犬冠状静脉窦肌肉组织电生理特性的研究

The study of electrophysiological characteristics of coronary sinus musculature in canine

目的探讨冠状静脉窦肌肉组织和细胞的电生理特性。方法采用标准玻璃微电极技术同时记录犬冠状静脉窦肌肉结构和冠状静脉窦口(CSO)外右房组织的心肌细胞动作电位,并对比观察异丙肾上腺素灌流和电刺激条件下,冠状静脉窦内、外心肌组织中细胞电活动特点。结果冠状静脉窦内细胞和CSO外右房肌细胞动作电位符合快反应细胞特点,两者动作电位指标无显著性差异(P>0.05),但冠状静脉窦内细胞平台期明显。异丙肾上腺素灌流后,24条(24/30)冠状静脉窦组织块产生自发电活动,15条组织块的最早兴奋点很快迁移至冠状静脉窦内肌肉结构,且伴有频率的增快(310±30msvs385±11ms)。在CSO离断冠状静脉窦与心房肌后给予异丙肾上腺素,仅冠状静脉窦外右房组织能够产生自发电活动。在电刺激和异丙肾上腺素同时作用下,冠状静脉窦内心肌细胞可产生持续性电活动。结论冠状静脉窦内、外的心肌细胞发生自发电活动的机制不同。

Objective To investigate the electrophysiological characteristics of coronary sinus musculature and it＇s myocytes. Methods The action potential characteristics of myocytes in the coronary sinus and outside the ostium was observed, and the response to isoproterenol and electrical stimulation of myocytes were studied through standard glass microelectrode technology. Results The action potential characteristics of myocytes both in coronary sinus and outside the ostium were similar to that of fast reaction cells, there was no significant difference between them in the action potential parameters（ P 〉 0.05 ）. Isoproterenol yielded spontaneous activity in 24 （ 24/30 ） coronary sinus musculature preparations. The initial excitation in 15 preparations shifted into the coronary sinus musculature, with faster frequency （310 ± 30 ms vs 385 ±11ms）. After the right atrium myocytes were separated from the coronary sinus, only the right atrium myocytes showed spontaneous activity. In the presence of both isoproterenol and electrical stimuli, persistent electronic activity in coronary sinus were induced under certain condition. Conclusion The mechanism of the myocytes in and out coronary sinus develop eetopia arrhythmia is different.