Fig. 4.

TEA induced contractions in human airway smooth muscle are relaxed by the chloride channel blocker niflumic acid. Left: Representative tracings of human tracheal strips muscle force with the addition of TEA and subsequently treated with either ethanol vehicle control or 100 μM niflumic acid. A and B, the gray bars represent the 45 min time point when treatments were applied. The associated muscle force at the time of treatment is also noted as 0.43 and 0.58 grams, respectively. Right: Muscle force expressed as a percent of plateau TEA-induced contraction. Human airway smooth muscle demonstrated a significant reduction in TEA-induced muscle force at 30 min after the addition of 100 μM niflumic acid (n=6) (29.6 ± 9.7% of the initial TEA-induced force) (** P<0.001 compared to ethanol control). Thirty minutes after treatment with ethanol vehicle (n=6) the resulting muscle force was not significantly different from the initial TEA-induced force (101 ± 1.9%).