Veselovskaya Y. Age-related peculiarities of neurophysiological mechanisms of the waking-sleep cycle in norm and in conditions of acute and chronic emotional stresses

Object - neurophysiological organization of the sleep-vigilance cycle during the ontogenesis. Purpose - the studying of age peculiarities of neurophysiological organi-zation of the sleep-vigilance cycle under normal conditions and under the conditions of acute and chronic emotional stress. Methods - stereotaxic technique, electroencephalog-raphy, electrocardiography, arterial pressure registration, forming of acute and chronic emotional stress conditions. Results, novelty: For the first time it has been shown that 1-month old rats form a chronic stress-resistant structural or-ganization of the sleep-vigilance cycle as a response to acute stress. In 3-months old rats the acute stress potentiates the sleep processes and the chronic stress alters the structure of sleep-vigilance cycle approaching it to the initial level of intact animals with the prevailing of the sleep over the vigi-lance processes. In 12-months old rats with different repre-sentation of sleep and vigilance the repartition of the sleep-vigilance cycle under the conditions of acute stress leads to the forming of the same kind of reaction to the chronic stress. In 24-months old rats the conditions of both acute and chronic stress damage mostly the paradoxical sleep phase. It has been shown that the influence of acute and chronic stress leads to the forming of a spasmodic activity center in the structures of brain limbic system where the part of pace-maker mechanism is played by hippocampus and new cortex in 1- and 3-months old rats, by hippocampus and hypothalamus in 12-months old rats, and by hippocampus in 24-months old rats. It has been established that chronic stress leads to the forming of arterial hypertension in rats of every age group, causing the heart activity disturbance in 1-month old rats and myocardium electrogenesis in the rats of older ages. Application field - neurophysiology, psychoneurol-ogy, cardiology.