The intrinsic gating of inward rectifier K+ channels expressed from the murine IRK1 gene depends on voltage, K+ and Mg2+.
J Physiol
; 475(1): 1-7, 1994 Feb 15.
Article
in En
| MEDLINE
| ID: mdl-8189383
ABSTRACT
1. We describe the cloning of the inward rectifier K+ channel IRK1 from genomic DNA of mouse; the gene is intronless. 2. The IRK1 gene can be stably expressed in murine erythroleukaemia (MEL) cells. Such transfected cells show inward rectification under whole-cell recording. 3. Channels encoded by the IRK1 gene have an intrinsic gating that depends on voltage and [K+]o. Rate constants are reduced e-fold as the driving force on K+(V-EK) is reduced by 24.1 mV. 4. Removal of intracellular Mg2+ permits brief outward currents under depolarization. The instantaneous current-voltage relation may be fitted by an appropriate constant field expression. 5. Removal of intracellular Mg2+ speeds channel closure at positive voltages. In nominally zero [Mg2+]i, rate constants for the opening and closing of channels, processes which are first order, are similar to those of native channels.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Potassium
/
Potassium Channels
/
Ion Channel Gating
/
Magnesium
Limits:
Animals
Language:
En
Journal:
J Physiol
Year:
1994
Document type:
Article