Ethanol consumption increases endothelin-1 expression and reactivity in the rat cavernosal smooth muscle.
BACKGROUND Low to moderate alcohol consumption is known to reduce the risk of cardiovascular diseases; however, chronic high-dose alcohol ingestion causes cardiovascular injuries such as hypertension. The time response of alcohol-induced hypertension and associated tissue oxidative stress response has not been fully explored. OBJECTIVES To investigate the time response of high-dose alcohol ingestion on blood pressure (BP) and to correlate the alterations in plasma nitric oxide (NO) levels and oxidative stress parameters in rats. METHODS Male Fisher rats (200 g to 250 g) were divided into two groups of 30 animals each and treated as follows: control (5% sucrose, orally) and 20% ethanol (4 g/kg, orally) daily for 12 weeks. The BP (systolic, diastolic and mean) was recorded every week using the tail-cuff method. Six animals from each group were sacrificed at six, eight, 10 and 12 weeks after treatment, and blood was collected and analyzed. RESULTS Systolic and mean BP were significantly elevated after six weeks, whereas diastolic BP was elevated after eight weeks of daily ethanol ingestion. BP elevation was related to a significant increase in plasma malondialdehyde and protein carbonyls, and a significant decrease in plasma NO, ratio of reduced to oxidized glutathione and the CuZn-superoxide dismutase and Mn-superoxide dismutase, catalase and glutathione peroxidase antioxidant enzyme activities in a time-dependent manner. CONCLUSIONS The duration of alcohol ingestion is important in the induction of hypertension and the associated NO and antioxidant depletion, and oxidative tissue injury.