Rat passive peritoneal anaphylaxis following sensitisation with guinea pig antiserum: an immediate hypersensitivity...

Antigen challenge of rats, sensitised by an intraperitoneal injection of guinea pig antiserum, produced an antibody-dependent increase in concentrations, in the peritoneal fluids. of slow-reacting substance of anaphylaxis (SRS-A) and of extravasated, dye-labelled, plasma proteins but not of histamine or 5-hydroxytryptamine. The SRS-A released may not be the main mediator of the extravasation since pre-treatment of the rats with the SRS-A antagonists FPL 55712 and BRL 19880 had no effect on extravasation, and a number of compounds, given in a similar way, were more potent as inhibitors of SRS-A release than of extravasation. Rat passive peritoneal anaphylaxis (PPA), following sensitisation with guinea pig antiserum, provides an example of an immediate hypersensitivity reaction in which there is no antibody-dependent release of histamine and in which the SRS-A released may not mediate all of the extravasation produced.