Comparison of immunocytochemical staining of astrocytes, oligodendrocytes, and myelinated fibers in the brains of carbonic anhydrase II-deficient mice and normal littermates.

Immunostaining for carbonic anhydrase (CA) was performed in paraffin sections from the brains of CA II-deficient mutant mice and their normal littermates. Double immunofluorescence staining showed CA in myelinated tracts and oligodendrocytes in the cerebellum of the normal but not the CA II-deficient mice, and also in astrocytes in the cerebral cortex of the normal mice but not the mutants. The data show that the CA in normal oligodendrocytes, astrocytes, and myelin is the II isoenzyme, because these structures in the mutants would be positively stained if the staining normally were due to a contaminant in the antiserum or an antibody against a different isoenzyme. The findings in normal gray matter also suggest that many neuronal cell bodies are surrounded by a network of fine, CA-positive astrocytic processes.