Alpha-latrotoxin (α-LTX) (α-LTX)

Alpha-latrotoxin (α-LTX) is a potent 130 kDa neurotoxin derived from the venom of spiders in the genus Latrodectus, most notably the black widow spider (Latrodectus mactans). It acts specifically at the presynaptic nerve terminals of vertebrates, where it induces a massive and exhaustive release of neurotransmitters such as acetylcholine, GABA, and glutamate (Südhof, 2001, PMID: 11773605). The toxin exerts its effects through two distinct pathways: by forming non-selective cation pores in the presynaptic membrane and by binding to high-affinity receptors, including latrophilin-1 (a G protein-coupled receptor) and neurexin-1α (Ushkaryov et al., 2008, PMID: 18411248). This dual mechanism leads to an influx of calcium and the stimulation of the exocytotic machinery, resulting in the clinical syndrome known as latrodectism. Latrodectism is characterized by severe muscle pain, abdominal rigidity, and autonomic instability, which can be life-threatening in vulnerable populations (StatPearls, 2023). While α-LTX is a significant public health concern, it is also a valuable pharmacological tool used to study the molecular basis of synaptic vesicle docking and fusion. Therapeutic management typically involves supportive care and the administration of equine-derived antivenom to neutralize the circulating toxin (Isbister & Fan, 2011, PMID: 21663530).

Other names

LatrotoxinBlack widow spider venom toxinLTXAlpha-latroinsectotoxinAlpha-latrocrustatoxin

Alpha-latrotoxin binds to presynaptic receptors (latrophilin and neurexin) and inserts into the membrane to form cation-selective pores, leading to massive, uncontrolled neurotransmitter release (PMID: 11773605, 18411248).