[Fine structure of pineal gland in some Chiroptera. (Vesperugo savi and Rinolophus f.e.). I. Histochemical and...

Fine structure of pineal gland was studied in some Chiroptera and compared with those of other micromammals. Three cells types were found in pineal parenchyma: pinealocytes, the most numerous cells, glial cells and Mastzellen. Some nervous cells were found in peripheral dorsal pineal gland. Pinealocytes show a clear or dark matrix which are different functional stages of the same cell. A large nucleus with irregular profiles and deep invaginations, several mitochondria and ribosomes, canalicular rough surfaced endoplasmic reticulum, large Golgi apparatus, lipid droplets, secretory and heterogeneous granules distinguish this cellular type. Centrioles often joined with a striated root (formed by alternating clear and dark discs), cytoplasmic process extending in the intercellular space as far as 3-4 mu including cilia showing a 9+0 pattern, osmiophilic vacuoles involved in secretion processes were observed too. Glial cells irregularly arranged tend to form small clusters: they show a dense and glycogen particles rich matrix. This matrix was very positive for non specific esterases reaction. Blood vessels are provided by a continuous endothelium resting on basal lamina, surrounded by a thick perivascular layer. Collagen fibers, pinealocytes processes, non-myelinated nerve fibers and Mastzellen were found in pervascular area.