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Ion trapping with fast-response ion-selective microelectrodes enhances detection of extracellular ion channel gradients

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dc.contributor.author Messerli, Mark A.
dc.contributor.author Collis, Leon P.
dc.contributor.author Smith, Peter J. S.
dc.date.accessioned 2009-04-23T15:41:32Z
dc.date.available 2009-04-23T15:41:32Z
dc.date.issued 2008-11
dc.identifier.uri http://hdl.handle.net/1912/2804
dc.description Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Biophysical Journal 96 (2009): 1597-1605, doi:10.1016/j.bpj.2008.11.025. en
dc.description.abstract Previously, functional mapping of channels has been achieved by measuring the passage of net charge and of specific ions with electrophysiological and intracellular fluorescence imaging techniques. However, functional mapping of ion channels using extracellular ion-selective microelectrodes has distinct advantages over the former methods. We have developed this method through measurement of extracellular K+ gradients caused by efflux through Ca2+-activated K+ channels expressed in Chinese hamster ovary cells. We report that electrodes constructed with short columns of a mechanically stable K+-selective liquid membrane respond quickly and measure changes in local [K+] consistent with a diffusion model. When used in close proximity to the plasma membrane (<4 μm), the ISMs pose a barrier to simple diffusion, creating an ion trap. The ion trap amplifies the local change in [K+] without dramatically changing the rise or fall time of the [K+] profile. Measurement of extracellular K+ gradients from activated rSlo channels shows that rapid events, 10–55 ms, can be characterized. This method provides a noninvasive means for functional mapping of channel location and density as well as for characterizing the properties of ion channels in the plasma membrane. en
dc.description.sponsorship This research was primarily funded by NIH:NCRR grant P41 RR001395 to PJSS. en
dc.format.mimetype application/pdf
dc.language.iso en_US en
dc.relation.uri http://dx.doi.org/10.1016/j.bpj.2008.11.025
dc.subject Noninvasive ion-selective microelectrode en
dc.subject rSlo en
dc.subject Single channel detection en
dc.title Ion trapping with fast-response ion-selective microelectrodes enhances detection of extracellular ion channel gradients en
dc.type Preprint en


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