Endothelial function is impaired in saphenous arteries of Panx1−/−mice. (A) Relative CD31/SM22 and Panx1/SM22 mRNA expression levels in endothelium-intact (+Endo) and endothelium-denuded (−Endo) arteries of WT mice (n = 4; 4 for CD31 and n = 3; 4 for Panx1; *p < 0.05,). Data were normalized to the amount of smooth muscle cells marker SM22 mRNA and expressed as % of the average level in corresponding endothelium-intact (+Endo) group. (B) Concentration-response relationships to cumulative addition of α1-adrenoceptor agonist phenylephrine of endothelium-denuded (thin curves; n = 11, 10, p = 0.14) or endothelium-intact (thick curves; n = 22, 24, *p < 0.05) saphenous arteries from WT and Panx1−/− mice. (C) Concentration-response relationships of endothelium-intact saphenous arteries from WT and Panx1−/−mice to KCl (n = 6; 9, *p < 0.05; the effect of noradrenaline released from sympathetic nerves was blocked by 1 μmol/L phentolamine). (D) Concentration-response relationships to acetylcholine after phenylephrine-induced preconstruction of endothelium-intact saphenous arteries from WT and Panx1−/−mice (n = 6, 6, *p < 0.05).