Protein kinase C delta but not PKC epsilon activity is involved in contractile potentiation by endothelin-1 in the porcine coronary artery.

To clarify the mechanism of contractile strengthening by endothelin-1 (ET-1), we measured translocation of protein kinase C (PKC) from the cytosol to the membrane fraction in the porcine coronary artery. ET-1 potentiated the serotonin- (5-hydroxytryptamine, 5-HT) induced contraction without any additional increase in myosin light chain phosphorylation. Four PKC isoforms (alpha, beta1, delta, and zeta) were identified but not PKC epsilon. Only PKC delta was translocated from the cytosolic to the membrane fraction during the contractile potentiation by ET-1. Our results suggest that the activity of PKC delta but not PKC epsilon is involved in the contractile strengthening by ET-1 in the porcine coronary artery.