Role of Protein Kinase C in $\alpha_1$-Adrenergic Regulation of $a^i_{Na}$ in Single Guinea Pig Ventricular Myocyles

Stimulation of $\alpha$$_1$-adrenergic receptor ($\alpha$$_1$-AR) by phenylephrine produced a decrease in intracellular N $a^{＋}$ activity ( $a_{Na}$ $^{i}$ ) in multicellular preparations of cardiac tissues. The role of protein kinase C (PKC) in $\alpha$$_1$-adrenergic regulation of $a_{Na}$ $^{i}$ was studied in single ventricular myocyte isolated from guinea pig hearts. $a_{Na}$ $^{i}$ and membrane potential were measured with N $a^{+}$ indicator, sodium-binding benzofuran isophthalate tetraacetoxy methyl ester (SBFI/AM) and microelectrodes respectively when ventricular myocyte was stimulated at 0.3 Hz.(omitted)d)