Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0406810 (NAME)
 13,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present in vitro study was designed to evaluate the effect of histamine on isolated rings of bovine oviductal artery and to characterize the histamine receptors involved in the histamine-induced response. Endothelial dependence of the response was also investigated. Cumulative addition of histamine and 2-pyridylethylamine (histamine H receptor agonist) induced a concentration-dependent relaxation in intact arterial segments precontracted with noradrenaline. The histamine H1 receptor antagonist mepyramine showed non-competitive antagonism in the histamine-induced concentration-response curve. However, when the response to histamine was evaluated in the presence of mepyramine and histamine H1 and H3 receptors were blocked, Schild analysis yielded a line with a slope of 1.10 and a pA2 value of 8.91, indicating simple competitive antagonism of mepyramine at histamine H1 receptor sites. The histamine H2 receptor agonist, dimaprit, caused marked dilatation only at high doses. Cimetidine, propranolol and mepyramine failed to inhibit this relaxant effect. In precontracted oviductal arteries, cimetidine did not modify the histamine-induced concentration-response curves. Combined treatment with histamine H1 and H2 receptor antagonists did not induce an additional displacement with respect to the isolated effect of mepyramine thus excluding activation of histamine H2 receptors. Histamine and (R)-alpha-methylhistamine, a selective histamine H3 receptor agonist, produced a moderate contractile effect on the resting tone of preparations. Pretreatment with the selective histamine H1 receptor antagonist decreased the (R)-alpha-methylhistamine response but increased the maximal relaxant effect and abolished the contractile effect of histamine, suggesting the presence of a limited population of contractile histamine H3 receptors. Removal of the endothelium or pretreatment with methylene blue produced a significant inhibition of the relaxant response to histamine. Remaining dilatation was practically abolished by mepyramine and also by indomethacin. The L-arginine analogue, N(omega)-nitro-L-arginine methyl ester (L-NAME) inhibited the effect of histamine and basal production of nitric oxide. L-Arginine, which on its own induced significant endothelium-dependent vasodilatation, reversed the effect of L-NAME on histamine relaxation. Indomethacin only caused a slight modification of the sensitivity of the vessels to histamine, suggesting that prostacyclin or other cyclo-oxygenase products did not make a significant contribution to the model. The absence of the endothelium did not modify the contractile effect of histamine. The results suggest that the relaxant response of isolated oviductal arteries to histamine is dependent on the functional integrity of the endothelium and is mainly mediated by histamine H1 receptors. These receptors may mask a minority presence of histamine H3 contractile receptors located on smooth muscle. The main relaxing factor released from the endothelium by mediation of histamine is nitric oxide, which may also exert an effect on vascular tone.
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PMID:Histamine receptors in isolated bovine oviductal arteries. 919 69

Responses to T-kinin and bradykinin were compared in the mesenteric vascular bed of the cat. Under constant-flow conditions, injection of T-kinin and bradykinin into the perfusion circuit induced similar dose-related decreases in perfusion pressure. Responses to T-kinin and bradykinin were inhibited by the kinin B2 receptor antagonist Hoe-140, but were not altered by the B1 receptor antagonist des-Arg9-[Leu8]-BK, the histamine H1 antagonist pyrilamine, the histamine H2 receptor antagonist cimetidine, or the H3 receptor antagonist thioperamide. Vasodilator responses to T-kinin and bradykinin were attenuated by the nitric oxide synthase inhibitor, N omega Nitro-L-arginine methyl ester (L-NAME), but were not altered by the cyclooxygenase inhibitor, sodium meclofenamate, or the K+ ATP channel antagonist, U37883A. These data suggest that vasodilator responses to T-kinin and bradykinin are mediated by kinin B2 receptor stimulated release of nitric oxide from the endothelium, but that the activation of kinin B1 receptors, the release of vasodilator prostaglandins, or the opening of K+ ATP channels are not involved in the response to T-kinin in the mesenteric vascular bed of the cat.
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PMID:Comparison of responses to T-kinin and bradykinin in the mesenteric vascular bed of the cat. 939 37

This study investigates the actions of Danshen crude extract (Salvia miltiorrhiza) on rat isolated femoral artery rings precontracted with phenylephrine. Low concentrations of Danshen (10 to 30 microg/mL) enhanced the phenylephrine-precontracted tone by a maximum of 31.20+/-2.71%. At concentrations 100 microg/mL or above, Danshen relaxed the precontracted tone, with full relaxation obtained at 1 mg/mL. Involvement of endothelium-dependant mechanisms in the dilator effect of Danshen was investigated by pretreatment of the artery rings with a cyclooxygenase inhibitor flurbiprofen (10 microM), a nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 100 microM), a muscarinic receptor antagonist atropine (100 nM), and by mechanical removal of the endothelium; none of these procedures produced a significant change on the Danshen-induced effect. Involvement of endothelium-independent mechanisms was investigated in endothelium-denuded artery rings pretreated with a histamine H2 receptor antagonist cimetidine (10 microM), a beta-adrenoceptor antagonist propranolol (100 nM), an adenylyl cyclase inhibitor 9-(tetrahydro-2-furanyl)-9H-purine-6-amine (SQ22536, 100 microM), a guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 10 microM), and a potassium channel inhibitor tetraethylammonium (TEA, 10 and 100 mM); only TEA was effective in partially inhibiting the Danshen-induced effect. These findings suggest the dilator action of Danshen on rat femoral artery was mediated in part by the opening of TEA-sensitive K+ channels in the smooth muscle cells. Muscarinic receptors, histamine receptors, beta-adrenoceptors, endothelium-derived relaxant factors, adenylyl cyclase, and guanylyl cyclase-dependent pathways did not play a role in its vasodilatory effect.
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PMID:Mechanisms of the dilator action of Danshen (Salvia miltiorrhiza) on rat isolated femoral artery. 1611 43