Introduction and methods: This study reports the effects of chronic L-carnitine (LC)-treatment on hypertension induced by N-nitro-L-arginine methyl ester (L-NAME) and evaluates possible mechanisms of action. Four groups of male Wistar rats were used: 1) control; 2) rats treated with L-NAME (35 mg/Kg body weight/day dissolved in tap water); 3) rats treated with LC (300 mg/kg/day); and 4) rats treated with L-NAME plus LC. All treatments were maintained for 12 weeks. Blood pressure was measured weekly; at the end of the treatment, rats were killed by decapitation after being anesthetized with pentobarbital. Blood samples were used to determine the ratio between reduced and oxidized glutathione (GSH/GSSG), and to measure in erythrocytes the specific activities of the antioxidant enzymes, glutathione peroxidase, glutathione reductase, and superoxide dismutase.

Results and conclusions: The administration of LC in L-NAME-treated animals produced a significant reduction of both diastolic and systolic arterial pressures. When looking into the oxidative stress, which plays a key role in the pathogenesis of hypertension, we found an improvement in the antioxidant defense of L-NAME-treated animals after the treatment with LC (namely, an enhancement of antioxidant enzyme activities and GSH/GSSG ratio). In conclusion, this study shows a clear hypotensive effect of LC when administered chronically to L-NAME-induced hypertension. The reduction of blood pressure was accompanied by a significant increase of the antioxidant enzyme activity and the GSH/GSSG ratio, thus showing a beneficial effect of LC on the hypertension-related oxidative stress.

Acknowledgments: Supported by Ministerio de Sanidad y Consumo (PI020179 & PI051026).