Protein kinase C is translocated to cell membranes during cerebral ischemia

The subcellular distribution of PKC(alpha) and PKC(gamma) was studied in homogenates of cerebral cortex from rats subjected to 10 and 15 min of ischemia and 15 min of ischemia followed by 1 h, 6 h, 24 h, 48 h, and 7 days of reperfusion. During ischemia no significant changes in the levels of PKC (alpha) were seen. During the first hour of reperfusion, a transient 2.5-fold (P less than 0.05) increase in PKC (alpha) levels was observed in the particulate fraction. In contrast, a three-fold increase of PKC(gamma) in the particulate fraction concomitant with a 40% decrease in the cytosol was noted during ischemia. In the postischemic phase the levels in the cytosol decreased to 35% of control values at 2 days following ischemia, with a concomitant decrease in the particulate fraction to control levels. The redistribution of PKC to the cell membranes during and following ischemia could be due to ischemia induced receptor activation, increased levels of diacylglycerols, arachidonate and intracellular calcium, and may be of importance for the development of ischemic neuronal damage.