Expression of inward rectifying K+ channels (KIR2.1, KIR2.2, KIR2.3) and the small – conductance CA2+- activated K+ channel SK2 in normal versus atherosclerotic human radial artery bypass grafts

2008 ◽  
Vol 56 (S 1) ◽  
Author(s):  
S Wildhirt ◽  
M Benz ◽  
J Grammer ◽  
R Lange
Circulation ◽  
2004 ◽  
Vol 110 (11_suppl_1) ◽  
pp. II-23-II-26 ◽  
Author(s):  
J. Cameron

1998 ◽  
Vol 111 (4) ◽  
pp. 565-581 ◽  
Author(s):  
Birgit Hirschberg ◽  
James Maylie ◽  
John P. Adelman ◽  
Neil V. Marrion

Small-conductance Ca-activated K+ channels play an important role in modulating excitability in many cell types. These channels are activated by submicromolar concentrations of intracellular Ca2+, but little is known about the gating kinetics upon activation by Ca2+. In this study, single channel currents were recorded from Xenopus oocytes expressing the apamin-sensitive clone rSK2. Channel activity was detectable in 0.2 μM Ca2+ and was maximal above 2 μM Ca2+. Analysis of stationary currents revealed two open times and three closed times, with only the longest closed time being Ca dependent, decreasing with increasing Ca2+ concentrations. In addition, elevated Ca2+ concentrations resulted in a larger percentage of long openings and short closures. Membrane voltage did not have significant effects on either open or closed times. The open probability was ∼0.6 in 1 μM free Ca2+. A lower open probability of ∼0.05 in 1 μM Ca2+ was also observed, and channels switched spontaneously between behaviors. The occurrence of these switches and the amount of time channels spent displaying high open probability behavior was Ca2+ dependent. The two behaviors shared many features including the open times and the short and intermediate closed times, but the low open probability behavior was characterized by a different, long Ca2+-dependent closed time in the range of hundreds of milliseconds to seconds. Small-conductance Ca- activated K+ channel gating was modeled by a gating scheme consisting of four closed and two open states. This model yielded a close representation of the single channel data and predicted a macroscopic activation time course similar to that observed upon fast application of Ca2+ to excised inside-out patches.


2020 ◽  
Vol 109 (3) ◽  
pp. 688-694 ◽  
Author(s):  
Mario Gaudino ◽  
Umberto Benedetto ◽  
Stephen E. Fremes ◽  
David L. Hare ◽  
Philip Hayward ◽  
...  

2006 ◽  
Vol 82 (1) ◽  
pp. 44-50 ◽  
Author(s):  
Davide Di Lazzaro ◽  
Temistocle Ragni ◽  
Gino Di Manici ◽  
Giuliana Bardelli ◽  
Uberto Da Col ◽  
...  

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