Comparison of the action of two protein kinase C activators on dihydropyridine-sensitive Ca2+ channels in neonatal rat ventricular myocytes.

Ca2+ channels can be modulated by protein kinase C which phosphorylates Ca2+ channel proteins. Two protein kinase C activators, 4 beta-phorbol 12-myristate 13-acetate (PMA) and 1-oleyl-2-acetyl-rac-glycerol (OAG), were used to investigate the effect of protein kinase C activation on dihydropyridine-sensitive Ca2+ channel currents (L-type) in neonatal rat ventricular myocytes using the whole cell version of the patch clamp technique. The results show that both of the activators increased the Ca2+ channel current in myocytes. However, these increases in Ca2+ channel current were different as function of time. Therefore, our results suggest that the temporal factor should be considered when the protein kinase C activators are used in studies of channel modulation.