Sustained Inhibition of Antigen-Induced Histamine Release from Human Lung by the β2-Adrenoceptor Agonist Terbutaline

Antigen-induced histamine release from passively sensitized human lung tissue was inhibited in the presence of the β₂-adrenoceptor agonist, terbutaline. A sustained and statistically significant suppression was detected in the concentration interval 3 × 10⁻⁸-1 × 10⁻⁶ M. Fifty per cent inhibition IC₅₀, was obtained at an interpolated concentration of 5.3 × 10⁻⁸± 0.4 × 10⁻⁸ M ( n = 13), when the histamine secretion was elicited with optimum concentration of antigen. Histamine release induced with a suboptimum concentration of antigen was inhibited to a greater extent than release initiated with optimum concentration. The data in the present investigation support the concept that terbutaline-induced inhibition of mediator release from human lung tissue can contribute to the clinical effectiveness of the drug during treatment of allergic asthma.