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

Polyclonal antibodies were raised against an oligopeptide containing an amino acid sequence specific for beta I protein kinase C (PKC) in order to localize this subspecies of PKC in the rat brain. beta I PKC immunoreactivity was widely distributed but discretely localized in particular brain regions. The immunoreactivity was associated with neurons but not glial cells and was generally weak in the neutrophils with the exception of areas such as the triangular septal nucleus, pontine nuclei, superficial layer of the superior colliculus, and gray matter of the spinal cord. The largest number of beta I PKC-immunoreactive cells was seen in the triangular septal nucleus and pontine nuclei. In these areas of dense beta I immunoreactivity, there was no or little gamma PKC immunoreactivity. The beta I PKC immunoreactivity was observed in perikarya, dendrites, and axons but not in nuclei or nucleoli. There were various patterns of cytoplasmic immunoreactivity, but the immunoreactivity was seen frequently in the periphery of the perikarya and dendrites. The intraneuronal localization of beta I PKC immunoreactivity differs from that of the subspecies that is coded by the gamma gene sequence. The results suggest that beta I PKC may play a role in the regulation of cell membrane responsiveness in particular neurons.