TY - JOUR
T1 - Ca2+-activated K+ channels from rabbit kidney medullary thick ascending limb cells expressed in Xenopus oocytes
AU - Lu, Luo
AU - Montrose-Rafizadeh, Chahrzad
AU - Guggino, William B.
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1990/9/25
Y1 - 1990/9/25
N2 - Ca2+-activated K+ channels are present in muscle, nerve, pancreas, macrophages, and renal cells. They are important in such diverse functions as neurotransmitter release, muscle excitability, pancreatic secretion, and cell volume regulation. Although much is known about the biophysics of Ca2+-activated K+ channels, the molecular structure, cDNA and amino acid sequences are unknown. We injected size-fractionated mRNA isolated from cultured rabbit kidney medullary thick ascending limb cells in Xenopus oocytes and observed newly expressed K+ currents using two-microelectrode voltage-clamp technique. The expressed K+ currents are Ca2+ dependent and inhibited by charybdotoxin, a specific blocker of Ca2+-activated K+ channels. Amplitudes of the current ranged from 30 nA to more than 1 μA at a membrane potential of +30 mV. Reversal potential of the current suggested a K+-selective channel. The peak activity of Ca2+-activated K+ channels were observed in fractions corresponding to a message RNA with size of approximately 4.5 kilobases.
AB - Ca2+-activated K+ channels are present in muscle, nerve, pancreas, macrophages, and renal cells. They are important in such diverse functions as neurotransmitter release, muscle excitability, pancreatic secretion, and cell volume regulation. Although much is known about the biophysics of Ca2+-activated K+ channels, the molecular structure, cDNA and amino acid sequences are unknown. We injected size-fractionated mRNA isolated from cultured rabbit kidney medullary thick ascending limb cells in Xenopus oocytes and observed newly expressed K+ currents using two-microelectrode voltage-clamp technique. The expressed K+ currents are Ca2+ dependent and inhibited by charybdotoxin, a specific blocker of Ca2+-activated K+ channels. Amplitudes of the current ranged from 30 nA to more than 1 μA at a membrane potential of +30 mV. Reversal potential of the current suggested a K+-selective channel. The peak activity of Ca2+-activated K+ channels were observed in fractions corresponding to a message RNA with size of approximately 4.5 kilobases.
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M3 - Article
C2 - 1697853
AN - SCOPUS:0025194164
SN - 0021-9258
VL - 265
SP - 16190
EP - 16194
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 27
ER -