scholarly journals M-Type K+ Channel Openers: In Vivo Neuroprotective Role During Cerebrovascular Stroke

2012 ◽  
Vol 102 (3) ◽  
pp. 132a
Author(s):  
Sonya M. Bierbower ◽  
Frank S. Choveau ◽  
Mark S. Shapiro
Keyword(s):  
K Channel ◽  
Type K ◽  
Cerebrovascular Stroke

M‐type K+ Channel Openers: In vivo Neuroprotective Role during Cerebrovascular Stroke

2013 ◽  
Vol 27 (S1) ◽  
Author(s):  
Sonya M Bierbower ◽  
Frank Choveau ◽  
Mark S. Shapiro
Keyword(s):  
K Channel ◽  
Type K ◽  
Cerebrovascular Stroke

scholarly journals Low molecular weight poly(A)+ mRNA species encode factors that modulate gating of a non-Shaker A-type K+ channel.

1993 ◽  
Vol 102 (4) ◽  
pp. 713-728 ◽  
Author(s):  
L D Chabala ◽  
N Bakry ◽  
M Covarrubias
Keyword(s):  
Molecular Weight ◽  
Xenopus Oocytes ◽  
Membrane Potentials ◽  
K Channel ◽  
Low Molecular Weight ◽  
K Channels ◽  
Fourfold Increase ◽  
Mrna Species ◽  
Type K

Voltage-dependent K+ channels control repolarization of action potentials and help establish firing patterns in nerve cells. To determine the nature and role of molecular components that modulate K+ channel function in vivo, we coinjected Xenopus oocytes with cRNA encoding a cloned subthreshold A-type K+ channel (mShal1, also referred to as mKv4.1) and a low molecular weight (LMW) fraction (2-4 kb) of poly(A)+ mRNA (both from rodent brain). Coinjected oocytes exhibited a significant (fourfold) increase in the surface expression of mShal1 K+ channels with no change in the open-channel conductance. Coexpression also modified the gating kinetics of mShal1 current in several respects. Macroscopic inactivation of whole oocyte currents was fitted with the sum of two exponential components. Both fast and slow time constants of inactivation were accelerated at all membrane potentials in coinjected oocytes (tau f = 47.2 ms vs 56.5 ms at 0 mV and tau s = 157 ms vs 225 ms at 0 mV), and the corresponding ratios of amplitude terms were shifted toward domination by the fast component (Af/As = 2.71 vs 1.17 at 0 mV). Macroscopic activation was characterized in terms of the time-to-peak current, and it was found to be more rapid at all membrane potentials in coinjected oocytes (9.9 ms vs 13.5 ms at 0 mV). Coexpression also leads to more rapid recovery from inactivation (approximately 2.4-fold faster at -100 mV). The coexpressed K+ currents in oocytes resemble currents expressed in mouse fibroblasts (NIH3T3) transfected only with mShal1 cDNA. These results indicate that mammalian regulatory subunits or enzymes encoded by LMW mRNA species, which are apparently missing or expressed at low levels in Xenopus oocytes, may modulate gating in some native subthreshold A-type K+ channels.

scholarly journals M-Type K+ Channels: IN Vivo Neuroprotective Role During Cerebrovascular Stroke

2011 ◽  
Vol 100 (3) ◽  
pp. 100a
Author(s):  
Sonya M. Bierbower ◽  
Lora T. Watts ◽  
Mark S. Shapiro
Keyword(s):  
K Channels ◽  
Type K ◽  
Cerebrovascular Stroke

Cation transport and volume regulation in sickle red blood cells

1993 ◽  
Vol 264 (2) ◽  
pp. C251-C270 ◽  
Author(s):  
C. H. Joiner
Keyword(s):  
Sickle Cell ◽  
Vascular Occlusion ◽  
Cell Swelling ◽  
K Channel ◽  
Transport Pathways ◽  
Root Cause ◽  
Sickle Cells ◽  
Cellular Dehydration ◽  
Mechanism Of Dehydration

Cellular dehydration is one of several pathological features of the sickle cell. Cation depletion is quite severe in certain populations of sickle cells and contributes to the rheological dysfunction that is the root cause of vascular occlusion in this disease. The mechanism of dehydration of sickle cells in vivo has not been ascertained, but three transport pathways may play important roles in this process. These include the deoxygenation-induced pathway that permits passive K+ loss and entry of Na+ and Ca2+; the K(+)-Cl- cotransport pathway, activated by acidification or cell swelling; and the Ca(2+)-activated K+ channel, or Gardos pathway, presumably activated by deoxygenation-induced Ca2+ influx. Recent evidence suggests that these pathways may interact in vivo. Heterogeneity exists among sickle cells as to the rate at which they become dense, suggesting that other factors may affect the activity or interactions of these pathways. Understanding the mechanism of dehydration of sickle cells may provide opportunities for pharmacological manipulation of cell volume to mitigate some of the symptoms of sickle cell disease.

scholarly journals In Vivo Measurements Of a Ca2+- And Voltage-Activated K+ Channel Intramolecular Distances Using Genetically Encoded Reporters

2009 ◽  
Vol 96 (3) ◽  
pp. 474a
Author(s):  
Cristian A. Zaelzer ◽  
Walter Sandtner ◽  
Clark Hyde ◽  
Ramon Latorre ◽  
Francisco Bezanilla
Keyword(s):  
K Channel ◽  
In Vivo Measurements

scholarly journals Kv5, Kv6, Kv8, and Kv9 subunits: No simple silent bystanders

2016 ◽  
Vol 147 (2) ◽  
pp. 105-125 ◽  
Author(s):  
Elke Bocksteins
Keyword(s):  
Therapeutic Strategies ◽  
K Channel ◽  
Biophysical Properties ◽  
Tissue Specific ◽  
Voltage Gated ◽  
Novel Treatments ◽  
Novel Therapeutic Strategies ◽  
Different Tissues ◽  
Novel Therapeutic

Members of the electrically silent voltage-gated K+ (Kv) subfamilies (Kv5, Kv6, Kv8, and Kv9, collectively identified as electrically silent voltage-gated K+ channel [KvS] subunits) do not form functional homotetrameric channels but assemble with Kv2 subunits into heterotetrameric Kv2/KvS channels with unique biophysical properties. Unlike the ubiquitously expressed Kv2 subunits, KvS subunits show a more restricted expression. This raises the possibility that Kv2/KvS heterotetramers have tissue-specific functions, making them potential targets for the development of novel therapeutic strategies. Here, I provide an overview of the expression of KvS subunits in different tissues and discuss their proposed role in various physiological and pathophysiological processes. This overview demonstrates the importance of KvS subunits and Kv2/KvS heterotetramers in vivo and the importance of considering KvS subunits and Kv2/KvS heterotetramers in the development of novel treatments.

scholarly journals PSD95 scaffolding of the Shaker ‐type K + channel enables PKA‐dependent phosphorylation and vasodilation of cerebral arteries (1057.7)

2014 ◽  
Vol 28 (S1) ◽  
Author(s):  
Christopher Moore ◽  
Piper Nelson ◽  
Nikhil Parelkar ◽  
Hillary Hanvey ◽  
Nancy Rusch ◽  
...  
Keyword(s):  
Cerebral Arteries ◽  
K Channel ◽  
Type K

scholarly journals Genetic dissection reveals unexpected influence of β subunits on KCNQ1 K + channel polarized trafficking in vivo

2010 ◽  
Vol 25 (2) ◽  
pp. 727-736 ◽  
Author(s):  
Torsten K. Roepke ◽  
Elizabeth C. King ◽  
Kerry Purtell ◽  
Vikram A. Kanda ◽  
Daniel J. Lerner ◽  
...  
Keyword(s):  
K Channel ◽  
Genetic Dissection ◽  
Polarized Trafficking

Dynamic regulation of the voltage-gated Kv2.1 potassium channel by multisite phosphorylation

2007 ◽  
Vol 35 (5) ◽  
pp. 1064-1068 ◽  
Author(s):  
D.P. Mohapatra ◽  
K.-S. Park ◽  
J.S. Trimmer
Keyword(s):  
Neuronal Excitability ◽  
Critical Role ◽  
Functional Characterization ◽  
K Channel ◽  
Delayed Rectifier ◽  
Dynamic Regulation ◽  
Voltage Gated ◽  
Voltage Dependent ◽  
Specific Regulation

Voltage-gated K+ channels are key regulators of neuronal excitability. The Kv2.1 voltage-gated K+ channel is the major delayed rectifier K+ channel expressed in most central neurons, where it exists as a highly phosphorylated protein. Kv2.1 plays a critical role in homoeostatic regulation of intrinsic neuronal excitability through its activity- and calcineurin-dependent dephosphorylation. Here, we review studies leading to the identification and functional characterization of in vivo Kv2.1 phosphorylation sites, a subset of which contribute to graded modulation of voltage-dependent gating. These findings show that distinct developmental-, cell- and state-specific regulation of phosphorylation at specific sites confers a diversity of functions on Kv2.1 that is critical to its role as a regulator of intrinsic neuronal excitability.

Sign in / Sign up

Export Citation Format

Share Document