Does Resveratrol Prevent Maladaptive Electrophysiological and Vascular Alterations in l-NAME Induced Hypertensive Rats?

Resveratrol has demonstrated various possible cardio-protective mechanisms, which may prove to be beneficial in the treatment and prevention of various complications seen in conditions such as diabetes and hypertension. Such disease states are widely understood to result in various biochemical alterations including an increase in oxidative stress and inflammation and a decrease in the bioavailability of the potent vasodilator nitric oxide. The aim of this study was to investigate the potential protective effects of resveratrol in preventing maladaptive vascular and cardiovascular alterations in a rodent model of induced hypertension. Animals commenced treatment at eight weeks of age for a total of eight weeks (l-NAME (400 mg/L) administered in the drinking water supplied and 2 mg/kg/day resveratrol via oral gavage). Vascular organ bath studies were carried out on thoracic aorta rings and mesenteric vessels. Electrophysiological studies were carried out on the left ventricular papillary muscle and various action potential parameters examined. l-NAME induced hypertensive animals displayed a marked increase in action potential durations at 20, 50 and 90% repolarisation (17.42 ± 2.35; 30.75 ± 5.31; 93.58 ± 15.28 respectively) in comparison to healthy control animals (13.19 ± 0.65; 20.38 ± 1.75; 54.00 ± 4.66 respectively). This prolongation was not significantly prevented in resveratrol treated l-NAME animals. Vascular tissues from l-NAME animals also demonstrated decreased contractile responses to noradrenaline. These responses were significantly improved in resveratrol treated l-NAME animals. As expected, l-NAME treated animals displayed a reduced relaxation response to acetylcholine and sodium nitroprusside. There was no significant improvement in relaxation in resveratrol treated l-NAME animals.