Crebanine inhibits voltage-dependent Na+current in guinea-pig ventricular myocytes简

AIM： To study the effects of crebanine on voltage-gated Na＋ channels in cardiac tissues. METHODS： Single ventricular myocytes were enzymatically dissociated from adult guinea-pig heart. Voltage-dependent Na＋ current was recorded using the whole cell voltage-clamp technique. RESULTS： Crebanine reversibly inhibited Na＋ current with an IC50 value of 0.283 mmol.L-1 （95% confidence range： 0.248-0.318 mmol.L-1）. Crebanine at 0.262 mmol.L-1 caused a negative shift （about 12 mV） in the voltage-dependence of steady-state inactivation of Na＋ current, and retarded its recovery from inactivation, but did not affect its activation curve. CONCLUSION： In addition to blocking other voltage-gated ion channels, crebanine blocked Na＋ channels in guinea-pig ventricular myocytes. Crebanine acted as an inactivation stabilizer of Na＋ channels in cardiac tissues.