MODULATION OF CILIARY BEAT FREQUENCY IN THE UPPER AIRWAY BY PROSTAGLANDINS

Prostaglandins are ubiquitous within tissues and participate in severa l local regulatory functions. Previous reports have presented conflict ing evidence on their role in ciliary activity in the upper airway. We studied the in vitro effects of prostaglandin E(2) (PGE(2)) and a pro staglandin I-2 analog (Iloprost) on the ciliary beat frequency (CBF) o f human adenoid explants and rabbit sinus mucosa. Tissue explants were maintained in culture at 35 degrees C. PGE(2) or Iloprost was added t o the culture media at concentrations of 10(-6), to 10(-12) M. CBF was determined using phase contrast microscopy and microphotometry. PGE(2 ) increased CBF with a maximum increase of 54.6% in rabbit mucose (P < 0.01) and 20.0% in human adenoid (P < 0.009). Iloprost increased CBF with a maximum increase of 35.2% in rabbit mucose P < 0.02) and 16.4% in human adenoid (P < 0.03). Induced production of endogenous prostagl andins was determined by treating specimens with a cyclooxygenase inhi bitor (diclofenac) prior to addition of PGE(2) or Iloprost. Diclofenac had no effect on the ciliostimulatory effects of PGE(2) (P > 0.36), h owever it significantly decreased the ciliostimulatory effect of Ilopr ost (P < 0.037). Both PGE(2) and Iloprost stimulate ciliary motility, yet the action of PGE(2) is direct, whereas Iloprost stimulates cilia by release of endogenous prostaglandins in both the human and rabbit.