Immunocytochemical localization of the alpha subspecies of protein kinase C in rat brain.

The distribution of the alpha subspecies of protein kinase C (PKC) in rat brain was demonstrated immunocytochemically by using polyclonal antibodies raised against a synthetic oligopeptide corresponding to the carboxyl-terminal sequence of alpha-PKC. The alpha-PKC-specific immunoreactivity was widely but discretely distributed in both gray and white matter. The immunoreactivity was associated predominantly with neurons, particularly with perikaryon, dendrite, or axon, but little was seen in the nucleus. Glial cells expressed this PKC subspecies poorly, if at all. The highest density of immunoreactivity was seen in the olfactory bulb, septohippocampal nucleus, indusium griseum, islands of Calleja, intermediate part of the lateral septal nucleus, and Ammon's horn. A moderately high density of the immunoreactivity was seen in the anterior olfactory nucleus, anterior commissure, cingulate cortex, dentate gyrus, compact part of the substantia nigra, interpeduncular nucleus, inferior olive, and olivocerebellar tract. This distribution pattern was consistent with that obtained by in situ hybridization histochemistry. The distribution of alpha-PKC immunoreactivity was different from that of beta I-, beta II-, and gamma-PKC immunoreactivity. These findings suggest that alpha-PKC is involved heavily in the control of specific functions of some restricted neurons.