Zhang X M, Yang S, Zhang Y, Zheng P, Jiang M H, Zhou Z N
Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 200032, China.
Acta Pharmacol Sin. 2001 Jan;22(1):10-4.
To study the mechanism of calcium overload induced by melittin in myocytes.
Whole cell patch-clamp technique was applied for recording the currents.
Mel 0.05, 0.1 micromol/L increased the peak amplitude of I(Na) (nA) from -2.1+/-0.8 to -3.2+/-1.0 (n=7, P < 0.05) and -3.7+/-1.5 (n=7, P < 0.05) respectively at testing potential of -40 mV. Mel 0.05, 0.1, 0.2 micromol/L had no significant effect on I(Ca), but enhanced I(Na-Ca) (pA) from 53+/-21 to 427+/-256 (n=5, P < 0.05), 349+/-147 (n=5, P<0.01) and 320+/-97 (n=5, P < 0.05) respectively at a testing potential of +50 mV.
The stimulating effect of Mel on I(Na-Ca) rather than the effect on I(Ca) contributes to the calcium overload of myocytes.
研究蜂毒肽诱导心肌细胞钙超载的机制。
采用全细胞膜片钳技术记录电流。
在-40mV的测试电位下，0.05、0.1μmol/L的蜂毒肽分别使I(Na)的峰值幅度（nA）从-2.1±0.8增加到-3.2±1.0（n = 7，P < 0.05）和-3.7±1.5（n = 7，P < 0.05）。0.05、0.1、0.2μmol/L的蜂毒肽对I(Ca)无显著影响，但在+50mV的测试电位下，分别使I(Na-Ca)（pA）从53±21增加到427±256（n = 5，P < 0.05）、349±147（n = 5，P<0.01）和320±97（n = 5，P < 0.05）。
蜂毒肽对I(Na-Ca)的刺激作用而非对I(Ca)的作用导致心肌细胞钙超载。
