Increased vascular permeability during passive peritoneal anaphylaxis in the rat. The effects of disodium...

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.