TIME-COURSE OF PHORBOL ESTER-INDUCED CONTRACTION AND PROTEIN-KINASE-CACTIVATION IN RAT AORTA (VOL 290, PG 253, 1995)

This study investigates the relationship between the rate of phorbol e ster-induced contraction of intact rat aorta and protein kinase C acti vation, as assessed by the translocation of protein kinase C from the cytosolic to the particulate fraction. Aorta was exposed to Ca2+-free physiological salt solution prior to phorbol ester to prevent Ca2+-ind uced protein kinase C translocation during tissue homogenization. Phor bol myristate acetate, as well as phorbol dibutyrate, decreased cytoso lic and/or increased particulate protein kinase C activity as early as 5 s following ester addition, which was prior to, or coincident with, the onset of contraction. These results suggest that phorbol ester-in duced contraction of intact vascular smooth muscle is associated in a time-dependent manner with protein kinase C activation.