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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 。
The purpose of this study was to investigate the mechanism of hyperpolarization induced by acetylcholine (ACh) in fresh isolated rat vas deferens smooth muscle cells. The intracellular microelectrode recording technique and intracellular fluorescent labeling were used to study the effect of ACh on vas deferens in different walking direction The role of cells. Electrophysiological recordings of smooth muscle cells were recorded on the tip of a recording electrode containing 0.1% propidium iodide (PI), of which 37 were outer longitudinal cells and 17 were inner peripheral cells. Their average resting membrane potentials were (-53.56 ± 3.88) mV and (-51.62 ± 4.27) mV, respectively, with membrane input impedances of (2 245.60 ± 372.50) MΩ and (2 101.50 ± 513.50) MΩ, respectively. The membrane hyperpolarization induced by ACh is concentration-dependent with an EC50 of 36 μmol / L. ACh-induced hyperpolarization can be induced by the non-selective muscarinic receptor (M) receptor blocker atropine (1 μmol / L) and the selective M3 receptor blocker diphenylacetoxy-N- methylpiperidine-methiodide (DAMP, 100 nmol / L). The hyperpolarization induced by ACh can also be blocked by N-nitro-L-arginine methyl ester (L-NAME, 300 μmol / L) It was partially blocked by the ATP sensitive potassium channel blocker glipizide (5 μmol / L) or the inward rectifier potassium channel blocker barium ion (50 μmol / L). The combination of Glipizide and barium ion completely blocked ACh-induced hyperpolarization. The above results indicate that ACh induces hyperpolarization by M3 receptors on the membrane of rat vas deferens smooth muscle cells. Nitric oxide, ATP-sensitive potassium channel and inward rectifier potassium channel are involved in ACh-induced hyperpolarization.