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| Format: | Artículo científico |
| Language: | en |
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Academia Brasileira de Ciências
2001
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| Online Access: | https://www.redalyc.org/articulo.oa?id=32773305 |
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| _version_ | 1866811646096179200 |
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| author | Otto W. Witte |
| author_facet | Otto W. Witte |
| contents | Cell swling and ion redistribution assessed with intrinsic optical signal Otto W. Witte Heike Niermann Knut Holthoff Multidisciplinaria (Ciencias Naturales y Exactas) brain slice spatial buffer spreading depression intrinsic optic signals extracellular space volume Cell volume changes are associated with alterations of intrinsic optical signals (IOS). In submerged brainslices in vitro, afferent stimulation induces an increase in light transmission. As assessed by measurementof the largely membrane impermeant ion tetramethylammonium (TMA) in the extracellular space, theseIOS correlate with the extent and time course of the change of the extracellular space size. They have ahigh signal to noise ratio and allow measurements of IOS changes in the order of a few percent. Underconditions of reduced net KCl uptake (low Cl solution) a directed spatial buffer mechanism (K syphoning)can be demonstrated in the neocortex with widening of the extracellular space in superficial layers associatedwith a reduced light transmission and an increase of extracellular K concentration. The nature of the IOSunder pathophysiological conditions is less clear. Spreading depressions first cause an increase of lighttransmission, then a decrease. Such a decrease has also been observed following application of NMDAwhere it was associated with structural damage. Pharmacological analyses suggest that under physiologicalconditions changes of extracellular space size are mainly caused by astrocytic volume changes while withstrong stimuli and under pathophysiological conditions also neuronal swelling occurs. With reflected lightusually signals opposite to those observed with transmitted light are seen. Recording of IOS from interfaceslices gives very complex signals since under these conditions an increase of light transmission has beenreported to be superimposed by a decrease of the signal due to mechanical lensing effects of the slice surface.Depending on the method of measurement and the exact conditions, several mechanisms may contribute toIOS. Under well defined conditions IOS are a useful supplementary tool to monitor changes of extracellularvolume both in space and time. 2001 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32773305 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.3 Vol.73 |
| format | Artículo científico |
| id | redalyc_32773305 |
| language | en |
| publishDate | 2001 |
| publisher | Academia Brasileira de Ciências |
| spellingShingle | Cell swling and ion redistribution assessed with intrinsic optical signal Otto W. Witte Multidisciplinaria (Ciencias Naturales y Exactas) brain slice spatial buffer spreading depression intrinsic optic signals extracellular space volume Cell swling and ion redistribution assessed with intrinsic optical signal Otto W. Witte Heike Niermann Knut Holthoff Multidisciplinaria (Ciencias Naturales y Exactas) brain slice spatial buffer spreading depression intrinsic optic signals extracellular space volume Cell volume changes are associated with alterations of intrinsic optical signals (IOS). In submerged brainslices in vitro, afferent stimulation induces an increase in light transmission. As assessed by measurementof the largely membrane impermeant ion tetramethylammonium (TMA) in the extracellular space, theseIOS correlate with the extent and time course of the change of the extracellular space size. They have ahigh signal to noise ratio and allow measurements of IOS changes in the order of a few percent. Underconditions of reduced net KCl uptake (low Cl solution) a directed spatial buffer mechanism (K syphoning)can be demonstrated in the neocortex with widening of the extracellular space in superficial layers associatedwith a reduced light transmission and an increase of extracellular K concentration. The nature of the IOSunder pathophysiological conditions is less clear. Spreading depressions first cause an increase of lighttransmission, then a decrease. Such a decrease has also been observed following application of NMDAwhere it was associated with structural damage. Pharmacological analyses suggest that under physiologicalconditions changes of extracellular space size are mainly caused by astrocytic volume changes while withstrong stimuli and under pathophysiological conditions also neuronal swelling occurs. With reflected lightusually signals opposite to those observed with transmitted light are seen. Recording of IOS from interfaceslices gives very complex signals since under these conditions an increase of light transmission has beenreported to be superimposed by a decrease of the signal due to mechanical lensing effects of the slice surface.Depending on the method of measurement and the exact conditions, several mechanisms may contribute toIOS. Under well defined conditions IOS are a useful supplementary tool to monitor changes of extracellularvolume both in space and time. 2001 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32773305 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.3 Vol.73 |
| title | Cell swling and ion redistribution assessed with intrinsic optical signal |
| topic | Multidisciplinaria (Ciencias Naturales y Exactas) brain slice spatial buffer spreading depression intrinsic optic signals extracellular space volume |
| url | https://www.redalyc.org/articulo.oa?id=32773305 |