Participation of thyroid hormone in the formation of higher brain functions is sufficiently known and widely represented in the literature. But the mechanisms of action of these hormones on the CNS unclear, and some part of the data is contradictory.

One of the possible mechanisms of formation of cognitive function is modulation of synaptic transmission, particularly monoaminergic. It is known that TH can change the content of saturated fatty acids in the brain tissues and in muscles.

We can assume that changes in the fatty acid spectrum will modulate lipid membrane viscosity properties and, consequently, the sensitivity of membrane receptors. That is why, determining the impact of age-action of thyroid hormones to fatty acid spectrum of the brain lipids can be seen as one way of correction the cognitive disorders occurring against the backdrop of thyroid dysfunction.

Objective: to identify the age characteristics of fatty acid lipid spectrum of rat brain under conditions of thyroid dysfunction.

In experiments on the white rats the fatty acid spectrum of free fatty acids in the hippocampus and neocortex of juvenile and old animals at conditions of thyroid dysfunction was studied.

Hyperthyroid state was modeled by administration of food crushed to powder with food L-thyroxine. Hypothyroid state was modeled by administration with food administration with food merkazolil. In order to determine the level of some free fatty acids brain tissue of rats was studied by chromatographic analysis.

The research results were processed using parametric statistical methods, using Student’s t-test for small samples. Changes parameters were considered likely at p < 0.05. The research was conducted under the European Convention for the Protection of vertebrate animals used for experimental and other scientific purposes.

It was found that the state of hyperthyroidism caused opposite changes in the content of fatty acids in rat neocortex depending on age. Juvenile rats (5 weeks) experienced a significant, more than tripled, increasing polyunsaturated fatty acids fractions leading to increase in the fate of total unsaturated compounds. In old rats content of linoleic and linolenic acids decreased significantly – by 66 % (p < 0.01).

State of hypothyroidism was accompanied by one-way changes in the number of fatty acids in the cerebral cortex of animals of two age groups: decrease in the concentration of pentakozanic acid in juvenile and old rats, respectively 47 % and 38 %, and linoleic and linolenic acids by 77 % in older individuals. Modification of fatty acid FFA range upward “unsaturated” can change the viscosity properties of lipids, in particular to increase the stiffness of the membranes and, consequently, enhance synaptic transmission. Perhaps thyroidin hormones regulate the fatty acid composition of membrane lipids and modifying effect on monoaminergic neurotransmitter system of the brain, including serotoninergic.

Added 25.11.2016

Keywords: experimental hyper- and hypothyroidism, neocortex, ontogeny, unsaturated and poly unsaturated fatty acids

Full text: PDF (Ukr) 894K

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