Rodynskіy O. Neurophysiological analysis of functioning of a spinal cord in conditions of specially high excitability and possibility of its correction

The object of this investigation - is electrophysiological activity of a spinal cord in conditions of specially high excitability. The purpose of this investigation - to elucidate neurophysiologic mechanisms of a spinal cord functioning in conditions of specially high excitability by studying of various forms of excitability increasing of neurons and nerve fibers with further inquiry of character of segmental and supraspinal impacts on spinal cord in this state and opportunities of correction of this state. The electrophysiological and statistical methods used in this investigation. As the result of this investigation - the important scientific problem was solved. Neurophysiologic mechanisms of development of fundamentally new level of increasing excitability of a spinal cord, hyperreflexia - spinal superreflexia - state at which amplitude of reflex responses is near the action threshold of the most excitative nerve fibers. Mechanisms of segmental and supraspinal impacts on neurons of a spinal cord inthese conditions and opportunities of correction of specially high excitability state of a spinal cord are investigated. Novelty of the investigation - for the first time was found, that manipulations with an afferent orifice of segmental reflex arcs or systemic action of humoral factors characterize mechanisms which underlie increase reflex activity of spinal cord, but individually each of these factors provides growth of monosynaptic reflex responses of no more than by (250-300) %. Only combination of denervation with action of a voltage-dependent potassium channels blocker allowed to create a state of specially high excitability of spinal cord - superreflexia (SR). It is revealed, that in this case amplitude of monosynaptic reflex discharges of ventral root (MD VR) exceeded the same finding in the intact animals by (800-900)% and reached the threshold of excitation of VR fibers. For the first time it was shown that in conditions of superreflexia there originates second component of MD VR, which representsexcitation of fibers that are not involved in reflex discharge. For the first time, segmental and supraspinal impacts on neurons of a spinal cord in conditions of specially high excitability of a spinal cord (superreflexia) and opportunities of correction of these states by means of a neuroprotector - riluzol, were investigated. There was drawn a conclusion about violation of the law of isolated conduction of excitation in the nervous trunk in conditions of superreflexia. This is advanced by excitation of the majority of the ventral root fibers, big amplitude of their total potential, synchronization growth. The results of the investigation are introduced into educational process on departments of pharmacology and technology of pharmaceuticals, normal physiology, pathological physiology, a neurology of the Dnipropetrovsk state medical academy, departments of normal physiology of the Ukrainian state medical stomatologic academy, O.O.Bogomolets Kyiv national medical university, Danyla Galitsky Lviv national medical university, I.Ya.Gorbachevsky Ternopol state medical university, M.I.Pyrogov Vinnitsa national medical university, the Zaporozhye state medical university, the Odessa state medical university, S.I.Georgievsky Crimean state medical university, departments of physiology of M.Gorky Donetsk state medical university, departments of human and animals physiology and Dnipropetrovsk national university. The area - medicine (physiology).