Acute Effects of Uridine 5′-Triphosphate on Mucociliary Clearance in Isolated Frog Palate

ABSTRACT Mucociliary velocity (MCV), transepithelial potential difference (PD), cilia beat frequency (CBF), mucus collection rate, rheology, and chloride concentration [Cl−] were analyzed in an in vitro study using the freshly isolated frog palate exposed to an aerosol of modified Ringer's injection, followed by uridine 5′-triphosphate (UTP) 10−4 mol/L either alone or immediately preceded by aerosolization of 5 × 10−4 mol/L 4,4′-diisothiocyano-2,2′ stilbenedisulfonate (DIDS), a chloride channel blocker. UTP increased PD and decreased MCV with a positive relationship between the two. UTP promoted the appearance of copious quantities of secretion and increased the collection rate; the computed mucus depth increased by more than sixfold. There was a significant increase in both [Cl−] and wet weight. The increase in PD and chloride secretion led to enhanced transepithelial fluid transport and a decrease in MCV. Rheology and CBF were not affected by UTP, indicating that the main effect was on the interaction b...