Effect of oxyphenamone on sodium and calcium channels of guinea pig myocardial cells.
- Author:
Li-li FAN
1
;
Zhen SONG
;
Tian-you WANG
Author Information
- Publication Type:Journal Article
- MeSH: Animals; Anti-Arrhythmia Agents; pharmacology; Calcium Channels, L-Type; drug effects; Cardiotonic Agents; pharmacology; Female; Guinea Pigs; Heart Ventricles; cytology; Male; Myocytes, Cardiac; drug effects; Organic Chemicals; Patch-Clamp Techniques; Sodium Channels; drug effects
- From: Acta Pharmaceutica Sinica 2004;39(6):410-414
- CountryChina
- Language:Chinese
-
Abstract:
AIMTo investigate the mechanism of the positive inotropic effect of oxyphenamone.
METHODSWith the patch clamp technique and whole cell recording, the sodium and L type calcium currents of myocytes isolated from ventricular myocardium of adult guinea pigs were studied.
RESULTS5 - 50 micromol x L(-1)-oxyphenamone not only significantly inhibited Na+ current, but also promoted the process of inactivation and prolonged the recovery time of the inactivation. The action of oxyphenamone on L type calcium channel was dual. The inward calcium current was increased with 2 - 10 micromol x L(-1) oxyphenamone but decreased when the concentration of the drug was elevated to 20 - 50 micromol x L(-1).
CONCLUSIONThe mechanism of the positive inotropic effect of oxyphenamone is neither due to the activation of sodium channel nor entirely depending upon the activation of L type calcium channel. The effects of inhibiting sodium current and, at a high concentration, blocking L type calcium current suggest that oxyphenamone may have an antiarrhythemia action.
