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Measuring Extracellular Ion Gradients from Single Channels with Ion-Selective Microelectrodes
- Publication Year :
- 2007
- Publisher :
- The Biophysical Society, 2007.
-
Abstract
- Under many different conditions activated plasma membrane ion channels give rise to changes in the extracellular concentration of the permeant ion(s). The magnitude and duration of these changes are dependent on the electrochemical driving force(s) on the permeant ion(s) as well as conductance, open time, and channel density. We have modeled the change in the extracellular [K+] due to efflux through Ca2+-activated K+ channels, mSlo, to determine the range of parameters that would give rise to measurable signals in the surrounding media. Subsequently we have used extracellular, K+-selective microelectrodes to monitor localized changes in [K+]ext due to efflux through mSlo channels expressed in Xenopus oocytes. The rapid changes in [K+] show a close fit with the predicted model when the time response of the ion-selective microelectrode is taken into account, providing proof of the concept. Measurement of the change in extracellular ion concentration with ion-selective microelectrodes provides a noninvasive means for functional mapping of channel location and density, as well as characterizing the properties of ion channels in the plasma membrane.
- Subjects :
- Patch-Clamp Techniques
Biophysical Letters
Analytical chemistry
Biophysics
02 engineering and technology
Sensitivity and Specificity
Ion
03 medical and health sciences
Xenopus laevis
Extracellular
Repolarization
Animals
Patch clamp
skin and connective tissue diseases
Large-Conductance Calcium-Activated Potassium Channel alpha Subunits
Ion channel
Cells, Cultured
030304 developmental biology
Ions
0303 health sciences
Voltage-gated ion channel
Chemistry
Conductance
Extracellular Fluid
021001 nanoscience & nanotechnology
Microelectrode
Oocytes
sense organs
0210 nano-technology
Ion Channel Gating
Microelectrodes
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....b2e3612381b70bbc96571c4689a623f0