INFLUENCE OF LONG-TERM VIBRATION ON THE ACTIVITY OF THE SUPERIOR VESTIBULAR NUCLEUS NEURONS UNDER THE CONDITIONS OF STIMULATION OF THE HYPOTHALAMUS NUCLEI.

Prolonged vibration exposure leads to alterations of the central control mechanisms of both the vestibulo-ocular and the vestibulo-autonomic systems, including a change in the hypothalamic-vestibular relationships associated, in particular, with the supraoptic nucleus and paraventricular nucleus. Post-vibration disturbances of the vestibular function are largely due to adaptive changes in neurotransmitter activity. The dynamics of spike activity of single neurons of the superior vestibular nucleus (SVN) in response to high-frequency stimulation of the paraventricular and supraoptic hypothalamic nuclei after long-term vibration exposure were analyzed. Analysis of impulse activity revealed the prevalence of tetanic potentiation in the responses of SVN neurons to high-frequency stimulation of paraventricular and supraoptic nuclei of rats. Exposure of animals to vibration led to a decrease in the number of neurons with tetanic potentiations and significant dominance of post-tetanic potentiation. Morphological and histochemical results showed that under hypothalamic stimulation in the SVN neurons of rats exposed to vibration, there is an increase in metabolism and dephosphorylation processes in the cellular structures of the studied brain area, which ultimately provides optimal conditions for the processes of cell survival and regeneration.

[THE EFFECTS OF THE STIMULATION OF HYPOTHALAMIC NUCLEI ON THE INFERIOR VESTIBULAR NUCLEUS AFTER LONG-TERM VIBRATION ACTION AND ADMINISTRATION OF PROLINE RICH PEPTIDE-1].

Vestibular dysfunctions after vibration action in a considerable degree by adaptive-adjustment changes of neurotransmitter processes are determined and regulation of which is possible by endogenous factors, particularly hypothalamic proline rich peptide-1. On Albino rats synaptic changes in single neurons of the inferior vestibular nucleus during high-frequency stimulation of hypothalamic supraoptic and paraventricular nuclei in condition of vibration action and systemic use of proline rich peptide-1 were studied. The poststimulus spike activity of inferior vestibular nucleus neurons in norm was manifested mainly in the form of tetanic potentiation and posttetanic potentation after vibration action. The combination of vibration action and proline rich peptide-1 restores the true balance of excitatory and inhibitory poststimulus reactions and increased level of survival the inferior vestibular nucleus neurons.

Responses of hypothalamic neurons to stimulation of the vestibular nerve and lateral vestibular nucleus in the rabbit.

Acute experiments were performed on rabbits to study the responses of neurons in the anterior, ventromedial, and posterior nuclei of the hypothalamus to single, paired, and rhythmic stimulation of the vestibular nerve and lateral vestibular nucleus of Deiters. The data obtained showed that neurons of the posterior nucleus of the hypothalamus were the most sensitive. Three types of response were seen from hypothalamic neurons, with short, long, and intermediate latent periods. This provides evidence that ascending afferent spike activity from the lateral vestibular nucleus of Deiters to the hypothalamus is mediated by mono-, oligo-, and polysynaptic pathways.