Pharmacological investigation of oedema induced by venom from the wasp Polistes fuscatus

Subplantar injection of Polistes fuscatus venom induced dose-dependent rat hindpaw oedema. The oedema was significant in the first hour and reached maximum size in the fifth hour after injection of the venom (20–600 μg/paw). Low doses of the venom (20–80 μg/paw) produced oedema which disappeared within 48 hr after injection, while at doses of 300–600 μg/paw, oedema was present in excess of 48 hr. Pharmacological studies suggested that P. fuscatus venom-induced oedema probably has a mechanism which is multimediated. Pretreatment of rats with a combination of cyproheptadine (5 mg/kg)- captopril (2 mg/kg)- dexamethasone (1 mg/kg) inhibited the formation of oedema (maximal swelling) produced by the venom (300 μg/paw) by about 79% and improved the time to recovery. Paw swellings caused by 20 and 40 μg/paw venom were completely eliminated by the same doses of this drug combination. The kinins, autacoids (histamine and serotonin) and lipogenase derivatives are probably involved in the venom-induced oedema.