文章基本信息

标题：Calcium Channel Inhibitor, Verapamil, Inhibits the Voltage-Dependent K+ Channels in Rabbit Coronary Smooth Muscle Cells
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作者：Eun A Ko ; Won Sun Park ; Youn Kyoung Son 等
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：2010
卷号：33
期号：1
页码：47-52
DOI：10.1248/bpb.33.47
出版社：The Pharmaceutical Society of Japan
摘要：We investigated the effect of the phenylalkylamine Ca²⁺ channel inhibitor verapamil on voltage-dependent K⁺ (Kv) channels in rabbit coronary arterial smooth muscle cells using a whole-cell patch clamp technique. Verapamil reduced the Kv current amplitude in a concentration-depenent manner. The apparent K _d value for Kv channel inhibition was 0.82 μ M . Although verapamil had no effect on the activation kinetics, it accelerated the decay rate of Kv channel inactivation. The rate constants of association and dissociation by verapamil were 2.20±0.02 μ M ⁻¹ s⁻¹, and 1.79±0.26 s⁻¹, respectively. The steady-state activation and inactivation curves were unaffected by verapamil. The application of train pulses increased the verapamil-induced Kv channel inhibition. Furthermore, verapamil increased the recovery time constant, suggesting that the inhibitory effect of this agent was use-dependent. The inhibitory effect of verapamil was not affected by intracellular and extracellular Ca²⁺-free conditions. Another Ca²⁺ channel inhibitor, nifedipine (10 μ M ) did not affect the Kv current, and did not alter the inhibitory effect of verapamil. Based on these results, we concluded that verapamil inhibited Kv current in a state-, time-, and use-dependent manner, independent of Ca²⁺ channel inhibition.
关键词：verapamil;voltage-dependent K+ channel;coronary arterial smooth muscle cell