Sustained inhibition of antigen-induced histamine release from human lung by the beta 2-adrenoceptor agonist terbutaline

Antigen-induced histamine release from passively sensitized human lung tissue was inhibited in the presence of the beta 2-adrenoceptor agonist, terbutaline. A sustained and statistically significant suppression was detected in the concentration interval 3 X 10(-8)-1 X 10(-6) M. Fifty per cent inhibition IC50, was obtained at an interpolated concentration of 5.3 X 10(-8) +/- 0.4 X 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.