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一氧化氮和K~(+)通道参与乙酰胆碱引起的大鼠离体输精管平滑肌细胞超极化

范平, 李丽, 刘政江, 司军强, 张志琴, 赵磊, 马克涛

石河子大学医学院民族高发病与地方病教育部重点实验室电生理学研究室.新疆,石河子 832002

摘要

该文旨在探讨大鼠新鲜离体输精管平滑肌细胞中乙酰胆碱（acetylcholine，ACh）引起超极化反应的机制，采用细胞内微电极记录技术和细胞内荧光标记技术研究ACh对大鼠输精管不同走行方向平滑肌细胞的作用。用尖端含0.1％碘化吡啶（propidium iodide，PI）的记录电极标记电生理记录后的平滑肌细胞，其中37个为外层纵行细胞，17个为内层环行细胞。它们的平均静息膜电位分别为（--53.56±3.88）mV和（--51.62±4.27）mV，膜输入阻抗分别为（2245.60±372.50）M#OMEGA#和（2101.50±513.50）M#OMEGA#。ACh引起的膜超极化反应是浓度依赖性的，EC_(50)为36 #mu#mol／L。ACh引起的超极化反应可被非选择性的毒草碱（muscarinic receptor，M）受体阻断剂阿托品（atropine，1 #mu#mol／L）和选择性的M_(3)受体阻断剂diphenylacetoxy--N--methylpiperidine--methiodide（DAMP，100nmol/L）阻断。ACh引起的超极化还能被一氧化氮合酶抑制剂L--硝基--精氨酸甲酯（N--nitro--L--arginine methylester，L--NAME，300#mu#mol／L）阻断，并可被ATP敏感的钾通道阻断剂glipizide（5#mu#mol／L）或内向整流钾通道阻断剂钡离子（50#mu#mol／L）部分阻断。Glipizide和钡离子联合使用可完全阻断ACh引起的超极化反应。上述结果表明：ACh通过作用于大鼠输精管平滑肌细胞膜上的M_(3)受体引起超极化反应，一氧化氮、ATP敏感性钾通道和内向整流钾通道参与了ACh引起的超极化反应。

关键词： 输精管; 平滑肌细胞; 超极化; 钾通道; 乙酰胆碱

ACh--evoked membrane hyperpolarization in smooth muscle cells of rat vas deferens {sl in vitro}： Involvement of K~(+) channels and NO

Fan Ping, Li Li, Liu Zhengjiang, Si Junqiang, Zhang Zhiqin, Zhao Lei, Ma Ketao

Laboratory of Xinjiang Endemic and Ethnic Diseases, Institute of Electrophysiology, Medical College Shihezi University.Shihezi 832002,Xinjiang

Abstract

To explore the underlying mechanism of acetylcholine （ACh）-evoked membrane hyperpolarizing response in isolated rat vas deferens smooth muscle cells （SMCs）, intracellular microelectrode recording technique and intracellular microelectrophoresis fluorescent staining technique were used to study ACh-evoked membrane hyperpolarizing response in SMCs freshly isolated from Wistar rat vas deferens. By using microelectrodes containing fluorescent dye 0.1% propidium iodide （PI）, 37 and 17 cells were identified as SMCs in outer longitudinal and inner circular muscular layers, respectively. The resting membrane potentials of SMCs were （-53.56±3.88） mV and （-51.62±4.27） mV, respectively. The membrane input resistances were （2245.60±372.50） M#OMEGA# and （2101.50±513.50）M#OMEGA#, respectively. ACh evoked membrane hyperpolarizing response in a concentration-dependent manner with an EC_(50) of 36 #mu#mol/L. This action of ACh was abolished by both a non-sepeific muscarinic （M） receptor antagonist atropine （1 #mu#mol/L） and a selective M_(3) receptor antagonist diphenylacetoxy-N-methylpiperidine-methiodide （DAMP, 100 nmol/L）. ACh-evoked membrane hyperpolarization was also abolished by a nitric oxide synthase inhibitor N-nitro-L-arginine methyl ester （L-NAME, 300 #mu#mol/ L） and suppressed by an ATP-sensitive potassium （K_(ATP)） channel blocker glipizide （5 #mu#mol/L） and an inward rectifier potassium （K_(ir)） channel inhibitor bariumion （50 #mu#mol/L）. A combination of glipizide and bariumion abolished ACh-evoked membrane hyperpolarizing response. The results suggest that ACh-evoked membrane hyperpolarization in rat vas deferens SMCs is mediated by M_(3) receptor followed with activation of K_(ATP) channels, K_(ir) channels, and NO release.

Key words: vas deferens;Smooth muscle cell;hyperpolarization;Potassium channel;Acetylcholine

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引用本文：

范平, 李丽, 刘政江, 司军强, 张志琴, 赵磊, 马克涛. 一氧化氮和K~(+)通道参与乙酰胆碱引起的大鼠离体输精管平滑肌细胞超极化[J]. 生理学报 2007; 59 (3): 331-338.

Fan Ping, Li Li, Liu Zhengjiang, Si Junqiang, Zhang Zhiqin, Zhao Lei, Ma Ketao. ACh--evoked membrane hyperpolarization in smooth muscle cells of rat vas deferens {sl in vitro}： Involvement of K~(+) channels and NO. Acta Physiol Sin 2007; 59 (3): 331-338 (in Chinese with English abstract).