Changes of alpha 1- and beta-adrenergic and cholinergic muscarinic receptors guinea pig lung sensitized with ovalbumin.

The effect of immunization of guinea pigs with ovalbumin on the number and affinity of alpha 1- and beta-adrenergic and cholinergic muscarinic receptors was studied in lung membranes by direct binding techniques using 3H-prazosin, 1-3H-dihydroalprenolol and 1-3H-quinuclidinyl benzilate. After immunization by intraperitoneal injection of ovalbumin to guinea pigs, the number and affinity of each receptor in sensitized animals were not significantly different from those of control animals. Sensitization of guinea pigs by an aerosol exposure with the antigen resulted in a decreased number of beta-adrenergic receptor (458 +/- 29 vs. 687 +/- 56 fmol/mg protein; p less than 0.01), and an increased number of alpha 1-adrenergic receptor (36 +/- 2 vs. 25 +/- 2 fmol/mg protein; p less than 0.01), but no change was observed in the number of muscarinic receptors, as compared with control animals. On the other hand, following a prolonged sensitization of guinea pigs with a low dose of the aerosolized antigen, the number of muscarinic receptors was significantly increased in the lung of sensitized animals (50 +/- 2 vs. 42 +/- 2 fmol/mg protein; p less than 0.01); however, we found no significant differences between sensitized and normal animals in the number of alpha 1- and beta-adrenergic receptors. There were no different changes in the affinity of these receptors in all experiments.