Kirichenko E. Yu.1, Logvinov A.K.2, Akimenko M. A.1
1 A. B. Koran’s Research institute of Neurocibernetics of South Federal University, Rostov-on-Don, Russia, firstname.lastname@example.org, email@example.com
2 Pathological department, State Organization of the Rostov Region "Regional Clinical Hospital № 2",
Rostov-on-Don, Russia, firstname.lastname@example.org
Gap junctions (GJ) play an important role in cell proliferation, migration, differentiation, provide development and maturation of the brain (E. Dere, 2013). Combining the cytosol of contacting cells, they are involved in the mechanisms of electrotonic coupling when they are located between the branches of neurons and in the regulation of cellular homeostasis when they are formed by glial cells. On the study there was investigated the expression of connexin 36 (protein of neuronal GJ) and connexin 43 (protein of astroglial GJ) on the LM level and the ultrastructure of neuronal and glial GJ. According to immunohistochemistry the general quantity of neuronal and glial GJ in the adult rat brain is concentrated in the neocortex, hippocampus, and ventral thalamic nuclei. There was moderately expressed membrane reaction of connexins, by which single large cells with long branching processes were identified. At the same time, significant differences between the expression of proteins of neuronal and glial GJ were not revealed. Ultrastructural study of the neocortex and ventral thalamic nuclei identified the cases of axo-axonal, axo-dendritic and dendro-dendritic gap junctional formation between the neurons, which may indicate their participation in the synchronization of activity on pre- and on postsynaptic levels. The main part of the branches which form GJ has ultrastructural features of astrocytes, while both on the single and on serial ultrathin sections of the cortex and the thalamus there was a regular case of forming astroglial branches and astroglial GJ around the axo-spiny chemical synapses. Single glial GJ are often close to the postsynaptic part (dendrite or spine) and to presynaptic part, near the axon terminal. In a few cases there were detected two GJ near chemical synapse: one was located in close proximity to the presynaptic side, and the other - to the postsynaptic part of the chemical synapse. Revealed regular arrangement of glial GJ may indicate their participation in the mechanisms of regulation of ion and glutamate metabolism.