Mammalian ciliated respiratory epithelium; studies with particular reference to effects of menthol, nicotine, and smoke of mentholated and nonmentholated cigarettes.

THE PRESENT study was undertaken to determine the effects of menthol, nicotine, and the smoke of mentholated and nonmentholated cigarettes on excised mammalian respiratory epithelium from humans, rabbits, and rats. Previous studies on the effects of menthol on ciliated epithelium and on the respiratory tract have given equivocal findings. Proetz 1 reported that a 1% solution of menthol in liquid petrolatum had no effect on the ciliary activity of excised tissue immersed in it for 84 minutes. Similarly, Haggard and Greenberg 2 could find no toxic or irritant action of menthol in concentrations contained in the smoke of mentholated cigarettes on the respiratory tract of rats. Mendenhall and Shreeve, 8 however, reported that smoke solutions from cigarettes produced a depression in the ciliary rate of sections of calf's trachea and that smoke solutions from mentholated cigarettes caused a greater decrease in rate than did those from nonmentholated cigarettes. Further, Fox