high performance liquid chromatography (HPLC). This paper presents the transfer of an existing chromatographic method for the determination of monoamines in brain tissues using 5 μm granulometry HPLC columns to columns with a particle diameter less than 3 μm. Several parameters (repeatability, linearity, accuracy, limit of detection, and stability of samples) for this new ultrafast high performance liquid chromatography (UHPLC) method were examined after optimization of the analytical conditions. The separation of seven compounds, noradrenaline, dopamine and three of its metabolites, dihydroxyphenylacetic acid, homovanillic acid, and 3-methoxytyramine, and serotonin and its metabolite, 5-hydroxyindole-3-acetic acid was analyzed using this UHPLC-electrochemical detection method. The final method, which was applied to brain tissue extracts from mice, rats, and cats, decreased analysis time by a factor of 4 compared to HPLC, while guaranteeing good analytical performance.

Microdialysis is an extensively used technique for both in vivo and in vitro experiments, applicable to animal and human studies. In neurosciences, the in vivo microdialysis is usually performed to follow changes in the extracellular levels of substances and to monitor neurotransmitters release in the brain of freely moving animals. Catecholamines, such as dopamine and their related compounds, are involved in the neurochemistry and in the physiology of mental diseases and neurological disorders. It is generally supposed that the brain's energy requirement is supplied by glucose oxidation. More recently, lactate was proposed to be the metabolic substrate used by neurons during synaptic activity. In our study, an innovative microdialysis approach for simultaneous monitoring of catecholamines, indolamines, glutamate and energy substrates in the striatum of freely moving rats, using an asymmetric perfusion flow rate on microdialysis probe, is described. As a result of this asymmetric perfusion, two samples are available from the same brain region, having the same analytes composition but different concentrations. The asymmetric flow perfusion could be a useful tool in neurosciences studies related to brain's energy requirement, such as toxin-induced models of Parkinson's disease.

The synthesis of (+)-(R)-2-cyano-N,N-dipropyl-8-amino-6,7,8,9-tetrahydro-3H- benz[e]indole [(R)-14, U92016A], a potent 5-HT1A agonist, and related analogs is described. In vitro binding studies show that the (R)-enantiomers of this series possess the highest potency for the 5-HT1A receptor. In vivo hypothermia correlates with this, with the (R)-enantiomers causing a greater temperature drop than the (S)-enantiomers. The most active compound in 5-HT1A binding and in the in vivo models was (R)-14, which was found to be highly potent as an agonist in single cell firing studies, as well as potent and of very high intrinsic activity in mouse hypothermia and the sympathetic nerve discharge (SND) models. An in vivo duration of action study, following SND, showed (R)-14 to possess a long duration of action. The synthesis via a nitrene insertion, determination of absolute configuration, and biological activities of this series is described.

The pineal gland is known to synthesize numerous indolamines. Since delta-sleep-inducing peptide (DSIP, a tryptophan nonapeptide) is found in the pineal gland, its effect on the secretion of indolamines was investigated. DSIP stimulated melatonin (MEL), 5-methoxytryptophol (5-ML) and serotonin (5-HT) synthesis and release, whereas it did not affect pineal cyclic AMP levels. The stimulatory effect of DSIP on MEL secretion was dose dependent between 5 x 10(-6) and 10(-4) M, whereas the minimal effective concentration of DSIP on 5-ML secretion was higher than 10(-5) M. The effect of DSIP (10(-4) M) was compared to the effect of isoproterenol (ISO, 10(-6) M) on MEL and 5-HT release. ISO stimulated MEL secretion and concomitantly decreased 5-HT release. With regard to kinetic characteristics, the effect of DSIP (10(-4) M) on MEL release was faster and of shorter duration than the effect of ISO (10(-6) M; 2 and 4 h, respectively). At 10(-4) M, DSIP potentiated the ISO-induced increase of MEL secretion. The DSIP-stimulated release of MEL was not significantly altered when the pineal glands were treated with 10(-5) M propranolol (a beta-adrenergic antagonist), 10(-5) M prazosin (an alpha 1-adrenergic antagonist) or 10(-5) M naloxone (an opioidergic antagonist). This study demonstrates that the DSIP-induced secretion of indolamines from rat pineal glands may not be elicited through the well-known noradrenergic or opioid systems.

1. Apart from octopamine, the same indolamines and catecholamines were detected in the whole nervous system of the cockroach Blaberus craniifer Burm., at the same time. 2. However, levels were found to depend on sex, age, and the anatomic region within the nervous system. 3. Although not established, it is thought that these substances act synchronously from the ganglia. 4. The differences in levels between males and females and between anatomical regions during imaginal life suggest, in this species of cockroach, the physiological importance of the metameric organization in metabolic pathways or functional aspects of biogenic amines.

1. Indolamine levels were determined in the cerebral ganglion, the thoraco-abdominal nerve cord (except the last ganglion), and the 6th abdominal ganglion of females of Blaberus craniifer . 2. Measurements were made at the imaginal molt and on fed and crowded imagos at 10, 20 and 30 post-imaginal days. 3. Indolamines were found in the nervous system of young females, but 5-hydroxytryptophan was only detected in the thoraco-abdominal nerve cord. 4. Amine levels were related to the age of the cockroach, particularly during this period, to post-ecdysi events and ootheca formation.

The effects of different doses of chronically administered carbaryl on rat pineal N-acetyltransferase (NAT) activity, hydroxyindole-O-methyltransferase (HIOMT) activity and pineal and serum melatonin levels during darkness (2300 h and 0100 h) when pineal melatonin synthesis is high were studied. Additionally, pineal levels of 5-hydroxytryptophan (5-HTP), serotonin (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) were estimated. Carbaryl was administered at total doses (over 6 days) of either 50, 125 or 250 mg/kg by gastric gavage. Control rats received vehicle (corn oil) only. During the study, the rats were exposed to light/dark cycles of 14:10 with lights off at 2100 h. Pineal NAT and HIOMT activities and pineal melatonin were increased at 0100 h following carbaryl administration at all three doses. Conversely, serum melatonin was increased at 2300 h after the 250 mg/kg dose of carbaryl while all three doses of the pesticide reduced serum melatonin levels at 0100 h. Pineal 5-HTP, 5-HT and 5-HIAA levels were usually increased at 2300 h but unaffected at 0100 h. The results indicate that carbaryl has significant effects on pineal melatonin synthesis and secretion.

Aromatic L-amino acid decarboxylase (AAAD) is an essential enzyme for the formation of catecholamines, indolamines, and trace amines. Moreover, it is a required enzyme for converting L-DOPA to dopamine when treating patients with Parkinson's disease (PD). There is now substantial evidence that the activity of AAAD in striatum is regulated by activation and induction, and second messengers play a role. Enzyme activity can be modulated by drugs acting on a number of neurotransmitter receptors including dopamine (D1-4), glutamate (NMDA), serotonin (5-HT(1A), 5-HT(2A)) and nicotinic acetylcholine receptors. Generally, antagonists enhance AAAD activity; while, agonists may diminish it. Enhancement of AAAD activity is functional, as the formation of dopamine from exogenous L-DOPA mirrors activity. Following a lesion of nigrostriatal dopaminergic neurons, AAAD in striatum responds more robustly to pharmacological manipulations, and this is true for the decarboxylation of exogenous L-DOPA as well. We review the evidence for parallel modulation of AAAD activity and L-DOPA decarboxylation and propose that this knowledge can be exploited to optimize the formation of dopamine from exogenous L-DOPA. This information can be used as a blue print for the design of novel L-DOPA treatment adjuvants to benefit patients with PD.

Intraerythrocytic malaria parasites develop in a highly synchronous manner. We have previously shown that the host hormone melatonin regulates the circadian rhythm of the rodent malaria parasite, Plasmodium chabaudi, through a Ca 2+ -based mechanism. Here we show that melatonin and other molecules derived from tryptophan, i.e. N-acetylserotonin, serotonin and tryptamine, also modulate the cell cycle of human malaria parasite P. falciparum by inducing an increase in cytosolic free Ca 2+ . This occurs independently of the extracellular Ca 2+ concentration, indicating that these molecules induce Ca 2+ mobilization from intracellular stores in the trophozoite. This in turn leads to an increase in the proportion of schizonts. The effects of the indolamines in increasing cytosolic free Ca 2+ and modulating the parasite cell cycle are both abrogated by an antagonist of the melatonin receptor, luzindole, and by the phospholipase inhibitor, U73122.

Hyperglycemia and acidosis are the key factors in diabetic complications. It has been shown that acute or chronic diabetes alters serotonin levels in brain. However, the mechanism of hyperglycemia- or acidosis-induced changes in serotonin levels remains poorly understood. Because Ca2+-dependent protein kinases play a major role in the regulation of serotonin synthesis and release, we investigated the effect of diabetes, hyperglycemia, and acidosis on the level of indolamines [5-hydroxytryptamine (5-HT) and/or 5-hydroxyindoleacetic acid (5-HIAA)] and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) enzyme activity or protein expression in different brain regions. Alloxan-induced (45 mg/kg bw) diabetic rats (30 days) showed increased level of 5-HT in striatum (ST; 183%), midbrain (MB; 199%), pons medulla (PM; 151%), cerebellum (CB; 214%), and cerebral cortex (CCX; 162%) compared with control (P < 0.05), and these changes were reversed after insulin administration. Rats treated with glucose (500 mg/kg bw) for 30 days showed a 146%, 183%, 208%, and 177% (P < 0.05) increase in 5-HT levels in ST, PM, CB, and CCX, respectively. 5-HIAA level increased in hippocampus (HC; 172%) and in MB (145%; P < 0.05). In addition, rats treated with sodium acetoacetate (NaAcAc) for 30 days (60 mg/kg bw) showed significant increases (P < 0.05) of 5-HT level in ST (152%) and MB (174%). However, the levels of 5-HIAA increased only in MB (151%, P < 0.05). Rats treated with NH4Cl, which induced acidosis (150 mg/kg bw), showed an increased level of 5-HT only in HC (165%, P < 0.05). The increased activity and protein expression of CaMKII in ST, MB, PM, CB, and CCX under diabetic conditions were correlated with the levels of indolamines changes during diabetic, hyperglycemic, or acidotic conditions. These results suggest that CaMKII may be involved in the regulation of indolamines in diabetic animals. © 2005 Wiley-Liss, Inc.

The purpose of this study was to determine whether the regional brain biogenic amine levels in adult rats were altered by pre- and post-natal exposure to 2,4-dichlorophenoxyacetic acid (2,4-D). Pregnant rats were daily orally exposed to 70 mg/kg per day of 2,4-D from gestation day (GD) 16 to post-partum day (PPD) 23. After weaning, the pups were assigned to one of two subgroups: T1 fed with untreated diet up to post-natal day (PND) 90 and T2 (maintained with 2,4-D diet up to PND 90). In addition, we wanted to know the effect of 2,4-D on lateralization in the monoamine systems of the basal ganglia of these adult rats and whether there was any correlation with the behavioral developmental pattern previously reported by us. In this study the content of noradrenaline (NA) was significantly increased in substantia nigra (SN) while it decreased in cerebellum in male and female rats of T2 group. The decreased dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovallinic acid (HVA) contents in cerebellum, midbrain, ventral tegmental area (VTA) and prefrontal cortex (PFc) showed an alteration in the mesocorticolimbic system. However, an increase of DA in SN and of DOPAC and HVA in nucleus accumbens (NAc) in both sexes and of DA and DOPAC (only in females) in striatum was detected. The contents of serotonin (5-hydroxytryptamine, 5-HT) were significantly increased in both sexes in PFc, striatum (St), midbrain, SN and cerebellum. Variations of any monoamine levels in NAc and VTA were determined. T1 rats were irreversibly altered: a diminution in DA and/or DOPAC levels in PFc, midbrain, VTA and cerebellum was determined. Indolamines of these rats were increased in both sexes in PFc and St. There was also a large increase in 5-HT levels in midbrain of male rats. Although no changes in the dopaminergic system with respect to their control values in any side of these brain structures were observed, DA and DOPAC levels were found to be decreased in the right side with respect to the left side in striata and accumbens nuclei in T2 female rats supporting the behavioral rotation previously registered by us in these rats. In addition, the increased 5-HT content detected in both the right and left striata observed in this study could be the answer to the behaviors observed and to the early alterations in dopamine in basal ganglia by 2,4-D in neonatal exposed rats, mediated by a serotonergic modulation on the dopaminergic system.

Intra-striatal infusion of a high dose (100 microg/3 microl) of methamphetamine produced long-lasting depletions of striatal dopamine and serotonin in both male and female mice. Male mice exhibited a greater depletion of striatal dopamine and serotonin than female mice. A similar trend of sexual differences was observed when 4 cumulative doses of methamphetamine were administered systemically. Thus, the sexual differences in methamphetamine-induced neurotoxicity in the striatum are probably not due to their differences in peripheral metabolism of methamphetamine. Moreover, ovariectomized (OVX) mice supplemented with 3 daily doses of estradiol benzoate (EB) at high or physiological levels, 3 daily doses of progesterone (P), and 2 doses of EB followed by 1 dose of P all demonstrated higher striatal dopamine levels following methamphetamine treatment as compared to vehicle-supplemented controls. The OVX mice pretreated with 3 daily doses of P exhibited the highest striatal serotonin levels after methamphetamine administration of all groups. In conclusion, sexual differences observed in methamphetamine-induced striatal neurotoxicity may be modulated by ovarian hormones.

To determine whether sustained hypoxia alters daily rhythms in brain and pituitary neurotransmitters, the daily variations in vasoactive intestinal peptide-like immunoreactivity (VIP-LI), neuropeptide Y-like immunoreactivity (NPY-LI), serotonin (5-HT), and 5-hydroxyindole-3-acetic acid (5-HIAA) content were determined in discrete brain regions, pineal gland and anterior pituitary of hypoxic (10% O2; 14 days) and normoxic rats. Hypoxia suppressed daily variations in VIP-LI in the suprachiasmatic nuclei (SCN) and the anterior pituitary, enhanced the daily rhythmicity in serotonergic elements of the caudal part of the dorsomedial medulla oblongata (DMMc), and even induced daily variations in NPY-LI in the DMMc as well as in the ventrolateral medulla oblongata. In addition, punctual alterations in the rhythmicity of 5-HT and 5-HIAA in the pineal gland and of plasma corticosterone were observed in hypoxic rats. Thus results of this study indicate that a permanent nonphotic stimulus, such as sustained hypoxia, may affect the functioning of the internal clock located in the SCN and may alter the daily rhythmicity in neurotransmitter content of some brain nuclei and the pituitary gland.

Long-term hypoxia induces changes in neuropeptide-Y-like immunoreactivity (NPY-LI) and/or in the content of serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) at the central level. To determine whether these alterations depend on the integrity of carotid body (CB) chemoreceptors, intact rats or those whose carotid sinus nerve was transected (CSNT) were exposed to hypoxia (10% O2) or to normoxia for 14 days. Thereafter, NPY-LI, 5-HT and 5-HIAA levels in discrete brain regions were determined. The increase in NPY-LI in the ventrolateral medulla oblongata (VLM) of intact hypoxic rats was mostly abolished after CSNT and therefore is mainly mediated by CB chemoreceptors. In contrast, other hypoxia-induced changes were similar or even enhanced in CSNT as compared to intact rats and therefore do not depend on the integrity of CB chemoreceptors. This was the case for the increase of NPY-LI in the striatum and the caudal dorsomedian medulla oblongata (DMM), as well as for all the changes in 5-HT and 5-HIAA in the DMM, the VLM, the raphe nuclei, the striatum and the frontal cortex. We propose that long-term hypoxia alters brain NPY-LI and indolamine content through the stimulation of CB chemoreceptors or ancillary chemoreceptors, as well as through local biochemical or morphological mechanisms.

Melatonin is an antioxidant. Since other antioxidants inhibit the production of tumor necrosis factor (TNF) induced by lipopolysaccharide, we investigated its effect on TNF production in vivo and in vitro and on lethality associated with endotoxic shock. Administration of melatonin to mice (5 mg/kg, s.c., 30 min before or simultaneously with lipopolysaccharide) inhibited serum TNF levels by 50-80% and improved survival of mice treated with a lethal dose of lipopolysaccharide. By studying other, structurally related, indolamines (N-acetyl-5-hydroxytryptamine, 5-methoxytryptamine and 5-hydroxytryptamine) we found a good correlation between antioxidant activity (for which the 5-methoxy group is essential) and the inhibition of TNF production in vivo and in vitro in mononuclear cells. Melatonin did not increase serum corticosterone and did not modify the elevation of serum corticosterone levels by lipopolysaccharide or by interleukin-1. Furthermore, it exerted its inhibitory effect in adrenalectomized or hypophysectomized mice also, indicating that its effect is independent of the hypothalamus-pituitary-adrenal axis.

An isocratic liquid chromatographic method with electrochemical detection for the determination of L-3,4-dihydroxyphenylalanine, dopamine, norepinephrine, epinephrine, serotonin, and their major metabolites, 3,4-dihydroxyphenylacetic acid, 4-hydroxy-3-methoxyphenylacetic acid and 5-hydroxyindole-3-acetic acid in chicken brain tissue is described. Chickens were killed at different ages, the brains were quickly frozen and 300-microm cryostat sections were made. From these sections, two to six tissue micropunches (1 mm in diameter) were punched out from 20 different areas of the hypothalamus and homogenated in 100 microl 0.1 M perchloric acid which included 0.01% cysteine as antioxidant. Fifty-microl supernatants were injected directly onto the LC system, separated on a 3-microm Phase II ODS column (100 x 3.2 mm I.D.) and detected by an electrochemical detector at a potential of +0.75 V. Standard curves, recoveries, analytical precision and detection limits were investigated for each monoamine neurotransmitter and its metabolites. The method was applied to study the influence of food restriction on the concentration of monoamine neurotransmitters in different brain areas, known to be involved in feeding and reproductive behaviour of female broiler chickens. Over 1000 micropunched tissue samples from ad libitum fed and food-restricted female broiler chickens were analyzed. Our results provide a possible role for catecholamines and indolamines in the altered feeding and reproductive behaviour of the broiler chicken.

In this study we investigated the effects of maternal Δ9-tetrahydrocannabinol on the developing serotonergic system. A daily dose of Δ9-tetrahydrocannabinol (5 mg/kg body weight) was administered p.o. to pregnant rats from gestational day 5 to postnatal day 1. Levels of indolamines were measured in four brain areas of the offspring on the day before or after birth. Levels of indolamines depended on the cerebral area, sex and pre- or postnatal age. Maternal exposure to Δ9-tetrahydrocannabinol decreased diencephalic levels of 5-hydroxytryptamine (5-HT), males being more susceptible than females. These perinatal changes could be responsible for the long-term neurophysiological alterations produced by cannabinoids.

The administration of purified cytokines to animals has been shown to cause a number of effects on the brain, including neuroendocrine effects, behavioral effects and alterations of brain biogenic amines. The best-documented effects are the activation by interleukin-1 (IL-1) of the hypothalamo-pituitary-adrenocortical (HPA) axis, and cerebral norepinephrine and indolamine metabolism. IL-6 and TNF alpha may also activate the HPA axis, and IL-6 activates cerebral indolamines. There are a few reports of other responses, but for proper evaluation it is important that studies be conducted using purified homologous cytokines, free of endotoxin contamination. The effects of the cytokines on the brain are believed to be a major mechanism by which infections and immune challenges signal the brain and activate endocrine and behavioral responses. The noradrenergic responses to IL-1 may be related to HPA activation, but the significance of the indolaminergic responses is unknown.

Amperometry has been used for real-time electrochemical detection of the quantal release of catecholamines and indolamines from secretory granules in chromaffin and mast cells. Using improved-sensitivity carbon fiber electrodes, we now report the detection of quantal catecholamine release at the surface of somas of neonatal superior cervical ganglion neurons that are studded with axon varicosities containing synaptic vesicles. Local application of a bath solution containing high K+ or black widow spider venom, each of which greatly enhances spontaneous quantal release of transmitter at synapses, evoked barrages of small-amplitude (2-20 pA), short-duration (0.5-2 ms) amperometric quantal "spikes". The median spike charge was calculated as 11.3 fC. This figure corresponds to 3.5 x 10(4) catecholamine molecules per quantum of release, or approximately 1% that evoked by the discharge of the contents of a chromaffin granule.

Parathion, an organophosphorous insecticide, was previously shown to enhance the nighttime rise in pineal N-acetyltransferase (NAT) activity and serum melatonin levels. The purpose of the present study was to test whether parathion acts on the pineal gland by means of a beta-adrenergic receptor mechanism. Whereas parathion (total dose 6.5 mg/kg body wt over 6 days) by itself significantly augmented nocturnal pineal NAT activity and serum melatonin levels in otherwise untreated rats, the insecticide was ineffective in reference to this enzyme when it was given in conjunction with the beta-adrenergic receptor antagonist propranolol (20 mg/kg body wt, 1 h before lights off). The augmentation of NAT activity by parathion also caused significant reductions in pineal serotonin (5-HT); again, this response was blocked by propranolol treatment. Neither pineal hydroxyindole-O-methyltransferase (HIOMT) activity nor pineal levels of 5-hydroxytryptophan or hydroxyindole acetic acid (5-HIAA) were significantly changed as a result of either parathion or propranolol treatment. The results are consistent with the idea that parathion influences pineal 5-HT metabolism either at the level of the beta-adrenergic receptor or via the sympathetic innervation to the pineal gland.

In vivo microdialysis was used to measure changes in extracellular concentrations of catecholamines and indolamines in freely moving rats in response to administration of endotoxin (lipopolysaccharide, LPS). Dialysis probes were placed stereotaxically in either the medial hypothalamus or the medial prefrontal cortex. We used a repeated-measures design in which each rat received LPS or saline, and each subject was retested with the other treatment one week later. With the dialysis probes in the medial hypothalamus, intraperitoneal (ip) administration of LPS (5 micrograms) increased dialysate concentrations of norepinephrine (NE, 187%), dopamine (DA, 119%), and all their measured catabolites, except normetanephrine. Dialysate concentrations of NE and DA were elevated significantly in the fourth or fifth (20 min) collection period with a peak response at around 2 hr. They returned to baseline by about 4 hr. When the dialysis probes were placed in the medial prefrontal cortex, the same dose of LPS also elevated dialysate concentrations of NE and DA, but the increases were much smaller (ca. 20%). However, a dose of 100 micrograms LPS increased dialysate concentrations of NE and DA from the medial prefrontal cortex to an extent comparable to that of the 5 micrograms dose in the hypothalamus, and the response was more prolonged. Dialysate concentrations of serotonin could not be measured reliably, but those of its catabolite, 5-hydroxyindoleacetic acid (5-HIAA), were also elevated in both regions. The peak of 5-HIAA occurred at around 4 hr. Pretreatment of the rats with indomethacin (10 mg/kg ip) completely prevented the changes due to 100 micrograms LPS in the medial prefrontal cortex.(ABSTRACT TRUNCATED AT 250 WORDS)

Aromatic L-amino acid decarboxylase (AADC) is involved in the biosynthesis of catecholamines and indolamines. AADC is present in the nervous system, in the chromaffin cells, and in non-neuronal tissues. We tested the capacity of a new polyclonal antibody, obtained by immunization of rabbits with a recombinant protein β-galactosidase-AADC, to detect monoaminergic neurons in the brainstem as well as monoaminergic paraneurons in the adrenal medulla from goldfish, frog, skink, quail, and mouse. In the adrenal gland we found an immunoreactivity that was consistent with the distributions of the chromaffin cells previously reported. In the brainstem, groups of immunoreactive neurons and several labelled fibers were observed in the five species studied. The raphe region showed cell bodies and processes similar to those previously identified as monoaminergic by other authors. In addition, in medulla oblongata and isthmic tegmentum we found, in goldfish, skink, and quail, neuronal groups similar to mammalian D groups which contain AADC but are devoided of serotonin and catecholamines.

1. Indolamines were assayed by HPLC-ECD in nervous tissue of fed and crowded young males Blaberus craniifer Burm. 2. In males, as in females housed in the same conditions, levels are depending on both age and region (= ganglia) of the central nervous system. 3. Registered sex differences are discussed in terms of anatomical, physiological and behavioral sexual dimorphism.

1. The effects of 5-hydroxytryptamine, 5-hydroxyindoleacetic acid and N -acetyl-5-hydroxytryptamine on oocytes of Blaberus craniifer , in which vitellogenesis was prevented by imaginal molt decapitation, were investigated. 2. Sites binding anti-egg-protein antibodies were detected in the periphery of basal oocytes of treated females, with individual variability. 3. In this ovoviviparous cockroach, the onset of vitellogenesis may thus not be triggered solely by juvenile hormone, and indolamines may play a role in the uptake of haemolymphatic proteins by oocytes.

The aim of the present investigation was to look for the mechanisms causing disturbances in carbohydrate metabolism during the action of the epileptogenic agent methionine sulfoximine The levels of glucose, glycogen, and indolamines were measured in seven different regions of rat brain. Methionine sulfoximine induced a decrease in serotonin level which was roughly dose-dependent. There were no obvious, changes in tryptophan and 5-hydroxyindoleacetic levels in any area. Methionine sulfoximine induced the known increase in glucose and glycogen levels. The direct precursor of serotonin, 5-hydroxytryptophan, and benserazide (a decarboxylase inhibitor) were then injected into rats in association with methionine sulfoximine. In this case, methionine sulfoximine failed to induce seizures. Moreover, the serotonin level was unchanged and the carbohydrate content did not significantly increase. There was only a rise in 5-hydroxyindoleacetic acid level. This work shows a striking parallelism between serotonin decrease and glycogen increase.

Drosophila melanogaster homogenates incubated with tritiated 5-hydroxytryptophan, 5-hydroxytryptamine, or N-acetylserotonin have the ability of converting them into labelled indolamines, including melatonin. All these compounds were characterized by two-dimensional thin-layer chromatography by comparison with nonradiolabelled standards, and melatonin by mass spectrometry and radioimmunoassay. On the other hand, the injection of pharmacological doses of melatonin into 2-day-old female flies diminishes the mating speed and the oviposition rate.

The pineal complex of the three-spined stickleback (Gasterosteus aculeatus L.) was investigated by light and electron microscopy, as well as fluorescence histochemistry for demonstration of catecholamines and indolamines. The pineal complex of the stickleback consists of a pineal organ and a small parapineal organ situated on the left side of the pineal stalk. The pineal organ, including the entire stalk, is comprised mainly of ependymal-type interstitial cells and photoreceptor cells with well-developed outer segments. Both unmyelinated and myelinated nerve fibres are present in the pineal organ. Nerve tracts from the stalk enter the habenular and posterior commissures. A small bundle of nerve fibres connects the parapineal organ and the left habenular body. The presence of indolamines (5-HTP, 5-HT) was demonstrated in cell bodies of both the pineal body and the pineal stalk, and catecholaminergic nerve fibres surround the pineal complex.

Chlordimeform is a relatively new acaricide/insecticide, whose mode of action we have investigated. It appears to interfere with amine-mediated control of nervous and endocrine systems in a variety of ways. Specifically, chlordimeform causes a build-up of the amines 5-hydroxytryptamine and to a lesser extent norepinephrine in the rat brain in vivo, antagonizes the in vivo action of reserpine in the rat (reserpine depletes amine stores in the CNS), inhibits monoamine oxidase from rat liver in vitro, and causes hypotension in rabbits. In the American cockroach it directly stimulates the heart in situ, acts synergistically with tryptamine in vivo, inhibits amine-N-acetyltransferase from cockroach head in vitro, causes accumulation of indolamines in cockroaches in vivo, and blocks the stimulation of adenylate cyclase by octopamine in the cockroach CNS in situ. It also inhibits tryptamine metabolism in whole mites in vitro. Images FIGURE 3. FIGURE 4. A FIGURE 4. B FIGURE 4. C FIGURE 4. D

Dense bodies containing high amounts of chrome were localized in the perikarya of substantia nigra and dorsal raphe neurons following the cytochemical reaction of endogenous dopamine and serotonin (respectively) with glutaraldehyde-dichromate (GDC). Energy dispersive X-ray analysis of these bodies revealed chrome levels two to four times higher than those recorded from the cytoplasmic background. Pretreatment with paraformaldehyde blocked the GDC reaction within the dense bodies in the substantia nigra (chrome levels similar to background), while the chrome levels in the dense bodies of the raphe neurons remained elevated. This demonstrates that pretreatment with paraformaldehyde allows selective localization of central nervous system serotonin stores by the GDC technique.

Temporal changes in monoaminergic activity in the locus coeruleus (LC) in response to hemorrhage of 10 or 20% of blood volume were assessed using normal pulse voltammetry in alpha-chloralose-urethan-anesthetized cats. Oxidation current was measured with a carbon microelectrode, and changes at 230 and 450 mV were used as estimates of catecholaminergic and indolaminergic activity, respectively. Plasma adrenocorticotropin (ACTH) was measured by radioimmunoassay. Hemorrhage of 20% blood volume caused a transient increase in the catecholaminergic activity in a compact area in the ventral LC (vLC) that preceded increases in the plasma ACTH. The increase in oxidation current at 450 mV was similar to that at 230 mV, suggesting no significant contribution from indolamines. Dorsal rostral pontine sites outside this area exhibited either sustained decreases in oxidation current or no change in response to hemorrhage. The proportion of sites that exhibited transient increases in oxidation current in the vLC after the 10% blood loss was less than that after the 20% blood loss, suggesting that this response was dependent on the magnitude of hemorrhage. Since the LC was implicated previously in the control of ACTH release, we suggest that hemodynamic signals traversing the LC activate catecholaminergic mechanisms that, in turn, participate in the regulation of ACTH release after hemorrhage.

Kynuramines occur endogenously in brain and peripheral tissues as metabolites of indoleamino acids and indolamines but little is known regarding their possible physiological and/or pharmacological activity. The present study has investigated the effects of kynuramine and 5-hydroxykynuramine on the cardiovascular system of pithed rats and attempted to correlate effects seen on adrenergic and serotonergic receptors with ligand binding experiments done in vitro using rat brain membranes. Kynuramine was found to release cardiac catecholamines and to act as a weak partial agonist on vascular alpha-adrenoceptors. Hydroxylation in the 5-position (5-hydroxykynuramine) did not alter cardiac potency but increased pressor activity 100-fold. Vasopressor responses to 5-hydroxykynuramine were mediated via a dual agonistic action on both postsynaptic alpha 2-adrenoceptors and vascular serotonin2 receptors. These findings were supported by ligand binding studies, in which both kynuramine and 5-hydroxykynuramine showed affinity for cortical [3H]spiroperidol and [3H]clonidine binding sites. Overall, the results show that kynuramines can exert peripheral (and possibly central) actions which may prove to be of physiological and/or pharmacological significance.

The effect of indolamine derivatives on beta-endorphin (beta-end) release has been studied in vitro using rat anterior pituitary cells. Incubation of primary cultures for 2 h with 100 nmol/l of melatonin, serotonin or 5-methoxytryptamine significantly increased the beta-end release in response to 20 nmol/l of ovine corticotropin-releasing factor (oCRF). Incubation of the cultures with 100 nmol/l of L-tryptophan, 5-hydroxy-L-tryptophan, 5-hydroxytryptophol or 5-methoxytryptophol had no effect on basal or CRF-induced beta-end release. The effect of serotonin and melatonin was further tested in a superfusion system of dispersed rat anterior pituitary cells. Superfusion with oCRF (200 nmol/l) for 4 min elicited an immediate rapid increase in beta-end release which lasted 30-40 min. Simultaneous superfusion with melatonin (1 mumol/l) or serotonin (1 mumol/l) significantly increased the effect of oCRF pulses on beta-end release. We conclude that melatonin and serotonin are able to act directly on anterior pituitary cells to potentiate the effect of oCRF on beta-end release.

The present modification of the formaldehyde condensation method for demonstrating catecholamines and indolamines involves generation of the formaldehyde gas at + 80°C followed by reaction at +25 or 0°C. This procedure results in improved sensitivity for demonstrating noradrenaline and dopamine. Because adrenaline and peptides with NH2-terminal tryptophan give no or very weak fluorescence under these reaction conditions the modification also offers possibilities for improved discrimination between primary catecholamines on one hand and adrenaline and tryptophyl peptides on the other. Under the conditions used, the fluorescence yield of 5-hydroxytryptamine did not seem to be improved by variations in the reaction temperature.

N-acetylated and tertiary indolamines, some of which are possible neurotransmitter candidates in the CNS, cannot be visualized with the standard Falck-Hillarp histofluorescence method and very little is known about their cellular localization. The present investigation demonstrates that glyoxylic acid (GA), formaldehyde (FA) in combination with aluminum ions (the ALFA method) and trifluoroacetic acid anhydride (TFAA) are capable of forming fluorescent compounds from N-acetylated (e.g. melatonin and N-acetyl-5-hydroxytryptamine) and tertiary (e.g. bufotenin) indolamines in histochemical protein models. With GA and FA-aluminum more vigorous reaction conditions were required for demonstration of these compounds compared to those needed for optimal visualization of primary catecholand indolamines (prolonged reaction time and higher concentration of GA and FA and aluminum ions). The fluorophore formation from N-acetylated and tertiary indolamines, which represents a new reaction principle in amine fluorescence histochemistry, is proposed to proceed as follows. In the first step, the indole reacts in 2-position with the reagent. The intermediate formed is dehydrated in the second step, yielding a strongly fluorescent 2-methylene derivative, which either per se or as the corresponding autoxidized dimer constitutes the main fluorophore. TFAA and related anhydrides represent new and potent reagents for histochemical visualization of N-acetylated indolamines such as melatonin. In contrast to the GA and ALFA reactions the optimal formation of fluorphores with TFAA required only mild reaction conditions (2–10 min at 0–20° C). The main fluorophore formed from melatonin has been identified and the reaction with TFAA is proposed to proceed as follows. An unstable intermediate, the isoimidinium carboxylate, is formed in the first step and this compound is then cyclized to form the fluorophore, 6-methoxy-1-methyl-3,4-dihydro-β-carboline. The GA and ALFA methods are already widely used for visualization of catecholamine systems. The fluorescence microscopical and microspectrofluorometric analysis did not, however, veveal any specific structures containing N-acetylated or tertiary indolamines in the rat CNS. The TFAA reaction was highly specific for N-acetylated indolamines when applied to protein models. However, in tissue a disturbing background fluorescence appeared, which under all reaction conditions tested, developed concomitantly with the specific fluorescence from melatonin. The problem with this background reaction has to be solved before the TFAA reaction can be applied for demonstration of N-acetylated indolamines in tissue.

The rhythmical activity of the liver fluke, Fasciola hepatica, was stimulated by 5-hydroxytryptamine and by lysergic acid diethylamide at very low concentrations. The effect was peripheral and was not mediated through the central ganglion. Other amines also stimulated rhythmical activity, the most potent being the indolamines. Bromolysergic acid diethylamide, and other analogues such as yohimbine, harmine, and dopamine depressed rhythmical movement and antagonized the stimulant action of 5-hydroxytryptamine and lysergic acid diethylamide. Evidence which suggests the presence of tryptamine receptors in the trematode is discussed.

Adult Syrian hamsters were given a subcutaneous injection of reserpine 3 days before an intraperitoneal injection of 3H-3,4 dihydroxyphenylalanine or 3H-5, hydroxytryptophan and the carotid bodies were subsequently prepared for electron microscopic radioautography. Other Syrian hamsters were given a subcutaneous injection of reserpine and the carotid bodies were subjected to a sensitive cytochemical test for the detection of unsubstituted amines. These studies were made to determine whether the labeled amine precursors were incorporated into the cells and to see whether the parenchymal cells were affected by reserpine treatment. Material from hamsters treated first with reserpine and subsequently injected with 3H-3,4 dihydroxyphenylalanine or 3H-5, hydroxytryptophan exhibited reduced grains of silver over the cells which were associated mainly with the dense cores of the cytoplasmic granules. These studies offer evidence that the granules of the carotid body incorporate catecholamine and indolamine precursors. Material from hamsters incubated for the presence of unsubstituted amines gave a positive reaction (opaque cytoplasmic granules) for catecholamines but not for indolamines. The latter substances may not be present in quantities sufficient to register a positive reaction in the cytochemical test. The opaque granules, indicative of the presence of catecholamines, decreased in density after reserpine treatment. 5 days after one reserpine injection the granules had regained opacity and were comparable to those seen in the control cells.

1. Neurons from rat superior cervical ganglia were grown in coculture with pineal cells. Action potentials of neurons in cocultures were 25% longer and were 25% greater in amplitude than those recorded from neurons grown in the presence of ganglionic nonneuronal cells alone. 2. Neurons showed an increase in action potential duration with increasing time in culture. This may have been related to the recovery of nonneuronal cell populations after an initial exposure to the antimitotic agent Ara-C. In cultures not initially exposed to Ara-C, a subsequent exposure after 7 days in culture resulted in a shortening of the action-potential duration. 3. Neuronal cultures were exposed to gel slabs containing the pineal indolamines, serotonin,N-acetylserotonin, and melatonin. Serotonin andN-acetylserotonin showed no effect on the neuronal action potentials at the concentrations tested. 4. Melatonin caused an increase in action-potential duration that was associated not with an increase in action-potential amplitude, but with a decrease in actionpotential rise rates. The effects of long-term exposure in melatonin appeared to be reversible in some cells but not in all. 5. Short-term effects of melatonin were observed in older cultures and in younger cultures after the cells were stimulated repeatedly. Older cultures also had higher levels of spontaneous activity. The dependence of the short-term effects of melatonin on electrical activity may suggest a role for melatonin as a neuromodulator.

Desoxyfructo-serotonin oxalate and free base produced a decrease of the blood pressure and heart rate of vagotomized cats (in total doses of 100 mg, i.v.) for 30 and 120 min. respectively, with total blocking of the carotid occlusion pressor response. With desoxyfructo-5-methoxytryptamine the decrease in the blood pressure lasts only 1 minute, followed by a 30 min. moderate increase. With this compound the C.O. pressor response is not blocked. On anaesthetized dogs with opened thorax low doses of the drug (100–200 μg/kg i.v.) produced a similar decrease of the blood pressure and heart rate, however, only for a short time (3 min.). An important increase in the sinusal coronary flow and partial oxygen pressure was also observed. Oral administration of desoxyfructo-serotonin oxalate (50 mg/kg) reduced to 40% the gastric ulcer formation by restraint in rats. With the same compound (100 mg/kg i.p. daily per 4 days) a very significant “anti-stress” activity was observed on mice by increased swimming endurance, Rota-Rod test performance, anti-ulcer effect and by elimination of milk induced leucocytosis.