Effects of benzyltetrahydropalmatine on the rapidly activating component of delayed rectifier potassium current in guinea pig ventricular myocytes.
- Author:
Yang LI
1
;
Li-ying FU
;
Wei-xing YAO
;
Guo-jin XIA
;
Ming-xing JIANG
Author Information
- Publication Type:Journal Article
- MeSH: Animals; Anti-Arrhythmia Agents; pharmacology; Berberine Alkaloids; pharmacology; Cell Separation; Delayed Rectifier Potassium Channels; Female; Guinea Pigs; Heart Ventricles; cytology; metabolism; Male; Myocytes, Cardiac; drug effects; metabolism; Patch-Clamp Techniques; Potassium Channels; drug effects; metabolism; Potassium Channels, Voltage-Gated
- From: Acta Pharmaceutica Sinica 2002;37(8):603-607
- CountryChina
- Language:English
-
Abstract:
AIMTo investigate the effect of benzyltetrahydropalmatine (BTHP) on the rapidly activating component of delayed rectifier K+ current (Ikr) in single guinea pig ventricular myocytes.
METHODSWhole-cell patch clamp technique was used to record Ikr.
RESULTSIkr was blocked by 1-100 mumol.L-1 BTHP in concentration-, voltage-, and specifically frequency-dependent fashion, with IC50 of 13.5 mumol.L-1 (95% confidence range: 11.2-15.8 mumol.L-1). 30 mumol.L-1 BTHP reduced Ikr and Ikr.tail by (31 +/- 4)% and (36 +/- 5)% (n = 6, P < 0.01), respectively. The time constant for deactivation (tau') of the tail current was decreased by 30 mumol.L-1 BTHP from (238 +/- 16) ms to (196 +/- 14) ms, while drug had no any effect on the time constant for activation (tau) of Ikr,tail.
CONCLUSIONBTHP inhibited Ikr in a frequency-dependent fashion.
