The aim of the study was to investigate changes in the plasma antioxidative activity and in lipid peroxidation after administration of endothelin-1 (ET-1) and endothelin receptor blockers and additionally, to estimate blood pressure. The study was performed on male Wistar rats (n = 6 per group) divided into 4 groups which received: (1) saline, (2) endothelin-1 (ET-1) (3 μg/kg b.w.) + saline, (3) BQ123 (1 mg/kg) + ET-1 (3 μg/kg), and (4) BQ788 (3 mg/kg) + ET-1 (3 μg/kg b.w.). The endothelin receptor antagonist was injected intravenously 30 min before ET-1 administration. Blood pressure was monitored, and the blood was collected before the saline or ET-1 administration as well as 60 and 300 min after their administration. The antioxidative properties were examined by FRAP method (ferric reducing ability of plasma), and the concentration of lipid peroxidation products was examined by the reaction with thiobarbituric acid (TBARS). It was estimated that intravenous administration of endothelin receptor blocker ETA increases plasma antioxidative properties (p < 0.01) and parallelly decreases the process of lipid peroxidation (p < 0.05 vs. ET-1) and blood pressure (p < 0.05).
Keywords: BQ123; BQ788; Entothelin 1; Oxidative stress.