Artemisinin blocks activating and slowly activating K+ current in guinea pig ventricular myocytes.
OBJECTIVE
To study the effect of artemisinin (Art) on outward rectifier potassium current in ventricular myocytes.


METHODS
In isolated guinea pig ventricular myocytes, the effects of Art on the two components of delayed outward rectifier K+ current (IK), the rapidly activating inward K+ current (IKr), and the slowly rectifying outward K+ current (IKs) were observed by the whole cell patch-clamp technique.


RESULTS
Art decreased IK in a concentration-dependent manner. The IKstep and IKtail were reduced from 387 +/- 46 pA to 240 +/- 48 pA and from 299 +/- 30 pA to 130 +/- 38 pA, respectively at holding potential of +40 mV by Art 50 mumol.L-1. The envelope of tail analysis suggested that both IKr and IKs were inhibited.


CONCLUSIONS
Art blocked the two components of delayed outward rectifier K+ current (IKr and IKs) in guinea pig ventricular cells.
Yang
B F
BF
Department of Pharmacology, Harbin Medical University, China. Yangbf@Ems.hrbmu.edu.cn
Luo
D L
DL
Bao
L H
LH
Zhang
Y C
YC
Wang
H Z
HZ
D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D037621:Artemisinins; D002478:Cells, Cultured; D005260:Female; D006168:Guinea Pigs; D006352:Heart Ventricles / Q000166:cytology; D008297:Male; D009206:Myocardium / Q000166:cytology*; D015221:Potassium Channels / Q000187:drug effects*; D012717:Sesquiterpenes / Q000494:pharmacology*
D000889:Anti-Arrhythmia Agents; D037621:Artemisinins; D015221:Potassium Channels; D012717:Sesquiterpenes; C031327:artemisinin