Nandiwada P A, Lokhandwala M F, Jandhyala B S
Eur J Pharmacol. 1980 May 16;63(4):281-6. doi: 10.1016/0014-2999(80)90256-3.
Intravenous infusion of histamine (6.0 microgram/kg/min) attenuated bradycardic responses to electrical stimulation of right vagus in anesthetized mongrel dogs. Similarily histamine also reduced reflexly mediated decreases in the heart rate to phenylephrine, while bradycardia induced by exogenous acetylcholine was not altered. This inhibitory action of histamine on responses to vagal stimulation could be antagonized by pretreatment with metiamide, an H2-receptor antagonist; but not by pyrilamine, and H1-receptor blocker. Metiamide significantly potentiated the negative chronotrophic effect of vagal stimulation. These results indicate that histamine could inhibit peripheral vagal transmission via a presynaptic action. The ability of histamine to alter vagal transmission may have physiological significance and play a role in histamine-induced tachycardia.
静脉输注组胺（6.0微克/千克/分钟）可减弱麻醉杂种犬对右侧迷走神经电刺激的心动过缓反应。同样，组胺也能减少去氧肾上腺素反射介导的心率下降，而外源性乙酰胆碱诱导的心动过缓则未受影响。组胺对迷走神经刺激反应的这种抑制作用可被H2受体拮抗剂甲硫米特预处理所拮抗；但不能被H1受体阻滞剂吡苄明所拮抗。甲硫米特显著增强了迷走神经刺激的负性变时作用。这些结果表明，组胺可通过突触前作用抑制外周迷走神经传递。组胺改变迷走神经传递的能力可能具有生理意义，并在组胺诱导的心动过速中起作用。
