Inhibitory effect of 2,3-butanedione monoxime(BDM)on Na~+/Ca~2+ exchange current in guinea-pig cardiac ventricular myocytes

摘要

The effect of 2,3-butanedione monoxime(BDM), a 'chemical phosphatase', on Na~+/Ca~2+ exchange current(I_NCX)was investigated using the whole-cell voltage-clamp technique in single guinea-pig cardiac ventricular myocytes and in CCL39 fibroblast cells expressing canine NCX1. I_NCX was identified as a current sensitive to KB-R7943, a relatively selective NCX inhibitor, at 140 mM Na~+ and 2 mM Ca~2+ in the external solution and 20 mM Na~+ and 433 nM freen Ca~2+ in the pipette solution. In guinea-pig ventricular cells, BDM inhibited I_NCX in a concentration-dependent manner.