A new class of scorpion toxin binding sites related to an A-type K+ channel: pharmacological characterization and localization in rat brain

FEBS Lett. 2001 Jul 13;501(1):31-6. doi: 10.1016/s0014-5793(01)02620-5.

Abstract

A new scorpion toxin (3751.8 Da) was isolated from the Buthus martensi venom, sequenced and chemically synthesized (sBmTX3). The A-type current of striatum neurons in culture completely disappeared when 1 microM sBmTX3 was applied (Kd=54 nM), whereas the sustained K+ current was unaffected. 125I-sBmTX3 specifically bound to rat brain synaptosomes (maximum binding=14 fmol x mg(-1) of protein, Kd=0.21 nM). A panel of toxins yet described as specific ligands for K+ channels were unable to compete with 125I-sBmTX3. A high density of 125I-sBmTX3 binding sites was found in the striatum, hippocampus, superior colliculus, and cerebellum in the adult rat brain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Autoradiography
  • Binding, Competitive
  • Cells, Cultured
  • Ion Channel Gating / drug effects
  • Molecular Sequence Data
  • Molecular Weight
  • Neostriatum / cytology
  • Neostriatum / drug effects
  • Neostriatum / metabolism*
  • Neurotoxins / chemical synthesis
  • Neurotoxins / chemistry
  • Neurotoxins / metabolism
  • Neurotoxins / pharmacology
  • Patch-Clamp Techniques
  • Potassium Channel Blockers*
  • Potassium Channels / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Scorpion Venoms / chemical synthesis
  • Scorpion Venoms / chemistry
  • Scorpion Venoms / metabolism*
  • Scorpion Venoms / pharmacology*

Substances

  • Neurotoxins
  • Potassium Channel Blockers
  • Potassium Channels
  • Scorpion Venoms