HIPPOCAMPAL EFFECTS OF A TOXIN ISOLATED FROM Tityus serrulatus SCORPION VENOM: A BEHAVIOURAL, ELETROENCEPHALOGRAFIC AND HISTOPHATOLOGIC STUDY

FREITAS M. M (1)., DORCE V.A.C.(1), LEBRUN I.(2)., NENCIONI A.L.A. (1)

(1) Pharmacology, (2) Biochemistry and Biophysic Laboratory, Butantan Institute, São Paulo – Brasil.

Scorpion venoms are composed among other substances by neurotoxins that act on ionic channels, mainly sodium and potassium. Previous studies showed that some toxins of Tityus serrulatus venom (vTs) have epileptic and neurotoxic effects. The aim of this study was to investigate the effects of IV–IV toxin isolated from this venom in the hippocampus of rats. Male Wistar rats (220 – 250g) were anesthetized and positioned in a stereotaxic frame. Stainless steel guide cannulas and bipolar twisted electrodes were chronically implanted in the hippocampus. One day after surgery the animals were injected with 1µg/µl of toxin (n=6) or Ringer solution (control group, n=6). After the injections, continuous eletroencephalografic recording (EEG) and observations of animals behavior were performed for periods of 4h. Seven days after the injections the animals were sacrificed and perfused. The brains were removed and prepared for histological analysis. The EEG showed intense epileptic-like discharge often accompanied by behavioral alterations as wet dog shake and mioclonia. The histopathological analysis showed neuronal death in CA1, CA3 and CA4 ipsilateral to injection and in CA4 contralateral. The toxin IV–IV causes neuronal death and has convulsive effect.

KEY WORDS: Tityus serrulatus, scorpion toxins, hippocampus, Neurodegeneration.

FINNANCIAL SUPPORT: Fundação Butantan, CCD -SES - SP

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