INHIBITION OF Na+/Ca2+ EXCHANGE BY TETRAPEPTIDE FMRFa IN INTACT RAT VENTRICULAR MYOCYTES
- VernacularTitle:四肽FMRFa对大鼠心室肌Na+/Ca2+交换的抑制
- Author:
Qinghua HAN
;
Dongmei WU
;
Jiyuan LU
;
Bowei WU
- Publication Type:Journal Article
- From:
Acta Pharmaceutica Sinica
2001;36(1):10-13
- CountryChina
- Language:Chinese
-
Abstract:
AIM To study the effects of Phe-Met-Arg-Phe-NH2 (FMRFa) on Na+/Ca2+ exchange and its specificity for Na+/Ca2+ exchange in rat ventricular myocytes. METHODS Na+/Ca2+ exchange current and other currents of ion channels were measured using whole cell voltage clamp techniques. RESULTS A dose-related inhibition of tetrapeptide FMRFa on Na+/Ca2+ exchange was observed in rat ventricular myocytes. Inward and outward INa+/Ca2+ were inhibited by 60.1% and 56.5%, respectively, at highest concentration (100 μmol*L-1) and its IC50 were 20 μmol*L-1 and 34 μmol*L-1 in inward and outward INa+/Ca2+, respectively. Inward and outward INa+/Ca2+ were inhibited 38.7% and 34.9%, respectively, at FMRFa 5 μmol*L-1. FMRFa 5 μmol*L-1 and 20 μmol*L-1 did not affect L-type calcium current, sodium current, transient outward current and inward rectifier potassium current. CONCLUSION These data indicate that FMRFa is a specific inhibitor of Na+/Ca2+ exchange in intact rat ventricular myocytes.
