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Type: Artigo de periódico
Title: Neuromuscular Action Of Bothrops Lanceolatus (fer De Lance) Venom And A Caseinolytic Fraction.
Author: Lôbo de Araújo, Albetiza
Donato, José Luiz
Leite, Gildo Bernardo
Prado-Franceschi, Júlia
Fontana, Marcos Dias
Bon, Cassian
Rodrigues Simioni, Léa
Abstract: A protein capable of inducing neuromuscular blockade in avian preparations and of depolarizing mouse diaphragm muscle was isolated from Bothrops lanceolatus venom using gel filtration and ion-exchange chromatography. The purified protein was a single chain polypeptide with an estimated molecular mass of 27.5 kDa by SDS-PAGE and had caseinolytic activity (13.3 units/mg), but no phospholipase A(2). B.lanceolatus venom (50 micro g/ml) and the caseinolytic protein (20 micro g/ml) produced contracture and progressive irreversible blockade (50% in 25+/-5 min (SEM) and 45+/-15 min, respectively), in indirectly stimulated chick biventer cervicis preparations. The contractile responses to acetylcholine (ACh; 37 and 74 micro M, n=6) were inhibited by venom and the caseinolytic protein, whereas those to potassium (13.4mM, n=6) were not. Membrane resting potential measurements in mouse hemidiaphragm preparations showed that B.lanceolatus venom and the purified protein caused depolarization which was prevented by D-tubocurarine (14.6mM). The venom produced a slight increase in the amplitude and frequency of miniature end-plate potentials, but this effect was not seen with the purified fraction. These results suggest that the purified protein acts exclusively post-synaptically.
Subject: Animals
Chromatography, Gel
Chromatography, Ion Exchange
Crotalid Venoms
Electrophoresis, Polyacrylamide Gel
Membrane Potentials
Motor Endplate
Muscle Contraction
Neuromuscular Blockade
Neuromuscular Blocking Agents
Neuromuscular Junction
Peptide Hydrolases
Citation: Toxicon : Official Journal Of The International Society On Toxinology. v. 40, n. 9, p. 1283-9, 2002-Sep.
Rights: fechado
Date Issue: 2002
Appears in Collections:Unicamp - Artigos e Outros Documentos

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