The renal effects of Bothrops jararacussu venom and the role of PLA(2) andPAF blockers

The most common complication in the lethal cases of ophidian bites in Brazi l is acute renal failure, but its pathogenesis is obscure. The effects of B othrops jararacussu venom (3, 10 and 30 mug/ml) were examined using the iso lated perfused kidney from Wistar rats. Dexamethasone, and WEB 2086, a tria zolobenzodiazepine substance, which is a platelet activating factor recepto r antagonist, were tested for a possible blockade of the renal effects in t he presence of 10 mug/ml of venom. The most intense effects of the venom we re noticed at 120 min after using 30 mug/ml. We observed a decrease in the perfusion pressure and in the renal vascular resistance. However, the glome rular filtration rate (GFR) and the urinary flow (UF) increased significant ly. The percent of sodium (%Na-tot(+)) and potassium (%K-tot(+)) tubular tr ansport were also decreased. Dexamethasone to to was unable to block the ef fects of B. jararacussu in the kidney, while WEB 2086 blocked its effect in glomerular filtration rate, urinary flow and in the percentage of total tu bular potassium reabsorption. We suggest that this venom promotes diuresis independently of perfusion pressure drop. The alterations in GFR, UF and %K -tot(+), are probably mediated by platelet activating to factor. Dexamethas one did not block the renal effects maybe because of the concentration used in this work or maybe the renal effects are promoted by the myotoxin, whic h does not have PLA, activity. (C) 2001 Elsevier Science Ltd. All rights re served.