Parvalbumin, a Neuronal Protein in Brain Cell Cultures

Dissociated brain cell cultures were derived from 14‐day‐old embryonic as well as from newborn mice. The cells were grown in a medium containing 10% fetal calf serum. Indirect immunofluorescence was performed using antisera directed against the Ca + ‐binding protein parvalbumin (M., 12,000). In embryonic cultures a large proportion of cells was intensely stained by anti‐ parvalbumin. In double‐labelling experiments involving the simultaneous application of antisera against parvalbumin and the neuron‐specific enolase, the enolase‐con‐ taining cells were also parvalbumin‐positive and both antisera revealed identical intracellular staining patterns. Conversely, almost no parvalbumin‐ and enolase‐positive cells were present in cultures derived from newbornmice. However, in these cultures many cells were immunoreactive toward the myelin basic protein, an accepted marker for oligodendrocytes. The presence of parvalbumin within the embryonic brain cell cultures was confirmed by analyses of the culture extracts (4 m M EDTA, pH 7.5) by HPLC on reverse‐phase supports, two‐dimensional polyacrylamide gel electrophoresis, and immunoblotting. The present study suggests that in mouse brain cell cultures, parvalbumin is localized in neurons.