Serotonin in nasal secretion.

The aim of this study was to investigate the serotonin content in nasal secretion. Histamine- and methacholine-induced nasal secretions were collected during a 5-min period after challenge in 33 normal subjects. Serotonin was determined radioenzymatically and was found in 66% of pure, blown secretions. The median concentration of serotonin in histamine- and methacholine-induced secretions was 6.3 nmol/l (range less than 1.6-52.0) and 2.3 nmol/l (range 1.6-140.0) (NS), respectively. The serotonin concentration in allergen-induced nasal secretions in 7 rhinitis patients was 0.8 to 159 nmol/l, median 10.4 nmol/l which did not differ from the serotonin levels in the normal subjects. The serotonin concentration in nasal lavage fluids in 5 subjects was low (below the detection limit in 78% of the samples). Further studies of serotonin in patients with nasal hypersecretion are indicated.