NAD(P)H Fluorescence Imaging of Postsynaptic Neuronal Activation in Murine Hippocampal Slices

作者：C. William Shuttleworth, Angela M. Brennan, John A. Connor · 发表于：Journal of Neuroscience · 年份：2003 · DOI：10.1523/jneurosci.23-08-03196.2003 · 被引用次数：155 · 研究领域：Neuroscience and Neuropharmacology Research、Neural dynamics and brain function、Photoreceptor and optogenetics research

We examined mechanisms contributing to stimulus-evoked changes in NAD(P)H fluorescence as a marker of neuronal activation in area CA1 of murine hippocampal slices. Three types of stimuli (electrical, glutamate iontophoresis, bath-applied kainate) produced biphasic fluorescence changes composed of an initial transient decrease ("initial component," 1-3%), followed by a longer-lasting transient increase ("overshoot," 3-8%). These responses were matched by inverted biphasic flavin adenine dinucleotide (FAD) fluorescence transients, suggesting that these transients reflect mitochondrial function rather than optical artifacts. Both components of NAD(P)H transients were abolished by ionotropic glutamate receptor block, implicating postsynaptic neuronal activation as the primary event involved in generating the signals, and not presynaptic activity or reuptake of synaptically released glutamate. Spatial analysis of the evoked signals indicated that the peak of each component could arise in different locations in the slice, suggesting that there is not always obligatory coupling between the two components. The initial NAD(P)H response showed a strong temporal correspondence to intracellular Ca+ increases and mitochondrial depolarization. However, despite the fact that removal of extracellular Ca2+ abolished neuronal cytosolic Ca2+ transients to exogenous glutamate or kainate, this procedure did not reduce slice NAD(P)H responses evoked by either of these agonists, implying that mecha...