Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/336646
Type: Artigo
Title: Neurotoxicity of micrurus lemniscatus lemniscatus (South American coralsnake) venom in vertebrate neuromuscular preparations in vitro and neutralization by antivenom
Author: Floriano, Rafael S.
Schezaro-Ramos, Raphael
Silva Jr., Nelson J.
Bucaretchi, Fabio
Rowan, Edward G.
Hyslop, Stephen
Abstract: We investigated the effect of South American coralsnake (Micrurus lemniscatus lemniscatus) venom on neurotransmission in vertebrate nerve-muscle preparations in vitro. The venom (0.1-30 mu g/ml) showed calcium-dependent PLA(2) activity and caused irreversible neuromuscular blockade in chick biventer cervicis (BC) and mouse phrenic nerve-diaphragm (PND) preparations. In BC preparations, contractures to exogenous acetylcholine and carbachol (CCh), but not KCl, were abolished by venom concentrations >= 0.3 mu g/ml; in PND preparations, the amplitude of the tetanic response was progressively attenuated, but with little tetanic fade. In low Ca2+ physiological solution, venom (10 mu g/ml) caused neuromuscular blockade in PND preparations within similar to 10min that was reversible by washing; the addition of Ca2+ immediately after the blockade temporarily restored the twitch responses, but did not prevent the progression to irreversible blockade. Venom (10 mu g/ml) did not depolarize diaphragm muscle, prevent depolarization by CCh, or cause muscle contracture or histological damage. Venom (3 mu g/ml) had a biphasic effect on the frequency of miniature end-plate potentials, but did not affect their amplitude; there was a progressive decrease in the amplitude of evoked end-plate potentials. The amplitude of compound action potentials in mouse sciatic nerve was unaffected by venom (10 mu g/ml). Pre-incubation of venom with coralsnake antivenom (Instituto Butantan) at the recommended antivenom:venom ratio did not neutralize the neuromuscular blockade in PND preparations, but total neutralization was achieved with a tenfold greater volume of antivenom. The addition of antivenom after 50% and 80% blockade restored the twitch responses. These results show that M. lemniscatus lemniscatus venom causes potent, irreversible neuromuscular blockade, without myonecrosis. This blockade is apparently mediated by pre- and postsynaptic neurotoxins and can be reversed by coralsnake antivenom
Subject: Venenos de serpentes
Antivenenos
Country: Alemanha
Editor: Springer
Rights: Fechado
Identifier DOI: 10.1007/s00204-019-02476-9
Address: https://link.springer.com/article/10.1007%2Fs00204-019-02476-9
Date Issue: 2019
Appears in Collections:FCM - Artigos e Outros Documentos

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