Inhibition of Na+/Ca2+ exchange by hexapeptide FRCRSFa in rat ventricular myocytes.
OBJECTIVE
To study the effect of Phe-Arg-Cys-Arg-Ser-Phe-CONH2 (FRCRSFa) on Na+/Ca2+ exchange and its specificity in rat ventricular myocytes.


METHODS
Na+/Ca2+ exchange current (INa+/Ca2+) and other currents were measured using whole-cell voltage clamp technique.


RESULTS
A concentration-dependent inhibition of hexapeptide FRCRSFa on Na +/Ca2+ exchange was observed in rat ventricular myocytes. IC50 of inward and outward INa+/Ca2+ were 2 and 4 micromol/L, respectively. FRCRSFa 5 micromol/L did not affect L-type Ca2+ current, voltage-gated Na+ current, transient outward K+ current, and inward rectifier K+ current.


CONCLUSIONS
These data indicate that FRCRSFa is an available inhibitor of Na+/Ca2+ exchange with relative selectivity and m ay be valuable for studies of the Na+/Ca2+ exchange in cardiac myocytes.
Han
Qing-Hua
QH
Department of Cardiology, First Hospital of Shanxi Medical University, Taiyuan 030001, China.
Wu
Dong-Mei
DM
Lu
Ji-Yuan
JY
Wu
Bo-Wei
BW
D000818:Animals; D002469:Cell Separation; D003864:Depression, Chemical; D006352:Heart Ventricles / Q000166:cytology; D032383:Myocytes, Cardiac / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D019831:Sodium-Calcium Exchanger / Q000037:antagonists & inhibitors*
D009842:Oligopeptides; D010455:Peptides; D019831:Sodium-Calcium Exchanger; C477158:phenylalanyl-arginyl-cysteinyl-arginyl-seryl-phenylalaninamide