Stimulation by melittin of Na+-Ca2+ exchange current in ventricular myocytes of guinea pigs

• Published in: Acta pharmacologica Sinica Vol. 22; no. 1; pp. 10 - 14
• Main Authors: Zhang, X M, Yang, S, Zhang, Y, Zheng, P, Jiang, M H, Zhou, Z N
• Format: Journal Article
• Language: English
• Published: United States 01.01.2001
• Subjects: Animals; Cell Separation; Electrophysiology; Guinea Pigs; Heart Ventricles - cytology; Melitten - pharmacology; Myocytes, Cardiac - drug effects; Myocytes, Cardiac - metabolism; Patch-Clamp Techniques; Sodium-Calcium Exchanger - drug effects; Sodium-Calcium Exchanger - metabolism
• ISSN: 1671-4083

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.