The in vitro Neurotoxic and Myotoxic Effects of the Venom from the Suta Genus (Curl Snakes) of Elapid Snakes

Abstract

Australia has a tremendous diversity of elapid snakes, including many unique smaller sized species of this venomous snake family. However, little if anything is known about the majority of the venoms of these lesser studied snakes. In the current study, the venoms of Suta suta (curl snake) and Suta punctata (spotted-curl snake) were examined for in vitro activity using a skeletal muscle preparation (i.e. chick biventer cervicis nerve-muscle preparation). Both venoms caused concentration-dependent (3-10 microg/ml) inhibition of nerve-mediated twitches, and inhibited responses to exogenous acetylcholine and carbachol, indicating the presence of postsynaptic neurotoxins. These effects were prevented by prior addition of CSL Ltd. polyvalent snake antivenom (5 units/ml) but only partially reversed by the addition of antivenom (5 units/ml) at the t(90) time-point (i.e. time at which twitches were inhibited by 90%). Suta punctata venom (10 microg/ml) was also myotoxic as indicated by the inhibition of direct twitches of the chick biventer cervicis nerve-muscle preparation. This effect was not reversed by antivenom (5 units/ml). This study highlights the danger of underestimating the potential severe clinical effects posed by these small but highly venomous snakes.