Burachyk A. Morphofunctional characteristics of the suprachiasmatic nuclei of the hypothalamus under stress

Object - the peculiarity of the structural organization of suprachiasmatic nuclei of rats’ hypothalamus under different photoperiod modifications; purpose - is finding out the patterns of morphofunctional changes of suprachiasmatic nuclei of rat hypothalamus and the expression of the c-fos early response gene, for different duration of the photoperiod and under its correction by melatonin; methods are histological, electron microscopic, morphometric, immunohistochemical, densitometric, immunofluorescence, mathematical statistics; the results - it was stated for the first time, that the general daily patterns of structural rearrangement of the suprachiasmatic nuclei of the hypothalamus are more pronounced under constant illumination than in light deprivation; based on the complex study of the nature of the density of melatonin receptors type 1a in the neurons of the suprachiosmatic nuclei, during the day, convincing evidence was obtained of its photo-induced disturbance with the discontinuation of daily oscillations in the middle trends; it has been shown for the first time that the indicator of early desynchronosis of central mechanisms of circadian rhythms in rat brain is a break of the expression of the c-fos early response gene and c-Fos immunospecific protein determined in the pacemaker neurons of the suprachiasmatic nuclei of the hypothalamus in dyspinealism, and the pattern according to which the administration of exogenous melatonin (1.0 mg / kg) contributed to rise of the resistance of ultrastructures to light stressors, the improvement of the parameters of the area of neurons of the suprachiasmatic nuclei and the concentration of RNA in them.