In rats, chronic administration of the nitric oxide (NO) inhibitor Nω-nitro-l-arginine methyl ester (L-NAME) causes arterial hypertension, cardiac hypertrophy and myocardial ischemic alterations such as necrosis and fibrosis. In this study, we evaluated the effect of 8 weeks of treatment with enalapril maleate on cardiac weight and on the development of the histological alterations induced by L-NAME. Enalapril significantly inhibited the development of both arterial hypertension (117.2 ± 5.8, 161.8 ± 8.8 and 122.0 ± 10.6 mm Hg, for control, L-NAME- and L-NAME + enalapril-treated animals, respectively) and left ventricular hypertrophy (1.36 ± 0.13, 1.60 ± 0.04 and 1.48 ± 0.05 mg/g, for control, L-NAME- and L-NAME + enalapril-treated animals, respectively), but had no effect on the myocardial lesions. These findings demonstrate that although the renin-angiotensin system plays a major role in the development of arterial hypertension and cardiac hypertrophy, it does not modulate the ischemia-induced myocardial alterations observed in this model. © 1995.28719396Baylis, Mitruka, Deng, Chronic blockade of nitric oxide synthesis in the rat produces systemic hypertension and glomerular damage (1992) J. Clin. Invest., 90, p. 278Brush, Cannon, III, Schenke, Bonow, Leon, Maron, Epstein, Angina due to coronary microvascular disease in hypertensive patients without left ventricular hypertrophy (1988) New Engl. J. Med., 319, p. 1302Buttrick, Malhotra, McDermott, Lam, Brodman, Isomyosin distribution on overloaded human atrial myocardium (1986) J. Am. Coll. Cardiol., 7 (2), p. 86AChilds, Adams, Mak, Regression of cardiac hypertrophy in spontaneously hypertensive rats by enalapril and the expression of contractile proteins (1990) Hypertension, 16, pp. 662-668Dunn, Oigman, Ventura, Messerli, Kobrin, Frohlich, Enalapril improves systemic and renal hemodynamics and allows regression of left ventricular mass in essential hypertension (1984) Am. J. Cardiol., 53, p. 105Factor, Bhan, Minase, Wolinsky, Sonnenblick, Hypertensive-diabetic cardiopathy in the rat (1981) Am. J. Pathol., 102, p. 219Jover, Herizi, Ventre, Dupont, Mimran, Sodium and angiotensin in hypertension induced by long-term nitric oxide blockade (1993) Hypertension, 21, p. 944Lund, Tomanek, Myocardial morphology in spontaneously hypertensive and aortic-constricted rats (1978) Am. J. Anat., 152, p. 141Moore, Al Swayeh, Chong, Evans, Mirzazadeh, Gibson, l-NG-Nitroarginine (NOARG) inhibits endothelium-dependent vasodilatation in the rabbit aorta and perfused rat mesentery (1989) Br. J. Pharmacol., 176, p. 219Moreno, Jr., Metze, Antunes, Zatz, De Nucci, Chronic nitric oxide blockade causes cardiac ischemia but not cardiac hypertrophy: an experiment of four weeks in rats (1994) Verh. Dtsch. Ger. Path., 78, p. 459Nemoto, Matsuoka, Hasegawa, Ueki, Kimura, Kawamura, Masuda, Miura, Effect of enalapril and E4177 on the heart under chronic nitric oxide suppression in in vivo rat model (1994) J. Mol. Cell. Cardiol., 26, p. 228Ribeiro, Antunes, De Nucci, Lovisolo, Zatz, Chronic inhibition of nitric oxide synthesis: a new model of arterial hypertension (1992) Hypertension, 20, p. 298Tan, Jalil, Pick, Janicki, Weber, Cardiac myocyte necrosis induced by angiotensin II (1991) Circ. Res., 69, p. 1185Ueki, Matsuoka, Hasegawa, Nemoto, Kimura, Kawamura, Masuda, Miura, Comparison the effects of long-term nitric oxide suppression on the heart between young and old rats (1994) J. Mol. Cell. Cardiol., 26, p. 228Weber, Brilla, Janicki, Signals for the remodeling of the cardiac interstitium in systemic hypertension (1991) J. Cardiovasc. Pharmacol., 17, p. 14Zatz, A low cost tail-cuff method for the estimation of mean arterial pressure in conscious rats (1990) Lab. Anim. Sci., 40, p. 198