Synaptic Processes in Raphe Magnus Nucleus under Activation Periaqueductal Gray Matter on the Model of Parkinson’s Disease

The electrophysiological studies on 4 Albino rats (230 ± 30?.) on the rotenone model of Parkinson’s disease (PD), induced by unilateral injection of rotenone and kept 4 weeks has been conducted. The extracellular online recording of spike activity of 149 single neurons of the Raphe Magnus (RMG) at high frequency stimulation (HFS) of Periaqueductal gray (PAG) had produced. The programmed mathematical analysis of spikes averaged frequency, with recalculation in interpulse intervals and frequencies to assess of degree of manifestation depressor and excitatory effects as well as the frequency of pre- and post-stimulus activation degree of manifestation in terms of diagrams of averaged frequency spikes are used. On the model of PD a significant reduction in quantity of RMG neurons, evoked at HFS PAG by depressor and depressor–excitatory manifestations of activity had been revealed. On the model of PD, the significant reduction in the number of neurons RMG, responding at PAG HFS by depressor and depressor-excitatory manifestations of activity has been revealed. Analysis of relative degree of intensity of depressor and excitatory effects, by way of example diagrams average frequency of spikes, led to the conclusion. It has been discovered the prevalence of excitatory post stimulus manifestations of activity over depressive (on the order of 1.63- and 2.0-multiple). The pre stimulus frequency of activity substantially prevailed in neurons, responding by excitatory effects (on the order of 2.46- and 17.0-multiple in uni- and multidirectional successions, respectively). As regards to post stimulus frequency, the difference is even higher proved– on the order of 14.6 and even 56.5-multiple for uni- and multidirectional sequences, respectively. Besides, especially larger for multidirectional successions. In other words, under PD excitotoxicity revealed, promoting the powerful frequency growth of pre- and post-stimulus activity in both excitatory sequences, testifying about deep neurodegenerative defeat of important ant nociceptive structure – RMG and promotes the emergence of resistant chronic pain.