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dc.contributor.authorMesserli, Mark A.
dc.contributor.authorCollis, Leon P.
dc.contributor.authorSmith, Peter J. S.
dc.date.accessioned2009-04-23T15:41:32Z
dc.date.available2009-04-23T15:41:32Z
dc.date.issued2008-11
dc.identifier.urihttp://hdl.handle.net/1912/2804
dc.descriptionAuthor 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.abstractPreviously, 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.sponsorshipThis research was primarily funded by NIH:NCRR grant P41 RR001395 to PJSS.en
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen
dc.relation.urihttps://doi.org/10.1016/j.bpj.2008.11.025
dc.subjectNoninvasive ion-selective microelectrodeen
dc.subjectrSloen
dc.subjectSingle channel detectionen
dc.titleIon trapping with fast-response ion-selective microelectrodes enhances detection of extracellular ion channel gradientsen
dc.typePreprinten


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