A new class of scorpion toxin binding sites related to an A-type K + channel: pharmacological characterization and localization in rat brain
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 μM sBmTX3 was applied ( K d=54 nM), whereas the sustained K + current was unaffected. 125I-sBmTX3 specifically bound to rat brain synaptosomes (maximum binding=14 fmol mg ‑1 of protein, K d=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:
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FEBS Letters
- Pub Date:
- January 2001
- DOI:
- Bibcode:
- 2001FEBSL.501...31V
- Keywords:
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- A-type K + current;
- Scorpion toxin;
- Distribution in rat brain