Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/195046
Type: Artigo de periódico
Title: Action Of Micrurus Dumerilii Carinicauda Coral Snake Venom On The Mammalian Neuromuscular Junction.
Author: Serafim, Francine G
Reali, Marielga
Cruz-Höfling, Maria Alice
Fontana, Marcos D
Abstract: The venoms of coral snakes (mainly Micrurus species) have pre- and/or postsynaptic actions, but only a few of these have been studied in detail. We have investigated the effects of Micrurus dumerilii carinicauda coral snake venom on neurotransmission in rat isolated phrenic nerve-diaphragm muscle and chick biventer cervicis preparations stimulated directly or indirectly. M. d. carinicauda venom (5 or 10 microg/ml) produced neuromuscular blockade in rat (85-90% in 291.8+/-7.3 min and 108.3+/-13.8, respectively; n=5) and avian (95.0+/-2.0 min; 5 microg/ml, n=5) preparations. Neostigmine (5.8 microM) and 3,4-diaminopyridine (230 microM) partially reversed the venom-induced neuromuscular blockade in rat nerve-muscle preparations. In neither preparation did the venom depress the twitch response elicited by direct muscle stimulation. The contractures induced by acetylcholine in chick preparations were inhibited by the venom (95-100%; n=4; p<0.05). In rat preparations, the venom produced a progressive decrease in the amplitude of miniature end-plate potentials (m.e.p.ps control frequency=69.3+/-5.0/min and control amplitude=0.4+/-0.2 mV) until these were abolished. Neostigmine (5.8 microM) and 3,4-diaminopyridine (230 microM) partially antagonized this blockade of m.e.p.ps. The resting membrane potential was not altered with the venom (10 microg/ml). M. d. carinicauda venom produced dose-dependent morphological changes in indirectly stimulated mammal preparations. Twenty-five per cent of muscle fibers were affected by a venom concentration of 5 microg/ml, whilst 60.7% were damaged by 10 microg of venom/ml. In biventer cervicis preparations, the morphological changes were slower in onset and were generally characterized by undulating fibers and, to a lesser extent, by zones of disintegrating myofibrils. A venom concentration of 5 microg/ml damaged 52.2% of the fibers. These findings indicate that M. d. carinicauda venom has neurotoxic and myotoxic effects and that the neuromuscular blockade involves mainly a postsynaptic action.
Subject: Animals
Chickens
Diaphragm
Dose-response Relationship, Drug
Elapid Venoms
Elapidae
Electric Stimulation
Lethal Dose 50
Male
Membrane Potentials
Mice
Motor Endplate
Muscle Contraction
Muscle, Skeletal
Neuromuscular Junction
Phrenic Nerve
Rats
Rights: fechado
Identifier DOI: 
Address: http://www.ncbi.nlm.nih.gov/pubmed/11689238
Date Issue: 2002
Appears in Collections:Unicamp - Artigos e Outros Documentos

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