Light microscopic histochemistry of the postnatal development and localization of carbonic anhydrase activity in glial and neuronal cell types of the rat central nervous system.

The postnatal expression of carbonic anhydrase (CA) activity in glia and neurons was investigated by a modified light microscopical method of Hansson. Strong CA activity was observed during the first postnatal week in ameboid microglia, clustering in the cingulum, the periaqueductal region, the roof of the lateral ventricles and the white matter of the cerebellum. The intensity of staining gradually decreased during the second week and finally disappeared. From the 9th postnatal day on, cerebellar Purkinje cells expressed strong CA activity, which completely disappeared by the end of the investigation period. CA staining of the oligodendrocytes and pericytes could be observed from the first postnatal day on. The present results raised the possibility that carbonic anhydrase activity may play a role in the regulation of the development and proliferation of some cell types, perhaps via intracellular pH changes.