Endogenous angiotensin II suppresses stretch-induced ANP secretion via AT1 receptor pathway

▶ Perfusion of angiotensin II into isolated beating atria decreased the ANP secretion. ▶ The suppression of ANP secretion by angiotensin II was more prominent in high-stretched beating atria. ▶ Angiotensin II-induced suppression of ANP secretion was blocked by AT1 receptor blocker. ▶ Losartan augmented stretch-induced ANP secretion. ▶ In renal hypertensive atria, the responses of ANP secretion to angiotensin II and losartan were accentuated because of upregulation of AT1 receptor.