Intrahippocampal injection of TsTX-I, a beta-scorpion toxin, causes alterations in electroencephalographic recording and behavior in rats

Autor(es)

Teixeira, Vanessa Fernanda ^{[1, 2]} ; Conceicao, Isaltino Marcelo ^[1] ; Lebrun, Ivo ^[3] ; Nencioni, Ana Leonor A. ^[1] ; Coronado Dorce, Valquiria A. ^[1]

Afiliação do(s) autor(es)

^[1] Butantan Inst, Pharmacol Lab, BR-05503900 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Pharmacol Lab, Sch Vet Med, BR-05508900 Sao Paulo - Brazil

^[3] Butantan Inst, Biochem & Biophys Lab, BR-05503900 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Life Sciences; v. 87, n. 15-16, p. 501-506, OCT 9 2010.
• Citações Web of Science: 8

Resumo

Aims: TsTX-I scorpion toxin, also known as gamma-toxin, is a beta-toxin which binds to site 4 of the sodium channel, shifting its activation potential. There are few studies about its pharmacological action in the central nervous system. The objective of this work was to determine the electroencephalographic, behavioral and histopathological effects of intrahippocampal injection of TsTX-I. Main methods: Rats were anesthetized and fitted with cannulae for injection into the hippocampus and with electrodes for cerebral recording. The animals were treated with Ringer solution, some doses of TsTX-I, DMSO 0.1% or veratridine. Behavioral and electrographic recordings were observed for 4 hours after the injection. After 7 days, the rats were perfused, and their brains removed for histological analysis. Key findings: Increasing doses of the toxin evoked epileptic-like discharges, wet dog shakes, and in some cases hind limb paralysis and intense respiratory difficulty followed by death. The histopathological analysis demonstrated no cell loss. Animals injected with veratridine developed epileptiform activity in the electrographic recording and neuronal loss. Significance: The results suggest that TsTX-I toxin may be responsible, at least in part, for the epileptic and behavioral effects observed with the crude venom, and although veratridine and TsTX-I act on Na-channel, the differences between them are remarkable, demonstrating that toxins can have different functional effects depending on the site of action in the channel. Thus, animal neurotoxins are often highly selective and may be useful for the identification of the sequence of events underlying neurotransmission. (C) 2010 Elsevier Inc. All rights reserved. (AU)

• Processo FAPESP: 03/09396-2 - Toxina tstx i isolada do veneno do escorpiao tityus serrulatus: efeitos sobre o hipocampo de ratos.
• Beneficiário: Valquiria Abrão Coronado Dorce
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 99/12869-2 - Estudo dos efeitos neurotoxicos dos venenos dos escorpioes tityus serrulatus e tityus bahiensis.
• Beneficiário: Valquiria Abrão Coronado Dorce
• Modalidade de apoio: Auxílio à Pesquisa - Regular