Effect of intranasal capsaicin on symptoms and mediator release

Differential nasal responsiveness to environmental tobacco smoke (ETS) has been documented in humans and we hypothesized that this reflects differential responsiveness to c-fiber stimulation. We compared the response to intranasal capsaicin in subjects with and without a history of ETS-rhinitis. We challenged 10 ETS-sensitive and 11 ETS-nonsensitive subjects intranasally with 25 mg of lactose powder followed by 25 pg to 25 ng of capsaicin in 25 mg of lactose. Subjects rated nasal symptoms and underwent nasal lavage. In each lavage, the concentrations of albumin (an index of vascular permeability), kinins and histamine (a marker of mast cell activation) were measured. Nasal lavage tosyl-L-arginine methyl ester (TAME)-esterase activity, which can be a reflection of mast cell activation, increased vascular permeability or glandular secretion, was also determined. Subjects with a history of ETS-rhinitis reported more rhinorrhea than subjects without a history of ETS-rhinitis (P less than .01). No significant increase occurred in nasal lavage histamine, albumin or kinins in either subject group. TAME-esterase activity (presumably a reflection of increased glandular secretion) increased greater than 1000 cpm in 12/21 subjects (designated "TAME-producers"), but this was unrelated to ETS-sensitivity. TAME producers showed a dose-dependent increase in TAME-esterase activity, whereas TAME nonproducers showed no change at any capsaicin dose. We conclude that capsaicin causes nasal symptoms and glandular stimulation without evidence of increased vascular permeability or mast cell activation. ETS-rhinorrhea symptoms in humans appear related to c-fiber stimulation. The absence of c-fiber-induced glandular secretion, although not related to ETS-sensitivity, was associated with decreased sneezing and increased symptoms of capsaicin-induced nasal burning.