Regulation of protein kinase C activity in cerebral microvessels.

Regulation of protein kinase C (PKC)-mediated responses may occur by inhibition of PKC-dependent phosphorylation or by dephosphorylation of targets by specific phosphatases. Mechanisms for the regulation of PKC were examined in isolated cerebral microvessels and compared to those in brain. The data demonstrated that inhibitors of phosphorylation are responsible for the regulation in brain microvessels while dephosphorylation by protein phosphatases accounts for a substantial portion of the regulation of the PKC response in brain. In addition, the inhibitory activity apparently increases with age. These results suggest that the control of PKC may be cell-type specific and developmentally regulated.