【摘要】 采用常规微电极技术,观察豚鼠乳头肌兴奋性在重复模拟缺血下的变化及其对电场梯度方向的依赖性,并探讨重复缺血是否有累积损伤作用。结果显示:在对照及缺血的情况下,心肌细胞横向电场梯度舒张期兴奋阈(DET)均显著高于纵向。缺血开始后纵、横向 DET 均迅速降低,复灌期得以恢复,重复缺血对 DET 的影响差别不明显。有效不应期(ERP)在首次缺血复灌过程中变化不显著,在第2次缺血开始后缩短明显,复灌后恢复。提示:缺血时心肌 DET 降低,但对电场方向的依赖性仍存在;重复缺血具有累积作用。更多还原

【Abstract】 The changes of excitability of papillary muscle in guinea pig under the condition of repeated simulating ischemia and reperfusion and its dependence on stimulating electric field direction were investigated by using the conventional microelectrode technique and the cumulative effect of injury to myocardium induced by repeated is- chemia was explored.It was shown that the diastolic excitatory threshold (DET) of papillary muscle across the electric field direction was significantly higher than that along the electric field direction either under the control or ischemic condition.After the onset of ischemia,DET of either direction was decreased rapidly and recovered during reperfusion.The similar changes induced by repeated ischemia were observed.The changes of effective refractory period (ERP) during the first episode of ischemia and reperfusion were not significant.During the second ischemic episode ERPs decreased sharply and recovered during reperfusion.The results indicated that DET decreased when ischemia occurred with dependence on electric field direction.The changes of ERP revealed that the repeated is- chemia had a cumulative effect in the isloated guinea pig papillary muscle.更多还原