降钙素基因相关肽对正常及模拟缺血缺氧心肌钙通道的作用及心肌细胞数学模型的仿真研究

Effects of CGRP on cardiac Ca^(2+) channel on normal,imitating ischemia and hypoxia conditions and simulation on mathematical model of cardiac myocytes

作者运用细胞培养、膜片钳和激光共聚焦技术 ,观察了降钙素基因相关肽 (CGRP)对正常及模拟缺血、缺氧心肌细胞钙通道的作用及其电生理离子机制 ,并利用计算机重建技术在心肌细胞通道动力学及电流重建等方面进行了探索性研究 ,得到了如下提示性结论 :1CGRP对心肌的保护作用有赖于适当剂量和浓度 ;2本课题建立的急性心肌细胞分离方法 ,能够得到具有正常电生理特性的耐钙心肌细胞 ,是膜片钳实验和激光扫描共聚焦技术测定胞内钙的基础 ;3CGRP对急性缺血、缺氧心肌细胞具有保护作用 ,在急性缺血、缺氧时 ,急性分离的心肌细胞胞内钙离子浓度降低 ,CGRP可引起胞内钙浓度稍微升高 ,且 CGRP可改善因急性缺血、缺氧引起的胞内钙浓度的降低 ,其机制有待于进一步探讨 ;4CGRP能促使正常及模拟缺血缺氧状态下豚鼠心室肌细胞 ICa内流的增加 ,是 CGRP正性作用的主要离子机制 ;CGRP对钙通道的作用机制还有待进一步研究 ;5本课题建立的对几种离子电流的计算机重建方法 ,提示可以被用来讨论离子电流机制 。

By using cell culture, the patch clamp technique and laser scanning confocal technique, this study focused on the effects of calcitonin gene related peptide(CGRP) on cardiac calcium channel on normal condition as well as on imitating ischemia and hypoxia conditions and the electrophysiological ionic mechanisms. Meanwhile by using computer construction technique, this study tried to reconstruct channel dynamic courses and currents. The studies suggested that: ①The appropriate dosage and concentration of CGRP showed protective effect on culture cardiomyocytes; ②The isolation method established in this study can provide calcium tolerant single ventricular myocytes which had normal electrophysiological properties and guaranteed a smooth operation of patch clamp and laser scanning confocal experiments; ③CGRP had protective effect on acute hypoxia and ischemia cardiomyocytes. But these effects might be the joint result of many factors and need to be further investigated; ④CGRP had significant enhancement effects on I Ca L in guinea pig ventricular myocytes under normal condition as well as under imitating ischemia and hypoxia conditions, which suggested that its effect might be the main ionic channel mechanism of its positive effects; ⑤The mathematical models of all ionic currents established in this study could simulate the properties of ionic currents and channel dynamic courses properly and could provide some theoretical proofs for further animal experiments.