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(英文)  

ACh-evoked membrane hyperpolarization in smooth muscle cells of rat vas deferens in vitro: Involvement of K^+ channels and NO

作　　者：范平[1,2] 李丽[1] 刘政江[1] 司军强[1,3] 张志琴[1] 赵磊[1] 马克涛[1] 

机构地区：[1]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 [2]新疆医科大学第一附属医院,乌鲁木齐830054 [3]武汉大学基础医学院生理学系,武汉430071

出　　处：《生理学报》2007年第3期331-338,共8页Acta Physiologica Sinica

基　　金：the National Natural Science Foundation of China (No. 30460043) ;the Doctor Foundation of Shihezi University (No. 200350)

摘　　要：本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(2 245.60±372.50) MΩ和 (2 101.50±513.50)MΩ。ACh 引起的膜超极化反应是浓度依赖性的, EC50 为 36 μmol/L。ACh 引起的超极化反应可被非选择性的毒蕈碱(muscarinic receptor, M) 受体阻断剂阿托品(atropine, 1 μmol/L)和选择性的 M3 受体阻断剂 diphenylacetoxy-N-methylpiperidine-methiodide (DAMP, 100 nmol/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 μmol/L)阻断,并可被 ATP 敏感的钾通道阻断剂 glipizide (5 μmol/L) 或内向整流钾通道阻断剂钡离子(50μmol/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M3 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 。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 （2 245.60±372.50） MΩ and （2 101.50±513.50） MΩ, respectively. ACh evoked membrane hyperpolarizing response in a concentration-dependent manner with an EC50 of 36 μmol/L. This action of ACh was abolished by both a non-sepeific muscarinic （M） receptor antagonist atropine （1 μmol/L） and a selective M3 receptor antagonist diphenylacetoxy-N-methylpiperidine-methiodide （DAMP, 100 nmol/L）. ACh-evoked mem- brane hyperpolarization was also abolished by a nitric oxide synthase inhibitor N-nitro-L-arginine methyl ester （L-NAME, 300 μmol/ L） and suppressed by an ATP-sensitive potassium （KATP） channel blocker glipizide （5 μmol/L） and an inward rectifier potassium （Kir） channel inhibitor bariumion （50 μmol/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 M3 receptor followed with activation of KATP channels, Kir channels, and NO release.

关 键 词：输精管 平滑肌细胞:超极化 钾通道 乙酰胆碱 

分 类 号：R339.2[医药卫生—人体生理学]