ON LOCALIZATION OF NEURO-GLIAL GROUPING AND INTERCELLULAR CONTACTS IN THE RAT SOMATIC CORTEX
Mogilevskaya M.Yu., Kirichenko E.Yu.
A.B.Kogan Research Institute for Neurocybernetics of Southern Federal University, Rostov-on-Don, Russia, firstname.lastname@example.org, email@example.com
The research aim was to investigate the localization of neuronal proteins, glial proteins and the proteins of the intercellular contacts in the rat somatic cortex. The study was conducted on the frontal slices of somatic cortex. Under deep anesthesia the animals were perfused through the aorta; brain pieces were filled in paraffin blocks. Immunohistochemical research was carried out on the paraffin 4 μm frontal sections using primary monoclonal mouse antibodies and polyclonal rabbit antibodies: Neurofilament; Myelin Basic Protein; Glial Fibrillar Acid Protein; Synaptophysin, anti-Connexin 36, anti-Connexin 43, the visualizing system was Dako EnVision System + Peroxidase (AEC), Dako Germany. The usage of GFAP antibody allowed to note that the first cortex layer generally contains a big amount of large sprouting astrocytes as well as small branches with a high expression of GFAP. The reaction on GFAP antibody also showed the presence of neuro-glial-vascular complexes, structural components of blood-brain barrier. The usage of Synaptophysin (the synaptic vesicles protein) antibody stained the sample homogeneously with more intensive reaction in the apical layer as in the reaction with GFAP. The expression of the Myelin Basic Protein (MBP) suggested the radial distribution of medullated branches in the cortex. Immunohistochemical reaction with Neurofilament antibody detected higher level of expression in the zone corresponding to barrel cortex. The estimation of transversely and longitudinally cut branches revealed their principally vertical disposition in the rat somatic cortex. The reaction on gap junction antibodies (Cx43, Cx36) allowed to identify all types of neurons layer wise whereas the reaction on microglial cells was negative. The positive reaction of apical layer neuropil was shown in the absence of neuronal cell bodies. In the low infragranular layers were indicated large dendrites and axons that were cut lengthwise and crosswise with a high level of connexin expression. In the absence of data regarding neuro-glial interactions in the apical cortex layer, the conducted research allows to suppose the uniqueness of structural and functional organization of the neuropil of this layer. The neuro-glial-vascular units that were detected in this study can prove to be a structural unit of functional column. The connexins’ expression assumes the formation of a considerable amount of dendro-somatic, axo-somatic and glia-glial gap junctions layer wise in somatic cortex.