Effect of chronic aldosterone treatment on phenylephrine-induced vasoconstriction in rat thoracic aortic rings. The thoracic aortic rings from Dahl SS rat treated with or without ALDO for three weeks was constricted with phenylephrine (10-9 - 10-4 M). Isometric tension was recorded and normalized by dry weight of aortic rings and expressed as g/mg ring weight. Values are means ± SEM, n = 6. *P ≤ 0.05, LS vs. LS-ALDO.