Effects of 7-bromoethoxybenzene-tetrahydropalmatine on voltage-dependent currents in guinea pig ventricular myocytes.
OBJECTIVE
To study the anti-arrhythmic mechanism of 7-bromoethoxybenzene-tetrahydropalmatine (EBP).


METHODS
Whole-cell current and voltage clamp on isolated guinea pig ventricular cells.


RESULTS
EBP 30 mumol.L-1 prolonged APD90 from 430 +/- 47 ms to 514 +/- 61 ms (n = 5, P < 0.05) without effects on the action potential amplitude and resting potential. Delayed outward K+ current and its tail current were blocked by EBP in a concentration-dependent fashion, while EBP did not change the amplitudes of the sodium current, the L type calcium current, and the inwardly rectifying potassium current.


CONCLUSIONS
The mechanism of anti-arrhythmic action of EBP was to prolong the APD through inhibiting the delayed rectified potassium current.
Niu
X W
XW
Institute of Biophysics & Biochemistry, Huazhong University of Science & Technology, Wuhan 430074, China.
Zeng
T
T
Qu
A L
AL
Kang
H G
HG
Dai
S P
SP
Yao
W X
WX
Jiang
M X
MX
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D001600:Berberine Alkaloids / Q000494:pharmacology*; D002478:Cells, Cultured; D006168:Guinea Pigs; D006352:Heart Ventricles; D008564:Membrane Potentials / Q000187:drug effects; D009206:Myocardium / Q000166:cytology*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects
D000889:Anti-Arrhythmia Agents; D001600:Berberine Alkaloids; D015221:Potassium Channels; C061390:7-(bromoethoxyphenyl)tetrahydropalmatine