scholarly journals Direct Measurement of K+ Channels in Thylakoid Membranes by Incorporation of Vesicles into Planar Lipid Bilayers

1989 ◽  
Vol 91 (1) ◽  
pp. 249-252 ◽  
Author(s):  
Mark Tester ◽  
Michael R. Blatt
Keyword(s):  
Lipid Bilayers ◽  
Direct Measurement ◽  
Thylakoid Membranes ◽  
Planar Lipid Bilayers ◽  
K Channels

scholarly journals Potassium blocks barium permeation through a calcium-activated potassium channel.

1988 ◽  
Vol 92 (5) ◽  
pp. 549-567 ◽  
Author(s):  
J Neyton ◽  
C Miller
Keyword(s):  
Skeletal Muscle ◽  
Lipid Bilayers ◽  
Dissociation Rate ◽  
Planar Lipid Bilayers ◽  
Rat Skeletal Muscle ◽  
K Channels ◽  
Calcium Activated Potassium Channel ◽  
Micromolar Range ◽  
High Conductance ◽  
External K

Single high-conductance Ca2+-activated K+ channels from rat skeletal muscle were inserted into planar lipid bilayers, and discrete blocking by the Ba2+ ion was studied. Specifically, the ability of external K+ to reduce the Ba2+ dissociation rate was investigated. In the presence of 150 mM internal K+, 1-5 microM internal Ba2+, and 150 mM external Na+, Ba2+ dissociation is rapid (5 s-1) in external solutions that are kept rigorously K+ free. The addition of external K+ in the low millimolar range reduces the Ba2+ off-rate 20-fold. Other permeant ions, such as Tl+, Rb+, and NH4+ show a similar effect. The half-inhibition constants rise in the order: Tl+ (0.08 mM) less than Rb+ (0.1 mM) less than K+ (0.3 mM) less than Cs+ (0.5 mM) less than NH4+ (3 mM). When external Na+ is replaced by 150 mM N-methyl glucamine, the Ba2+ off-rate is even higher, 20 s-1. External K+ and other permeant ions reduce this rate by approximately 100-fold in the micromolar range of concentrations. Na+ also reduces the Ba2+ off-rate, but at much higher concentrations. The half-inhibition concentrations rise in the order: Rb+ (4 microM) less than K+ (19 microM) much less than Na+ (27 mM) less than Li+ (greater than 50 mM). The results require that the conduction pore of this channel contains at least three sites that may all be occupied simultaneously by conducting ions.

scholarly journals Ca2+-activated K+ channels from an insulin-secreting cell line incorporated into planar lipid bilayers

Diabetologia ◽  
1992 ◽  
Vol 35 (7) ◽  
pp. 619-623 ◽  
Author(s):  
Y. Oosawa ◽  
S. J. H. Ashcroft ◽  
F. M. Ashcroft
Keyword(s):  
Cell Line ◽  
Lipid Bilayers ◽  
Planar Lipid Bilayers ◽  
Secreting Cell ◽  
K Channels

scholarly journals Ca2+-dependent K+channels from rat olfactory cilia characterized in planar lipid bilayers

FEBS Letters ◽  
2005 ◽  
Vol 579 (7) ◽  
pp. 1675-1682 ◽  
Author(s):  
Karen Castillo ◽  
Juan Bacigalupo ◽  
Daniel Wolff
Keyword(s):  
Lipid Bilayers ◽  
Planar Lipid Bilayers ◽  
Olfactory Cilia ◽  
K Channels

scholarly journals Saturation behavior of single, amiloride-sensitive Na+ channels in planar lipid bilayers

1984 ◽  
Vol 46 (6) ◽  
pp. 831-835 ◽  
Author(s):  
L. Olans ◽  
S. Sariban-Sohraby ◽  
D.J. Benos
Keyword(s):  
Lipid Bilayers ◽  
Planar Lipid Bilayers ◽  
Na Channels

scholarly journals Stimulation‐dependent gating of TRPM3 channel in planar lipid bilayers

2015 ◽  
Vol 30 (3) ◽  
pp. 1306-1316 ◽  
Author(s):  
Kunitoshi Uchida ◽  
Lusine Demirkhanyan ◽  
Swapna Asuthkar ◽  
Alejandro Cohen ◽  
Makoto Tominaga ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Planar Lipid Bilayers

Ryanodine receptor dysfunction in porcine stunned myocardium

1997 ◽  
Vol 273 (2) ◽  
pp. H796-H804 ◽  
Author(s):  
C. Valdivia ◽  
J. O. Hegge ◽  
R. D. Lasley ◽  
H. H. Valdivia ◽  
R. Mentzer
Keyword(s):  
Coronary Artery ◽  
Lipid Bilayers ◽  
Ryanodine Receptor ◽  
Myocardial Stunning ◽  
Single Channel ◽  
Stunned Myocardium ◽  
Wall Thickening ◽  
Planar Lipid Bilayers ◽  
Open Probability ◽  
Single Channel Recordings

We investigated the effects of myocardial stunning on the function of the two main Ca2+ transport proteins of the sarcoplasmic reticulum (SR), the Ca(2+)-adenosinetriphosphatase and the Ca(2+)-release channel or ryanodine receptor. Regional myocardial stunning was induced in open-chest pigs (n = 6) by a 10-min occlusion of the left anterior descending coronary artery (LAD) and 2 h reperfusion. SR vesicles isolated from the LAD-perfused region (stunned) and the normal left circumflex coronary artery (LC)-perfused region were used to assess the oxalate-supported 45Ca2+ uptake, [3H]ryanodine binding, and single-channel recordings of ryanodine-sensitive Ca(2+)-release channels in planar lipid bilayers. Myocardial stunning decreased LAD systolic wall thickening to 20% of preischemic values. The rate of SR 45Ca2+ uptake in the stunned LAD bed was reduced by 37% compared with that of the normal LC bed (P < 0.05). Stunning was also associated with a 38% reduction in the maximal density of high-affinity [3H]ryanodine binding sites (P < 0.05 vs. normal LC) but had no effect on the dissociation constant. The open probability of ryanodine-sensitive Ca(2+)-release channels determined by single channel recordings in planar lipid bilayers was 26 +/- 2% for control SR (n = 33 channels from 3 animals) and 14 +/- 2% for stunned SR (n = 21 channels; P < 0.05). This depressed activity of SR function observed in postischemic myocardium could be one of the mechanisms underlying myocardial stunning.

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