Influences of ascorbic acid on interaction between endothelin-1 and oxidative-nitrosative stress markers

Objective: This study was designed to investigate the effects of ascorbic acid before exogenous endothelin-I administration on oxidative-nitrosative stress markers and trace element concentrations. Material: Wistar-Albino male rats, 9 - 10 weeks old, with mean body weight of 295 g were used in the study. Systolic blood pressures were recorded by tail plethysmography. For the determination of plasma total nitrite, nitrite, nitrate and MDA concentrations and red cell Cu-Zn/SOD and catalase activities spectrophotometry was used. Plasma and red cell zinc and copper concentrations were determined by atomic absorption spectrophotometry. Method: After a training period daily systolic blood pressures of both the control (n = 10) and the experimental groups (n = 15) were recorded by tail plethysmography. Following ascorbic acid treatment for 3 days in maximum dose (100 mg/kg/day), exogenous endothelin-I was administered (1 nmol/kg) and systolic blood pressures were recorded. Results: The results showed that plasma total nitrite, nitrate, copper, zinc concentrations, red cell catalase activity, copper, zinc concentrations and systolic blood pressure and heart rates were increased statistically in the experimental group compared to controls. However, red cell superoxide dismutase activity was decreased significantly compared to controls. As reported in our other study, the increase in systolic blood pressure was not as high as in the group administered endothelin-I only. Conclusions: Ascorbic acid administration has affected the interaction between exogenous endothelin-I and oxidative-nitrosative stress markers.