Preventive and reverse effects of nifedipine on human bronchoconstriction "in vitro"

The effects of nifedipine, a calcium channel blocking agent, on human bronchoconstriction induced by acetylcholine and histamine were studied in vitro. Bronchial preparations were obtained from 13 patients undergoing surgery for bronchial carcinoma. Bronchial strips were mounted for continuous isometric tension recording. Acetylcholine and histamine caused bronchoconstrictions, but the constrictive effects were inhibited by 2.9 X 10(-6) M nifedipine. At a concentration of 2.9 X 10(-6) M nifedipine increased by 22-fold the concentration of acetylcholine required to produce a 50% of maximal contraction of bronchial strips, and by 160-fold the concentration of histamine required. Nifedipine also reversed already established bronchoconstrictions by acetylcholine and histamine. The percentage of contraction at 20 min after 2.9 X 10(-6) M nifedipine was 7 +/- 11.1% (mean +/- SEM) and - 21 +/- 20.0% of the control maximal response by 10(-3) M acetylcholine and 10(-3) M histamine, respectively. Thus, nifedipine clearly prevented and reversed pharmacologically-induced bronchoconstriction in humans. These results suggest that it is valuable to administer nifedipine to prevent and treat asthma attack.