THE EFFECTS OF FORMOTEROL, A LONG-ACTING BETA(2)-ADRENOCEPTOR AGONIST, ON MUCOCILIARY ACTIVITY

The effect on mucociliary function of formoterol, a beta(2)-adrenocept or agonist bronchodilator with a prolonged duration of action (as comp ared with salbutamol or terbutaline), was investigated both in vitro a nd in vivo with a photoelectric technique. Formoterol, and its (R,R)-e nantiomer, increased ciliary beat frequency in vitro in guinea pig tra chea preparations (peak increase 17.2 +/- 2.0% at a concentration of 1 0(-7) M) and in vivo in the rabbit maxillary sinus (peak increase 23.0 +/- 4.0% at a dosage of 1 nmol/kg). Formoterol was approximately 100 times more potent than terbutaline in vitro, as judged from the dose-r esponse curve. The main difference between their effect in vivo was th e 2-fold longer duration of the mucociliary acceleration after formote rol at 1 nmol/kg than after terbutaline at the equi-effective dosage o f 10 nmol/kg terbutaline (20 vs. 10 min, respectively). The findings i ndicate formoterol to be a powerful, long-acting ciliostimulant, a pro perty which may be of clinical advantage in the treatment of airway di sease.