ASSESSMENT OF RAT BRAIN MORPHOFUNCTIONAL STATE IN A PARKINSON'S MODEL: INFLUENCE OF THERAPEUTIC AGENTS OF ANIMAL AND SYNTHETIC ORIGINS.

In neurodegenerative diseases, particularly in Parkinson's disease (PD), antinociceptive centers are often implicated in neurodegeneration, leading to persistent pain unresponsive to narcotic substances. This study investigated the periaqueductal gray matter (PAG) and the nucleus raphe magnus (NRM), components of the brain's antinociceptive system. In conditions of rotenone intoxication (an experimental PD model), morphological changes in intracellular structures were observed in PAG and NRM neurons, indicating metabolic disorders characteristic of PD (alterations in the shape and size of neuronal bodies and processes, disruption of acid phosphatase activity in neuron cytoplasm). Under the influence of bacterial melanin and in combination with synoestrol, positive changes in structural properties were observed in PAG and NRM neurons compared to the rotenone model of PD. This included the preservation of the morphological characteristics typical of these brain regions, with cells exhibiting shapes and sizes close to normal. Furthermore, under the influence of these therapeutic agents, an increase in phosphatase activity in cell cytoplasm was detected, indicating an acceleration of metabolic processes (metabolic activation) disrupted by rotenone intoxication. The data obtained suggests that bacterial melanin and synoestrol may act as potential neuroprotective agents against PAG and NRM neurons in the rat brain in the rotenone model of PD. Further research is needed to elucidate the mechanisms of action of therapeutic doses and propose their use in the treatment of PD, either in isolation or combination therapy.

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.

SYNAPTIC PROCESSES IN PERIAQUEDUCTAL GRAY UNDER ACTIVATION OF LOCUS COERULEUS IN A ROTENONE MODEL OF PARKINSON'S DISEASE.

The aim of the study was investigation the ratio of excitatory and depressor post-stimulus manifestations of Periaqueductal gray (PAG) single neuron activity during Locus coeruleus (LC) stimulation in a Parkinson's disease (PD) model to identify excitotoxicity in neurodegeneration and the formation of persistent pain, which is poorly treatable. The electrophysiological studies were performed on 6 Albino rats (230±30g.): intact (n=3) and on the rotenone model of Parkinson's disease (PD) induced by unilateral injection of rotenone for 4 weeks holding of animals (n=3). The extracellular on-line registration of spike activity of 236 single neurons of the Periaqueductal gray (PAG) at high frequency stimulation (HFS) of Locus coeruleus (LC) in intact animals (116 neurons) and on the model of PD (120 neurons) was produced. According to programmed mathematical analyses were detected changes in depressor and excitatory responses (TD and TP), accompanied by post-tetanic depression and potentiation. In the neurons PAG at HFS LC on the model of PD the full suppression of synaptic depressor poststimulus manifestations of activity, accompanied by posttetanic and the prevalence of such excitatory has been revealed. Was the conclusion about serious neurodegenerative damage of the important antinociceptive structure - PAG, that promotes resistant chronic pain in parkinsonian patients.