海洛因成瘾模型大鼠心肌细胞的动作电位和L型钙通道电流

摘要

BACKGROUND:Calcium channel abnormalities can damage myocardium. Heroin can directly affect calcium ion channel, and alter myocardial structure. OBJECTIVE:To study the changes of heroin-induced myocardial ultrastructure, L-type calcium channel current and action potential of myocardial cel s after rat cardiac arrhythmia. METHODS:Sprague-Dawley rats were randomly divided into control group and model group. In the model group, rats were administered heroin at initial dose of 5 mg/kg•d. The daily dose escalation method was used (increasing dose:2.5 mg/kg•d) to replicate rat models of heroin addiction. At 20 days, models of heroin addiction were successful y established. At 30 days after increasing the dose, rat models of heroin addiction-induced arrhythmias were further established. RESULTS AND CONCLUSION:Compared with the control group, the electron microscopy demonstrated that myocardial structure changes mainly presented nuclear membrane shrinkage, nuclear condensation, nuclei became smal , chromatin assembled into blocks, mitochondria disordered and disappeared, sarcomeres disordered, focal fracture, and unclear myofilament in rat models of heroin addiction. Electric current-voltage curve of myocardial cel L-type calcium channel current showed the increasing trends. The 90%repolarization action potential was significantly shortened. These data indicated that heroin can directly lead to the pathological change of myocardial structure. Calcium channel current change is one of the main reasons for myocardial injury.%背景：钙离子通道异常可导致心肌受损，海洛因可直接作用钙离子通道，从而改变心肌结构。　　目的：观察海洛因成瘾致大鼠心律失常后心肌细胞超微结构、L 型钙离子通道电流及心肌细胞动作电位的变化情况。　　方法：SD大鼠随机分为对照组和模型组，模型组大鼠以海洛因初使剂量5 mg/(kg•d)，采用逐日剂量递增法[递增剂量2.5 mg/(kg•d)]复制海洛因成瘾大鼠模型；20 d海洛因成瘾模型成功建立，继续递增剂量至第30天，进一步建立海洛因成瘾大鼠心律失常模型。　　结果与结论：与对照组相比，海洛因成瘾大鼠心肌电镜结构改变主要表现在细胞核膜皱缩、核浓缩、变小，染色质集结成块，线粒体嵴排列紊乱、消失，肌小节排列紊乱、灶性断裂，肌丝辨识不清等，心肌细胞 L 型钙通道电流-电压曲线呈现上移趋势，90%去极化动作电位显著缩短。表明海洛因可直接致心肌结构发生病理改变，钙通道电流发生改变是造成心肌损伤的主要原因之一。