Hydrogen peroxide mimics the responses to oxygen in chicken ductus arteriosus

Abstract

Oxygen-induced vasoconstriction is an initial trigger for ductus arteriosus (DA) closure. The aim of this study was to investigate the developmental responses to O2 in chicken DA. Experiments were performed in the pulmonary and the aortic sides of the DA isolated from embryos incubated for 15 or 20 days. In 20-day embryos, the increase in O2 tension from 0 to 21% caused a contraction in rings obtained from the pulmonary side while a relaxant response was elicited in those obtained from the aortic side. In contrast, no changes were found following 21% O2 exposure in either the pulmonary or the aortic sides of the 15-day DA. The contraction to O2 was markedly prevented by the NADPH oxidase inhibitor apocynin, the mitochondrial electron transport chain inhibitor rotenone and by polyethylenglycol-catalase. Furthermore, addition of t-butyl-hydroperoxide mimicked the responses induced by 21% O2 (no effect in 15-day and contraction and relaxation in pulmonary and aortic sides of the 20-day DA, respectively). Our results are in favor of H2O2 as a possible mediator in the contractile responses to O2 in the DA. Supported by AGL2004-06685/ALI and SAF2005-03770