Nitric oxide production in the sphenoidal sinus

Abstract Problem: Nitric oxide (NO) is considered to prevent local infections in paranasal sinus. As sphenoidal sinusitis is rare our hypothesis was that NO concentration is higher in spenoidal sinus than in maxillary sinus. The sphenoidal sinus is not easily accessible and NO concentration in this sinus has been reported in one patient. We studied the presence of NO and NO-synthesizing enzymes (NOS), in the maxillary and sphenoidal sinus. Methods: Ten patients (3 male; mean age, 55 years) undergoing surgery for pituitary adenomas were examined perioperatively. Patients were orally intubated and gas samples were taken during the first hour of surgery. By using chemiluminiscence technique the presence of NO gas in the maxillary and sphenoidal sinus was measured. Distribution of different NOS and NADPH-diaphorase in mucosal biopsies was also studied. Results: The individual concentration of NO was approximately half in the sphenoidal sinus compared to the maxillary sinus. Mean value of NO in the sphenoidal sinus was 2575 ppb and in the maxillary sinus 6792 ppb. Morphological analyses revealed presence of the isozymes: inducible NOS, neuronal NOS, and endothelial NOS, as well as NADPH-diaphorase, in the mucosa of the maxillary and sphenoidal sinus. Most abundant was inducible NOS. Conclusion: In this small study we found lower concentrations of NO in the sphenoidal sinus than the maxillary sinus. Significance: The concentration of NO, and the abundant presence of inducible NOS in the sphenoidal sinus in these nonallergic, noninfected patients will be discussed. Support: None reported.