Protein kinase C activity in permanent focal cerebral ischemia

Protein kinase C (PKC) activity was investigated in a model of focal stroke in the rat. Following 6 h of left middle cerebral artery occlusion, rat brains were frozenin situ. In the peripheral ischemic zone, total PKC activity declined by close to two-thirds (1.07±0.35 vs 2.77±0.12 nmol/min/mg protein;p<0.05,n=4), and the proportion of total activity associated with the particulate fraction decreased from 33.3±1.5% to 16.2±1.4% (p<0.01,n=4). Thus, overall particulate PKC activity in the ischemic zone was <20% of control. The cerebral energy metabolite profile of tissue from the ipsilateral hemisphere, corresponding to the region where samples were obtained for PKC activity assay, suggests that this tissue may have been part of the ischemic penumbra before further deterioration.