[SECRETORY ACTIVITY OF ATRIAL CARDIOMYOCYTES IN NORMOTENSIVE AND HYPERTENSIVE RATS DURING STRESS].

The pioneer overall ultrastructural and immune-enzymatic evaluation of the secretory activity of atrial myoendocrine cells in WAG strain (control) and in ISIAH rats with inherited stress induced arterial hypertension has been carried out. It was revealed that under basal conditions the cardiac hormone synthesis, storage and secretion in myoendocrine cells of hypertensive rats were certainly intensified, and the atrial natriuretic peptide (ANP) blood concentration was reliably higher than in normotensive WAG rats. All rats demonstrated the unidirectional reaction during the subchronic restraint stress: the ANP release was depressed, the peptides accumulated in the cardiomyocyte numerous large secretory granules, and ANP blood concentration 6 times decreased, while interline differences preserved. It is concluded that the cardiac natriuretic peptides as a hypotensive chain of the hemodynamic regulation, compensatory response to the development of inherited arterial hypertension and participate in the realization of stress reactions.