RENAL AND VASCULAR EFFECTS OF VENOMS FROM BRAZILIAN NORTHEAST ANIMALS

HELENA SERRA AZUL MONTEIRO(1)

(1)Depto. Fisiologia e Farmacologia, UFC, Brazil

Crotalus durissus cascavella (C.d.c) is a snake usually found in scrubland of Brazilian Northeast and its bite constitutes a public health problem. C.d.c venom in isolated perfused rat kidney method increased perfusion pressure (PP), urinary flow (UF), and decreased glomerular filtration rate (GFR), and percent of sodium tubular transport (%TNa+).The proximal renal tubule was the major site for its toxic effect. Dexamethasone (Dexa) and Indomethacin (Indo) protected against effects on PP, UF, GFR, %TNa+. Nifedipine reversed all functional changes. The infusion of the supernatant of macrophages stimulated with C.d.c. venom increased PP, GFR, UF and decreased %TNa+. Dexa and quinacrine provided protection against the effect of the supernatant on GFR, UF, %TNa+, and PP. Indo and nordiidroguaretic acid reversed all functional changes, except PP. These results suggest that macrophages stimulated with C.d.c. venom release mediators capable of promoting nephrotoxicity. Phospholipase A2 and cyclooxygenase products are involved in these biologic effects. Convulxin had no effect and Gyroxin produced a minor effect compared to Crotoxin. Crotoxin is the main component responsible for acute nephrotoxicity, because it altered all evaluated renal parameters. Bothrops erythromelas venom on the renal perfusion decreased PP, RVR, GFR, and %TNa+. The anti-bothropic factor incubated with this venom blocked the effects on PP, RVR, %TNa+, and %TK+. A higher concentration reversed all renal effects. Tityus serrulatus (Tsv) venom on the renal perfusion increased PP, RVR, and decreased GFR, and UF. TsV increased the basal perfusion pressure of isolated arteriolar mesenteric bed and affected renal haemodynamics, probably by a direct vasoconstriction effect, leading to a decrease on renal flow. Gamma toxin (gT) of T. serrulatus venom increased renal PP, RVR, GFR ,UF and decreased %TNa+, %TK+, %TCl-.Gamma toxin also increased the basal PP on mesenteric bed. gT affected renal hemodynamics increasing vascular resistance and PP in isolated kidney and mesenteric bed, suggesting a direct action. T. nattereri (Niquim) venom was studied on renal perfusion and caused increases on PP, RVR, GFR and UF. A higher dose promoted alterations in all renal parameters.

KEY WORDS: renal and vascular effects, venoms

FINANCIAL SUPPORT: CNPQ, CAPES, FUNCAP