Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the effect of electroconvulsive shock (ECS), administered five times over 10 days, on 5-HT1A and 5-HT2A receptor mRNA and binding site densities in the rat brain using in situ hybridization histochemistry and quantitative autoradiography. ECS treatment increased 5-HT1A receptor mRNA abundance and binding site densities in the dentate gyrus, but decreased these parameters in the CA3c layer of the hippocampus. No changes in 5-HT1A receptor mRNA and binding sites occurred in other hippocampal subfields, neocortex or raphe nuclei. Repeated ECS was also found to increase 5-HT2A receptor binding site densities in the neocortex and this was accompanied by a non-significant increase in cortical 5-HT2A receptor mRNA abundance. Our study demonstrates that in the rat, repeated ECS produces anatomically and molecularly discrete effects on 5-HT1A and 5-HT2A receptor gene expression. These changes may be relevant to the therapeutic effect of repeated ECS in depression.
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PMID:Repeated ECS differentially affects rat brain 5-HT1A and 5-HT2A receptor expression. 761 79

Although many serotonin (5-hydroxytryptamine; 5-HT) receptors have been identified, our knowledge of many of the subtypes is limited. However, we do know that 5-HT1A agonists are involved in the treatment of certain anxiety disorders, that 5-HT1C and 5-HT2 receptor antagonists may be indicated for the treatment of generalized anxiety disorder, and that 5-HT1D receptor agonists are used in the treatment of migraine. Recent research has identified that various abnormalities in serotonergic function are involved in the pathogenesis of depression and anxiety, and has facilitated the development of new pharmacological agents with great therapeutic potential, for example the selective serotonin reuptake inhibitors (SSRIs). These agents appear to be effective in the treatment of many anxiety states and may have greater efficacy than other agents in the treatment of certain affective disorders. As the central serotonergic system continues to be "mapped", newer and more selective drugs are likely to be introduced, thereby possibly improving the overall successful management of depression and anxiety disorders.
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PMID:The role of serotonin in depression and anxiety. 762 23

On the basis of a previous report suggesting the effectiveness of the beta-adrenoceptor/5-HT1A antagonist pindolol to accelerate the antidepressant effect of a selective serotonin reuptake inhibitor (SSRI) and to produce a therapeutic effect in drug-resistant depressed patients, these open studies were undertaken to further explore the safety and efficacy of this strategy. In a first study, nine untreated unipolar depressed patients were given the SSRI paroxetine (20 mg/day) together with pindolol (2.5 mg thrice daily). One patient stopped taking pindolol because of increased irritability after 3 days. One week later, seven patients had their Hamilton Rating Scale for Depression Score decreased by more than 50%. In a second study, 19 drug-resistant unipolar depressed patients (9 on paroxetine, 5 on sertraline, 3 on fluoxetine, and 2 on moclobemide) were also given pindolol at the same regimen and were assessed weekly. Two patients (one on sertraline, one on moclobemide) stopped taking pindolol also because of increased irritability after 2 and 3 days, respectively. After 1 week of pindolol addition, 10 patients had a more than 50% decrease of their depression score. By day 14, all of the patients had a score of 10 or less, with the exception of those on sertraline. Improvement was maintained in all patients for at least 28 days on this combination. The results of these studies indicate that pindolol is safe when used in combination with an SSRI or moclobemide. Given the positive results obtained in this second open trial in 28 patients, this treatment strategy should be tested under double-blind conditions to establish its efficacy.
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PMID:Effectiveness of pindolol with selected antidepressant drugs in the treatment of major depression. 878 61

Nefazodone is a new antidepressant drug with a pharmacologic profile distinct from that of the tricyclic, monoamine oxidase inhibitor, and serotonin selective reuptake inhibitor antidepressants. Nefazodone was initially discovered for its ability to block 5-HT2A receptors and its reduced potency as an alpha 1-adrenergic blocker. It was later shown to inhibit both serotonin and norepinephrine uptake in vitro, attributes which most likely impart its clinical efficacy and which differentiate nefazodone from its chemical predecessor trazodone. The combination of these two mechanisms may ultimately result in a facilitation of 5-HT1A-mediated neurotransmission, which may be beneficial for treating symptoms of depression as evidenced by recent clinical findings. In addition, the preclinical profile of nefazodone demonstrates that it has decreased anticholinergic and antihistaminic activity relative to traditional agents. Clinical findings to date are consistent with these observations.
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PMID:Pharmacology and neurochemistry of nefazodone, a novel antidepressant drug. 1081 10

Variations in serotonin neurotransmission influence alcohol consumption (AC). Levels of 5-HT and metabolites are low in some brain regions of alcohol preferring rats and in CSF of alcoholics. Pharmacological treatments which enhance serotonergic neurotransmission (uptake inhibitors, releasers, agonists) consistently reduce AC in rats. Serotonin uptake inhibitors (SUI; e.g., citalopram, fluoxetine) have been studied extensively in humans. In several double-blind randomized, placebo-controlled clinical trials, SUI have consistently decreased AC by averages of 15% to 20% in nondepressed mildly/moderately dependent alcoholics who received no other treatment. Effects were dose-dependent and not related to side effects (few and mild) or changes in anxiety or depression (not observed). SUI also decreased desire to drink and liking for alcohol, thus suggesting a mechanism for effects. Other drugs acting on the 5-HT system have been tested in humans, but results are difficult to interpret. For example, buspirone, a 5-HT1A receptor partial agonist, reduced anxiety and alcohol craving, but not AC; a 5-HT partial agonist, m-CPP, increased alcohol craving in abstinent alcoholics; modest reductions in AC were observed with a 5-HT3 antagonist, ondansetron (0.5 mg/day, but not 4 mg/day). The therapeutic potentials of these medications are being studied. For example, SUI effects on AC were enhanced by a brief psychosocial intervention. Since SUI decrease urge to drink, they may be suitable pharmacological adjuncts in relapse prevention strategies. SUI and other serotonin-altering medications are promising new neuropharmacological treatments for reducing AC.
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PMID:Clinical pharmacology of serotonin-altering medications for decreasing alcohol consumption. 774 4

Male rats housed in mixed-sex groups quickly established dominance hierarchies in which subordinates appeared severely stressed. Subordinate rats had elevated basal corticosterone (CORT) levels relative to dominants and individually housed controls. Several subordinates had blunted CORT responses to a novel stressor, leading to the classification of subordinates as either stress-responsive or nonresponsive. Binding to 5-HT1A receptors was reduced in stress-responsive subordinates compared to controls throughout hippocampus and dentate gyrus. Decreased binding was observed in nonresponsive subordinates only in CA3 of hippocampus. In addition, 5-HT1A binding was decreased in CA1, CA3, and CA4 in dominants compared to controls. Binding to 5-HT2 receptors was increased in parietal cortex in both responsive and nonresponsive subordinates compared to controls. No changes were observed in binding to 5-HT1B receptors. These results are discussed in the context of regulation of the serotonergic system by stress and glucocorticoids and possible relevance to the pathophysiology of depression.
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PMID:Serotonin receptor binding in a colony model of chronic social stress. 777 47

The hypothesis that a dysfunction of serotonergic neurotransmission is implicated in depression is supported by the clinical efficiency of selective serotonin (5-hydroxytryptamine, 5-HT) reuptake inhibitors (SSRIs) in the treatment of depressive disorders. These drugs, such as fluoxetine and paroxetine, exert their antidepressant activity by increasing 5-HT concentration in the synaptic cleft and thus enhancing serotonergic neurotransmission. However, two to three weeks of treatment are necessary to see the first signs of clinical efficiency. Several hypothetical mechanisms have been put forward to account for this delay, taking into account pharmacokinetic considerations, neurotransmitter metabolism, and/or adaptive regulation of pre and/or post-synaptic receptors. The aim of this study was to look for such adaptive changes in the course of a 3-week treatment with fluoxetine (5 mg/kg/day, i.p.) or paroxetine (5 mg/kg/day, i.p.) in adult rats. In vitro binding and quantitative autoradiographic studies showed that neither 5-HT1A, 5-HT1B, 5-HT2A, nor 5-HT3 receptor binding sites in various brain areas were affected by these treatments. Furthermore, comparison of the specific binding of [3H]8-OH-DPAT to 5-HT1A receptors functionally coupled to G proteins with that of [3H]WAY 100635 to all 5-HT1A receptor binding sites (i.e. coupled and uncoupled with regard to G proteins) revealed no significant change in rats treated with either SSRI. Accordingly, the proportion of functional 5-HT1A receptors (i.e. those physically coupled to G proteins) appeared to remain unaltered all along a 3-week treatment with either fluoxetine or paroxetine. Nevertheless, in vitro electrophysiological recordings of serotonergic neurons in the dorsal raphe nucleus allowed the demonstration of a clearcut functional desensitization of somatodendritic 5-HT1A autoreceptors. Thus, the potency of the 5-HT1A autoreceptor agonist, 8-OH-DPAT, to depress the firing of serotonergic neurons in brain stem slices was significantly reduced as soon as after a 3-day treatment with either SSRI. The proportion of recorded neurons showing desensitization of somatodendritic 5-HT1A autoreceptors then increased along the treatment, and was generally larger with fluoxetine than with paroxetine. As 5-HT1A autoreceptor desensitization can contribute to facilitate serotoninergic neurotransmission, the remarkable efficiency of fluoxetine to trigger this adaptive regulatory mechanism might account, at least partly, for its potent antidepressant activity.
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PMID:[Central serotonin receptors and chronic treatment with selective serotonin reuptake inhibitors in the rat: comparative effects of fluoxetine and paroxetine]. 778 83

Serotonergic neurotransmission represents a complex mechanism involving pre- and post-synaptic events and distinct 5-HT receptor subtypes. Serotonin (5-HT) receptors have been classified into several categories, and they are termed as 5-HT1, 5-HT2, 5-HT3, 5-HT4, 5-HT5, 5-HT6 and 5-HT7 type receptors. 5-HT1 receptors have been further subdivided into 5-HT1A, 5-HT1B, 5-HT1D, 5-HT1E and 5-HT1F. 5-HT2 receptors have been divided into 5-HT2A, 5-HT2B and 5-HT2C receptors. All 5-HT2 receptor subtypes are linked to the multifunctional phosphoinositide (PI) signalling system. 5-HT3 receptors are considered ion-gated receptors and are also linked to the PI signalling system by an unknown mechanism. The 5-HT2A receptor subtype is the most widely studied of the 5-HT receptors in psychiatric disorders (for example, suicide, depression and schizophrenia) as well as in relation to the mechanism of action of antidepressant drugs. The roles of 5-HT2C and 5-HT3 receptors in psychiatric disorders are less clear. These 5-HT receptors also play an important role in alcoholism. It has been shown that 5-HT2A, 5-HT2C and 5-HT3 antagonists cause attenuation of alcohol intake in animals and humans. However, the exact mechanisms are unknown. The recent cloning of the cDNAs for 5-HT2A, 5-HT2C and 5-HT3 receptors provides the opportunity to explore the molecular mechanisms responsible for the alterations in these receptors during illness as well as pharmacotherapy. This review article will focus on the current research into the pharmacological properties, molecular biology, and clinical correlates of 5-HT2A, 5-HT2C and 5-HT3 receptors.
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PMID:Phosphoinositide system-linked serotonin receptor subtypes and their pharmacological properties and clinical correlates. 778 83

This is a report of a controlled trial of gepirone, a 5-hydroxytryptamine (5-HT1A) partial agonist azapirone related to buspirone, in the treatment of atypical depression. The azapirones are of particular interest because their highly selective actions on the serotonergic system may possibly make them useful pharmacologic probes and potentially selective therapeutic agents. Sixty outpatients meeting Columbia criteria for definite or probable atypical depression were enrolled in a double-blind, randomized, placebo-controlled, 8-week clinical trial at a single site. The dosage schedule was fixed flexible, with 10-mg capsules given on a thrice-daily schedule, with doses of up to 120 mg daily. The response rate at 8 weeks for the intention-to-treat sample analyzed with the last observation carried forward was 62% (18 of 29 patients) for gepirone and 20% (6 of 30 patients) for placebo (chi 2 = 9.1; df = 1; p < 0.001). Robust and consistent drug-placebo differences are seen across virtually all rating scales post-treatment. The effect of gepirone was consistent across the levels of concomitant variables, including duration of episode and presence of dysthymia or panic. Gepirone is a novel antidepressant that holds promise for the treatment of atypical depression and that may be of heuristic value because of its relatively specific actions on the serotonergic system.
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PMID:Gepirone treatment of atypical depression: preliminary evidence of serotonergic involvement. 780 92

This study deals with the characterization of 5-hydroxytryptamine (5-HT, serotonin) receptors positively linked to adenylyl cyclase in membranes from pig brain caudate. 5-HT and related agonists induced a concentration-dependent stimulation of adenylyl cyclase activity in pig caudate membranes, with the following rank order of potency (mean pEC50 values): 5-HT (7.1) > or = 5-methoxytryptamine (6.9) > 5-carboxamidotryptamine (5.6) > sumatriptan (< 5). Maximal stimulation by 5-HT averaged 35 pmol cyclic AMP/min/mg protein over a basal activity of 159 pmol cyclic AMP/min/mg protein. 5-Methoxytryptamine and 5-carboxamidotryptamine had similar efficacies to that of 5-HT, whereas sumatriptan was about half efficacious. Other compounds known as agonists at some 5-HT receptors were weakly potent (mean pEC50 values < 5). They include the 5-HT1A receptor agonist, 8-hydroxy-2-(di-n-propylamino)tetralin hydrobromide (8-OH-DPAT), the 5-HT4 receptor agonist, renzapride and the 5-HT2 receptor agonist, (1-(2,5-dimethoxy-4-iodophenyl)-2 aminopropane) (DOI). In antagonist studies, methiothepin (0.1 and 1 mumol/l) shifted the 5-HT curve to the right with no depression of the Emax, yielding pKB values of 7.4-8.0. Clozapine (1 mumol/l) also produced surmountable antagonism of 5-HT-induced effects (pKB 6.9). Ketanserin (10 mumol/l) weakly antagonized 5-HT (pKB 5.0). The 5-HT4 receptor antagonists, tropisetron (ICS 205-930) and SDZ 205-557 (2-methoxy-4-amino-5-chloro-benzoic acid 2-(diethylamino) ethyl ester), each at 1 mumol/l, did not significantly alter the concentration-response curve of 5-HT.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:5-Hydroxytryptamine receptors with a 5-HT6 receptor-like profile stimulating adenylyl cyclase activity in pig caudate membranes. 784 73


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