Effect of menthol on cytosolic Ca2+ levels in canine airway epithelium in culture.

Intracellular Ca2+ concentration ([Ca2+]i) in canine cultured tracheal epithelium in response to cyclic alcohols was measured by a fura-2 method. Menthol rapidly increased [Ca2+]i in a concentration-dependent fashion, the maximal increase from the baseline levels and the concentration of menthol required to produce a half-maximal effect (EC50) being 148 +/- 23 nM (mean +/- SE, p < 0.001) and 0.3 mM, respectively, whereas other cyclic alcohols including menthone and cyclohexanol had no effect. The menthol-induced increase in [Ca2+]i was not affected by verapamil but partially inhibited by low Ca2+ medium in the presence of EGTA. These results indicate that menthol specifically increases cytosolic Ca2+ in airway epithelium, which may be derived from intracellular Ca2+ stores.