Impicciatore M, Morini G, Chiavarini M, Bordi F
Eur J Pharmacol. 1983 Jun 3;90(2-3):231-5. doi: 10.1016/0014-2999(83)90242-x.
Dose-response curves of histamine were studied on the mesenteric circulation of the anaesthetized rat. The vasodilation produced by small doses of histamine was prevailingly H2-receptor-dependent, as shown by its inhibition by cimetidine but not by mepyramine, and by its reproducibility by some H2-receptor agonists, but not by specific H1-receptor agonists. The vasodilation produced by high doses of histamine was mainly due to stimulation of H1-receptors, as shown by its 70% inhibition by mepyramine. Mepyramine and cimetidine given simultaneously nearly completely inhibited the vasodilating action of high doses of histamine. Certain H2-receptor agonists, administered at high doses, induced a paradoxical vasoconstriction. It is suggested that a small number of H2-receptors is present in rat mesenteric arterioles, and that these receptors may play a physiological role in the control of mesenteric circulation.
在麻醉大鼠的肠系膜循环上研究了组胺的剂量-反应曲线。小剂量组胺产生的血管舒张主要依赖于H2受体，西咪替丁可抑制该反应而甲氧苄二胺则不能，并且一些H2受体激动剂可重现该反应，而特异性H1受体激动剂则不能，这些均证明了这一点。大剂量组胺产生的血管舒张主要是由于H1受体的刺激，甲氧苄二胺对其有70%的抑制作用即证明了这一点。同时给予甲氧苄二胺和西咪替丁几乎可完全抑制大剂量组胺的血管舒张作用。某些高剂量给药的H2受体激动剂可诱发反常的血管收缩。提示大鼠肠系膜小动脉中存在少量H2受体，并且这些受体可能在肠系膜循环的控制中发挥生理作用。
