Dietary L-arginine attenuates blood pressure in mineralocorticoid-salt hypertensive rats.

The present study was designed to investigate the influence of dietary L-arginine supplementation on blood pressure and on ex vivo vascular reactivity in mineralocorticoid-salt (DOCA-salt) hypertensive rats. Systolic blood pressure and heart rate were determined throughout the experimental period in unanaesthetized rats. Plasma and urine electrolyte levels were measured. Vasoconstrictor response to noradrenaline and vasodilator responses to acetylcholine and sodium nitroprusside were evaluated in the isolated perfused mesenteric vascular bed. DOCA-salt hypertensive rats were divided into 2 groups: a control group and a treated group receiving 0.8% L-arginine supplementation in drinking water. Dietary L-arginine supplementation attenuated systolic blood pressure in conscious DOCA-salt hypertensive rats, but did not modify heart rate. Plasma calcium and sodium concentrations and urinary magnesium excretion were decreased by L-arginine supplementation. Noradrenaline-induced vasoconstriction decreased and acetylcholine-induced vasodilatation increased, whereas sodium nitroprusside-induced vasodilatation was not modified, in the L-arginine-supplemented rats. It is concluded that dietary L-arginine supplementation in the diet lowers systolic blood pressure in DOCA-salt hypertensive rats, probably through vascular action.