Monitoring Neural Activity and [Ca<superscript>2+</superscript>] with Genetically Encoded Ca<superscript>2+</superscript> Indicators.
In: Journal of Neuroscience, Jg. 24 (2004-10-27), Heft 43, S. 9572-9579
Online
academicJournal
Zugriff:
Genetically encoded Ca2+ indicators (GECIs) based on fluorescent proteins (XFPs) and Ca2+-binding proteins [like calmodulin (CAM)] have great potential for the study of subcellular Ca2+ signaling and for monitoring activity in populations of neurons. However, interpreting GECI fluorescence in terms of neural activity and cytoplasmic-free Ca2+ concentration ([Ca2+]) is complicated by the nonlinear interactions between Ca2+ binding and GECI fluorescence. We have characterized GECIs in pyramidal neurons in cultured hippocampal brain slices, focusing on indicators based on circularly permuted XFPs [GCaMP (Nakai et al., 2001), Camgaroo2 (Griesbeck et al., 2001 ), and Inverse Pericam (Nagai et al., 2001)]. Measurements of fluorescence changes evoked by trains of action potentials revealed that GECIs have little sensitivity at low action potential frequencies compared with synthetic [Ca2+] indicators with similar affinities for Ca2+. The sensitivity of GECIs improved for high-frequency trains of action potentials, indicating that GECIs are supralinear indicators of neural activity. Simultaneous measurement of GECI fluorescence and [Ca2+] revealed supralinear relationships. We compared GECI fluorescence saturation with CaM Ca2+-dependent structural transitions. Our data suggest that GCaMP and Camgaroo2 report CaM structural transitions in the presence and absence of CaM-binding peptide, respectively. [ABSTRACT FROM AUTHOR]
Titel: |
Monitoring Neural Activity and [Ca<superscript>2+</superscript>] with Genetically Encoded Ca<superscript>2+</superscript> Indicators.
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Autor/in / Beteiligte Person: | Pologruto, Thomas A. ; Yasuda, Ryohei ; Svoboda, Karel |
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Zeitschrift: | Journal of Neuroscience, Jg. 24 (2004-10-27), Heft 43, S. 9572-9579 |
Veröffentlichung: | 2004 |
Medientyp: | academicJournal |
ISSN: | 0270-6474 (print) |
DOI: | 10.1523/JNEUROSCI.2854-04.2004 |
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