Effect of methylamphetamine on action potential and delayed rectifier potassium current in guinea-pig ventricular myocytes

VernacularTitle:甲基苯丙胺对豚鼠心室肌细胞动作电位及延迟整流钾电流的影响
Author: Yanming ZHOU ; Ruobing LIANG ; Xiuli ZHAO ; Minghui ZHANG ; Feng WU ; Bo ZHU
Publication Type:Journal Article
Keywords: methylamphetamine; myocytes,cardiac; action potentials; delayed rectifier channels
From: Chinese Journal of Pharmacology and Toxicology 2010;24(6):449-454
CountryChina
Language:Chinese
Abstract: OBJECTIVE To explore the mechanism of methylamphetamine (MA) on heart toxicity. METHODS The effects of MA on delayed rectifier potassium current (IK) and action potential (AP) were analyzed in isolated decreased AP from 121.6 to 106.0 mV and delayed the action potential duration (APD), but had no effect on the resting potential. The 10%, 25%, 50%, 75% and 90% of APD (APD10, APD25, APD50, APD75 and APD90)inhibited the membrane potential of rapidly activating delayed rectifier potassium current (IKr) and slowly activating delayed rectifier potassium current (IKs), downward shifted the Ⅰ -Ⅴ curve, but had no effect on the curve shape and could be partly recovered after flushing. The tail current IKr was blocked concentration-dependently after simiarly inhibited by MA. CONCLUSION MA has inhibitory effects on Ik and AP in ventricular myocytes,which may be one of the possible electrophysiological mechanisms of the cardiac damage caused by MA.