TTX, cations and spider venom modify avian muscle tone in vitro

Research Report

J Venom Res (2011), Vol 2, 1-5

Published online: 02 January 2011

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Volker Herzig †*, Wayne C Hodgson ‡ and Edward G Rowan §

† Division of Chemical and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Building 80, Service Road, St Lucia, QLD 4072, Australia

‡ Monash Venom Group, Department of Pharmacology, Monash University, Clayton, Victoria 3800, Australia

§ Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, G4 0NR, United Kingdom

*Correspondence to: Volker Herzig, Email:, Tel: +61 7 3346 2014, Fax: +61 7 3346 2101

Received: 21 December 2010, Accepted: 02 January 2011

© Copyright The Authors


Agents that reduce skeletal muscle tone may have a number of useful clinical applications, e.g., for muscle spasticity and other muscle disorders. Recently, we reported that the venoms of two species of Australian theraphosid (Araneae, Theraphosidae) spiders (Coremiocnemis tropix andSelenotholus foelschei) reduced the baseline tension of chick biventer cervicis nerve-muscle preparation. The purpose of this study was to determine the underlying physiology mediating the change in muscle tension, which was addressed by conducting isometric tension experiments.We found that MgCl 2 (20mM), CaCl 2 (20mM), tetrodotoxin (1µM) or C. tropix venom (2µl/ml) produced a similar decrease in baseline tension, whereas d-tubocurarine (100µM), gadolinium (1mM), verapamil (10mM), an increase in osmotic pressure by the addition of glucose (40mM), or the presence/absence of electrical stimulation did not produce a significant change in baseline tension.We suggest that mechanosensitive or muscle TTX-sensitive sodium channels are activated during muscle stretch. This may have implications for the treatment of stretch induced muscle damage.

KEYWORDS: Theraphosidae, Coremiocnemis tropix, venom, baseline muscle tension, chick biventer cervicis nerve-muscle preparation