乙酰胆碱和环核苷酸对牛蛙心房肌的作用。

Effects of acetylcholine and cyclic nucleotides on the bullfrog atrial muscle.

作者信息

Ikemoto Y, Goto M

出版信息

Recent Adv Stud Cardiac Struct Metab. 1976;11:57-61.

PMID:201995

Abstract

Effects of ACh on the slow inward current and tension components of bullfrog atrial muscle were examined with voltage-clamp technique. ACh decreased the phasic component of contractile tension and the slow inward current with a reduction of gCa. Contracture tensions were augmented by ACh and decreased by adrenaline. Intracellularly injected cGMP through microelectrode decreased the overshoot and the plateau level of action potential without affecting the resting membrane potential, indicating a decrease in the slow inward current. cAMP enhanced the overshoot and the plateau. ACh seems to reduce the slow inward current through an elevation of intracellular cGMP concentrations.

摘要

采用电压钳技术研究了乙酰胆碱（ACh）对牛蛙心房肌慢内向电流和张力成分的影响。ACh使收缩张力的时相成分和慢内向电流降低，同时钙电导（gCa）减小。ACh可增强挛缩张力，而肾上腺素则使其降低。通过微电极向细胞内注入环磷酸鸟苷（cGMP）可降低动作电位的超射值和平台期水平，而不影响静息膜电位，提示慢内向电流减小。环磷酸腺苷（cAMP）则增强超射值和平台期。ACh似乎通过提高细胞内cGMP浓度来降低慢内向电流。