A Novel Optical Intracellular Imaging Approach for Potassium Dynamics in Astrocytes
| Autor: | Jean-Yves Chatton, Theresa S. Rimmele |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Pigments
Macroglial Cells Potassium lcsh:Medicine Mice 0302 clinical medicine Animal Cells lcsh:Science Dyes Cells Cultured 0303 health sciences Multidisciplinary Optical Imaging Glutamate receptor Gap junction Cations Monovalent Fluorescence medicine.anatomical_structure Physical Sciences Cellular Types Intracellular Astrocyte Research Article Imaging Techniques Materials Science Biophysics chemistry.chemical_element Glutamic Acid Glial Cells Neuroimaging Research and Analysis Methods 03 medical and health sciences Fluorescence Imaging medicine Extracellular Animals Materials by Attribute 030304 developmental biology Fluorescent Dyes Ion Transport lcsh:R Biology and Life Sciences Glutamic acid Cell Biology Mice Inbred C57BL Spectrometry Fluorescence chemistry Astrocytes lcsh:Q 030217 neurology & neurosurgery Neuroscience |
| Zdroj: | PLoS ONE Plos One, vol. 9, no. 10, pp. e109243 PLoS ONE, Vol 9, Iss 10, p e109243 (2014) PLoS One |
| ISSN: | 1932-6203 |
| Popis: | Astrocytes fulfill a central role in regulating K+ and glutamate, both released by neurons into the extracellular space during activity. Glial glutamate uptake is a secondary active process that involves the influx of three Na+ ions and one proton and the efflux of one K+ ion. Thus, intracellular K+ concentration ([K+]i) is potentially influenced both by extracellular K+ concentration ([K+]o) fluctuations and glutamate transport in astrocytes. We evaluated the impact of these K+ ion movements on [K+]i in primary mouse astrocytes by microspectrofluorimetry. We established a new noninvasive and reliable approach to monitor and quantify [K+]i using the recently developed K+ sensitive fluorescent indicator Asante Potassium Green-1 (APG-1). An in situ calibration procedure enabled us to estimate the resting [K+]i at 133±1 mM. We first investigated the dependency of [K+]i levels on [K+]o. We found that [K+]i followed [K+]o changes nearly proportionally in the range 3-10 mM, which is consistent with previously reported microelectrode measurements of intracellular K+ concentration changes in astrocytes. We then found that glutamate superfusion caused a reversible drop of [K+]i that depended on the glutamate concentration with an apparent EC50 of 11.1±1.4 µM, corresponding to the affinity of astrocyte glutamate transporters. The amplitude of the [K+]i drop was found to be 2.3±0.1 mM for 200 µM glutamate applications. Overall, this study shows that the fluorescent K+ indicator APG-1 is a powerful new tool for addressing important questions regarding fine [K+]i regulation with excellent spatial resolution. |
| Databáze: | OpenAIRE |
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