title: Does nasal nitric oxide come from the sinuses?
abstract: OBJECTIVE
  The purpose of this study was to assess nitric oxide (NO) output by the nose and sinuses.
  
  
  METHODS
  In one volunteer, the osteomeatal complex and sphenoethmoidal recess were occluded to isolate the nose from the sinuses. The antrum and frontal sinus were each punctured by two catheters and irrigated with air at constant flow. Nitric oxide output and its rate of accumulation in the absence of air flow were measured in each sinus and in the adjacent nasal cavity.
  
  
  RESULTS
  Prior to ostial occlusion, NO output in the nose was 96 nL/min. It decreased by 12% after blockage of all of the ostia. In the isolated sinuses, it was 190 nL/min (antrum) and 68 nL/min (frontal). After 5 minutes stagnation; NO concentration [NO] rose in the occluded sinuses to 24,700 nL/L in the antrum and 22,300 nL/L in the frontal sinus. In the nose, it increased to 29,000 nL/L. When the period of stagnation was prolonged in the frontal sinus, the [NO] reached a plateau. NO output and accumulation were not altered in the nose or either sinus by opening their ostia. In the antrum and frontal sinus, lidocaine reduced NO output and the rate of NO accumulation, but not in the nose.
  
  
  CONCLUSIONS
  In this volunteer, 88% of nasal NO was derived from the nose itself. Nitric oxide exchange between the frontal sinus, antrum, and nose was negligible. In the absence of air flow, [NO] rose to a plateau in the nose and frontal sinus. Lidocaine inhibited NO output in the sinuses but not the nose.
authors.affiliation: Phil Cole Laboratories, University of Toronto, Ontario.
authors.forename: J S
authors.initials: JS
authors.lastname: Haight
authors.forename: P G
authors.initials: PG
authors.lastname: Djupesland
authors.forename: W
authors.initials: W
authors.lastname: Qjan
authors.forename: J M
authors.initials: JM
authors.lastname: Chatkin
authors.forename: H
authors.initials: H
authors.lastname: Furlott
authors.forename: J
authors.initials: J
authors.lastname: Irish
authors.forename: I
authors.initials: I
authors.lastname: Witterick
authors.forename: P
authors.initials: P
authors.lastname: McClean
authors.forename: R S
authors.initials: RS
authors.lastname: Fenton
authors.forename: V
authors.initials: V
authors.lastname: Hoffstein
authors.forename: N
authors.initials: N
authors.lastname: Zamel
mesh_terms: D006801:Humans; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000378:metabolism*; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism*; D010256:Paranasal Sinuses / Q000378:metabolism*
chemical_list: D009569:Nitric Oxide