Temperature conditioning of inspired air by the nose: is nitric oxide involved?

Inspired air is warmed as it Hows through the nasal passages of humans. It is postulated that Wood flow and/or Wood volume of the nasal mucosa has a role in temperature conditioning, but there is little evidence for this hypothesis Nitric oxide (NO), a potent vasodilator, ia present in nasal air in high concentrations. We have previously reported that the inhaled vasoconstrictor oxymciazoUnc reduces release of NO into nasal air (FASEB J. 9: A326,1995). In dus study, we asked if nasal vasoconstriction might alter warming of inspired air. We measured the nasal airway temperature in six healthy, adult males at rest breathing room air through the nose. Temperature was measured from the nasal sill (0 cm) to a depth of 10 cm into die nasal passage at 1 cm increments. One hour after nasal administration of oxymetazoline (0.05%, 4 whiffs each nostril) measurements of nasal air temperature were repeated. (Figure Presented) Distance (cm) Temperature of inspired nasal air increased with distance into the nasal passage. After nasal oxymetazoline, there was less wanning of inspired nasal air. In combination with our previous observation of reduced nasal NO release after oxymetazoline, our results are consistent with the hypothesis that warming of nasal air is modulated by mucosa] blood flow and/or blood volume, and that nasal NO is involved in this modulation.