Nifedipine inhibits human bronchial smooth muscle contractions induced by leukotrienes C4 and D4, prostaglandin F2 alpha, and potassium.

The effects of nifedipine, a calcium channel blocker, on human bronchial smooth muscle contractions induced by leukotrienes C4 and D4 (LTC4, LTD4), prostaglandin F2 alpha (PGF2 alpha), and potassium were studied in vitro. The LTC4, LTD4, PGF2 alpha, and potassium caused bronchial smooth muscle contractions. After incubation with nifedipine at 2.9 X 10(-6)M, the contractions caused by LTC4, LTD4, PGF2 alpha, and potassium were significantly decreased. Nifedipine also significantly reversed human bronchial smooth muscle contractions previously initiated by these agonists. The effect of nifedipine on potassium contraction was significantly greater than that on LTC4, LTD4, and PGF2 alpha-induced contractions. The pharmacologic feature of nifedipine is that it inhibits the calcium influx associated with membrane depolarization. Therefore, these results suggest that there are two mechanisms of calcium movements in human bronchial smooth muscle contractions induced by LTC4, LTD4, and PGF2 alpha: membrane-depolarization-dependent and -independent mechanisms.