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Type: Artigo de periódico
Title: Presynaptic Action Of Bothriopsis Bilineata Smargadina (forest Viper) Venom In vitro.
Author: Rodrigues-Simioni, Léa
Floriano, Rafael Stuani
Rostelato-Ferreira, Sandro
Sousa, Norma Cristina
Marangoni, Sergio
Ponce-Soto, Luis Alberto
Carregari, Victor Corasolla
Hyslop, Stephen
Abstract: In this work, we examined the neuromuscular activity of Bothriopsis bilineata smargadina (forest viper) venom in vertebrate isolated nerve-muscle preparations. In chick biventer cervicis preparations the venom caused concentration-dependent (0.1-30 μg/ml) neuromuscular blockade that was not reversed by washing, with 50% blockade occurring in 15-90 min. Muscle contractures to exogenous acetylcholine and KCl were unaffected by venom, but there was a slight increase in creatine kinase release after 120 min (from 80 ± 15 to 206 ± 25U/ml, n=6, p<0.05). In mouse phrenic nerve-diaphragm preparations, the venom (1, 10 and 30 μg/ml) produced marked facilitation (∼120% increase above basal) at the highest concentration followed by neuromuscular blockade; the effects at lower concentrations were considerably less marked. Venom increased the quantal content values after 15 and 30 min followed by significant inhibition at ≥ 90 min. However, venom did not alter the muscle membrane resting potential or the response to exogenous carbachol. In both preparations, incubation at 22 °C instead of 37 °C delayed the onset of blockade, as did inhibition of venom PLA(2) activity. In curarized mouse preparations, the venom produced only muscle facilitation. These results indicate that B. b. smargadina venom causes neuromuscular blockade in vitro by a presynaptic mechanism involving PLA(2).
Subject: Acetylcholine
Creatine Kinase
In Vitro Techniques
Membrane Potentials
Muscle Contraction
Neuromuscular Blocking Agents
Neuromuscular Junction
Phrenic Nerve
Synaptic Transmission
Viper Venoms
Citation: Toxicon : Official Journal Of The International Society On Toxinology. v. 58, n. 1, p. 140-5, 2011-Jul.
Rights: fechado
Identifier DOI: 10.1016/j.toxicon.2011.05.002
Date Issue: 2011
Appears in Collections:Unicamp - Artigos e Outros Documentos

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