TABLE 1

EC50 (μM) values of the test molecules

The EC50 values of the test compounds calculated at 20, 30, and 50 mM KCl-induced tracheal contractions.

Compound20 mM KCl30 mM KCl50 mM KCl
Drotaverine9.2>10>10
Papaverine0.65.8>10
Nifedipine0.60.60.7
Diltiazem0.84.45.7
Theophyline> 10> 10> 10
Theophyline + nifedipine< 0.1< 0.1< 0.1