Protective effect of forskolin against acetylcholine provocation in healthy volunteers - Comparison of two doses with fenoterol and placebo

Forskolin, a potent adenylate cyclase activating diterpene-derivative, isolated from the Indian plant Coleus forskohlii, was tested (double-blind and cross-over) in 12 healthy volunteers (nonsmokers) by whole body plethysmography. All drugs were administered by metered dose inhalers. The bronchodilating effect (after 5 minutes) was as good as following fenoterol. At the beginning (after 3 and 5 minutes) the protective effect against inhaled acetylcholine was as good as following fenoterol while later on (after 15 and 30 minutes) fenoterol resulted in a stronger action.