Immunohistochemical study of the pineal astrocytes in the postnatal development of the cat and dog pineal gland.

The expression of glial antigens vimentin (VIM) and glial fibrillary acidic protein (GFAP) is described in the pineal gland of cats and dogs from the first postnatal days to adulthood. VIM immunopositive cells were observed from the first postnatal days in both species. GFAP expression starts from the second postnatal week. In adults, a notable population of stellate cells immunopositive for GFAP and VIM was found dispersed throughout the gland. According to their immunocytochemical profile, these cells could be identified as astrocytes.