The influence of hyperoxia on the cutaneous vasodilator responses to iontophoretic applications of acetylcholine (ACh) and sodium nitroprusside (SNP) was examined in healthy subjects. The breathing of 100% O2 decreased (P < 0.05) the vasodilator response to Ach, but not to SNP, suggesting that hyperoxia attenuates endothelial-mediated vasodilation of the human skin.
