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目的 :研究乙酰胆碱 (ACh)对离体豚鼠心室肌的直接负性作用及机制。方法 :采用标准玻璃微电极细胞内记录技术记录动作电位 (AP)及肌力换能器记录心肌收缩力 (FC)的方法观察 ACh对离体豚鼠心室肌的作用 ,并观察几种受体或通道水平的阻断剂阿托品、氯化铯 (Cs Cl)、氯化镉 (Cd Cl2 )对 ACh直接作用的影响。结果 :10 - 5 mol/LACh对心室肌动作电位持续时间 (APD)及 FC的抑制率分别为 7.31%和 37.5 7% (P<0 .0 5 ) ,10 - 5 mol/L阿托品和 2 0 m mol/L Cs Cl可阻断该作用 ,0 .1m mol/L Cd Cl2 对该作用无影响。结论 :10 - 5 m ol/L ACh对离体豚鼠心室肌有直接负性作用 ,ACh的作用与毒蕈碱型胆碱受体及 K+电流有关 ,而与 Ca2 +电流的关系可能不大。
Objective: To study the direct negative effect of acetylcholine (ACh) on isolated guinea pig ventricular myocytes and its mechanism. Methods: The effect of ACh on ventricular myocardium of isolated guinea pigs was observed by recording the action potential (AP) and muscle transducer (FC) using standard glass microelectrode intracellular recording technique and observed the effects of several receptors or Effects of Atropine, Cs Cl and Cd Cl2 at Channel Level on Direct Action of ACh. Results: The duration of ventricular action potential (APD) and FC inhibition of 10-5 mol / L ACh were 7.31% and 37.5 7%, respectively (P <0.05). The inhibitory rates of 10-5 mol / L atropine and 20 m mol / L CsCl can block this effect, and 0.1 mol / L CdCl2 has no effect on this effect. CONCLUSION: ACh exerts a direct negative effect on isolated ventricular myocytes in vitro. The effect of ACh on muscarinic receptors and K + currents may not be related to Ca2 + currents.