Anti-allergic effect of beta-2 agonists and cholinoceptor antagonists in vitro

Human lung tissue passively sensitized with anti-grass pollen IgE antibodies releases histamine upon exposure to specific grass pollen antigen. Beta-sympathomimetic agents inhibit the antigen-induced release of histamine, thus beta-sympathomimetic drugs might exhibit a combination of prophylactic and direct bronchodilating properties in the treatment of allergic bronchial asthma. The anticholinergic agent ipratropium bromide had no direct effect on the immunologically induced release of histamine. Acetylcholine increased the antigen-induced release of histamine significantly. This enhanced release was almost completely inhibited by ipratropium bromide as a result of competitive inhibition. This mode of action may add to the usefulness of anticholinergic agents in vagus-controlled chronic obstructive ventilatory disorders.