Distribution and expression of G-protein in rat cerebral cortical cells. II. Primary tissue culture

In continuing an assessment of the cellular distribution and developmental expression of brain guanine nucleotide-binding protein (G-protein) (Go), this component was investigated in primary cultures of dissociated cerebral cortical cells derived from fetal rat. Using a polyclonal antibody recognizing brain Gi/Go, G-protein was detected through immunohistochemical staining and a Western immunoblot procedure. In initial studies, the presence of G-protein in cultures containing mature cells was demonstrated using the immunoblot technique; this G-protein corresponded predominately to the Go form as the alpha- and beta-subunits were revealed, and these co-migrated with similar antigens from the intact tissue and of purified bovine brain G-protein. The pattern of cellular localization or distribution in stained cultures was very similar to that observed in vivo, as differentially high staining was present in neurons, ependymal cells and microglia. In neurons, the immunofluorescent staining was relatively uniform over the cell body and at least the initial segment of processes. When cultures of different ages were assessed, the G-protein exhibited a developmental pattern of increase in expression similar to that observed in whole tissue, as determined by immunoblotting. The cortical cultures reflect the distribution and expression of G-protein in vivo and, thus, specific cell types therein may be useful in investigating the functional role of the predominate type of this protein in brain tissue (Go).