omegaagatoxins

Omega-agatoxins are a group of peptide toxins found in the venom of certain spiders. They are part of the agatoxin family and are notable for their selective action on voltage-gated calcium channels. Omega-agatoxins specifically block P-type calcium channels (CaV2.1) at presynaptic terminals, reducing calcium influx in response to action potentials and thereby inhibiting neurotransmitter release.

Most omega-agatoxins are small peptides, typically around 35–45 amino acids, rich in cysteines that form several disulfide bonds. They belong to the CSα/β class of peptide toxins and are produced as larger precursors containing a signal peptide and a propeptide, which are processed to yield the mature toxin.

Pharmacologically, omega-agatoxins have been used as tools to study presynaptic calcium channels and to distinguish channel subtypes in various organisms. Their high affinity for CaV2.1 has helped characterize the distribution and function of these channels in synapses and neural circuits.

In envenomation, these toxins contribute to neurotoxic effects by dampening transmitter release, which can result in motor impairment or paralysis in affected animals. While not used clinically, omega-agatoxins have informed the broader understanding of calcium-channel pharmacology and are frequently cited in toxinology literature.