Demchenko O. The role of thyroid hormones in realization of physiological mechanisms of inborn and acquired behavioral forms on the rats of different age

Researches are devoted to the analysis of age features of integrative reaction of rats CNS in conditions of the changed thyroid status and also in a combination with the emotional - pain state caused by a postoperative pain (laparotomy). The subject of investigation: behavioral activity of rats of different age groups; fatty acids content of lipids of cerebral cortex and hippocampus; state of antioxidant system; content of astroglial cytoskeleton protein in different structures of the animals brain (cerebral cortex, hippocampus, brainstem, thalamus). The methods of investigation: physiological, biochemical; clinical, statistical. The experimental hypothyroidism and hyperthyroidism was simulated by adding to food L-Thyroxin (10 mcg/day) or Mercazole (10 мg/kg) within 2 weeks. The laparotomy as a model of emotional-pain state was lead under etherization. The experiment was started in 16-20 hours after laparotomy. Findings of the study indicate that thyroid hormones play an important role in organizationof inborn and acquired reflexes during ontogenesis. Thyroid dysfunctions cause behavioral and cognitive deficiency on the degree of which manifestation the animals were distributed in the next order juvenile>old>young. The inhibition of orientative-trying and emotional reactions increases in proportion to process of unsaturated and polyunsaturated fatty acids storage in lipids of cerebral cortex and hippocampus of the different age groups: most intensify in juvenile animals (in 3-6 times), less intensify- in old animals and less essential - in young animals (70-130%). Such relationship in hyperthyroid animals decreases with age but in hypothyroid animals it increases. The laparotomy strengthens character of thyroid dysfunctions influence on inborn reflex activity by of common deprivation effect converted to activation. On functional level it was shown by increasing of emotionality while on structural level - decreasing content of unsaturated and polyunsaturated fatty acids in lipids of hippocampus (by 40 % injuvenile rats, 34% in young rats and 50-62% in the old animals). The level of acquired reflex activity was investigated by the thyroid state of organism because deficiency of thyroid hormones is attended by decreasing of represent engrams amount of space memory. The optimization of space memory (hyperthyroidism) is attended by decreasing content of glial fibrous acidic protein (GFAP) in a hippocampus of young animals by 42-55 % and in old animals by 41% (p<0,01). Thus, possible mechanisms of realization of inborn and acquired forms of behavior rats of different age groups in conditions of thyroid disbalance is the regulation of fatty-acid spectrum of cerebral cortex also regulation of protein synthesis activity in system of neuro-glial complex of hippocampus.