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
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Autoradiography
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Binding, Competitive
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Cells, Cultured
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Ion Channel Gating / drug effects
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Molecular Sequence Data
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Molecular Weight
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Neostriatum / cytology
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Neostriatum / drug effects
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Neostriatum / metabolism*
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Neurotoxins / chemical synthesis
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Neurotoxins / chemistry
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Neurotoxins / metabolism
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Neurotoxins / pharmacology
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Patch-Clamp Techniques
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Potassium Channel Blockers*
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Potassium Channels / metabolism*
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Rats
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Rats, Sprague-Dawley
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Scorpion Venoms / chemical synthesis
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Scorpion Venoms / chemistry
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Scorpion Venoms / metabolism*
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Scorpion Venoms / pharmacology*
Substances
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Neurotoxins
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Potassium Channel Blockers
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Potassium Channels
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Scorpion Venoms