Undifferentiated Catecholaminergic and NO-Producing Cells of Forebrain Matrix Zones and Intercellular Relationships in Periventricular Diencephalon of Juvenile Oncorhynchus masou

Abstract

Localization of TH- and NO-producing systems in the diencephalon of juvenile masu salmon Oncorhynchus masou was investigated by using histofluorescence labeling of glyoxylic acid (GA), and ICH labeling of tyrosine hydroxylase (TH) and neuronal nitric oxide synthase (nNOS). High density distribution of catecholaminergic and NO-ergic cells has been found in preoptic, posterior tuberal and hypothalamic areas. Cells revealed in above mentioned diencephalic areas were assigned to three main types: pear-shaped, bipolar and rounded. Most of the TH- and NO-producing cells had the phenotype of undifferentiated elements localized on territory of diencephalic matrix zones. Paracrine and autocrine relationships between TH- and NO-producing cells in periventricular diencephalon of juvenile O. masou before formation of blood-brain barrier have been hypothesized. The lack of differentiated cells and the presence of a large variety of size groups of cells indicate a possible heterochrony in growth and differentiation of O. masou diencephalic areas. Location of catecholaminergic and NO-producing cells in the territory of diencephalic matrix zones suggests that catecholamines and nitric oxide are involved in the regulation of post-embryonic neurogenesis in diencephalon of O. masou.