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Type: Artigo de periódico
Title: Biophysical, histopathological and pharmacological characterization of crotamine isoforms F22 and F32
Author: Toyama, MH
Marangoni, S
Novello, JC
Leite, GB
Prado-Franceschi, J
da Cruz-Hofling, MA
Rodrigues-Simioni, L
Abstract: Two major crotamine isoforms (F22 and F32) were obtained after three chromatographic steps and were assayed in mouse phrenic nerve-diaphragm preparations. F32 and F22 (0.5 mug/ml, n = 4) produced a facilitatory effect, which increased isometric twitch-tension by 300 and 230%, respectively, after a 120 min incubation. At a concentration of 0.1 mug/ml, both isoforms increased the twitch-tension by about 160%. However, when the isoforms were co-incubated (final concentration, 0.5 mug/ml) for 30 min prior to testing, they did not cause the facilitation seen with greater than or equal to0.1 mug/ml of each isoform alone. Histologically, F32 and F22 at 0.5 and 1 mug/ml were quantitatively alike in inducing tissue myonecrosis. However, a mixture of the two isoforms (final concentration, 0.5 mug/ml) significantly attenuated the damage seen with either toxin alone. Mass spectrometry analysis showed that the isoforms had the same molecular mass (4.8 kDa) and that they existed as monomers with a highly stable structure. These results indicate that F22 and F32 acted on muscle cells of the mouse phrenic-nerve diaphragm preparation through similar mechanisms. Since the isoforms did not produce the expected summation in the increase in muscle twitch-tension, it is possible that they may have different affinities for the sodium channel subunits. (C) 2003 Elsevier Science Ltd. All rights reserved.
Subject: Crotalus durissus terrificus
Country: Inglaterra
Editor: Pergamon-elsevier Science Ltd
Citation: Toxicon. Pergamon-elsevier Science Ltd, v. 41, n. 4, n. 493, n. 500, 2003.
Rights: fechado
Identifier DOI: 10.1016/S0041-0101(02)00390-2
Date Issue: 2003
Appears in Collections:Unicamp - Artigos e Outros Documentos

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