Quantitative distribution of protein kinase C α, β, γ, and ϵ mRNAS in the hippocampus of control and nictitating membrane conditioned rabbits
Abstract We used oligonucleotide in situ hybridization and film autoradiography to quantitate the distributions of protein kinase C (PKC) α, β, γ, and ϵ mRNAs in subregions of rabbit hippocampus. Levels of each of the hippocampal PKC isozyme mRNAs and patterns of their regional distributions were remarkably invariant between individuals. Within stratum pyramidale, the highest levels of PKC α mRNA were in the CA2 region, while PKC β mRNA was maximally expressed in CA1, and PKC ϵ mRNA in CA3; PKC γ mRNA was abundantly expressed throughout Ammon's horn. Previous experiments employing quantitative autoradiography for [ 3 H]PDBU (Olds et al., Science , 245 (1989) 866–869) revealed an increase in membrane-bound PKC in the CA1 region of rabbit hippocampus up to 3 days following classical conditioning of the nictitating membrane response. We report here that there were no differences in levels of PKC α, β, γ, or ϵ mRNA between conditioned and control rabbits in any hippocampal region one day after training. These data are consistent with the hypothesis that PKC is post-translationally activated and translocated to the membrane during memory storage.