Inhibition of cGMP accumulation in rabbit aorta by ALDH inhibitors (1 mM × 20 min, followed by washout) and tolerance (Tol)-inducing amounts of GTN (0.3 mM × 30 min, followed by washout). Rings were (+) or were not (−) exposed to 1 μM GTN for 1 min. All bars are significantly less than control (Con) + GTN to P < 0.01, except cyanamide (Cya) + GTN, where P < 0.05. Data are presented as the means ± SD of three aortic rings. Chl, chloral hydrate; Ace, acetaldehyde.