哌仑西平对兔急性心肌缺血心室颤动阈值的影响及其机制

Effect of pirenzepine on the ventricular fibrillation threshold during acute myocardial ischemia in rabbits and its mechanism

目的 :观察小剂量哌仑西平对兔急性心肌缺血心室颤动阈值的影响。探讨自主神经作用及其机制。方法 :建立兔急性心肌缺血模型。采用颈迷走神经切断术、心脏交感神经化学切割技术建立不同自主神经支配的心脏模型。以心率变异频域指标测定心脏自主神经活性 ,应用心电生理研究方法测定急性心肌缺血心室颤动阈值 (VFT)。结果 :兔急性心肌缺血时 ,哌仑西平预处理组较单纯结扎组频域指标 VL F,L F与 L F/ HF降低 ,HF增高 ;电生理指标VFT增高。颈迷走神经切断后 ,急性心肌缺血时 ,哌仑西平预处理组较单纯结扎组频域指标 VL F,L F,L F/ HF降低 ,HF无显著变化 ,VFT增加。心脏交感神经化学切除后 ,急性心肌缺血时 ,哌仑西平预处理组较单纯结扎组频域指标 VL F,L F,L F/ HF降低 ,HF增加 ,VFT增大。结论 :小剂量哌仑西平预处理能改善兔急性心肌缺血时的心电生理不稳定状态。

AIM:To observe the effect of low dose pirenzepine (PZP) on the ventricular fibrillation threshold(VFT) in myocardial ischemia model of rabbits and its mechanism.METHODS:In the model,VFT was measured with electrophysiological methods and the power domain parameters of heart rate variability (HRV) including VLF,LF,HF and LF/HF were assessed. The activity of cardiac autonomic nervous sytem was changed by vagotomy and chemical sympathectomy.RESULTS:When acute myocardial ischemia haeppened,in PZP pretreatment group,compared with the single ligation group,VLF,LF and LF/HF decreased;HF increased and VFT increased. With cervical vagotomy,when acute myocardial ischemia happened,in PZP pretreatment group, compared with the single ligation group,VLF,LF and LF/HF decreased;HF did not changed and VFT increased. With cardiac sympathectomy,when acute myocardial ischemia happened,in PZP pretreatment group,compared with the single ligation group,VLF,LF and HF/HF decreased;HF increased and VFT increased.CONCLUSION:The pretreatment of low dose PZP enhanced the cardiac electrical stability in acute myocardial ischemia through decreasing cardiac sympathetic activity directly and increasing cardiac parasympathetic activity directly.