老年大鼠心肌磷脂和钙通道变化及其与心律失常的关系

目的探讨老年大鼠心肌磷脂和钙通道的变化及其与心律失常发生的关系。方法比较老年（２４～２６月龄）和青年（３～４月龄）大鼠极小量肾上腺素诱发心律失常的发生率、持续时间、病死率以及心室晚电位、心肌膜磷脂组分、钙通道二氢吡啶（ＤＨＰ）受体活性、超氧化物歧化酶（ＳＯＤ）活性的变化。结果老年大鼠心律失常诱发率高达１００％，病死率２３．５％，同时还存在膜卵磷脂降解；ＤＨＰ受体平均解离常数（ｋｄ值）增大４４％，最大结合率（Ｂｍａｘ）增高３２％；ＳＯＤ活性降低近５０％。结论老年大鼠易发心律失常，其机理可能与心肌膜稳定性降低及分子受体活性衰退有关。

The relationship between the chauges of myocardium phospholipids and calcium channel with cardiac arrkythmiar in aged rets

Objective To investigate the changes of myocardium phospholipids and calcium channel in aged rats,and their relationship with cardiac arrhythmias.Methods One hundred and thirtyfour SD rats were divided into four groups:younger control(3-4 months) and arrhythmia groups,aged control(24-26 months) and arrhythmia groups.Arrhythmias induced by epinephrine myocardium phospholipids,calcium channel and SOD activity were observed.Results The resuits showed that 100% aged rats had arrhythmias and 23.5% died with total phospholipids, phosphatidyl choline(PC) decreased significantly, kd and Bmax of dihydropyridine(DHP) calcium channel increased.Concluslons These facts suggest that arrhythmias found more frequently in aged rats,may be due to the ageing changes of myocardium phospholipids and calcium channel.