Effect of ibudilast on mucociliary transport using frog palate.

For the determination of mucociliary transport, we have used a method to measure mucociliary transport force (MCTF), which was defined as the tension developed by the mucus flow and ciliary motility of a frog palate between a force transducer and a glass boat on the palate. 3-isobutyryl-2-isopropylpyrazolo [1,5-a] pyridine (ibudilast) is supposed to increase intracellular cyclic adenosine monophosphate (cAMP) level by the inhibition of cAMP phosphodiesterase and to potentiate the effect of prostacyclin. The effect of ibudilast on MCTF was investigated for 15 min after the drug application. Ibudilast induced a significant, dose-related increase in MCTF at concentrations of higher than 10(-7) M. Therefore, these results indicate that ibudilast, an anti-allergic agent, activates mucociliary transport in respiratory tract.