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目的:研究在模拟缺氧-复氧再灌注条件下机械牵张对钙预适应(CPC)离体豚鼠乳头肌电生理特性的影响。方法:利用细胞内标准玻璃微电极技术,记录并观察一定牵张力(200mg强度)作用下钙预适应乳头肌细胞动作电位(AP)和有效不应期(ERP)的变化。结果:牵张可使单纯缺氧-复氧再灌注(AR)组和CPC组在整个缺氧期除兴奋传导时间(CT)明显延长外,Vmax、RP、APA、APD50、APD90和ERP等参数明显缩短,但对CPC组的影响较小。而牵张可使两组在复氧再灌注期的动作电位的Vmax、RP、APA、APD50和ERP降低,CT和APD90延长,但对CPC组的影响较小。链霉素可抑制机械牵张对CPC组上述参数的影响。结论:在模拟缺氧-复氧再灌注条件下,CPC乳头肌对机械牵张的耐受性增强;链霉素则可抑制牵张对CPC心肌电生理特性的影响。
OBJECTIVE: To study the effect of mechanical stretch on the electrophysiological characteristics of guinea pig papillary muscle after calcium preconditioning (CPC) under hypoxia-reoxygenation reperfusion. Methods: The changes of action potential (AP) and effective refractory period (ERP) of preconditioned papillary muscle cells under certain stretch (200mg intensity) were recorded and observed by intracellular standard glass microelectrode technique. Results: Extrinsic hypoxic-reperfusion (AR) group and CPC group could prolong the duration of excitatory conduction time (CT), but Vmax, RP, APA, APD50, APD90 and ERP parameters Significantly shorter, but less impact on the CPC group. However, distraction decreased Vmax, RP, APA, APD50 and ERP, prolonged CT and APD90, but had less effect on CPC in reperfusion. Streptomycin can inhibit the mechanical stretch on the CPC parameters of these effects. Conclusion: Under hypoxia-reoxygenation reperfusion, CPC papillary muscle is more resistant to mechanical stretch. Streptomycin can inhibit the electrophysiological characteristics of CPC.