Leukotriene C4 decreases the activity of respiratory cilia in vitro

In the present study we assessed the effect of leukotriene C4 on ciliary beat frequency in vitro. Chicken tracheas were sliced into thin rings and ciliary activity was viewed microscopically. Ciliary beat frequency was measured through an optical fibre by a fast Fourier transformer analyser and recorded on an oscilloscope. Ciliary beat frequency was measured at one fixed point during 30 min at room temperature in RPMI-HEPES medium alone and in medium containing leukotriene C4 at a range of concentrations (10(-6)-10(-9) M). Our results demonstrate that leukotriene C4 (10(-7) and 10(-8) M) caused a significant decrease in ciliary beat frequency in all tracheal rings tested (mean decrease of 24%). The specificity and Ca2(+)-dependency of leukotriene C4 activity was elucidated by the ability of FPL 55712 (SRS-A specific antagonist), Ca2(+)-free medium, calcium channel blockers (nifedipine and verapamil) and the calmodulin inhibitor trifluroperazine to abrogate its effect on ciliary beating.