MECHANISMS AND SITES OF PYROGENIC ACTION EXERTED BY STAPHYLOCOCCAL-ENTEROTOXIN-A IN RABBITS

The febrile responses induced by i.v. administrations of staphylococca l enterotoxin A (SEA) was mimicked by direct injection of SEA into the organum vasculosum laminae terminalis (OVLT) in unanesthetized rabbit s. Compared with the febrile responses induced by i.v. injection of SE A, the OVLT route of injection required a much lower dose of SEA to pr oduce a similar fever. Furthermore, the fever induced by intra-OVLT or i.v. injection of SEA was significantly attenuated by pretreatment wi th intra-OVLT injection of anisomycin (a protein synthesis inhibitor), indomethacin or diclofenac (inhibitors of cyclo-oxygenase (COX)), and aminoguanidine or dexamethasone (inhibitors of inducible nitric oxide synthase (iNOS)). These results suggest that COX or iNOS pathway in t he OVLT mediate the SEA-induced fever in rabbits. (C) 1997 Elsevier Sc ience Ireland Ltd.