Functional characterization of RK5, a voltage-gated K+ channel cloned from the rat cardiovascular system.
A voltage-sensitive K+ channel previously cloned from rat heart designated RK5 (rat Kv4.2) (Roberds and Tamkun, 1991, Proc. Natl. Acad. Sci. USA 88, 1798-1802) was functionally characterized in the Xenopus oocyte expression system. RK5 is a homolog of the Drosophila Shal K+ channel, activates with a rise time of 2.8 ms, has a midpoint for activation of -1 mV and rapidly inactivates with time constants of 15 and 60 ms. RK5 is sensitive to 4-AP, IC50 = 5 mM, and is insensitive to TEA and dendrotoxins. The voltage dependence and kinetics of the RK5 induced currents suggest this channel contributes to the Ito current in heart.
Blair
T A
TA
Department of Pharmacology, Oregon Health Sciences University, Portland 97201.
Roberds
S L
SL
Tamkun
M M
MM
Hartshorne
R P
RP
D000818:Animals; D004247:DNA / Q000235:genetics; D004594:Electrophysiology / Q000379:methods; D005071:Evoked Potentials; D005260:Female; D006321:Heart / Q000502:physiology*; D009865:Oocytes / Q000502:physiology*; D016133:Polymerase Chain Reaction / Q000379:methods; D015221:Potassium Channels / Q000235:genetics / Q000502:physiology*; D012313:RNA / Q000235:genetics; D014981:Xenopus
D015221:Potassium Channels; D012313:RNA; D004247:DNA