Disease relevance of IMPROMIDINE

• The effects of a specific H2 receptor agonist impromidine, on gastric acid secretion were measured in six patients with duodenal ulcer in clinical remission before and after three months treatment with ranitidine 150 mg nocte [1].
• The specificity of H-2 effect of impromidine was confirmed by simultaneous tachycardia and hypotension; pentagastrin did not produce cardiovascular effects [2].
• 4 Histamine H2-receptor agonists, impromidine and dimaprit, produced hyperthermia which was antagonized by cimetidine [3].
• During continuous intravenous infusions of impromidine, the fall in blood pressure is due to a reduction in total peripheral resistance; cardiac output increases during hypotension [4].
• Three days after infarction, the positive inotropic effects of isoproterenol (2.8 X 10(-9) mol/L) and tyramine (5.5 X 10(-5) mol/L) were nearly abolished, while the inotropic effects of impromidine (4.6 X 10(-7) mol/L) and dimaprit (8.5 X 10(-6) mol/L) were not impaired [5].

Psychiatry related information on IMPROMIDINE

• In normal subjects and in DU2, the administration of the lowest dose of impromidine induced a motor pattern similar to that of the basal period of groups DU and GD, whereas the highest dose disrupted the MMC pattern that was replaced by an irregular motor activity [6].

High impact information on IMPROMIDINE

• At this age, the effect of pentagastrin in acid secretion is not blocked by the H-2 receptor antagonist cimetidine, nor is it potentiated by impromidine [7].
• Gastric secretory studies in humans with impromidine (SK&F 92676)--a specific histamine H2 receptor agonist [8].
• There were small cardiovascular changes: an increased heart rate with a decreased diastolic pressure during infusion of impromidine [9].
• Neither impromidine (10 microM) nor R(-)-alpha-methylhistamine (10 microM), selective H2 or H3 agonists, respectively, significantly affected the membrane potential, input resistance or AHPslow [10].
• Histamine H2 agonists (dimaprit and impromidine), but not H1 agonists (2-methylhistamine and 2-thiazolylethylamine), also reduced hepatic LDL receptor expression [11].

Chemical compound and disease context of IMPROMIDINE

• The gastric secretory response to impromidine (SKF 92676), a potent selective histamine H2 agonist, has been studied in 40 patients with peptic ulcer disease or ulcer-like dyspepsia [12].
• Left ventricular infarction (AMI) was produced in experimental animals and the contractile response to beta-adrenergic and H2-histaminergic stimulation by isoproterenol and impromidine tested in the isolated perfused heart preparation [13].

Biological context of IMPROMIDINE

• In this study, the specific HA H1 agonist, pyridylethylamine, and the specific H2 agonist, impromidine, were used to examine the nature of this tachyphylaxis [14].
• Impromidine also reduced the average size of the evoked excitatory postsynaptic potential [15].
• The H2 receptor agonist impromidine reduced only the postganglionic compound action potential [15].
• In both species, an impromidine infusion rate that decreased total peripheral vascular resistance and increased left ventricular output without lowering blood pressure was identified [16].
• Impromidine administered intra-arterially also causes vasodilatation in the femoral and mesenteric vasculature by interaction with H2-receptors [4].

Anatomical context of IMPROMIDINE

• Impromidine is a partial histamine H2-receptor agonist on human ventricular myocardium [17].
• Comparison of the agonist activity of impromidine (SK & F 92676) in anaesthetized rabbits and on the rabbit isolated fundic mucosa [18].
• Effect of impromidine (SK&F 92676) on the isolated papillary muscle of the guinea-pig [19].
• The H1-receptor antagonists mepyramine, promethazine, triprolidine and chlorpheniramine competitively antagonized the potentiation of impromidine-stimulated cyclic AMP accumulation elicited by histamine and 2-thiazolylethylamine in rabbit cerebral cortex without affecting the response to impromidine alone [20].
• Finally exogenous histamine inhibited [3H]histamine release from depolarized synaptosomes of rat cerebral cortex, with an EC50 value similar to that found with slices and was antagonised by impromidine with an apparent Ki value similar to that displayed at H3-receptors [21].

Associations of IMPROMIDINE with other chemical compounds

• The increased response to the H2 agonist impromidine and the H2 antagonist ranitidine after treatment with ranitidine suggests an enhanced sensitivity of the H2 receptor [1].
• Mepyramine had no effect on methacholine- or impromidine-stimulated gastric acid secretion or mucosal blood flow [22].
• In vitro, histamine and 2,2-pyridylethylamine (PEA, H1 agonist) caused contraction of resting arteries while impromidine (H2 agonist) was without effect [23].
• Cimetidine competitively inhibited the effects of impromidine with similar pA2 values for each effect (acid, 5.99; chloride, 6.03; change in HR, 6.03; and change in systolic blood pressure, 6.32) [24].
• 4 Impromidine produced some inhibition of the uptake of [3H]-noradrenaline, but this did not account for the enhancement of the stimulation-induced efflux of radioactivity, since impromidine (50 mumol/l) still increased release in the presence of cocaine (30 mumol/l) [25].

Gene context of IMPROMIDINE

• H2 receptor antagonists and an agonist (impromidine) inhibit intestinal DAO [26].
• Impromidine, a potent H2-receptor agonist, however, was found to be ineffective [27].
• 4. The 'selective' H1-receptor agonists pyridylethylamine, 2-methylhistamine and thiazolylethylamine, and the H2-receptor agonists dimaprit, impromidine and 4-methylhistamine all mimicked the histamine response, but all except impromidine were less potent than histamine [28].
• 3. The H2 receptor agonist, impromidine, dose-dependently increased basal acid secretion, reaching a maximal value of 145.5 +/- 11.7 mumol h-1 with impromidine (10 mumol 1(-1)), and maximal gastrin-stimulated acid secretion to 167.4 +/- 15.1 mumol h-1 with impromidine (10 mumol 1(-1)) [29].
• Impromidine, a potent inhibitor of histamine methyltransferase (HMT) and diamine oxidase (DAO) [30].

Analytical, diagnostic and therapeutic context of IMPROMIDINE

• Microinjection of impromidine (an H2-receptor agonist) into the same area had no effect on either the cortical EEG or W [31].
• After treatment basal acid output increased from 1.2 to 2.8 mmol/h and after maximal impromidine stimulation from 36.9 (4.7) to 44.2 (6.2) mmol/h (p less than 0.02) [1].
• A constant intravenous infusion of impromidine was used to stimulate gastric acid secretion for 6 hr [32].
• In arteries, impromidine, but not pyridylethylamine, inhibited constriction resulting from exogenous norepinephrine [33].
• The H2 agonist impromidine produced a significant inhibition of nerve-stimulated hindquarter vasoconstrictor responses without altering perfusion pressure responsiveness to either intraarterial norepinephrine or nitroglycerin [34].

References