Abstract:Treatment of egg albumin sensitized guinea pigs with repeated concentrations of egg albumin changed the Schultz‐Dale response. The dose‐response curve of egg albumin on the trachea was shifted to the right. Both the amount of SRS‐A and histamine released by antigen exposure from sensitized or desensitized guinea pig lungs were almost similar. Regarding the number of H1‐receptors in an isolated membrane fraction from the lungs of sensitized and desensitized guinea pigs, no significant differences was observed. On the contrary, the receptor‐response to SRS‐A was found to be decreased in desensitized trachea in comparison with sensitized trachea. The treatment of guinea pigs with repeated threshold concentrations of histamine did not change the contractile response neither to histamine nor to egg albumin. The decreased Schultz‐Dale response after repeated egg albumin treatmentin vivomight depend on desensitization of a hypothetical S