Inhibition of immediate hypersensitivity reactions in the rat by disodium cromoglycate and nitroindanedione.

A nitroindanedione (BRL 10833) and disodium cromoglycate (DSCG) showed similar activities as inhibitors of IgE-mediated passive cutaneous anaphylaxis (PCA) and passive peritoneal anaphylaxis (PPA) reactions in the rat. BRL 10833 was more active than DSCG when given parenterally and unlike DSCG it inhibited the PCA reaction in the rat after oral administration. In the PCA test both compounds produced a state of refractoriness both to themselves and to each other. Isoprenaline also inhibited the PCA reaction but its activity was not reduced when the rats were refractory to DSCG.