钙离子对犬原位心脏胆碱能效应的增强作用。

Enhancement by Ca2+ ions of cholinergic effects on the canine heart in situ.

作者信息

Chah Q T, Bertrix L, Lang J, Bouzouita K, Faucon G

出版信息

Naunyn Schmiedebergs Arch Pharmacol. 1983 Feb;322(1):59-64. doi: 10.1007/BF00649353.

Abstract

The effects of Ca2+ ions were studied on the canine heart in situ, submitted to vagal influence or not. In addition to heart rate, conduction time was determined separately in atrial muscle, atrioventricular node and His-Purkinje system by means of His bundle potential recording and the effective refractory period (ERP) measured in atrioventricular node, atrial and ventricular muscle according to the extrastimulus method. In the presence of acetylcholine (ACh) released by vagal endings, an increase in plasma calcium concentration from 2.40 to 4.12 mmol/l, acutely induced by the infusion of calcium chloride, elicits the following alterations: slowing down of sinus rate, lengthening of conduction time in atrioventricular node without change of this time in atrial muscle and His-Purkinje system, prolongation of atrioventricular node ERP, but notable decrease of atrial muscle ERP and slight decrease of ventricular muscle ERP. These effects are similar to those of ACh:Ca2+ ions probably enhance the responsiveness to ACh.

摘要

研究了钙离子对处于迷走神经影响或未受迷走神经影响的犬原位心脏的作用。除心率外，通过希氏束电位记录分别测定心房肌、房室结和希氏-浦肯野系统的传导时间，并根据额外刺激法测定房室结、心房肌和心室肌的有效不应期（ERP）。在迷走神经末梢释放乙酰胆碱（ACh）的情况下，通过输注氯化钙急性诱导血浆钙浓度从2.40 mmol/l升高至4.12 mmol/l，会引发以下改变：窦性心率减慢、房室结传导时间延长，而心房肌和希氏-浦肯野系统的传导时间无变化，房室结ERP延长，但心房肌ERP显著缩短，心室肌ERP略有缩短。这些效应与ACh的效应相似：钙离子可能增强了对ACh的反应性。