Adrenaline-induced tracheal relaxation ex vivo is depressed following aerosol antigen challenge of sensitized guinea-pigs.

We investigated the changes in beta-adrenoceptor responses induced in guinea-pig tracheal and cardiac tissues by the anaphylactic reaction. Antigen aerosol challenge in sensitized guinea-pigs resulted in a marked reduction in adrenaline relaxation in isolated trachea ex vivo. The isoprenaline effect was also slightly decreased by antigen exposure, suggesting a possible impairment of tracheal beta-adrenoceptor function. On the other hand, the chronotropic and inotropic activity of adrenaline in isolated atria was not modified by the anaphylactic shock, suggesting a specific involvement of lung beta-adrenoceptors in the allergic reaction.