Inhibition of Secretory Activity of Atrial Myocytes in Hypertensive Rats after Losartan Treatment

Male ISIAH rats with inherited stress-induced arterial hypertension (BP 174.0±1.3 mm Hg) received antagonist of angiotensin II receptors losartan in a dose of 10 mg/kg/day for 16 days. Ultrastructural study of the right atrium showed signs of dramatic and pronounced inhibition of synthesis of the natriuretic peptides (changes in the composition of secretory granules and decrease in their population density and size) the atrial myocytes against the background of persistent BP decrease in hypertensive rats to 142.0±4.2 mm Hg. We concluded that myoendocrine cells in rats with stable hypertension retain ability to respond adequately to distention of the atria with blood.