Anodal polarization induces protein kinase C gamma (PKC gamma)-like immunoreactivity in the rat cerebral cortex

Protein kinase C gamma (PKC gamma)-like immunoreactivity was examined in the rat brain, employing the monoclonal antibody 36G9 raised against purified PKC gamma, after an application of weak anodal direct current to the surface of the sensorimotor cortex. Anodal polarization with 3.0 microA for 30 min resulted in a pronounced increase in the number of PKC gamma-like-positive neurons in accordance with the intensity of PKC gamma-like immunostaining in the neocortex, cingulate cortex and piriform cortex ipsilateral to the polarization. The number of PKC gamma-like-positive neurons began to increase at 1 h after polarization, peaked at 3 h, and thereafter decreased to the control levels by 72 h. The increase in expression of PKC gamma-like immunoreactivity in specific areas of the cerebral cortex is suggested to serve as a basis for the long-lasting hyperexcitability in situ following anodal polarization.