Acute nicotine administration stimulates ciliary activity via α3β4 nAChR in the mouse trachea

• Published in: International immunopharmacology 2020-07, Vol.84, p.106496-106496, Article 106496
• Main Authors: Perniss, Alexander, Latz, Ariane, Boseva, Ivelina, Papadakis, Tamara, Dames, Claudia, Meisel, Christian, Meisel, Andreas, Scholze, Petra, Kummer, Wolfgang, Krasteva-Christ, Gabriela
• Format: Article
• Language: English
• Subjects: Acceleration; Acetylcholine receptors (muscarinic); Acetylcholine receptors (nicotinic); Agonists; Animals; Antagonists; Beat frequencies; Cilia; Cilia - drug effects; Cilia - metabolism; Cilia beat frequency; Cotinine; Desensitization; Environmental changes; Environmental effects; Epibatidine; Mecamylamine; Mice; Mice, Inbred C57BL; Mice, Knockout; Movement - drug effects; Mucociliary clearance; Mucosa; Mucus; nAChR; Nicotine; Nicotine - pharmacology; Nicotinic Agonists - pharmacology; Nicotinic Antagonists - pharmacology; Non-neuronal acetylcholine; Protein Subunits - physiology; Receptors; Receptors, Nicotinic - deficiency; Receptors, Nicotinic - drug effects; Receptors, Nicotinic - metabolism; Trachea; Trachea - drug effects; Trapped particles; Tubocurarine
• ISSN: 1567-5769; 1878-1705
• DOI: 10.1016/j.intimp.2020.106496

•Nicotine leads to a fast, but not long lasting increase in ciliary activity.•Genetic ablation of nAChR subunits α5, 7, 9, 10 and β2 does not influence the effect.•Ablation of nAChR β4 and pharmacological studies reveales α3β4 nAChR as crucial. Mucociliary clearance, the continuous removal of mucus-trapped particles by cilia-driven directed transport of the airway lining fluid, is the primary innate defense mechanism of the airways. It is potently activated by acetylcholine (ACh) addressing muscarinic receptors with a currently less defined role of nicotinic ACh receptors (nAChR). We here set out to determine their contribution in driving ciliary activity in an explanted mouse trachea preparation utilizing selected agonists and antagonists and nAChR-subunit deficient mice. Nicotine (100 µM) induced an increase in ciliary beat frequency, accompanied by a sharp, but not long lasting increase in particle transport speed (PTS) on the mucosal surface showing marked desensitization within the next 30 min. Nicotine-induced PTS acceleration was sensitive to the general nAChR inhibitors mecamylamine and d-tubocurarine as well as to the α3β4-nAChR antagonist α-conotoxin AulB, but not to other antagonists primarily addressing α3β2-nAChR or α4-, α7- and α9-containing nAChR. Agonists at α3β*-nAChR (epibatidine, cytisine), but not cotinine mimicked the effect. Tracheas from mice with genetic deletion of nAChR subunits α5, α7, α9, α10, α9/10, and β2 retained full PTS response to nicotine, whereas this was entirely lost in tracheas from mice lacking the β4-subunit. Collectively, our data show that nicotinic stimulation of α3β4-nAChR acutely increases PTS to the same extent as the established strong activator ATP. In view of the marked desensitization observed in the present setting, the physiological relevance of these receptors in adapting mucociliary clearance to rapidly changing endogenous or environmental stimuli remains open.