Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

5-HT3 receptors have an exclusive neuronal location and evidence is presented of their involvement in behaviour. 5-HT3 receptor antagonists such as ondansetron, tropisetron and zacopride have provided the critical pharmacological tools to reveal a potent and efficacious ability to regulate disturbed behaviour. Thus the 5-HT3 receptor antagonists will restore to normal rodent and primate behaviour disturbed by increasing limbic dopamine function, aversive situations, cognitive impairments and drug abuse. The remarkable feature of their action is a failure to modify normal behaviour. This unique pharmacological signature has ensured a wide interest in the potential role of the 5-HT3 receptor antagonists in the treatment of schizophrenia, anxiety, age related memory impairment and the problems of withdrawal from drugs of abuse. The preclinical data and preliminary clinical observations are presented.
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PMID:Astra Award Lecture. The psychopharmacology of 5-HT3 receptors. 136 67

Ondansetron hydrochloride dihydrate is a 5-hydroxytryptamine (5-HT3) antagonist that was recently approved by the Food and Drug Administration for the treatment of chemotherapy-induced emesis. The mechanism of action is thought to be due to competitive inhibition of specific serotonin receptors in the central nervous system and gastrointestinal tract. In clinical trials with cisplatin-induced emesis, ondansetron resulted in complete control of vomiting (0-2 episodes) in 55-87% of patients during the first 24 hours of chemotherapy administration. It was significantly more effective than metoclopramide in comparative trials. Ondansetron is also being investigated for the treatment of radiation- and anesthesia-associated nausea and vomiting. Studies in animals demonstrate potential efficacy in the treatment of anxiety, drug withdrawal, and schizophrenia. The drug is generally well tolerated, with no reported extrapyramidal reactions.
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PMID:Parenteral ondansetron for the treatment of chemotherapy- and radiation-induced nausea and vomiting. 153 80

Evidence is reviewed that 5-HT (5-hydroxytryptamine, serotonin) acting through the 5-HT3 receptor subtype can influence behaviour relevant to anxiety, schizophrenia and cognitive disorders, and that 5-HT3 receptor antagonists such as ondansetron (CAS 116002-70-1) can correct behavioural disturbance in the absence of effect on normal behaviour. The 5-HT3 receptor antagonists exert a breadth of action over a wide dose range in rodent and primate models to inhibit aversive behaviour in animal models of anxiety and certain symptoms of withdrawal from drugs of abuse, alcohol, nicotine, diazepam and cocaine, to antagonise increased locomotor activity caused by mesolimbic dopamine excess, and facilitate performance in cognitive tests. The studies reveal an important role for 5-HT3 receptors in the regulation of limbic-cortical functioning, and a critical role for 5-HT3 receptor antagonists to establish the role of 5-HT3 receptors in schizophrenia, anxiety, drug withdrawal phenomena and cognitive disturbance. Preliminary clinical trials indicate a positive effect of ondansetron in anxiety, schizophrenia, alcohol withdrawal and age associated memory impairment.
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PMID:Serotonin and psychiatric disorders. A key to new therapeutic approaches. 158 95

Thirty-three years ago, Gaddum and Picarelli classified the serotonin receptors in the guinea pig ileum into D and M types based on the activity of dibenzyline and morphine to block contractions of intestinal smooth muscle caused by serotonin. The subsequent location of specific ligand binding sites for serotonin in the brain has led to the identification of at least eight serotonin receptor sub-types in rat brain. While there is some controversy over the functional importance of many of these receptor sub-types, there is evidence that they fall into two major groups according to the nature of their coupling to secondary messengers or ion channels. Thus the 5-HT1 and 5-HT2 receptors appear to occupy the G protein receptor sub-family which may be coupled either to adenylate cyclase (most 5-HT1 sub-types) or phosphatidyl inositol (5-HT2 sub-types). The central "M" receptors (now termed 5-HT3) appear to occupy a ligand gated ion channel super-family. The cloning of three of the serotonin receptor sub-types in 1989 (5-HT1A, 5-HT1C and 5-HT2) has been of importance in enabling the receptor sub-types to be classified as specific protein molecules encoded by specific genes. The problem now arises with regard to the linking of the changes in the cellular activity of the various receptor sub-types with the plethora of behavioural changes that arise as a consequence of the actions of serotonin in the brain. The present review summarizes the evidence implicating the role of specific serotonin receptor sub-types in eating disorders, sleep, sexual activity, anxiety states, aggression, schizophrenia and depression. A summary of the relationship between these receptor sub-types and their possible involvement in the aetiology of these diseases is shown in Table 2.
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PMID:Sub-types of serotonin receptors: biochemical changes and pharmacological consequences. 162 53

Several developments in serotonin neuropharmacology have implications for psychiatric disorders and have already begun to impact their treatment. Selective inhibitors of serotonin uptake, which enhance serotonergic function by preventing the removal of serotonin from the synaptic cleft via the membrane transporter, have been introduced for the treatment of depression and may be effective in other disorders. Precursor loading can increase serotonin concentrations in the synaptic cleft, and tryptophan--which has been available in health food stores and drug stores--had become increasingly used for self-medication of depression, insomnia, and premenstrual syndrome. Conversion to serotonin is not the major metabolic pathway for tryptophan, and large increases in other tryptophan metabolites (such as quinolinic acid, a substance that is excitotoxic at high concentrations) accompany small increases in extracellular serotonin. The recent epidemic of the eosinophilia-myalgia syndrome associated with tryptophan now appears due to a trace contaminant in the product from a single manufacturer. A major advance in serotonin pharmacology has been the elucidation of serotonin receptor heterogeneity. At least seven receptor subtypes (5-HT1A, 5-HT1B, 5-HT1C, 5-HT1D, 5-HT2, 5-HT3, 5-HT4) have been identified in brain. Direct-acting agonists and antagonists can have selective affinity for specific receptor subtypes. Selective activation of 5-HT1A receptors seems to cause anxiolytic and possibly antidepressive effects. Selective antagonists of 5-HT2 or 5-HT3 receptors may be useful in treating anxiety and schizophrenia. Drugs that enhance serotonergic function suppress aggression in animals, but the specific receptor subtypes involved are not known. The advances being made in serotonin pharmacology will help define the role of this brain neurotransmitter in psychiatric and other disorders and can be expected to lead to further therapeutic advances.
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PMID:Role of serotonin in therapy of depression and related disorders. 167 51

Ligands of various chemical classes (e.g., indoles, indazoles, benzamides, carbazoles, and quinolines) have demonstrated high affinity for the 5-HT3 receptor in radiolabeled ligand-binding studies, and have shown 5-HT3 receptor antagonistic activity in functional assays which utilize the excitatory effects of 5-HT on enteric neurons and autonomic afferents. Several 5-HT3 antagonists are currently being evaluated for potential use in the treatment of migraine, schizophrenia, and anxiety, and a few have already demonstrated high efficacy as antiemetics in cancer chemotherapy. The purpose of this presentation is to highlight the significant structure-affinity relationships (SAFIR) and common geometrical features among 5-HT3 receptor ligands, and to describe the three-dimensional pharmacophore for the 5-HT3 recognition site derived from computational techniques. The chemical template containing the recognition elements (functional groups) for the 5-HT3 receptor are: an aromatic or heteroaromatic ring system, a coplanar carbonyl group, and a nitrogen center, interrelated by well-defined distances. Two "binding shapes" or "active shapes" for 5-HT3 ligands have been identified from detailed conformational analyses.
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PMID:Molecular modeling of 5-HT3 receptor ligands. 181 57

Binding studies with [3H]8-hydroxy-2-(di-n-propylamino)tetralin ([3H]8-OH-DPAT), a specific serotonin1A (5-HT1A) receptor agonist, were done on the autopsied brains from control subjects and from patients with chronic schizophrenia. All the patients and controls were of the Japanese race. In the controls, representative Scatchard plots for the specific [3H]8-OH-DPAT bindings in the prefrontal cortex and hippocampus revealed a single component of high affinity binding site (Kd value = 5.7 and 5.9 nM, Bmax value = 80.1 and 101.0 fmol/mg protein, respectively). The [3H]8-OH-DPAT bindings to the prefrontal cortex and hippocampus were potently inhibited by serotonin (IC50 = 6.3 x 10(-9) M) and 5-HT1A agonists (IC50 = 5.0 x 10(-9) - 2.3 x 10(-7) M), while other neurotransmitters, 5-HT2 and 5-HT3 related compounds did not inhibit the binding (IC50 greater than 10(-5) M). The bindings were decreased in the presence of 0.1mM GTP and 0.1mM GppNHp but not in the presence of 0.1mM GMP. In the prefrontal and temporal cortices of schizophrenics, there was a significant increase in the specific [3H]8-OH-DPAT binding, by 40% and 60%, respectively, with no change in the hippocampus, amygdala, cingulum, motor cortex, parietal or occipital cortex, as compared to findings in the controls. Scatchard analysis showed that this increased binding reflects changes in the number of sites but not in the affinity. The effect of 0.1mM GppNHp on the binding to prefrontal cortex was observed in both controls and schizophrenic patients. The bindings were significantly greater in the schizophrenic patients than in controls, in the presence of 0.1mM GppNHp. Our findings suggest that there are GTP-sensitive 5-HT1A sites in the human brain and that selective increases in GTP-sensitive 5-HT1A sites in the prefrontal and temporal cortices of schizophrenics relate to the pathophysiology of schizophrenia.
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PMID:Increase in serotonin 5-HT1A receptors in prefrontal and temporal cortices of brains from patients with chronic schizophrenia. 182 56

5-HT3 receptors or recognition sites have been located in the brain of many animal species and man, and are considered to mediate an increase in cation conductance. The functional relevance of the central 5-HT3 receptors is being established using selective 5-HT3 receptor antagonist ligands, which have been shown to modify behaviour in animal tests that is predictive of an action to reduce anxiety, schizophrenia and cognitive disorders. A remarkable feature of the effect of 5-HT3 receptor antagonists is their ability and potency to control a disturbed behaviour in the absence of effect on normal behaviour. This reveals an important role for 5-HT in different behaviours: indeed, the breadth of action of the 5-HT3 receptor antagonists may be indicative of the critical importance of 5-HT in the control of catecholaminergic, cholinergic and peptidergic systems throughout the forebrain. Precisely how such effects are achieved remains a significant investigative challenge, with the potential for novel therapeutic developments being a major goal.
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PMID:Pharmacological properties and functions of central 5-HT3 receptors. 184 Feb 28

The review presents evidence that 5-HT3 receptors within the brain may contribute to the control of behavior. 5-HT3 receptor antagonists GR38032F, zacopride, ICS 205-930 and other agents are very potent in reducing mesolimbic dopamine hyperactivity caused by the injection of amphetamine or infusion of dopamine into the rat nucleus accumbens and amygdala, and the ventral striatum of the marmoset. Such actions are distinguished from those of neuroleptic agents by a failure to reduce normal levels of activity or to induce a rebound hyperactivity after discontinuation of treatment. Indeed, the 5-HT3 receptor antagonists can prevent the neuroleptic-induced rebound hyperactivity. Further evidence that 5-HT3 receptors moderate limbic dopamine function is shown by their ability to reduce both the behavioral hyperactivity and changes in limbic dopamine metabolism caused by DiMe-C7 injection into the ventral tegmental area. The 5-HT3 receptor antagonists also have an anxiolytic profile in the social interaction test in the rat, the light/dark exploration test in the mouse, the marmoset human threat test and behavioral observations in the cynomolgus monkey. They differ from the benzodiazepines by an absence of effect in the rat water lick conflict test and a withdrawal syndrome. Importantly, the 5-HT3 receptor antagonists are highly effective to prevent the behavioral syndrome following withdrawal from treatment with diazepam, nicotine, cocaine and alcohol. Intracerebral injection techniques in the mouse indicate that the dorsal raphe nucleus and amygdala may be important sites of 5-HT3 receptor antagonist action to inhibit aversive behavior. Studies with GR38032F indicate an additional effect in reducing alcohol consumption in the marmoset. The identification and distribution of 5-HT3 receptors in the brain using a number of 5-HT3 receptor ligands, [3H]65630, [3H]zacopride and [3H]ICS 205-930 correlates between studies, and the 5-HT3 recognition sites in cortical, limbic and other areas meet the criteria for 5-HT3 receptors to mediate the above behavioral effects. Thus the use of 5-HT3 receptor antagonists reveals an important role for 5-hydroxytryptamine in the control of disturbed behavior in the absence of effect on normal behavior. The profile of action of the 5-HT3 receptor antagonists has generated a major clinical interest in their potential use for schizophrenia, anxiety and in the control of drug abuse.
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PMID:The psychopharmacology of 5-HT3 receptors. 220 69

Identification of 5-HT receptor subtypes--5-HT1A, 5-HT1B, 5-HT1C, 5-HT1D, 5-HT2 (possibly A and B), 5-HT3 subtypes, and possibly 5-HT4--has encouraged the manufacture of 5-HT receptor inhibitors with greater subtype specificity. However, it appears that the receptors interact, and drugs initially thought to be specific may have multiple actions. For some conditions such as anxiety/depression, almost all receptors are implicated. Clinical studies provide clear evidence that manipulation of the 5-HT system has a role in treating depression, anxiety, obsessional illness, migraine, and eating disorders. Interactions between the various receptor subtypes make it difficult to identify specific clinical functions. The 5-HT1A receptors may be involved in aggression, anorexia, and hypotension. The 5-HT1B receptors may be involved in aggression, while the 5-HT1C receptors may play a role in central aversion systems and anxiety/depression. The role of the 5-HT1D receptors remains speculative; 5-HT2 receptors appear to be involved in depression, anxiety, appetite, sleep, vasoconstriction, and hypertension. Many drugs that are effective in treating migraine are potent 5-HT2 antagonists. 5-HT3 antagonists at high doses are effective in treating nausea and at low doses in treating anxiety. Treatment of aggression, suicidal behaviour, addiction behaviour, memory impairment, dementia, and schizophrenia with 5-HT inhibitors requires further testing.
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PMID:Is there a relationship between serotonin receptor subtypes and selectivity of response in specific psychiatric illnesses? 269 41


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