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目的 :观察腺苷在正常和“缺血”条件下对浦肯野纤维起搏离子流 If的影响。 方法 :成年绵羊离体心室浦肯野纤维分腺苷组、“缺血”+腺苷组及“缺血”+腺苷 +异丙肾上腺素组 (n均 =10 ) ,用双微电极电压钳制术 ,分别观察不同膜电位水平的起搏离子流 If幅值和激活时间。 结果 :腺苷组起搏离子流 If 幅值降低 (P<0 .0 5 ) ;“缺血”+腺苷组起搏离子流 If 幅值在“缺血”时不仅降低 (P<0 .0 5 ) ,且激活时间延长 ;加腺苷后起搏离子流 If幅值进一步降低 (与“缺血”对照 P<0 .0 5 ) ;而“缺血”+腺苷 +异丙肾上腺素组起搏离子流 If幅值低于正常对照 (P<0 .0 5 )。 结论 :腺苷对浦肯野纤维自律活动在正常和“缺血”液中都有抑制作用 ,大量儿茶酚胺只能部分逆转“缺血”抑制效应。
OBJECTIVE: To observe the effect of adenosine on Purkinje fiber Pacing current If under normal and “ischemic” conditions. Methods: Adult sheep were divided into adenosine group, ischemic group and adenosine group and ischemic group + adenosine + isoproterenol group (n = 10), with double microelectrode voltage The technique of clamping was used to observe the amplitude and activation time of pacing ion current If with different membrane potential. Results: The amplitude of pacing ion flow in adenosine group was decreased (P <0.05). The amplitude of pacing ion flow in ischemic group and adenosine group was not only decreased at ischemia (P <0. 0 5), and the activation time was prolonged; the amplitude of paced ion flow If was further reduced with adenosine (compared with “ischemic” control P <0.05); while “ischemia” + adenosine + isoproterenol Group pacing ion current If amplitude lower than the normal control (P <0. 05). CONCLUSION: Adenosine inhibits Purkinje fiber autonomic activity in both normal and “ischemic” fluids. A large amount of catecholamines can only partly reverse the “ischemic” inhibitory effect.