pp60c-src increases voltage-operated calcium channel currents in vascular smooth muscle cells

Intracellular application of pp60c-src, a nonreceptor tyrosine kinase present in large amounts in smooth muscle cells increased voltage-operated calcium channel currents in rabbit ear artery cells. Intracellular peptide-A, an inhibitor of pp60c-src, reduced calcium channel currents and abolished the action of pp60c-src. Selective tyrosine kinase inhibitors, tyrphostin-23 and genistein also abolished the effect of pp60c-src, but inhibition of protein kinase C did not prevent the action of pp60c-src. These results suggest that endogenous pp60c-src modulates voltage-operated calcium channels by a mechanism dependent on tyrosine phosphorylation but not involving activation of protein kinase C.