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The effect of inhaled ouabain on bronchial reactivity to histamine in man
A J Knox1, A E Tattersfield, J R Britton
1Respiratory Medicine Unit, City Hospital, Nottingham.
Abstract:
To determine the role of Na/K ATPase in determining bronchial reactivity in man, we studied the effect of 1 mg inhaled ouabain on histamine reactivity in six normal and 10 asthmatic subjects in a placebo controlled, crossover study. sGaw was measured before and up to 2 h after drug, followed by a histamine challenge test to estimate the dose of histamine causing a 35% reduction in sGAW (PD35). sGAW values after ouabain and placebo did not differ significantly. Ouabain did not affect bronchial reactivity, geometric mean (95% CI) PD35 histamine values following ouabain and placebo were 8.98 (3.8-21.2) and 7.75 (3.2-18.7) mumol respectively in normal subjects and 0.46 (0.18-1.21) and 0.69 (0.22-2.13) in asthmatic subjects. We were thus unable to demonstrate a role for Na/K ATPase in determining bronchial reactivity to histamine in man.