J Venom Res (2014), Vol 5, 6-15
Published online: 18 June 2014
Carla T Fernandes α, Vânia MA Giaretta α, Luiz S Prudêncio ß, Edvana O Toledo α, Igor RF da Silva §, Rita CO Collaço §, Ana M Barbosa ¥, Stephen Hyslop §, Léa Rodrigues-Simioni §, José C Cogo α,*
α Serpentário do Centro de Estudos da Natureza e Instituto de Pesquisa & Desenvolvimento (IP&D), Universidade do Vale do Paraíba (UNIVAP), Avenida Shishimi Hifumi, 2911, Urbanova, 12240-000, São José dos Campos, SP, Brazil
ß Escola de Enfermagem Wenceslau Braz, Avenida Cesário Alvin, 566, 37501-059, Itajubá, MG, Brazil
§ Departamento de Farmacologia, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Rua Tessália Vieira de Camargo, 126, Cidade Universitária Zeferino Vaz, 13083-887, Campinas, SP, Brazil
¥ Faculdade Anhanguera Educacional – Unidade I, Taubaté, SP, Brazil
*Correspondence to: José C Cogo, Email: email@example.com, Tel.: +55 12 3947 1106
Received: 05 February 2014; Revised: 11 June 2014; Accepted: 18 June 2014
© Copyright The Author(s). First Published by Library Publishing Media. This is an open access article, published under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0). This license permits non-commercial use, distribution and reproduction of the article, provided the original work is appropriately acknowledged with correct citation details.
The neuromuscular activity of venom from Bothrops fonsecai, a lancehead endemic to southeastern Brazil, was investigated. Chick biventer cervicis (CBC) and mouse phrenic nerve-diaphragm (PND) preparations were used for myographic recordings and mouse diaphragm muscle was used for membrane resting potential (RP) and miniature end-plate potential (MEPP) recordings. Creatine kinase release and muscle damage were also assessed. In CBC, venom (40, 80 and 160mg/ml) produced concentration- and time-dependent neuromuscular blockade (50% blockade in 85±9 min and 73±8 min with 80 and 160ug/ml, respectively) and attenuated the contractures to 110uM ACh (78-100% inhibition) and 40mM KCl (45-90% inhibition). The venom-induced decrease in twitch-tension in curarized, directly-stimulated preparations was similar to that in indirectly stimulated preparations. Venom (100 and 200ug/ml) also caused blockade in PND preparations (50% blockade in 94±13 min and 49±8 min with 100 and 200ug/ml, respectively) but did not alter the RP or MEPP amplitude. In CBC, venom caused creatine kinase release and myonecrosis. The venom-induced decrease in twitch-tension and in the contractures to ACh and K+ were abolished by preincubating venom with commercial antivenom. These findings indicate that Bothrops fonsecai venom interferes with neuromuscular transmission essentially through postsynaptic muscle damage that affects responses to ACh and KCl. These actions are effectively prevented by commercial antivenom.
Keywords: Bothrops fonsecai, myotoxicity, neuromuscular blockade, neurotransmission, post-synaptic