Endothelial function is impaired in conduit arteries of pannexin1 knockout mice

Pannexin1 is ubiquitously expressed in vertebrate tissues, but the role it plays in vascular tone regulation remains unclear. We found that Pannexin1 expression level is much higher in the endothelium relative to smooth muscle of saphenous artery. The ability of endothelium-intact arteries for dilation was significantly impaired whereas contractile responses were considerably increased in mice with genetic ablation of Pannexin1. No such increased contractile responses were detected in the endothelium-denuded arteries. Combined, our findings suggest a new function of Pannexin1 as an important player in normal endothelium-dependent regulation of arterial tone, where it facilitates vessel dilation and attenuates constriction.