Is nitric oxide involved in cutaneous vasodilation during body heating in humans?

The neurotransmitter responsible for neurogenic vasodilation in human skin during body heating is unknown. We sought to determine whether the vasodilating substance nitric oxide (NO) is involved in this phenomenon. Six subjects were heated for 50 min by use of a water-perfused suit while forearm blood flow (FBF) was measured with plethysmography and skin blood flow (SkBF) was measured by the laser-Doppler method in both arms. In one forearm, NG-monomethyl-L-arginine (L-NMMA), an NO synthase blocker, was infused into the brachial artery. Bolus doses of L-NMMA ( 0.05, control vs. treated response).(ABSTRACT TRUNCATED AT 250 WORDS)