| Abstract: | The relationship between ANF activity and hypertension was determined by measuring ANF atrial content and vascular reactivity in two different models: spontaneous hypertensive rats (SHR) and renal hypertensive rats (RHR). Atrial extracts and aortic strips were prepared from hypertensive and normotensive animals. Relaxant activities of extracts, synthetic ANF and nitroglycerin were assayed on superfused aortic strips previously contracted by norepinephrine. ANF atrial content was statistically significantly lower in both models of hypertension, presumably by increased ANF release into the circulation which results in depletion of tissue storage sites. Vascular subsensitivity to ANF and nitroglycerin was found in both models of hypertension. Diminished ANF vascular reactivity in hypertension could be due to receptor down-regulation and/or to a decrease in the ability of cGMP to induce relaxation. |
