Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P46098 (5-HT3 receptor)
 2,290 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There is interest in the development of antiemetics other than dopamine receptor antagonists for the treatment of postoperative nausea and vomiting. A ferret model of morphine-induced emesis may have wider application in evaluating newer agents than the apomorphine dog model. This study describes the conditions for morphine-induced emesis in ferrets and evaluates five antiemetics that are prototypical of three different mechanisms. The average numbers of vomiting and retching episodes induced by morphine (0.1-2.5 mg/kg s.c.) were distributed as a bell-shaped curve. Maximum number of vomits occurred at 0.3 mg/kg (11.8 +/- 2.1 vomits; 45 +/- 12.5 retches). Antiemetics or vehicle were given i.v. 5 min prior to morphine while each ferret was maintained under isoflurane-O2 anesthesia. Ondansetron, a 5-HT3 receptor antagonist, reduced vomiting episodes by 47% and 70% (3 and 10 mg/kg). Granisetron, a 5-HT3 receptor antagonist was inactive at doses of 0.1, 1.0, 3.0 and 10 mg/kg. Metoclopramide reduced vomiting episodes by 48% and 82% (3 and 10 mg/kg). Droperidol reduced vomiting episodes by 84% at 3 mg/kg. Naloxone reduced vomiting episodes by 91% and 43% at doses of 0.1 and 1.0 mg/kg. In most cases, prolonged latency times to the first episodes accompanied the reduction in total numbers of episodes. The significant reduction of morphine-induced emesis in the ferret by ondansetron, metoclopramide and droperidol is consistent with the reduction of postoperative emesis in man by these compounds when morphine was a component of the anesthetic regimen. These results suggested that the morphine ferret model may be useful for evaluating compounds having the potential for preventing and treating postoperative vomiting.
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PMID:The effects of different antiemetic agents on morphine-induced emesis in ferrets. 822 24

The plasma aldosterone response following the administration of drugs with antagonist and agonist activity at Serotonin 3 and 4 (5-HT3&4) receptors has been examined in 9 healthy male volunteers receiving the following four treatments i.v. in a randomised, cross-over sequence: ondansetron 8 mg, granisetron 3 mg, metoclopramide 20 mg, and saline 20 ml. Metoclopramide significantly increased the mean plasma aldosterone level to 196% of basal level at 5 min. It rose to 234% at 15 min and remained at more than 185% of basal level for the duration of the experiment. The response to ondansetron and granisetron did not differ significantly from placebo. If dopamine antagonism is discounted, the results suggest that metoclopramide-induced aldosterone secretion results from its agonist activity at 5-HT4 receptors, although slow neuronal depolarization via an unidentified receptor remains a possibility. Antagonism at the 5-HT3 receptor plays no role, as the selective antagonist, granisetron, did not elicit a significant response. It seems unlikely that the 5-HT4 receptor is the second, low affinity binding site of ondansetron, unless it had no agonist activity at this receptor.
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PMID:Effect of metoclopramide, ondansetron and granisetron on aldosterone secretion in man. 839 Mar 68

In the past few years important progress in the prevention of chemotherapy-induced nausea and vomiting has been made mainly thanks to the introduction of the 5-HT3 receptor antagonists in clinical practice (ondansetron, granisetron, tropisetron). In the prevention of acute emesis induced by cisplatin, an intravenous combination of a 5-HT3 receptor antagonist plus single dose dexamethasone (20 mg) should be considered the treatment of choice. This is also the case in the prevention of acute emesis induced by moderately emetogenic chemotherapy (intravenous cyclophosphamide, doxorubicin, epirubicin, carboplatin, used alone or in combination), but high and repeated doses of dexamethasone should be used (8 mg intravenously plus 4 mg orally every 6 hours for four doses starting contemporarily to chemotherapy administration). Several-well conducted double-blind comparative studies among intravenously administered 5-HT3 receptor antagonists have been carried out. Almost all showed that they have identical antiemetic activity and tolerability. Therefore, the choice among 5-HT3 receptor antagonists should be based only on their acquisition cost in each country. In the prevention of delayed emesis (from day 2 to day 4) induced by cisplatin oral metoclopramide (0.5 mg/kg or 20 mg every 6 hours for four doses daily) and oral ondansetron (8 mg twice daily), both combined with dexamethasone, showed similar antiemetic efficacy. Metoclopramide plus dexamethasone should be considered the antiemetic regimen of choice due to its lower cost. Ondansetron plus dexamethasone is a valid alternative regimen that should be preferred in patients who not tolerate metoclopramide and in patients who suffer from acute vomiting. In the prevention of delayed emesis induced by moderately emetogenic chemotherapy oral dexamethasone or oral ondansetron showed a good antiemetic efficacy, but the results from a recently published study seem suggest the necessity to treat only patients who present acute vomiting or moderate-severe nausea. In fact, patients obtaining complete protection from vomiting and nausea (or at most mild acute nausea) have a very low incidence of delayed emesis.
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PMID:[Recent improvements in antiemetic therapy]. 923 27

We performed a systematic review of the effectiveness of anti-emetics for prophylaxis of cisplatin-induced delayed emesis using meta-analysis. We selected 12 reports of randomized controlled trials from MEDLINE (1966-2003. 4) and The Cochrane Library Issue 1, 2003. Nine of these reports were evaluated as high quality and the others as low quality according to the evaluation criteria of Jadad et al., and only the high-quality reports were subjected to meta-analysis. The statistical results obtained from all 12 reports were also compared with those obtained from the 9 reports of high quality. Corticosteroids significantly reduced the occurrence of delayed emesis. Metoclopramide tended to reduce the occurrence of delayed emesis, although not to a significant extent. In contrast, 5-HT3 receptor antagonists did not show a significant prophylactic effect on delayed emesis. Combination treatments using corticosteroids with metoclopramide or 5-HT3 receptor antagonists did not show significant additional benefits over corticosteroids alone. In conclusion, treatment with corticosteroids without additional metoclopramide or 5-HT3 receptor antagonists appears to be preferable for the prevention of delayed emesis induced by cisplatin.
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PMID:[Effectiveness of anti-emetics for the prophylaxis of cisplatin-induced delayed emesis: a systematic review]. 1476 49

The development of serotonin 5-HT3 receptor antagonists dramatically improved the treatment of chemotherapy-induced nausea and vomiting. Ondansetron, a serotonin 5-HT3 receptor antagonist in combination with dexamethasone is widely used to treat chemotherapy-induced nausea and vomiting. This treatment regimen is effective against acute nausea and vomiting, but fails to control delayed nausea and vomiting. Metoclopramide along with other antiemetics are used to treat delayed nausea and vomiting. The high doses of metoclopramide needed may produce extra pyramidal side effects. The recent developments of 5-HT3 and dopamine D2 dual receptor antagonists have been found to exhibit a broad spectrum of activity against peripherally and centrally acting stimuli, but are not much effective against delayed emesis associated with chemotherapy. In various animal models, neurokinin NK1 receptor antagonists showed promising results against acute and delayed emesis, but the clinical trials revealed that triple therapy (NK1 receptor antagonist, 5-HT3 receptor antagonist and dexamethasone) is superior than standard therapy (5-HT3 receptor antagonist & dexamethasone) or NK1 receptor antagonist alone, in controlling acute as well as delayed nausea and vomiting. Ginger, which is used traditionally for controlling emesis induced by various stimuli, also showed good activity against chemotherapy-induced nausea and vomiting in animal models. Non-pharmacological methods such as acupressure and acustimulation are good adjunct methods in treating nausea and vomiting. Since many mediators are involved in emesis induced by chemotherapy, cocktail treatment is proven to be more efficacious than a single drug, but increases treatment costs. So there is a need of further research in this field to get economically useful methods for the treatment of acute and delayed chemotherapy-induced nausea and vomiting.
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PMID:Cancer chemotherapy-induced nausea and vomiting: role of mediators, development of drugs and treatment methods. 1573 95

The actions of metoclopramide and ergotamine, drugs which are used as a combined migraine medication, on human (h)5-HT3A receptors and 5-HT reuptake carriers, stably expressed in HEK-293 cells, were studied with patch-clamp- and ([3H]5-HT)-uptake techniques. At clinical concentrations, metoclopramide inhibited peak and integrated currents through h5-HT3A receptors concentration-dependently (IC50 = 0.064 and 0.076 microM, respectively) when it was applied in equilibrium (60 s before and during 5-HT (30 microM) exposure). The onset and offset time constants of metoclopramide action were 1.3 and 2.1 s, respectively. The potency of metoclopramide when exclusively applied during the agonist pulse decreased more than 200-fold (IC50 = 19.0 microM, peak current suppression). Metoclopramide (0.10 microM) did not alter the EC50 of 5-HT-induced peak currents. In contrast to the lack of competitive interaction between metoclopramide and 5-HT in this functional assay, metoclopramide inhibited specific [3H]GR65630 binding to human h5-HT3A receptors in a surmountable manner. This seeming discrepancy between functional studies and radioligand binding experiments may be accounted for by (1) the slow kinetics of inhibition of peak currents by metoclopramide compared with the fast onset and offset kinetics of 5-HT-induced currents and (2) the low efficacy of metoclopramide in inhibiting radioligand binding (e.g. only 20% binding inhibition compared to 79% peak current suppression by 200 nM metoclopramide). At low concentrations (1-10 nM), ergotamine had no effect on 5-HT (30 microM)-induced peak currents. Above clinical concentrations, ergotamine (>3 microM) inhibited them. When both drugs were applied together (0.10 microM metoclopramide +0.001 to 0.01 microM ergotamine), an inhibition of both, peak and integrated current responses was observed. Neither metoclopramide (< or =30 microM) nor ergotamine (< or =30 microM) had an effect on the 5-HT reuptake carrier as they did not alter the citalopram-sensitive [3H]5-HT uptake.
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PMID:Interactions of metoclopramide and ergotamine with human 5-HT(3A) receptors and human 5-HT reuptake carriers. 1604 95

Nausea is one of a cluster of symptoms described subjectively by patients with delayed gastric emptying. The mechanisms and treatments are unclear (anti-emetic drugs are not fully effective against nausea). Can nausea be relieved by stimulating gastric emptying? Physostigmine (together with atropine) has been shown experimentally to stimulate gastric motility, relieve nausea and restore normal gastric motility. Is this mimicked by gastric prokinetic drugs? The answer is complicated by mixed pharmacology. Metoclopramide increases gastric motility by activating myenteric 5-HT4 receptors but also directly inhibits vomiting via D2 and 5-HT3 receptor antagonism; relationships between increased gastric motility and relief from nausea are therefore unclear. Similarly, the D2 receptor antagonist domperidone has direct anti-emetic activity. Nevertheless, more selective 5-HT4 and motilin receptor agonists (erythromycin, directly stimulating gastric motility) inhibit vomiting in animals; low doses of erythromycin can also relieve symptoms in patients with gastroparesis. Ghrelin stimulates gastric motility and appetite mostly via vagus-dependent pathways, and inhibits vomiting in animals. To date, ghrelin receptor activation has failed to consistently improve gastric emptying or symptoms in patients with gastroparesis. We conclude that nausea can be relieved by gastric prokinetic drugs, but more clinical studies are needed using drugs with selective activity. Other mechanisms (e.g. ghrelin, vagal and central pathways, influencing a mechanistic continuum between appetite and nausea) also require exploration. These and other issues will be further explored in a forthcoming special issue of the European Journal of Pharmacology, which focusses on mechanisms of nausea and vomiting.
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PMID:The relationship between gastric motility and nausea: gastric prokinetic agents as treatments. 2383 91


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