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The gene expression of thermosensitive TRP (transient receptor potential) ion channels was studied by the method of quantitative reverse transcription-polymerase-chain-reaction (RT-PCR) in hypothalamus of control (normal) rats (5 weeks at the room temperature 20 +/- 22 degrees C) and rats adapted to cold (5 weeks at the room temperature 4 +/- 6 degrees C). For the first time in this brain region the expression of Trpv3 and Trpm8 genes was found, that was the evidence of the presence of TRPV3 and TRPM8 ion channels in the hypothalamus; it was made a comparison of the gene expression of the 6 thermosensitive ion channels (TRPV1, TRPV2, TRPV3, TRPV4, TRPA1, TRPM8) and found that there was rather high expression of the genes of thermosensitive ion channels activated at temperatures above 30 degrees C, while, the gene expression level of cold sensitive TRPM8 and TRPA1 proved to be much lower; it was found that long-term cold adaptation modified the gene expression of TRPV3 ion channel. The findings support the assumption that thermosensitive TRP ion channels of hypothalamus may be involved in the mechanisms of thermal adaptation at the level of gene expression.

The mRNA expression of serotonin receptors 5-HT1A and 5-HT2A was investigated by the quantitative method RT-PCR in rats adapted to cold (5 weeks at +4 -(+6) degrees C) and in control (5 weeks at +20-22 degrees C). Four brain regions were examined: frontal cortex, hypothalamus, hippocampus, and midbrain. The influence of cold adaptation on the mRNA expression of 5-HT15 receptor was not found to be absent. The mRNA expression of 5-HT2A receptor changed under long-term cold exposure. These changes in different brain regions were various: in hypothalamus, there was an increase of the 5-HT2A receptor mRNA expression; in the cortex, a decrease; in the hippocampus and midbrain, significant changes of the mRNA expression were absent. The findings appear bo te adaptive and, according to their localization in the central nervous system, regulatory. They also suggest involvement of brain serotoninergic system in mechanism of adaptive reorganization of temperature regulation.