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Measuring extracellular ion gradients from single channels with ion-selective microelectrodes

Measuring extracellular ion gradients from single channels with ion-selective microelectrodes
Measuring extracellular ion gradients from single channels with ion-selective microelectrodes
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
0006-3495
L52-L54
Messerli, Mark A.
94a8bd34-95d7-4a52-b4d8-1ccded0e8fe7
Corson, Erica D.
fad3acf2-3467-4a81-af78-df69cb148718
Smith, Peter J.S.
003de469-9420-4f12-8f0e-8e8d76d28d6c
Messerli, Mark A.
94a8bd34-95d7-4a52-b4d8-1ccded0e8fe7
Corson, Erica D.
fad3acf2-3467-4a81-af78-df69cb148718
Smith, Peter J.S.
003de469-9420-4f12-8f0e-8e8d76d28d6c

Messerli, Mark A., Corson, Erica D. and Smith, Peter J.S. (2007) Measuring extracellular ion gradients from single channels with ion-selective microelectrodes. Biophysical Journal, 92 (7), L52-L54. (doi:10.1529/biophysj.106.102947). (PMID:17259274)

Record type: Article

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

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Published date: April 2007
Organisations: University of Southampton

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Local EPrints ID: 188799
URI: http://eprints.soton.ac.uk/id/eprint/188799
ISSN: 0006-3495
PURE UUID: 94279841-f562-4422-9f13-980b2636020d
ORCID for Peter J.S. Smith: ORCID iD orcid.org/0000-0003-4400-6853

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Date deposited: 01 Jun 2011 10:40
Last modified: 26 Nov 2019 01:39

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Author: Mark A. Messerli
Author: Erica D. Corson

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