Acetylcholine-induced ex vivo ATP release from the human nasal mucosa

Abstract Objective The present study aimed at investigating ATP release in response to acetylcholine (Ach) and pharmacologically elucidating the intracellular signal transduction pathway of this reaction in an ex vivo experiment. Methods The inferior turbinate mucosa was collected from 21 patients with chronic hypertrophic rhinitis who underwent endoscopic turbinectomy. The mucosa was shaped into a filmy round piece, and incubated with chemical(s) in Hank's balanced salt solution for 10 min. After incubation, the ATP concentration was measured by a luciferin-luciferase assay. Results The baseline release of ATP without stimulus was 57.2 ± 10.3 fM. The ATP release was significantly increased by stimulation with 100 μM Ach. The Ach-induced ATP release was completely inhibited by removing extracellular Ca 2+ . Significant inhibition of the Ach-induced ATP release was also observed by the addition of 1 μM atropine, 40 μM 2-APB, 10 μM CBX, and 100 μM PPADS, whereas 30 nM bafilomycin A1 did not affect the ATP release. Conclusion These results indicate that the Ach-induced ATP release from the human nasal mucosa is dependent on the pannexin-1 channel and purinergic P2X7 receptor, suggesting that these two molecules constitute a local autocrine/paracrine signaling system in the human nasal epithelium.