Beta-adrenergic receptor function and oxygen radical production in bovine pulmonary alveolar macrophages

Abstract

Reactive oxygen species production by bovine pulmonary alveolar macrophages was evaluated by a chemiluminescence assay utilizing luminol and opsonized zymosan. Incubation with dobutamine (5 x 10(-8) and 5 x 10(-7) M) or isoproterenol (5 x 10(-8) and 5 x 10(-7) M) prior to zymosan challenge significantly (p less than 0.05) increased the time for chemiluminescence to begin, and significantly decreased the level of maximum chemiluminescence. The agonists' inhibitory effects on maximum chemiluminescence were significantly reduced by pre-incubation with the appropriate antagonist (atenolol at 1 x 10(-6) M for dobutamine; and propranolol at 1 x 10(-6) M for isoproterenol). Salbutamol at 1 x 10(-6) M significantly reduced the level of maximum chemiluminescence only, but did not increase the time for chemiluminescence to begin. This effect was significantly reduced by the presence of the beta 2-antagonist ICI 118,551 at 1 x 10(-6) M. The results reveal the presence of beta 1- and beta 2-adrenoceptors on bovine pulmonary alveolar macrophages, and suggest that these receptors are important in the regulation of reactive oxygen species production by these cells.