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Query: UMLS:C0042963 (vomiting)
 31,883 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cardiovascular effects of dopamine (DA) were studied in anesthetized dogs with special attention to the susceptibility of these effects to inhibition by catecholaminergic receptor blocking drugs. Dopamine given by rapid i.v. injection at 1 and 3 mug/kg produced depressor responses whereas doses from 9 to 81 mug/kg produced pressor resposes and increases in cardiac contractile force. Propranolol inhibited the increases in cardiac contractility whereas phenoxybenzamine potentiated the depressor effect of low doses of DA and reversed the pressor effect of high doses. Bulbocapnine blocked the depressor effect of DA in both phenoxybenzamine and propranolol-treated dogs. Pimozide, however, had no effect on the depressor response to DA. In hemodynamic studies, DA reduced blood pressure, total peripheral resistance and renal vascular resistance. Cardiac output and renal blood flow were increased. Bulbocapnine, but not pimozide, abolished the effects of DA on blood pressure, vascular resistance and renal blood flow. In conscious dogs, pimozide abolished apomorphine-induced emesis (an effect mediated by DA receptors in the central nervous system) whereas bulbocapnine had no effect. Therefore, the peripheral vascular and central dopamine receptors may be pharmacologically distinct.
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PMID:The cardiovascular actions of dopamine and the effects of central and peripheral catecholaminergic receptor blocking drugs. 112 Sep 64

Dopamine antagonists are effective anti-emetics. Domperidone does not readily cross the blood-brain barrier and is less likely to cause central nervous system side-effects than metoclopramide. However, a direct comparison of the safety and efficacy of the two drugs has not hitherto been made. Ninety-five patients, with symptoms of nausea and vomiting due to a variety of oesophageal or gastric disorders, were recruited into a randomised, double-blind, three-part, parallel-group comparative study of controlled release metoclopramide 15 mg (Gastrobid Continus tablets, Napp Laboratories) given twice daily, and domperidone 10 mg or 20 mg given three times daily. Assessments for nausea, vomiting, reflux symptoms and adverse events were made on entry to the study. Patients were randomly allocated to one of the three treatment regimes for a period of seven days, throughout which daily symptomatology and use of escape medication were recorded on a diary card. At the end of the treatment period, nausea, vomiting and reflux symptoms, adverse events and a global assessment of patients' symptom control were recorded by the investigator. Both controlled release metoclopramide and high and low dose domperidone significantly reduced symptoms of belching, flatulence, distension, heartburn, regurgitation, reflux, nausea and vomiting compared to baseline. There were no significant differences between the three treatments in efficacy or in the number and severity of side-effects.
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PMID:A comparison of controlled release metoclopramide and domperidone in the treatment of nausea and vomiting. 181 Mar 56

The intravenous injection of cisplatin (10 mg/kg), the subcutaneous injection of apomorphine (0.125-1 mg/kg) and lisuride (0.001-0.1 mg/kg), the oral administration of ipecacuanha (0.3-2.4 mg/kg) and the intragastric administration of copper sulphate (25-100 mg/kg), induced a vomiting and retching response in the ferret. Pretreatment with dl-fenfluramine (5 mg/kg i.p.) prevented or reduced the emesis induced by cisplatin, apomorphine, ipecacuanha and lisuride but failed to significantly antagonise copper sulphate-induced emesis. The 5-HT3 receptor antagonist ICS 205-930 (0.1 mg/kg i.p.) prevented emesis induced by cisplatin and ipecacuanha but failed to prevent or significantly reduce the emesis induced by apomorphine, lisuride or copper sulphate. Dopamine receptor antagonists, including fluphenazine (0.1-1.0 mg/kg i.p.) prevented apomorphine- and lisuride-induced emesis but were less potent or had inconsistent actions to antagonise cisplatin- or ipecacuanha-induced emesis and failed to inhibit the emesis induced by copper sulphate. The data indicate that dopamine and/or 5-HT3 receptor systems are involved in drug-induced emesis but that emesis caused by gastric irritation induced by copper sulphate is mediated by different receptor mechanisms.
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PMID:Fluphenazine, ICS 205-930 and dl-fenfluramine differentially antagonise drug-induced emesis in the ferret. 197 49

Nausea and vomiting are serious problems for patients receiving cancer chemotherapy. Dopamine receptor and cholinergic receptor antagonism have been the target mechanism for agents used to combat drug-induced nausea and vomiting; more recently, blockade of serotonin receptors has been used for this indication. Current therapies are limited by extrapyramidal adverse effects, as well as drowsiness, sedation, respiratory depression, and cardiac effects. Ondansetron is an investigational serotonin antagonist that has documented effectiveness for cancer chemotherapy-induced emesis. Ondansetron appears to be well tolerated, with the possible exception of headaches and transient increases in liver enzymes. No extrapyramidal toxicities have been reported with this agent. While ondansetron looks promising, further studies are needed to fully define its role as an antiemetic.
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PMID:Ondansetron: a new entity in emesis control. 214 59

With the advent of new chemotherapeutic agents, and their well-known side effect of emesis, the need for a greater facility with anti-emetics has emerged. As well as the common problem of chemotherapy-induced emesis, other problems have become apparent such as delayed emesis and anticipatory emesis. The control of such emetic problems may be affected by certain patient characteristics, such as a history of chronic high alcohol intake, and age. Blockade of the different types of neuroreceptors can lead to effective emetic control. Dopamine receptor blockers such as the phenothiazines, butyrophenones and substituted benzamides have been among the most effective agents. However, newer agents, such as ondansetron, which specifically bind to serotonin receptors, may preserve the anti-emetic efficacy of the dopamine-blockers, but without the associated extrapyramidal side effects of these agents.
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PMID:An outline of anti-emetic treatment. 269 42

Dopamine receptor stimulation causes vascular and neurohumoral responses that may be beneficial in patients with heart failure. Oral inactivity, emesis and adrenergic-induced arrhythmias have limited the use of currently available compounds. Fenoldopam (SKF-82526-J) is a new, orally available, selective, dopamine-receptor agonist with potent renal vasodilating properties (six times that of dopamine) without positive inotropic or adrenergic activity. Drug efficacy was clinically evaluated in 10 patients with heart failure after single oral doses of placebo and 50, 100 and 200 mg of medication. Placebo produced no changes. Peak efficacy was noted 30 minutes to 1 hour after the 200 mg dose with mean blood pressure decreasing from 96 +/- 15 (mean +/- SD) to 83 +/- 8 mm Hg (p less than 0.05), pulmonary capillary wedge pressure decreasing from 23 +/- 6 to 20 +/- 8 mm Hg (p less than 0.05) and mean pulmonary artery pressure decreasing from 32 +/- 9 to 29 +/- 8 mm Hg (p less than 0.05). Systemic vascular resistance decreased from 1,987 +/- 887 to 1,191 +/- 559 dynes.s.cm-5 (p less than 0.05) with a subsequent 55% increase in cardiac index from 2.2 +/- 1.1 to 3.1 +/- 1.3 liters/min per m2 (p less than 0.05). Heart rate and right atrial pressure did not change (p greater than 0.05). No emesis or new tachycardia was noted at any dose. Baseline hemodynamics generally returned within 3 to 4 hours. Fenoldopam, therefore, is a short-acting, orally effective drug that decreases systemic vascular resistance and increases cardiac index in patients with heart failure and represents a new class of oral compounds that may be useful in treating such patients.
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PMID:Hemodynamic effects of an oral dopamine receptor agonist (fenoldopam) in patients with congestive heart failure. 286 95

The purpose of the study was to elucidate the effects of dopamine on gastroduodenal motility and gastric emptying of an acaloric viscous meal. In four conscious dogs, antral, pyloric and duodenal contractions were recorded with extraluminal strain gage force transducers and induction coils. Gastric emptying was assessed radiographically. Dopamine at low dose (5 micrograms/kg x min) significantly diminished gastric emptying. It was mainly caused by a reduction in the contraction force of the antral waves. Dopamine at higher dose (10-15 micrograms/kg x min) induced retrograde power contractions accompanied by enterogastric reflux. When the dopamine infusion was stopped after the occurrence of a reverse power contraction, the antrum exhibited forceful contractions but gastric emptying ceased due to a profound decrease in antral tone. The results suggest that dopamine 1) inhibits gastric emptying of viscous meals, 2) induces reverse power contractions independently from vomiting, and that 3) antral tone is a basic requirement for gastric emptying of viscous meals.
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PMID:Dopamine delays gastric emptying and induces retrograde power contractions with enterogastric reflux. 340 41

Thirty-six patients suffering from disseminated epithelial tumors under treatment with Cisplatin alone or in combination with Vindesine entered a randomized, double-blind, cross-over study comparing the antiemetic activity of low-dose IV Metoclopramide (total dose: 0.8 mg/kg) with that of a combination of Metoclopramide (same schedule) plus Nortriptyline (2 X 50 mg PO) plus Thiethylperazine (3 X 10 mg IV). This combination was designed in an attempt to act simultaneously on gastrointestinal motility and neuroreceptors at central emetic pathways (Dopamine D-2, Histamine H-1 and muscarinic cholinergic). The antiemetic combination significantly reduces the median number of emetic episodes (p less than 0.01), the median volume of vomiting (p less than 0.01) and the median time of emesis (p less than 0.01) when compared with Metoclopramide alone and was also preferred by a significant number of patients (p = 0.0001) after passing through both antiemetic treatment arms being compared.
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PMID:Antiemetic combination for cisplatin-induced emesis. Results from a controlled study. 375 65

The cardiovascular effects of dopexamine and dopamine were compared in the anaesthetized and conscious dog by the use of intravenous infusions over the dose range 3 X 10(-9) - 10(-7)mol kg-1 min-1. In the anaesthetized dog, dopexamine produced a dose-related fall in blood pressure due to peripheral vasodilatation and a small rise in heart rate and contractility. By contrast, dopamine did not significantly reduce blood pressure but produced a larger dose-related increase in contractility. At the highest infusion rate (10(-7)mol kg-1 min-1) blood pressure and heart rate were increased by dopamine. Dopexamine dilated the renal and mesenteric vascular beds with a potency similar to that of dopamine. Femoral vascular responses produced by both agents were inconsistent but the highest infusion rate of dopamine did produce vasoconstriction. With the aid of selective receptor antagonists (haloperidol, propranolol and bulbocapnine) the vasodepressor activity of dopexamine was shown to be mediated by stimulation of DA2-, beta- and DA1-receptors. The cardiac stimulation and renal vasodilatation produced by both compounds were due to stimulation of beta-adrenoceptors and DA1-receptors respectively. In the conscious dog, intravenous infusion of dopexamine caused a dose-related fall in blood pressure, renal vasodilatation and an increase in cardiac contractility and heart rate. Dopamine also increased cardiac contractility, and renal blood flow due to renal vasodilatation but without affecting heart rate. At the highest infusion rate, blood pressure was increased. Dopexamine and dopamine produced a similar incidence of panting and repetitive licking at 3 X 10(-8)mol kg-1 min-1 and emesis at 10(-7)mol kg-1 min-1, due to stimulation of dopamine receptors in the chemoreceptor trigger zone. Dopexamine produces a different cardiovascular profile from dopamine in the anaesthetized and conscious dog. Both compounds reduce renal vascular resistance, but in contrast to dopamine, dopexamine reduces afterload and produces only mild inotropic stimulation. These differences reflect contrasting activity at adrenoceptors.
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PMID:The effects of dopexamine on the cardiovascular system of the dog. 402 82

The endogenous catecholamine dopamine lowers blood pressure by acting on two receptor subtypes: dopamine 1 and dopamine 2. Dopamine 1 receptors subserve vasodilation, especially in the renal, coronary, mesenteric, and cerebral vascular beds. Dopamine 2 receptors have been located at the endings of postganglionic sympathetic nerves and, when activated, inhibit norepinephrine release. Inhibition of emesis and inhibition of prolactin release also appear to be dopamine 2-mediated phenomena. The receptor subtypes have been classified by differences in chemical structure of agonists and by specific antagonists. Dopamine also acts on beta 1 receptors to stimulate the heart and alpha 1 and alpha 2 receptors to cause vasoconstriction. Alpha adrenergic activity and lack of oral availability limit the use of dopamine in the treatment of hypertension. However, studies with the selective dopamine 1 agonist, fenoldopam, and dopamine 2 agonists such as LY 141865 and bromocriptine, indicate that agonists of both receptor subtypes can lower blood pressure in experimental animals and in hypertensive patients. Initial use of dopamine agonists in the treatment of hypertension and its possible involvement in the etiology and maintenance of hypertension are discussed.
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PMID:Dopamine receptors and hypertension. Physiologic and pharmacologic implications. 614 92


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