Morphometric characteristics of the ventrolateral preoptic nucleus of the hypothalamus of mature rats under modification of the photoperiod

Abstract

The aim of the study is to investigate the effect of different light regimes and melatonin on the morphometric characteristics of the ventrolateral preoptic (anterior-lateral preoptic) nucleus of the hypothalamus of mature rats.Material and methods. The experiments were performed on 28 white non-linear male rats. Animals in the first series were under normal light conditions. Animals of the second series were under light deprivation. The rats of the third series were under light stimulation. The fourth series were rats under light stimulation and intraperitoneally injection of melatonin (Sigma, USA) at a dose of 0.5 mg/ kg of body weight. Morphological analysis of neurons was performed using a LUMAM-8 microscope.Results. The asymmetric location of ventrolateral preoptic nuclei of the hypothalamus in the cerebral hemispheres has been revealed. The nucleus on the sections had a spherical or oval shape, and the neurons were the same in the center and periphery of the nucleus. The morphometric data indicate that in the studied parameters (average neurocyte volume, average neurocyte nucleus volume, the nuclear-cytoplasmic ratio in neurocytes, and average neurocyte count in the standard histological slice plane), no clear differences were observed in the mean trends.Conclusions. The histological examinations indicate that the studied parameters do not respond to the light conditions and time of day when the corresponding experimental conditions were simulated.