Parasympathetic and sympathetic influences on mucociliary activity in vivo.

An in vivo test model has been developed to measure the influence of pharmacological substances on mucociliary activity in the rabbit maxillary sinus. Test solutions are administered via the feeding vessel to the investigated mucous membrane. The model permits administration of test substances and simultaneous recording of the obtained effects under conditions that closely mimic the normal situation. The parasympathomimetic agonist methacholine accelerates the mucociliary wave frequency dose-dependently. Atropine has no influence on the resting mucociliary activity but reduces or abolishes the effect of methacholine. The sympathomimetic beta 2-adrenoceptor agonist salbutamol accelerates the mucociliary activity dose-dependently whereas beta 1-adrenoceptor stimulation with prenalterol is without effect. Agonists acting on alpha 1- and alpha 2-adrenoceptors, phenylephrine and oxymetazoline, retard the mucociliary activity dose-dependently. beta- and alpha-adrenoceptor antagonists (propranolol and phentolamine, respectively) have no influence on the resting mucociliary activity but reduce the effect of beta- and alpha-adrenoceptor agonists, respectively. It is concluded that the resting mucociliary activity during anesthesia functions independently of parasympathetic and sympathetic nervous activity, and that the role of the parasympathetic and sympathetic innervation is to increase the mucociliary activity.