omega-Aga-I: a presynaptic calcium channel antagonist from venom of the funnel web spider, Agelenopsis aperta

J Neurobiol. 1989 Jun;20(4):171-88. doi: 10.1002/neu.480200402.


Spider venoms are proving to be important sources of specific ion channel toxins. Venom of Agelenopsis aperta, a funnel web spider, contains a class of polypeptide toxins which blocks neuromuscular synapses at nanomolar concentrations. Detailed physiological analyses of block caused by one of these toxins, omega-Aga-I, show that it suppresses transmitter release at insect and frog neuromuscular junctions and blocks calcium spikes in insect neuronal cell bodies. omega-Aga-I may define a binding site on neuronal calcium channels which is common to both vertebrates and invertebrates.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Agatoxins
  • Animals
  • Arthropod Venoms / pharmacology*
  • Calcium / pharmacology
  • Calcium Channel Blockers / pharmacology*
  • Evoked Potentials / drug effects
  • Grasshoppers
  • Houseflies
  • In Vitro Techniques
  • Neuromuscular Junction / drug effects
  • Neuromuscular Junction / physiology
  • Neurons / drug effects
  • Neurons / physiology
  • Rana pipiens
  • Spider Venoms / isolation & purification
  • Spider Venoms / pharmacology*
  • Synapses / drug effects
  • Synapses / physiology


  • Agatoxins
  • Arthropod Venoms
  • Calcium Channel Blockers
  • Spider Venoms
  • omega-agatoxin I
  • Calcium