Increased vascular permeability during passive peritoneal anaphylaxis in the rat. The effects of disodium cromoglycate and a nitroindanedione.

Following intraperitoneal sensitisation of rats with rat serum containing reaginic antibody, intravenous injection of blue dye and intraperitoneal challenge with antigen caused a release of histamine, slow-reacting substance of anaphylaxis (SRS-A) and dye into their peritoneal fluids. The times taken to reach peak concentrations after challenge were less than 2 min for histamine and between 5 and 10 min for SRS-A, whilst concentrations of dye were still increasing after 2 1/2 h. The amounts of histamine released by antigen were sufficient to account for about 60% of this extravasation of dye. Disodium cromoglycate (DSCG) and a nitroindanedione (BRL 10833) inhibited extravasation by inhibition of mediator release. BRL 10833, unlike DSCG, was active after oral administration, and for a given inhibition of histamine release it produced a greater effect on extravasation when given orally than when injected intraperitoneally.