Functional expression of the rat heart I Na+ channel isoform. Demonstration of properties characteristic of native cardiac Na+ channels.
We describe the expression of functional Na+ channels in Xenopus oocytes injected with cRNA transcribed from the rat heart I cDNA clone. The expressed rat heart I Na+ currents show kinetic properties and resistance to tetrodotoxin and saxitoxin which are characteristic of native cardiac Na+ currents. The primary amino acid sequence of the rat heart I alpha-subunit is therefore sufficient for expression of tetrodotoxin resistance, and the rat heart I clone is likely to account for the tetrodotoxin-resistant phenotype of cardiac and denervated skeletal muscle.
Cribbs
L L
LL
Department of Medicine, University of Chicago, IL 60637.
Satin
J
J
Fozzard
H A
HA
Rogart
R B
RB
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D004594:Electrophysiology; D015870:Gene Expression; D008845:Microinjections; D008969:Molecular Sequence Data; D009206:Myocardium; D009841:Oligonucleotides; D012333:RNA, Messenger / Q000235:genetics; D012530:Saxitoxin / Q000378:metabolism / Q000494:pharmacology; D012964:Sodium / Q000502:physiology; D015222:Sodium Channels / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D013779:Tetrodotoxin / Q000378:metabolism / Q000494:pharmacology; D014981:Xenopus
D009841:Oligonucleotides; D012333:RNA, Messenger; D015222:Sodium Channels; D012530:Saxitoxin; D013779:Tetrodotoxin; D012964:Sodium