摘要
目的:观察乙醇对豚鼠心室肌细胞L-型钙离子通道电流(ICa,L)和电压依赖性钠离子通道电流(INa)的影响,并探讨两者在乙醇致心肌损伤中的意义。方法:采用蛋白酶消化的成年豚鼠单个心室肌细胞及膜片钳全细胞技术,记录不同浓度乙醇对ICa,L和INa的作用。结果:(1)乙醇抑制ICa,L峰值,24mmol/L和240mmol/L乙醇抑制率差异有统计学意义(P<0.05)。(2)24、80、240mmol/L乙醇使ICa,L的电流-电压(I-V)曲线上移,在各测试电压下,电流均减小,但不影响曲线形状,用乙醇后最大激活电压仍在0mV左右。(3)24mmol/L乙醇基本不影响INa峰值,80、240mmol/L乙醇抑制INa峰值,与24mmol/L乙醇的抑制率差异有统计学意义(P<0.05)。(4)24mmol/L乙醇对INa的I-V曲线无明显影响。80、240mmol/L乙醇使INa的I-V曲线上移,在各测试电压下,电流均减小,曲线形状无明显改变,用药后最大激活电压仍在-30mV左右。结论:致毒浓度(24mmol/L)的乙醇对ICa,L具有明显抑制作用,可导致心肌产生负性肌力作用,动作电位时程缩短,诱发心律失常。但致毒浓度(24mmol/L)的乙醇不影响INa,而致死浓度(80mmol/L)对INa有明显抑制作用。
Objective： To study the effects of ethanol at different concentrations on L-type calcium channel current （ICaL） and voltage-dependent sodium channel current （INa） in guinea pig ventricular myocytes, and to explore the significance in ethanol- induced cardiomyocyte injury. Methods： Using whole-cell patch-clamp technique in isolated guinea pig ventricular myocytes with an enzymatic procedure, ICaL and INa were recorded before and after application of different concentrations of ethanol respectively. Results： The concentrations of ethanol, both 24 mmol/L and 240 mmol/L reduced the peak current of ICaL. The percentage inhibitions for both concentrations of ethanol were significantly different （P 〈 0.05 ）. The concentration of ethanol, 24, 80 and 240 mmol/L shifted the I-V curve of ICaL upwardly. The contour of I-V curve kept unchanged, and the peak current induced voltage remained 0 mV. The concentration of ethanol 24 mmol/L did not affect the peak current of INa. Ethanol of 80 and 240 mmollL inhibited the peak current of INa.. The percentage inhibition was significantly different compared with that of 24 mmol/ L （P 〈 0.05）. Ethanol of 24 mmol/L did not affect the I-V curve of INa. The concentration of ethanol 80 and 240 mmol/L shifted the I-V curve of Is upwardly. The contour of I-V curve kept unchanged, and the peak current stimulating voltage remained -30 mV. Conclusion： The toxic concentration of ethanol （24 mmol/L）significanfly inhibited ICaL and contributed to a negative inotropic effect, decrease in action potential duration and development of arrhythmias. The toxic concentration of ethanol （24 mmol/L）did not affect I~ but the lethal concentration of ethanol （80 mmol/L） significantly inhibited it.
出处
《天津医药》
CAS
北大核心
2007年第4期281-283,共3页
Tianjin Medical Journal
关键词
乙醇
心室
肌细胞
钙通道
钠通道
膜片钳术
豚鼠
ethanol
heart ventricles
muscle cells
calcium channels
sodium channels
patch-clamp techniques
guinea pigs
