Leukotrienes C4 and D4 increase the ciliary beat frequency in human upper airway mucosa in vitro

It has been suggested that leukotrienes C4 (LTC4) and D4 (LTD4) released from upper respiratory mucosa influence mucociliary transport during allergic reactions. We studied the in vitro effects of leukotrienes C4 and D4 on the ciliary beat frequency (CBF) of human adenoid explants over a 5-hour period. Tissue explants were cultured at 35 degrees C in Minimum Essential Medium Eagle (MEM). The CBF was measured using phase contrast microscopy and microphotometry. Measurements of CBF were recorded in medium alone and in medium containing LTC4 or LTD4 at concentrations of 10(-8) and 10(-6) M. LTC4 and LTD4 increased CBF at concentrations of 10(-8) and 10(-6) M with increases of 20.51% +/- 2.69% and 29.84% +/- 4.06%, respectively. To determine the specificity of the LTC4 and LTD4 effects, the ciliated epithelium was treated with the specific leukotriene receptor antagonist LY-171,883 before administration of LTC4 and LTD4. LY-171,883 (10(-6) M) significantly inhibited the ciliostimulatory effects of both leukotrienes. Our findings indicate that LTC4 and LTD4 increase CBF in vitro by activation of the LTD4 receptor.