Guz L. The neurometabolic features and integrative activity of central nervous system in conditions of experimental hyperthyroxinemia in rats.

The object of study: parameters of behavioral and cognitive activity of rats, level of activity of prooxidant and antioxidant systems in some structures of brain, content of fatty acids of cerebral cortex, hippocampus and brain stem lipids. Purpose: determination of peculiarities of neurometabolic processes and behavioral activity of white rats in conditions of experimental hyperthyroxinemia. Methods of study: physiological methods: "open field" - for the determination of rats behavioral activity; conditional reaction of passive avoid - for the determination of cognitive functions; electrophysiological studies - determination of parameters of excitability of monosynaptic reflex arc and character of posttetanic potentiating, determination of threshold and hronaxy of efferent fibers of sciatic nerve. The parameter of functional activity of cells of some brain structures was study of the state of prooxidant and antioxidant systems, fatty acids content in cortex, hippocampus and brain stem lipids. The hyperthyroxinemia model was created by the introduction of L-thyroxin (10-140 mcg in a day) with food during two weeks. Theoretical and practical results, novelty: by the complex study it was at first shown that changes of behavioral and mnestic activity under the experimental hyperthyroxinemia were accompanied by essential increase of excitability of monosynaptic reflex arcs, that was proved by increase of the amplitude of monosynaptic reflex response, decrease of latent period and threshold of origin of monosynaptic reflex reaction. This points at the state of plasticity of synapses and may result in to violation of integrative activity of central nervous system. It was shown that in conditions of experimental hyperthyroxinemia tetanization resulted in depression of reflex responses. Dependence between functional processes of central nervous system and structural cell rearrangements of metabolic character was established. It was shown that experimental hyperthyroxinemia was accompanied by changes of the balanceof prooxidant and antioxidant systems in studied brain structures depending on thyroid hormones level. Field of application: human and animal physiology.