α-Latrotoxin (α-LTX) can naturally be found in widow spiders of the genus Latrodectus. The most widely known of those spiders are the black widows, Latrodectus mactans. The venom of widow spiders (Latrodectus) contains several protein toxins, called latrotoxins, which selectively target against either vertebrates, insects or crustaceans. One of these toxins is α-latrotoxin and targets selectively against vertebrates; it is ineffective in insects and crustaceans. α-LTX has a high affinity for receptors that are specific for neuronal and endocrine cells of vertebrates. α-LTX affects motor nerve endings and endocrine cells. No major enzymatic activities are associated. Instead, the toxin can form pores in the lipid membranes and induce Ca2+ ion flow. The onset of effects by intoxication can occur with a lag-period of 1 to 10 minutes, even at subnanomolar concentration levels. At nanomolar concentrations, bursts of neurotransmitter release occur.
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