Recent Insights in Latrodectus (“Black Widow” Spider) Envenomation: Toxins and Their Mechanisms of Action

Abstract

The Latrodectus genus (Araneae: Theridiidae) includes species commonly named black widow spiders. Due to highly potent neurotoxins present in Latrodectus venom, these spiders have medical interest. Envenomation is called LatrodectismLatrodectismand the symptoms include diaphoresis, hypertension, muscle cramping, weakness, and severe abdominal and/or back pain; however, cases of death are rare. The Latrodectus venom contains a cocktail of neurotoxic proteins collectively named latrotoxinsLatrotoxins(LTX). α-LTX strongly binds to a specific presynaptic receptor creating ionic pores, thus provoking a massive release of neurotransmitters. It displays no selectivity for specific synapse types and has no effect on non-neuronal cell types. Studies of Latrodectus venom, concerning toxin isolation, are mainly restricted to few species, although some molecular biology approaches reveal new putative latrotoxins in other Theridiidae species. This chapter offers a brief historical review and the current knowledge on Latrodectus venom and toxins.