Effect of prostaglandin e₂ and bacterial endotoxin on the rate of dye transport in the eustachian tube of the chinchilla

To determine the effects of various biologic agents on the rate of fluid transport in the eustachian tube of the chinchilla, we have established an in situ method of measuring dye transport in which the bulla remains intact. The normal rate of dye transport from an injection site in the superior bulla to the nasopharyngeal orifice of the eustachian tube was 130 ± 10 seconds. Inhibition of ciliary activity with the local anesthetic bupivacaine resulted in a saturable delay of transport (> 15 minutes), while exposure to the β-adrenergic stimulator isoproterenol caused a significant increase in transport rate (79 ± 7 seconds). Two inflammatory mediators commonly found in chronic middle ear effusions were also tested for their effect on fluid transport by the mucociliary apparatus. Bacterial endotoxin reduced transport rates at high concentrations, while prostaglandin E₂ had no effect at any concentration tested.