Influence of outer pore residue K533 on the inhibition of Kv1.4 potassium channels by n -alkyl sulphate anions

1998 ◽  
Vol 436 (4) ◽  
pp. 623-626 ◽  
Author(s):  
S. MacDonald ◽  
A. A. Elliott ◽  
J. A. Harrold ◽  
J. R. Elliott
Keyword(s):  
Potassium Channels ◽  
Alkyl Sulphate ◽  
Outer Pore

scholarly journals Mechanisms Underlying Modulation of Neuronal KCNQ2/KCNQ3 Potassium Channels by Extracellular Protons

2003 ◽  
Vol 122 (6) ◽  
pp. 775-793 ◽  
Author(s):  
David L. Prole ◽  
Pedro A. Lima ◽  
Neil V. Marrion
Keyword(s):  
Potassium Channels ◽  
Neuronal Activity ◽  
Single Channel ◽  
High Sensitivity ◽  
Open Probability ◽  
M Current ◽  
Specific Effects ◽  
Single Channel Activity ◽  
Outer Pore ◽  
Hyperpolarizing Shift

Changes in extracellular pH occur during both physiological neuronal activity and pathological conditions such as epilepsy and stroke. Such pH changes are known to exert profound effects on neuronal activity and survival. Heteromeric KCNQ2/3 potassium channels constitute a potential target for modulation by H+ ions as they are expressed widely within the CNS and have been proposed to underlie the M-current, an important determinant of excitability in neuronal cells. Whole-cell and single-channel recordings demonstrated a modulation of heterologously expressed KCNQ2/3 channels by extracellular H+ ions. KCNQ2/3 current was inhibited by H+ ions with an IC50 of 52 nM (pH 7.3) at −60 mV, rising to 2 μM (pH 5.7) at −10 mV. Neuronal M-current exhibited a similar sensitivity. Extracellular H+ ions affected two distinct properties of KCNQ2/3 current: the maximum current attainable upon depolarization (Imax) and the voltage dependence of steady-state activation. Reduction of Imax was antagonized by extracellular K+ ions and affected by mutations within the outer-pore turret, indicating an outer-pore based process. This reduction of Imax was shown to be due primarily to a decrease in the maximum open-probability of single KCNQ2/3 channels. Single-channel open times were shortened by acidosis (pH 5.9), while closed times were increased. Acidosis also recruited a longer-lasting closed state, and caused a switch of single-channel activity from the full-conductance state (∼8 pS) to a subconductance state (∼5 pS). A depolarizing shift in the activation curve of macroscopic KCNQ2/3 currents and single KCNQ2/3 channels was caused by acidosis, while alkalosis caused a hyperpolarizing shift. Activation and deactivation kinetics were slowed by acidosis, indicating specific effects of H+ ions on elements involved in gating. Contrasting modulation of homomeric KCNQ2 and KCNQ3 currents revealed that high sensitivity to H+ ions was conferred by the KCNQ3 subunit.

Dopamine and GABA outflow is modulated by ATP-sensitive potassium channels in the rat caudate nucleus

2006 ◽  
Vol 33 (S 1) ◽  
Author(s):  
H. Fuellgraf ◽  
M. Steinkamp ◽  
M. Kolbe ◽  
A. Moser
Keyword(s):  
Potassium Channels ◽  
Caudate Nucleus

Design of New Openers of ATP-Sensitive Potassium Channels of the Cell Membranes

2016 ◽  
Vol 12 (4) ◽  
pp. 36-44
Author(s):  
R.B. Strutynskyi ◽  
◽  
N.A. Strutynska ◽  
O.P. Maximyuk ◽  
M.O. Platonov ◽  
...  
Keyword(s):  
Potassium Channels ◽  
Cell Membranes
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