Human cardiac sodium channels expressed in Xenopus oocytes.
We report the expression of voltage-dependent Na+ channels in Xenopus oocytes injected with total RNA isolated from explanted human hearts. The expressed channels demonstrate characteristic voltage-dependent gating, inhibition by tetrodotoxin, and selectivity for Na+. Oocytes injected with sterile water or intentionally degraded RNA had no similar channel activity. The antiarrhythmic agent lidocaine (20 microM) inhibits current flow through the channel in a voltage-dependent fashion. Na+ channels expressed by injection of human cardiac RNA into Xenopus oocytes qualitatively resemble channels in the native tissue.
Department of Medicine, Howard Hughes Medical Institute, Johns Hopkins School of Medicine, Baltimore, Maryland 21205.
G F
GF
Tomaselli
A M
AM
Feldman
G
G
Yellen
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E
Marban
D000818:Animals; D004594:Electrophysiology; D015870:Gene Expression; D006706:Homeostasis; D006801:Humans; D007267:Injections; D008012:Lidocaine / Q000494:pharmacology; D009206:Myocardium / Q000032:analysis / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism*; D012313:RNA / Q000494:pharmacology; D012146:Rest; D012964:Sodium / Q000494:pharmacology; D015222:Sodium Channels / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D014982:Xenopus laevis / Q000378:metabolism*
D015222:Sodium Channels; D012313:RNA; D008012:Lidocaine; D012964:Sodium