NIFEDIPINE INHIBITS HUMAN BRONCHIAL SMOOTH-MUSCLE CONTRACTIONS INDUCED BY LEUKOTRIENE-C-4 AND LEUKOTRIENE-D-4, PROSTAGLANDIN-F-2-ALPHA, AND POTASSIUM

Publisher Website
Google Scholar
Abstract
The effects of nifedipine, a Ca channel blocker, on human bronchial smooth muscle contractions induced by leukotrienes C4 and D4 (LTC4, LTD4), prostagladin F2.alpha. (PGF2.alpha.), and K were studied in vitro. The LTC4, LTD4, PGF2.alpha., and K caused bronchial smooth muscle contractions. After incubation with nifedipine at 2.9 .times. 10-6 M, the contractions caused by LTC4, LTD4, PGF2.alpha. and K were significantly decreased. Nifedipine also significantly reversed human bronchial smooth muscle contractions previously initiated by these agonists. The effect of nifedipine on K contraction was significantly greater than that on LTC4, LTD4 and PGF2.alpha. induced contractions. The pharmacologic feature of nifedipine is that it inhibits the Ca influx associated with membrane depolarization. There apparently are 2 mechanisms of Ca movements in human bronchial smooth muscle contractions induced by LTC4, LTD4, and PGF2.alpha.: membrane-depolarization-dependent and -independent mechanisms.