title: Toxin and kinetic profile of rat brain type III sodium channels expressed in Xenopus oocytes.
abstract: Sodium (Na+) channels are members of a multigene family and are responsible for generation and propagation of the action potential in excitable cells. We have assembled, in a transcription-competent vector, a full-length cDNA clone encoding the rat brain type III Na+ channel. Xenopus oocytes microinjected with in vitro synthesized mRNA expressed functional rat brain Na+ channels from such 'cloned' RNA transcripts. We found that type III Na+ currents in whole cell microelectrode voltage clamp and in cell-attached patch recordings decayed much more slowly than any other reported Na+ current. In addition, we saw typical and additive effects of alpha- and beta-scorpion toxins, suggesting that the Na+ channel alpha-subunit itself contains functional and distinct toxin binding sites.
authors.affiliation: Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030.
authors.forename: R H
authors.initials: RH
authors.lastname: Joho
authors.forename: J R
authors.initials: JR
authors.lastname: Moorman
authors.forename: A M
authors.initials: AM
authors.lastname: VanDongen
authors.forename: G E
authors.initials: GE
authors.lastname: Kirsch
authors.forename: H
authors.initials: H
authors.lastname: Silberberg
authors.forename: G
authors.initials: G
authors.lastname: Schuster
authors.forename: A M
authors.initials: AM
authors.lastname: Brown
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000378:metabolism; D004558:Electric Stimulation; D008564:Membrane Potentials / Q000187:drug effects; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000494:pharmacology; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012604:Scorpion Venoms / Q000494:pharmacology*; D015222:Sodium Channels / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D014982:Xenopus laevis
chemical_list: D009498:Neurotoxins; D012333:RNA, Messenger; D012604:Scorpion Venoms; D015222:Sodium Channels; D004247:DNA