Using computerized microphotometry, we studied the effects of prostaglandin E2 (PGE2), the prostacyclin analog Iloprost, and the thromboxane A2 analog U46619 on the ciliary beat frequency (CBF) of human nasal mucosa. Thirty-two normal subjects underwent nasal cytologic brushing of the inferior meatus to obtain ciliary samples, and a total of 5,640 ciliated cell clusters were analyzed. Each subject served as their own control. PGE2, 10(-10) to 10(-6) M, produced a significant dose dependent increase in CBF of up to 12% versus control. This increase was not significantly inhibited by the addition of the cyclooxygenase inhibitor indomethacin (10(-6) M). Iloprost, 10(-12) to 10(-6) M, also significantly increased CBF by 12.7% at 10(-8) M. This ciliostimulatory effect, however, was abolished by indomethacin. The thromboxane A2 analog, 10(-10) to 10(-6) M, did not significantly effect CBF. The present study demonstrates that a thromboxane A2 analog has no effect on ciliary motility, PGE2 has a direct ciliostimulatory effect, and a prostacyclin analog has a ciliostimulatory effect likely mediated by stimulation of the cyclooxygenase pathway within human cells.