[Utrastructural organization of the dorsomedial hypothalamic nuclei in rats with experimental chronic stress]

The dynamics of structural and ultrastructural changes of dorsomedial the hypothalamic nuclei in rats with chronic emotional stress within 10 months has been studied. It was found that stress loading increases the signs of damages of the nervous tissue. These signs were manifested as disorders of the structural organization of synaptic terminals and synaptic vesicles, and in the change of relation of types of synaptic contacts. Disorders in mitochondria structures, appearance of multivesicle little bodies and other osmiophil membrane structures of various types and edema development indicate on progressing destructive processes in the nervous tissue. The structures of the hypothalamus area underwent damages of different degree, thus causing a mosaic character of changes. Along with the adaptive processes we noticed rough destructive damages of structures up to the death of dendrites, pointing to systemic and irreversible character of changes in the brain tissue. Such changes can reflect adaptation-disadaptation changes in the tissue of the hypothalamic area under a long-term stress exposure and signs of decompensation or prepathological state of overstrain and to be morphofunctional basis of chronic fatigue.