Jpn. J. Pharmacol. 81 (1), 99 - 106 (1999)

Mechanism of Structural Remodelling of the Rat Aorta
During Long-Term N^G-Nitro-l-arginine Methyl Ester Treatment

Iveta Bernatova, Ol'ga Pechanova and Frantisek Kristek


Department of Cardiovascular Physiology, Institute of Normal and Pathological Physiology, Slovak Academy of Sciences,
Sienkiewiczova 1, 813 71 Bratislava, Slovak Republic

Abstract: The aim of the present study was to determine whether decreased nitric oxide (NO) synthase production or rather N^G-nitro-l-arginine methyl ester (L-NAME)-induced hypertension was responsible for metabolic and structural remodelling of the rat aorta during four-week L-NAME treatment. Three groups of male Wistar rats were investigated: control, treated with 20 mg/kg per day L-NAME (L-NAME₂₀), and treated with 40 mg/kg per day L-NAME (L-NAME₄₀). Systolic blood pressure significantly increased in L-NAME₂₀ to 146% and in L-NAME₄₀ to 149% of the control value. NO synthase activity in the aorta significantly decreased in L-NAME₂₀ and L-NAME₄₀ to 86% and 65% of the control values, respectively. Proteosynthesis was significantly elevated in both L-NAME groups, while nuclear DNA concentration was significantly elevated only in the L-NAME₄₀ group. Cyclic GMP concentration significantly decreased in L-NAME₂₀ to 73% and in L-NAME₄₀ to 46% of the control. Cyclic AMP concentration significantly increased in L-NAME₂₀ and L-NAME₄₀ to 128% and 145% of the control value, respectively. The diameter and wall thickness-to-diameter ratio were significantly elevated only in the L-NAME₄₀ group. We conclude that remodelling of the aorta in L-NAME-treated rats was rather associated with NO deficiency than
L-NAME-induced hypertension.

Keywords: Nitric oxide, N^G-Nitro-l-arginine methyl ester, Blood pressure, cAMP, Aorta