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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。
Objective To investigate the changes of myocardial phospholipid and calcium channels in aged rats and its relationship with arrhythmia. Methods The incidence, duration and mortality of minimal adrenergic-induced arrhythmia in the aged (24-26 months) and young (3-4 months) rats were compared. The ventricular extracellular potential, myocardial phospholipid component, calcium Changes in channel dihydropyridine (DHP) receptor activity and superoxide dismutase (SOD) activity. Results The induction rate of arrhythmia in aged rats was as high as 100% and the mortality rate was 23.5%. At the same time, membrane lecithin degradation was observed. The mean dissociation constant (kd) of DHP receptor increased 44% and the maximum binding rate (Bmax) increased 32%; SOD activity decreased by nearly 50%. Conclusion The incidence of arrhythmia in elderly rats may be related to the decrease of myocardial membrane stability and the decline of molecular receptor activity.