Cloning and expression of a rat cardiac delayed rectifier potassium channel.
AUTOR(ES)
Paulmichl, M
RESUMO
We have cloned a cDNA (designated RAK) coding for a delayed-rectifier K current (IRAK) from adult rat heart atrium and expressed it in Xenopus oocytes. RAK differs from the cloned rat brain K current, BK2 [McKinnon, D. (1989) J. Biol. Chem. 264, 8230-8236], by one amino acid at residue 411. RAK expressed in oocytes compares closely to the intrinsic adult rat atrial delayed-rectifier current measured by using whole-cell recording of single isolated cells. Northern blot analysis confirmed the presence of the channel in adult rat atrium, and to a lesser extent, in rat ventricle. IRAK activates with time constants ranging from 58 ms at -20 mV to 6 ms at +60 mV and does not show significant inactivation over 800 ms. It is blocked by 4-aminopyridine greater than barium much greater than tetraethylammonium chloride, which is similar to the relative potencies of these blockers on the native delayed rectifier current. We conclude that the main delayed rectifier K current in adult rat atria is virtually identical to a neuronal delayed rectifier, BK2.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=52410Documentos Relacionados
- Cloning, functional expression and brain localization of a novel unconventional outward rectifier K+ channel.
- Cloning and expression of the delayed-rectifier IsK channel from neonatal rat heart and diethylstilbestrol-primed rat uterus.
- Cloning and expression of a human voltage-gated potassium channel. A novel member of the RCK potassium channel family.
- Cloning, expression, pharmacology and regulation of a delayed rectifier K+ channel in mouse heart.
- Molecular determinants for activation and inactivation of HERG, a human inward rectifier potassium channel.