银杏酮酯对缺血豚鼠心室肌细胞Ⅰ_(Ca-L)和游离钙的影响

Effect of GBE50 on L-type calcium current and cytosolic[Ca^(2+)]_i in ischemic guinea pig ventricular myocytes

目的观察银杏酮酯GBE50对模拟缺血游离豚鼠心室肌细胞L型钙电流和游离钙浓度的影响,探讨GBE50抗心肌缺血的作用机制。方法应用单酶酶解法分离游离单个豚鼠心室肌细胞,采用膜片钳全细胞记录心室肌细胞L型钙电流,通过激光共聚焦显微镜扫描测定细胞内游离钙浓度的动态变化。结果缺血抑制豚鼠心室肌细胞的ICa-L(n=9,P<0.01),使豚鼠心室肌细胞内游离钙增加(n=10,P<0.01),而50mg·mL-1GBE50减轻缺血对ICa-L的抑制效应(n=6,P>0.05),减少缺血后心室肌细胞内游离钙浓度的增加(n=10,P>0.05)。结论GBE50可减轻心肌缺血区域与非缺血区域电生理的异质性,维持缺血后豚鼠心肌细胞电生理的稳定性,并减轻缺血后心肌细胞内钙超载介导的心肌损伤。

Aim To observe the effect of Ginkgo biloba extract 50（GBE50）on L-type calcium current and cytosolic[Ca2＋]i in ischemic guinea pig ventricular myocytes.Methods Single ventricular myocytes were isolated by enzymatic dissociation.ICa-L was recorded by whole-cell patch clamp technique in voltage clamp mode.[Ca2＋]i was detected by laser confocal micros-copy and represented by relative fluorescent intensity（FI）.Results During ischemia,the peak Ca2＋ current was reduced,and the I-U curve of ICa-L was shifted upward.50 mg·L-1 GBE50 reversed the change induced by ischemia（n=6,P0.05）.After perfusing ischemic solution for 12 min,intracellular calcium concentration was increased（n=10,P0.01）.After perfusion with ischemic solution containing 50 mg·L-1 GBE50,the increase of intracellular calcium concentration was markedly inhibited（n=10,P0.05）.Conclusion GBE50 can reverse the decrease of ICa-L and partially inhibit calcium overloading during ischemia.