Gamma-aminobutyric acid, glutamic acid decarboxylase and tyrosine hydroxylase in rat striatum demonstrated by single and dual immunocytochemistry.

By means of dual ultrastructural immunostaining the followings patterns are visualized: gamma-aminobutyric acid (GABA) immunoreactive neurons, dendrites, axons and axon terminals and tyrosine hydroxylase (TH) immunopositive fibers, varicosities and boutons in rat striatum. Additionally single glutamic acid decarboxylase (GAD) immunolabeling is carried out. Four subgroups of GABA and GAD immunoreactive striatal neurons are revealed. These neuronal types are identified on the basis of sectional diameters, nuclear form and nuclear envelope invaginations, quantity of cytoplasm and cell organelles. Plasmalemmal appositions between GABAergic and between GABAergic and immunonegative neurons are observed. All subgroups of striatal GABAergic neurons contact with GABA and GAD immunoreactive, TH immunoreactive and immunonegative boutons. In the striatal neuropil numerous GABAergic, dopaminergic and immunonegative axonal endings synapsed with dendrites and spines are found out. Massive dopaminergic striatal structures using dual immunostaining is evident. Some GABA and GAD immunoreactive dendrites are revealed in direct contact with capillary walls.