title: 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 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.
authors.affiliation: UMR 6560 CNRSUniversité de la Mediterranée, Faculté de Médecine Nord, Marseille, France.
authors.forename: H
authors.initials: H
authors.lastname: Vacher
authors.forename: R
authors.initials: R
authors.lastname: Romi-Lebrun
authors.forename: C
authors.initials: C
authors.lastname: Mourre
authors.forename: B
authors.initials: B
authors.lastname: Lebrun
authors.forename: S
authors.initials: S
authors.lastname: Kourrich
authors.forename: F
authors.initials: F
authors.lastname: Masméjean
authors.forename: T
authors.initials: T
authors.lastname: Nakajima
authors.forename: C
authors.initials: C
authors.lastname: Legros
authors.forename: M
authors.initials: M
authors.lastname: Crest
authors.forename: P E
authors.initials: PE
authors.lastname: Bougis
authors.forename: M F
authors.initials: MF
authors.lastname: Martin-Eauclaire
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001345:Autoradiography; D001667:Binding, Competitive; D002478:Cells, Cultured; D015640:Ion Channel Gating / Q000187:drug effects; D008969:Molecular Sequence Data; D008970:Molecular Weight; D017072:Neostriatum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009498:Neurotoxins / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012604:Scorpion Venoms / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*
chemical_list: D009498:Neurotoxins; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D012604:Scorpion Venoms