Sympathetic sprouting reverses decreases in membrane-associated activity of protein kinase C following septohippocampal denervation of the rat hippocampus

Hippocampal sympathetic ingrowth (HSI), a form of neuronal plasticity, is induced by medial septal lesions and consists of the sprouting of peripheral sympathetic fibers, arising from the superior cervical ganglion, into the dentate gyrus and CA(3) region of the hippocampus. HSI has been previously shown to alter learned and spontaneous behaviors, phosphatidyl inositide hydrolysis, and the antagonist binding kinetics of both muscarinic cholinergic receptors and phorbol ester receptors. We now report that sympathetic sprouting reverses decreases in membrane-associated activity of protein kinase C (PKC) following septohippocampal denervation of the rat hippocampus. Further, no changes were found in alpha, beta or gamma PKC isoenzymes among experimental groups, suggesting that the group A PKC isoforms do not mediate the observed changes in activity and phorbol ester binding.