Li Qian, Cheng Yan-Ping, He Rui-Rong
Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang 050017.
Sheng Li Xue Bao. 2003 Oct 25;55(5):511-5.
The cardiac electrophysiological effects of capsaicin (CAP) were examined in guinea pig papillary muscles using intracellular microelectrode technique. The results obtained are as follows: (1) the duration of action potential (APD) in normal papillary muscles was decreased by CAP (30, 60, 120 micromol/L) in a concentration-dependent manner; (2) in partially depolarized papillary muscles, 60 micromol/L CAP not only reduced APD, but also decreased the amplitude of action potential, overshoot and maximal velocity of phase 0 depolarization; (3) pretreatment with L-type Ca(2+) channel agonist Bay K8644 (0.5 micromol/L) could completely block the effects of CAP (60 micromol/L); (4) pretreatment with ruthenium red (20 micromol/L), a vanilloid receptor (VR) blocker, did not affect the actions of capsaicin on papillary muscles. All these results suggest that the effects of CAP on papillary muscles are likely due to a decrease in calcium influx which is not mediated by VR.
采用细胞内微电极技术，在豚鼠乳头肌中研究了辣椒素（CAP）的心脏电生理效应。获得的结果如下：（1）正常乳头肌中的动作电位时程（APD）被CAP（30、60、120微摩尔/升）以浓度依赖性方式缩短；（2）在部分去极化的乳头肌中，60微摩尔/升的CAP不仅缩短了APD，还降低了动作电位幅度、超射值和0期去极化的最大速度；（3）用L型钙通道激动剂Bay K8644（0.5微摩尔/升）预处理可完全阻断CAP（60微摩尔/升）的作用；（4）用香草酸受体（VR）阻断剂钌红（20微摩尔/升）预处理不影响辣椒素对乳头肌的作用。所有这些结果表明，CAP对乳头肌的作用可能是由于钙内流减少，而这并非由VR介导。
