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


CONCLUSIONS
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.
Yunnan University of Traditional Chinese Medicine, Kunming 650500, China.
He
H
Xiao-Shan
Yunnan University of Traditional Chinese Medicine, Kunming 650500, China.
Lin
L
Qing
Yunnan University of Traditional Chinese Medicine, Kunming 650500, China.
Ma
M
Yun-Shu
Yunnan University of Traditional Chinese Medicine, Kunming 650500, China.
Yu
Y
Ze-Pu
D000818:Animals; D001060:Aporphines / Q000494:pharmacology*; D002478:Cells, Cultured; D015536:Down-Regulation / Q000187:drug effects; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism; D031607:Stephania / Q000737:chemistry; D061567:Voltage-Gated Sodium Channel Blockers / Q000494:pharmacology*; D061566:Voltage-Gated Sodium Channels / Q000378:metabolism*
D001060:Aporphines; D004365:Drugs, Chinese Herbal; D061567:Voltage-Gated Sodium Channel Blockers; D061566:Voltage-Gated Sodium Channels; C061009:crebanine
Arrhythmia; Crebanine; Myocardium; Patch-clamp techniques; R285; Sodium channels