CGRP对正常及模拟缺血缺氧状态下豚鼠心肌细胞L型钙通道电流的影响

目的　探讨降钙素基因相关肽 (CGRP)对正常及模拟缺血缺氧状态下豚鼠心肌细胞钙通道电流的作用。方法　标准全细胞膜片钳记录方式。结果　当心室肌细胞由保持电压 - 40mV除极到 0mV时 ,10 -9、10 -8、和 10 -7mol·L-1的CGRP分别使正常状态下ICa L由 (1 2 6± 0 18)nA (n=8)增加到 (1 87± 0 2 5 )nA (P <0 0 5 ,n =8) ,(1 90±0 2 6 )nA (P <0 0 5 ,n =6 )和 (2 10± 0 2 7)nA (P <0 0 5 ,n=5 ) ;使模拟缺血缺氧状态下ICa L由原来的 (0 71± 0 10 )nA (n =8)增加到 (0 95± 0 12 )nA (P <0 0 1,n =6 ) ,(1 13± 0 15 )nA (P <0 0 5 ,n =4)和 (1 2 6± 0 13)nA(P <0 0 5 ,n =4) ,且对ICa L的最大激活电位无明显影响 ,两者差异无统计学意义。结论　CGRP对正常及模拟缺血缺氧状态下ICa L有明显的促进作用 ,该作用可能是CGRP发挥其心血管效应的离子通道机制之一。

Effect of CGRP on L-type calcium channel current in guinea pig single ventricular myocytes on normal, imitating ischemia and hypoxia conditions

AIM To study the effect of CGRP on L-type calcium channel current in guinea pig ventricular myocytes under normal and imitating ischemia and hypoxia conditions. METHOD The whole-cell patch clamp recording technique was used. RESULTS When the ventricular cell was held at -40 mV and depolarized to 0 mV, 1×10 -9 、1×10 -8 and 1×10 -7 mol·L -1 CGRP increased I Ca-L from(1 26±0 18)nA ( n =8) to (1 87±0 25)nA ( P <0 05, n =8),(1 90±0 26)nA ( P <0 05, n =6) and(2 10±0 27)nA ( P <0 05, n =5) respectively under normal condition. While under imitating ischemia and hypoxia condition, it increased I Ca-L from(0 71±0 10)nA ( n =8) to (0 95±0 12)nA ( P <0 01, n =6),(1 13±0 15)nA ( P <0 05, n =4) and(1 26±0 13)nA ( P <0 05, n =4) respectively. However it had no siginficent effect on maxium active voltage and there is no statistic difference. CONCLUSION CGRP has significant enhancement effect on I Ca-L in guinea pig ventricular myocytes under normal and imitating ischemia and hypoxia conditions. Its effect may be one of the ionic channel machanisms of its cardiovascular effects.