Alpha-latrotoxin (Latrodectus hasselti) (α-LTX)

Alpha-latrotoxin is a potent 130 kDa neurotoxin derived from the venom of the Redback spider, Latrodectus hasselti (UniProt: P0C2C6). It is the principal agent responsible for latrodectism, a clinical syndrome marked by severe muscle pain, profuse sweating, and autonomic instability (PMID: 12084515). The toxin functions by binding to specific presynaptic receptors, including latrophilin-1 and neurexin-1a, which triggers its insertion into the neuronal membrane to form cation-permeable pores (PMID: 10713896). These pores cause a massive, uncontrolled release of neurotransmitters, leading to initial overstimulation of the nervous system followed by synaptic depletion and potential paralysis (Toxicon, 2006). In clinical practice, the primary therapeutic intervention is the administration of Redback spider antivenom, which contains equine IgG fragments designed to neutralize the circulating toxin (Australian Medicines Handbook). Beyond its toxicological role, alpha-latrotoxin is a critical tool in neurobiology for investigating the molecular mechanisms of regulated exocytosis and vesicle trafficking.

Other names

Redback spider toxinAlpha-latrotoxin-LhLTX

Alpha-latrotoxin acts by binding to high-affinity presynaptic receptors, primarily latrophilin-1 and neurexin-1a, which facilitates its oligomerization and insertion into the plasma membrane to form non-selective cation-permeable pores (PMID: 10713896). This pore formation leads to a massive, uncontrolled influx of calcium and sodium ions, triggering the exhaustive release of neurotransmitters such as acetylcholine, glutamate, and GABA from the nerve terminal (PMID: 12084515).