The Effect of Various Conditions on Tracheal Mucociliary Transport in Dogs 1

Summary Tracheal mucociliary transport rate in dogs was measured by a radioactive particle transport technique. The transport rates averaged 10.5 mm/min in a condition of 24°, 78% RH (wvp 18 mm Hg). Neither change in relative humidity (100% RH, wvp 22 mm Hg and 21% RH, wvp 6 mm Hg) at the same temperature (24°), nor in both temperature and relative humidity (7.2°, 32% RH wvp 3 mm Hg) showed significant difference in mucociliary transport rate. These results indicate the excellent capacity of the canine nose to condition inhaled air. Pilocarpine stimulated the mucociliary transport rate. Nine puffs of nonfiltered smoke showed inconsistent effects on transport rates, while 12 puffs had a consistent inhibitory effect on mucociliary activity. It is suggested that cigarette smoke disturbs both ciliary beating and ciliary coordination in the trachea of the dogs. The technical assistance of Mr. Alberto J. Colon is gratefully acknowledged.