Effects of catalase and endothelin on anoxia-induced vasoconstriction of porcine basilar artery in vitro.

AIM: To study whether anoxia-induced vasoconstriction was related to the release of endothelin (ET). METHODS: Acute anoxia was induced by gassing the organ chamber with 95% N2 + 5% CO2. Changes in tension of porcine basilar arterial ring was recorded. RESULTS: Anoxia-induced increases in tension were 0.21 g +/- 0.08 g and 0.24 g +/- 0.09 g under basal tension and during ET 3 nmol.L-1-induced contractions, respectively. In the rings tension did not further augment following the increase of ET from 100 to 300 nmol.L-1, acute anoxia did cause further increase in tension of 0.16 g +/- 0.10 g (n = 4). Catalase 800 and 2400 kU.L-1 decreased the anoxia-induced contraction, with inhibitory rate of 33% +/- 7% and 47% +/- 9%, respectively. CONCLUSION: Anoxia-induced vasoconstriction was related to release of hydrogen peroxide from endothelial cells.