Neurotoxicity ofMicrurus altirostris(Uruguayan coral snake) venom and its neutralization by commercial coral snake antivenom and specific antiserum raised in rabbits

Abstract

In this work, we studied the neuromuscular blockade caused by Micrurus altirostris venom (0.1-10 microg/mL) in indirect stimulated chick biventer cervicis and mouse phrenic nerve-diaphragm preparations and the ability of commercial antivenom (Instituto Butantan) and antiserum raised in rabbits to neutralize neurotoxicity and lethality in chicks and mice (LD(50) 0.042 and 0.255 mg/kg), injected i.m. and i.p., respectively, with venom (5 LD(50)):antivenom or antiserum mixtures (n = 6) of 1:1-1:2.5-1:5-1:10-1:20. The venom caused a complete and irreversible neuromuscular blockade in both preparations, inhibited the acetylcholine and carbachol contractures, without interfering on KCl response. The neuromuscular blockade was not Ca(2+) or temperature-dependent and did not affect the response to direct stimulation. Only a venom:antivenom or antiserum ratio of 1:20 neutralized the neuromuscular blockade in vitro and protected chicks and mice against 5 LD(50) of venom. Our results indicated that Micrurus altirostris venom interferes with postsynaptic neurotransmission and that commercial antivenom and rabbit antiserum have low efficacy in neutralizing the neurotoxicity and lethality of this venom.

Mipartoxin-I, a novel three-finger toxin, is the major neurotoxic component in the venom of the redtail coral snake Micrurus mipartitus (Elapidae)

“…However, possible species differences in the affinity of this toxin for its receptors cannot be ruled out. Mipartoxin-I inhibited contractures to exogenous ACh, indicating a predominantly post-synaptic action through the blockade of cholinergic nicotinic receptor, as also suggested for other studies using Micrurus venoms (Goularte et al, 1995;Serafim et al, 2002;Abreu et al, 2008;Camargo et al, 2011;Renjifo et al, 2012). The post-synaptic action of mipartoxin-I was also indicated by the absence of fade in the response to tetanic indirect stimulation at 70 Hz.…”

Envenomation by Micrurus coral snakes in the Brazilian Amazon region: report of two cases

“…Specific Micrurus antivenoms, produced in Brazil by the Butantan Institute (São Paulo) and the Ezequiel Dias Foundation (Minas Gerais), are produced in horses immunized with the venoms of M. corallinus and M. frontalis 29 . However, some studies suggest that the neutralizing capacity of antivenoms may be improved by including venom from other Micrurus species in the venom pool used in the immunization protocol 1,10,15,36 .…”

Pharmacological and partial biochemical characterization of Bmaj-9 isolated from Bothrops marajoensis snake venom

“…In vitro studies have shown that some Bothrops venoms and their major toxins are typically myotoxic in rodents; however, neurotoxic effects have been also revealed in mouse and chick. The neurotoxicity was observed by the blockade of neuromuscular transmission, either presynaptically, in a dose range similar to that of elapid venoms, or postsynaptically (6)(7)(8)(9)(10)(11)(12)(13)(14).…”