Fig. 3.

Acetylcholine (ACh)-mediated relaxation in the presence or absence of N^ω-nitro-l-arginine methyl ester (l-NAME) in small mesenteric arteries from adult (16 wk old) Dahl S rats fed Teklad (N = 6; A) or AIN (N = 6; B) since weaning (3 wk old). At 12 wk old, weaning-diet groups were divided, and a subset of rats underwent a diet switch, generating two additional diet groups: Teklad→AIN (N = 10; C) and AIN→Teklad (N = 6; D). N^ω-nitro-l-arginine methyl ester (l-NAME) was used at 100 μM to nonselectively inhibit nitric oxide synthese(NOS). Values are means ± SE. *P < 0.05 for maximum sensitivity to the vasoactive agonists (logEC₅₀) of l-NAME-treated vs. untreated mesenteric artery segments. Data were analyzed by t-test. PE, phenylephrine.