中文摘要：

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（2245．60±372．50）MQ和（2101．50±513．50）MQ。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草碱（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，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，300μmol／L）阻断，并可被ATP敏感的钾通道阻断剂glipizide（5μmol／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。

英文摘要：

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.