Non-Neuronal GABA in Neocortical Neurografts of the Rats

Abstract

Gamma aminobutyric acid (GABA) plays an important role in regulating the development and functioning of the brain. The aim of this work was to study the involvement of GABA contained in non-neuronal cells in the differentiation and maturation of rat neocortical grafts. Pieces of fetal somatosensory neocortex were transplanted into the acute cavity of the homotopic region of the cortex of adult male rats. 4 months after the operation, the histological and electron microscopic examinations of the grafts were performed. The grafts were well vascularized and consisted of neuronal and glial cells. The localization of GABA in non-neuronal cells was studied by an ultrastructural immunocytochemistry using antibodies conjugated with colloidal gold. The highest expression of immunolabels in the form of electron-dense globules ranging in size from 20 to 60–80 nm was found in protoplasmic astrocytes and their processes. The pericapillary astrocytic endfeets also contained GABA-positive granules. In addition, GABA-positive granules have been observed in some myelin-forming cells and in the endothelial wall of blood vessels. The results obtained showed that GABAergic signaling via non-neuronal cells is involved in the morphofunctional differentiation of the transplanted neocortical tissue.