降钙素基因相关肽对大鼠心肌细胞L-型钙电流的影响

Effects of calcitonin gene-related peptide on L-calcium current in rat ventricular myocytes

目的观察降钙素基因相关肽(CGRP)对人鼠心肌细胞L-型钙电流(I_(Ca-1))的影响。方法SD大鼠,雌雄不拘,体重260～280g,急性分离其心肌细胞,用全细胞膜片钳方法记录I_(Ca-l)。1．依次记录经台氏液灌流(基础值)、含10^(-9)、10^(-8)、10^(-7)、10^(-6)mol/L CGRP的台氏液灌流和用台氏液洗脱后I_(Ca-L)峰值；2．记录含10^(-7)mol/L的CGRP台氏液灌流前后I_(Ga-L),并绘制I-V曲线。结果10^(-7)、10^(-6)mol/L CGRP可抑制大鼠心肌细胞I_(Ga-I)(P＜0．05),10^(-7)mol/L CGRP使大鼠心肌细胞I_(Ga-L)I-V曲线明显上移(P＜0．05),其电流峰值仍在OmV。结论CGRP可抑制大鼠心肌细胞I_(Ca-L)。

Objective To investigate the effects of calcitonin gene-related peptide （CGRP） on L-type calcium current （ICa-L ） in rat cardiomyocytes. Methods Ventricular myocytes were isolated from SD rats （260-280 g） by retrograde perfusion of the heart via the aorta with an enzyme-contalning solution as previously described. Whole-cell patch-clamp recording was made using Apopatch 200 B amplifier. 1. The cells were perfused first with Tyrode solution, then with Tyrode solution containing CGRP 10^-9 , 10^-8 , 10^-7 , 10^-6 mol. L^-1 and again washed with Tyrode solution. 2. ICa-L was recorded before and after the cells were perfused with solution containing CGRP 10^-7 mol.L^-1 and Ⅰ-Ⅴ curve was made. All experiments were performed at room temperature and solutions were saturated with 100% oxygen. Results CGRP 10^-7 and 10^-6 mol. L^-1 significantly inhibited the peak of ICa-L by 41% ± 7% and 92% ± 6% respectively as compared with control. CGRP 10^-7 mol. L^- 1 significantly inhibited Ⅰ-Ⅴ curve of ICa-L. Conclusion CGRP can inhibit ICa-L in rat cardiomyocytes.