BIOCHEMICAL STUDIES ON THE TX3 GROUP OF TOXINS, ACTIVE ON ION-CHANNELS, OBTAINED FROM THE VENOMS OF THE SPIDERS Phoneutria nigriventer AND Phoneutria spp

Ferreira-de-Oliveira, R.(1,4), Richardson, M.(1), Figueiredo, S. G.(2), De Lima, M. E.(3), Calegário-Oliveira, L.(1,3), Bloch Jr., C.(5), Diniz, C. R.(1), Cordeiro, M. N.(1)

(1)Fundação Ezequiel Dias - DCPD - Belo Horizonte - MG, (2)UFES - Departamento de Ciências Biológicas - Vitória - ES, (3)UFMG - ICB - Departamento de Bioquímica e Imunologia - Belo Horizonte - MG, (4)UFMG - ICEx - Departamento de Química - Belo Horizonte - MG, (5)Embrapa  - CENARGEN- Brasília - DF

Comparative biochemical studies on venoms of spiders of the genus Phoneutria have enabled the isolation of various peptides with biological activity against insects and mammals (Ferreira-de-Oliveira et al., 2002). These have been classified in groups (PhTx1, PhTx2, PhTx3 and PhTx4) on the basis of the effects they induced in biological assays (Rezende et al., 1991). In more recent work we have begun to compare the polypeptides of the type Tx3 obtained from the venom of a presently unidentified Phoneutria sppwith those obtained from Phoneutria nigriventer. The various components were purified by a combination of different steps of liquid chromatography (HPLC and FPLC) and their purity checked by PAGE (acid/urea) and mass spectrocospy. Biological assays performed with mice gave an indication of the toxicity for mammals of each component, via the production of effects such as increased respiration, anti-clockwise gyration, reduction of muscle tone, paralysis of the rear legs, flaccid paralysis and death. The similarities observed underline the need for new pharmacological investigations such as those which indicated that the Tx3 toxins from Phoneutria nigriventer act on Ca²⁺ and K⁺ ion channels. (Reis et al., 2000, Kushmericket al., 1999, Guatimosim et al., 1997, Prado et al. 1996).

Financial support: CNPq and FAPEMIG.

CORRESPONDENCE TO:

Reginaldo Ferreira de Oliveira, R. Célio Diniz, 39, Belo Horizonte, MG, CEP: 31535-150, Brasil, Email: regifull@yahoo.com.br