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 describe a patient with chronic depression who was treated with the selective serotonin-reuptake-inhibitor sertraline. Following surgery, the patient developed severe nausea and vomiting, necessitating an efficient antiemetic treatment, possibly including the 5-HT3-receptor antagonist ondansetrone. Because both drugs, sertraline and ondansetrone, interact with the serotonin system at the synapsis, a possible interaction was discussed. Since the effect of the selective serotonin-reuptake inhibitors mainly depends on 5-HT1 and 5-HT2-receptors, a pharmacodynamic interaction between an 5-HT3-antagonist and a serotonin-reuptake-inhibitor at the synapsis leading to the relapse of depression seems to be very unlikely. There exist also no conclusive data suggesting a clinically relevant pharmacokinetic interaction between the two drugs. A treatment with ondansetrone was considered to be safe in this patient.
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PMID:[The clinicopharmacological case (5). serotonin reuptake inhibitor and 5-HT3-receptor antagonists: are there clinically relevant interactions?]. 898 72

In vitro experiments were conducted on neonatal rat brainstem-spinal cord preparations to test the hypothesis of an inhibitory modulation of phrenic activity by serotonin (5-HT) via non-5-HT2A receptors [Lindsay, A.D. and Feldman, J.L., Modulation of respiratory activity of neonatal rat phrenic motoneurones by serotonin, J. Physiol., 461 (1993) 213-233]. The changes induced by 5-HT and related agents on phrenic root discharges and membrane currents in identified phrenic motoneurons were analysed after blockade of spinal 5-HT2A receptors. Spinal application of 5-HT1B (but not 5-HT1A) receptor agonists depressed the phrenic activity and the effect was prevented by pretreatment with 5-HT1B (but not 5-HT1A, 5-HT2A and 5-HT3) receptor antagonists. Results from phrenic motoneuron whole cell recordings do not reject a presynaptic location of the 5-HT receptors responsible for this depression.
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PMID:Serotonergic inhibition of phrenic motoneuron activity: an in vitro study in neonatal rat. 925 56

The 5-hydroxytryptamine (5-HT) receptor(s) that mediate(s) contraction of the rat ileum longitudinal muscle was studied. 5-HT and alpha-methyl-5-HT equipotently induced contractions, whereas 5-methoxytryptamine and 2-methyl-5-HT (partial agonist) were less potent; this rank order of potency suggests involvement of a 5-HT2 receptor. Neither tetrodotoxin nor atropine affected the contraction to 5-HT, suggesting a smooth muscle localization of these 5-HT2 receptors. The presence of either a selective 5-HT2B (SB 204741), 5-HT3 (granisetron) or 5-HT4 (SB 204070) antagonist, slightly affected the contractions to 5-HT. Thus, they were also included in the organ bath solution in all subsequent experiments in order to pharmacologically isolate the main contractile component. Using (if possible) 5-HT2A receptor-selective concentrations, ketanserin, ritanserin, metergoline, spiperone, mianserin, methiothepin, mesulergine, methysergide and cisapride all inhibited the contractions to 5-HT, causing a depression of the curve to 5-HT (i.e. surmountable antagonism was not observed with any of the above agents). Comparison of the affinities of these compounds for the various 5-HT2 receptor subtypes revealed that the receptor involved in the contractions to 5-HT most closely resembles the 5-HT2A receptor. However, cinanserin at a concentration expected to inhibit 5-HT2A receptor-mediated effects, failed to affect the contractions to 5-HT. It is thus concluded that on the longitudinal smooth muscle of the rat ileum, at least a part of the contraction to 5-HT is mediated by 5-HT receptors resembling the 5-HT2A receptor subtype.
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PMID:5-HT receptor types in the rat ileum longitudinal muscle: focus on 5-HT2 receptors mediating contraction. 943 Jul 91

Serotonin (5-HT) may be inhibitory to micturition at a spinal level. A potential mechanism of action for serotonergic inhibition of bladder function is a depression of the ascending limb of the supraspinal reflex mediating micturition. Ascending activity evoked by pelvic nerve stimulation was recorded in the thoracic spinal cord of anesthetized cats. For comparison, spinal reflex activity evoked by pelvic nerve stimulation was recorded on the pudendal nerve. The effects of intrathecal administration of serotonergic agents were examined to determine whether spinal and supraspinal responses to bladder afferent activation were modulated by 5-HT. Methysergide (60 nmol), a non-selective serotonergic antagonist, increased ascending activity by 61+/-7% and depressed spinal reflex activity by 38+/-6%. Zatosetron (10 nmol), a 5-HT3 antagonist had a similar effect on both activities (increased by 93+/-24% and decreased by 77+/-7%, respectively). The effect on ascending activity of blocking 5-HT3 receptors was also confirmed with ICS 205930 and MDL 72222. 2-Methyl-5-HT (800 nmol), a 5-HT3 agonist, depressed ascending activity to 46+/-9% of control, but enhanced spinal reflex activity by 73+/-92%. These results demonstrate that stimulation of 5-HT3 and methysergide-sensitive 5-HT receptors can inhibit ascending activity and facilitate spinal reflex activity elicited by activation of bladder afferents. It is suggested that descending serotonergic pathways may participate in the spinal coordination of urinary continence.
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PMID:Serotonergic modulation of spinal ascending activity and sacral reflex activity evoked by pelvic nerve stimulation in cats. 966 94

To obtain gastroprokinetic agents with more potent and selective activity than metoclopramide and cisapride, a series of N-(4-benzyl-2-morpholinylmethyl)benzamides were designed and prepared. Their synthesis and structure-activity relationships were described. As a result, mosapride was selected as a promising candidate for potent gastroprokinetic activity with selective 5-HT4 receptor agonistic activity. As an extension to this project, the novel benzamide and the carboxamide derivatives having 1-benzyl-4-methylhexahydro-1,4-diazepine ring in the amine moiety were prepared and evaluated for 5-HT3 receptor antagonistic activity. DAT-582 was identified as an antiemetic agent in cancer chemotherapy. The asymmetric synthesis of DAT-582 and the SAR studies were briefly reviewed. In further modifications of the N-(1-benzyl-4-methylhexahydro-1,4-diazepin-6-yl)benzamides, the novel nicotinamides with 1-ethyl-4-methylhexahydro-1,4-diazepin ring were found to have potent 5-HT3 and dopamine D2 and D3 receptor antagonistic activities and to show weak central nervous system depression and extrapyramidal syndrome. After extensive SARs, AS-8112 was selected as a broad antiemetic agent.
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PMID:Nitrogen-containing heteroalicycles with serotonin receptor binding affinity: development of gastroprokinetic and antiemetic agents. 991 93

The present article reviews studies conducted either in collaboration with Jac Herberg, or in parallel with those studies that used consummatory behavior and responding for intracranial self-stimulation (ICSS) to investigate interactions between neurotransmitter systems. The studies reviewed include investigations of the role of dopamine in 8-OH-DPAT-induced feeding; the role of 5-HT3 receptors in the stimulant and depressant effects of nicotine on responding for ICSS; the interaction of D2 and 5-HT2 antagonists in sucrose consumption, and the differential contributions of alpha2-adrenoceptor and 5-HT2 antagonism to the rapid recovery of ICSS responding from depression produced by atypical neuroleptics. Further studies of the role of alpha2-adrenoceptor antagonism in the pattern of response decrements produced by neuroleptics on schedule-controlled responding for food confirm that the behavioral effects of monoamine interactions vary, depending on the specific receptor subtypes targeted and the behavioral paradigm employed. Consequently, the clinical relevance of findings will crucially depend on the choice of appropriate behavioral measures.
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PMID:Neurotransmitter system interactions revealed by drug-induced changes in motivated behavior. 1020 70

The understanding of mechanisms of antidepressant action has evolved over time. The strong antidepressant activity of the tricyclic antidepressants (TCAs) has supported the role of both norepinephrine and serotonin (5-HT) in depression and the mechanism involved in antidepressant action. The next generation of antidepressants included the selective serotonin reuptake inhibitors (SSRIs), further supporting the role of serotonin, while the selective norepinephrine reuptake inhibitors such as maprotiline and reboxetine underlined the relevance of norepinephrine. These developments suggest that either facilitation of serotonin or norepinephrine or both may lead to an antidepressant response. The next step was the development of mixed serotonin-norepinephrine reuptake inhibitors (SNRIs), exemplified by venlafaxine and milnacipran. As with the TCAs, the antidepressant activity of SNRIs is based on inhibition of norepinephrine and serotonin reuptake, but unlike TCAs they do not have anticholinergic, antihistaminergic, and cardiotoxic effects. Although norepinephrine is known to stimulate serotonin cell firing rate via the alpha1-adrenoceptors, norepinephrine and serotonin have independent antidepressant actions. The latest development has been the introduction of the noradrenergic and specific serotonergic antidepressant mirtazapine. Its antidepressant effect appears to be related to dual enhancement of central noradrenergic and serotonergic neurotransmission by blockade of alpha2-adrenoceptors. In addition, mirtazapine directly blocks 5-HT2 and 5-HT3 receptors, which may account for its anxiolytic and sleep-improving properties as well as its lack of adverse events that are typical of SSRIs.
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PMID:Pharmacology of antidepressants: selectivity or multiplicity? 1044 34

There is currently available evidence that suggests that drugs combining 2 synergistic mechanisms of action (e.g., enhancement of both noradrenergic and serotonergic neurotransmission) may yield superior therapeutic efficacy compared with a single therapeutic mechanism of highly selective agents such as selective serotonin reuptake inhibitors (SSRIs). The differences in antidepressant efficacy favoring dual-acting drugs may exist in particular for 3 difficult-to-treat groups of patients: those with endogenous depression, those with severe depression, or hospitalized depressed patients. Mirtazapine differs from other new dual-acting antidepressants by not being a reuptake inhibitor. Its antidepressant activity may be related to a direct enhancement of noradrenergic neurotransmission by blockade of alpha2-autoreceptors. The rapid increase in serotonin (5-HT) synaptic levels by blockade of alpha2-heteroreceptors indirectly enhances 5-HT1A-mediated neurotransmission since 5-HT2 and 5-HT3 are blocked by mirtazapine. The antidepressant efficacy of mirtazapine was established in several placebo-controlled trials. Currently available evidence suggests that mirtazapine is effective in all levels of severity of depressive illness, as well as is in a broad range of symptoms associated with depression.
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PMID:Mirtazapine: clinical overview. 1044 35

Electroconvulsive therapy (ECT) is used to treat drug-resistant depressive disorders. The results of studies on the mechanism underlying the effectiveness of ECT on depression are still controversial. ECT stimulus is usually larger than the threshold of induction of seizures and activation of whole-brain is believed to be necessary to produce therapeutic effects. A single ECT session induces alterations of the electroencephalogram (EEG) including initial epileptic discharges, then slow waves, and finally flattened EEG. Repeated ECT results in an increasing number of slower waves in the EEG for as long as a month. ECT-induced changes in various neurotransmitter systems have also been reported. Serotonin (5-hydroxytryptamine, 5-HT) is one of the most important neurotransmitters involved in depressive illness, and ECT alters several 5-HT-receptor subtypes in the central nervous system. 5-HT1A receptors in post-synaptic neurons are sensitized by repeated ECT, but those in pre-synaptic neurons (auto-receptors) are not changed. In addition, our electrophysiological studies have shown that ECT increases sensitivity to 5-HT of 5-HT3 receptors in the hippocampus, resulting in an increase in release of neurotransmitters such as glutamate and gamma-aminobutyric acid. In contrast, ECT decreases the auto-receptor functions in noradrenergic and dopaminergic neurons in the locus coeruleus and substantia nigra, respectively, resulting in an increase in release of noradrenaline and dopamine. In conclusion, 5-HT1A-receptor sensitization may be important for explaining the effectiveness of ECT, as this change induces a decrease in the number of 5-HT2A receptors that are elevated in depressive patients. Facilitation of neurotransmitter releases due to 5-HT3-receptor sensitization by ECT may also play an important role in effective treatment of depressive patients refractory to therapeutic drugs.
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PMID:Mechanism underlying the therapeutic effects of electroconvulsive therapy (ECT) on depression. 1046 62

The irritable bowel syndrome (IBS) is a consortium of symptoms including abdominal pain and alterations in the pattern of defaecation. There is no single pathophysiological marker of IBS although it is generally accepted that some patients do have abnormalities of intestinal motility and/or enhanced visceral sensitivity. There is also an increasing acceptance that the central nervous system, an important component of the brain-gut axis, also plays an important role in symptom production both in the response to stress and when there is an underlying affective disorder. During the past decade new therapeutic targets have been identified that have permitted the development of new drugs with therapeutic potential for IBS. Identification and characterization of 5-hydroxytryptamine (5-HT) receptors in the gastrointestinal tract particularly 5-HT3 and 5-HT4 receptors, which are involved not only in modulating gut motility but in visceral sensory pathways, has led to a number of studies of 5-HT3 (Alosetron, Granisetron and Ondansetron) and 5-HT4 (SB-207266A) antagonists. Both classes of drug appear to reduce visceral sensitivity and have inhibitory effects on motor activity in the distal intestine. Early clinical studies suggest that these agents may have a role in painful, diarrhoea-predominant IBS. 5-HT4 agonists (HTF919, Zelmac) may improve constipation-predominant IBS by normalizing bowel habit and thereby reducing abdominal pain. Alternative approaches to reducing visceral sensation include the use of the opioid kappa agonists, which have no central opioid effects although clinical trials have suggested that these agents are not highly effective in relieving IBS pain. There are in addition, new approaches to modify intestinal motility including the development of gut selective muscarinic M3 receptor antagonists such as zamifenacin and the 5-HT4 partial agonist, HTF919. Preliminary studies suggest that these agents may have therapeutic potential in IBS. Anti-depressants are increasingly used to treat affective disorder in IBS but in addition appear to have added value because of their ability to reduce visceral hypersensitivity and alter gut transit. Therapeutic effects are often obtained at doses below those normally used to treat depression. IBS continues to be a therapeutic challenge because of its diverse symptomatology and lack of a single pathophysiological target for drug intervention.
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PMID:Irritable bowel syndrome: new pharmaceutical approaches to treatment. 1058 Sep 22


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