The neuromuscular activity of Micrurus pyrrhocryptus venom and its neutralization by commercial and specific coral snake antivenoms

J Venom Res (2011), Vol 2, 24-31

Published online: 24 June 2011

Full Text: (PDF ~823kb) | (PubMed Central Record HTML)

Thiago Magalhães Camargo †, Adolfo Rafael de Roodt ‡ , Maria Alice da Cruz-Höfling § , Léa Rodrigues-Simioni †*

† Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (Unicamp), P.O. Box 6111, 13083-970, Campinas, SP, Brazil

‡ Instituto Nacional de Producción de Biológicos, Administración Nacional de Laboratorios e Institutos de Salud (A.N.L.I.S.) “Dr. Carlos G. Malbrán”, Ministerio de Salud, Av. Vélez Sarsfield 563, CP 1281, Buenos Aires, Argentina

§ Department of Histology and Embryology, Institute of Biology, University of Campinas (Unicamp), P.O. Box 6109, 13083-970, Campinas, SP, Brazil

*Correspondence to: Léa Rodrigues-Simioni, E-mail: simioni@unicamp.br, Tel: +55 19 35219533, Fax: +55 19 32892968

Received: 27 May 2011, Accepted: 20 June 2011

© Copyright The Authors

ABSTRACT

The neuromuscular activity of Micrurus pyrrochryptus venom was studied in chick biventer cervicis (BC) and mouse phrenic nerve-diaphragm (PND) preparations. The venom (0.5-50µg/ml) caused irreversible, time- and concentration-dependent blockade, with BC being more sensitive than PND (50% blockade with 10µg/ml in 22±3min and 62±4min, respectively; mean±SEM, n=6; p<0.05). In BC preparations, venom (0.5µg/ml) progressively abolished ACh-induced contractures, whereas contractures to exogenous KCl and muscle twitches in curarized preparations were unaffected. The venom neither altered creatine kinase release (venom: 25.8±1.75IU/l vs control: 24.3±2.2IU/l, n=6, after 120min), nor it caused significant muscle damage (50µg of venom/ml vs control: 3.5±0.8% vs1.1±0.7% for PND; 4.3±1.5% vs 1.2±0.5% for BC, n=5). The venom had low PLA 2 activity. Neurotoxicity was effectively neutralized by commercial Micrurus antivenom and specific antivenom. These findings indicate that M. pyrrhocryptus venom acts postsynaptically on nicotinic receptors, with no significant myotoxicity.

KEYWORDS: Coral snake venom, neuromuscular blockade, neurotoxin, nicotinic receptor, postsynaptic