SODIUM-CHANNEL BLOCKING EFFECT OF SCORPIO N-VENOM ON CULTURED MOUSE MYOCARDIOCYTES

Myocardiocytes of mice were cultured. Action potentials were recorded with microelectrodes inside the cells. Scorpion venom from Buthus mart ensii Karsch 3.75 or 7.5 mug . ml-1 decreased the duration of action p otential and all of the depolarization concerned parameters of myocard iocytes. The V(max), TP, APA behaved apparently in a dosage-dependent way. Restoration happened after washing out. Tetrodotoxin 2.5 mug . ml -1 acted in a similar way. Nimodipine 3.0 mug . ml-1 led to a decrease in action potential duration. BaCl2O. 1 mmol . L-1 elongated the acti on potential duration, while decreased the parameters concerned with d epolarization. These results indicate that the scorpion venom has Nachannel blocking action.