快速刺激对豚鼠心房肌动作电位的影响及自主神经受体激动剂的干预作用

目的：了解自主神经受体激动剂对豚鼠离体心房肌电生理参数的影响及其对20min快速刺激引起的心房肌动作电位的变化的干预作用。方法：采用玻璃微电极技术，观察乙酰胆碱（Ach）、丙基肾上腺素（Iso）和去甲肾上腺素（NA）灌流前后3种频率（120，60，40次/min）下豚鼠离体心房肌动作电位的变化，然后给予20min400次/min快速刺激，比较对照组和3个药物灌流组的恢复过程。结果：Ach可缩短动作电位时程（APD）和不应期（ERP），延长快速刺激后的APD和ERP的恢复过程，Iso可缩短ERP，增加与起搏有关的心律失常的发生，延长快速刺激后ERP的恢复过程，对APD90的恢复过程无明显影响。NA延长APD90及ERP，对恢复过程无负性影响。结论：迷走神经在房颤中发挥重要作用并加重电重构的发生，钙离子超负荷不是惟一的机制。交感神经兴奋利于房颤的诱发，但由于α、β受体的作用相拮抗，交感神经在电重构中不发挥主要作用。

The Influence of Rapid Stimulation on Atrial Action Potential and Intervention of Autonomic Receptor Activator in Guinea Pig

Objective:To study the influence of rapid stimulation on artial action potential and intervention of autonomic receptor activator in guinea pig.Methods:Using standard microelectrode technique to examine the effects of autonomic receptor agonists(acetylcholine,isoproterenol,noradrenaline)on the electrophysiological characteristic of atrial muscles in guinea pigs under three rates(120,60,40 times/min,respectively),and to evaluate the effects on the recovery of action potential after 20 min 400 times/min rapid stimulation.Results:Acetylcholine decreased APD and ERP of atrial muscles,delayed the recovery of action potential after rapid stimulation.Isoproterenol shortened ERP,delayed the recovery of ERP,increased the occurrence of arrhythmia.Noradrenaline increased ADP 90 and ERP,but had no adverse effects on recovery course after stimulation.Conclusion:Parasympathetic nerve may play an important role in electrical remodeling,and sympathetic nerve facilitates the occurrence of atrial fibrillation.