SYNAPTIC PROCESSES IN THE ANTINOCICEPTIVE SOMATOSENSORY CORTEX SI OF THE BRAIN ACTIVATED BY THE VENTRAL POSTERIOR-LATERAL THALAMIC NUCLEUS IN A ROTENONE MODEL OF PARKINSON'S DISEASE.

This study aimed to investigate the ratio of excitatory and depressor post-stimulus manifestations of SI single neuron activity during VPL stimulation of the thalamic nucleus in a PD model to identify excitotoxicity in neurodegeneration and the formation of persistent pain, which is poorly treatable. Electrophysiological studies were performed on 6 albino rats (230±30 g): intact (n=3) and rotenone model (n=3) of Parkinson's disease (PD) induced by unilateral administration of rotenone for 4 weeks (n=3). We performed extracellular recordings of spike activity of 207 single neurons in the primary somatosensory cortex (SI) of the ventral posterolateral thalamic nucleus (VPL). Changes in depressor and excitatory responses (TD and TP), accompanied by post-tetanic depression and potentiation, were detected using the analysis. A significant excess in the frequency of the prestimulus (background) activity of SI neurons in a PD model was revealed as a result of the inevitable development of excitotoxicity. At the post-stimulus level, excitotoxicity under pathological conditions should also be recognized. In conclusion, the PD model revealed excitotoxicity in the SI neurons with the emergence of persistent chronic pain.