Temperature conditioning of nasal air: Effects of vasoactive agents and involvement of nitric oxide

Nitric oxide (NO) is released into nasal air, but its function is unknown. We hypothesized that nasal vascular tone and/or flow influences temperature conditioning of nasal air and that NO participates in this process. We measured nasal air temperature (via a thermocouple) and exhaled nasal NO release (by chemiluminescence) in five humans and examined the effects of an aerosolized vasoconstrictor (oxymetazoline), a vasodilator (papaverine), N(G)-nitro-L-arginine methyl ester, an inhibitor of NO synthase, or saline (control). Compared with saline (which caused no changes in nasal air temperature or exhaled NO release), oxymetazoline (0.05%) reduced nasal air temperature and NO release (130.8 ± 15.1 to 81.3 ± 12.8 nl · min^-1 · m^-2; P < 0.01). Papaverine (0.01 M) increased nasal air temperature and NO release (131.8 ± 13.1 to 157.2 ± 17.4 nl · min^-1 · m^-2; P < 0.03). N(G)-nitro-L-arginine methyl ester reduced nasal air temperature and NO release (123.7 ± 14.2 to 44.2 ± 23.7 nl · min^-1 · m^-2; P < 0.01). The results suggest that vascular tone and/or flow modulates temperature conditioning and that NO may participate in that function.