Toxin Name δ-hexatoxin-Ar1a
Source Species Atrax  robustus (Sydney funnel-web spider)
Toxin Group Hexatoxin
Description Insecticidal and vertebrate-active toxin from the Sydney funnel-web spider Atrax robustus. A. robustus is one of the most dangerous spiders in the world and this toxin is responsible for the symptoms observed in humans following envenomation by this spider. δ-HXTX-Ar1a slows the inactivation of both vertebrate tetrodotoxin-sensitive voltage-gated sodium (Nav) channels and insect para-type sodium channels by binding to site 3 of the channel. It is not known whether δ-HXTX-Ar1a is specific for particular vertebrate Nav subtypes.

An antivenom that neutralizes the effect of δ-HXTX-Ar1a was introduced in Australia in 1981 and there have been no recorded deaths due to bites from Atrax robustus or related funnel-web spiders since this time.
Discovered 1985
Sex: Female, Prosoma length: 12mm
Photo courtesy of Volker Herzig
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This toxin last updated on Apr 17, 2018

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