Small is fast: Astrocytic glucose and lactate metabolism at cellular resolution
Front. Cell. Neurosci.. 2013-01-01; 7:
DOI: 10.3389/fncel.2013.00027
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Brain tissue is highly dynamic in terms of electrical activity and energy demand.
Relevant energy metabolites have turnover times ranging from milliseconds to
seconds and are rapidly exchanged between cells and within cells. Until recently
these fast metabolic events were inaccessible, because standard isotopic
techniques require use of populations of cells and/or involve integration times
of tens of minutes. Thanks to fluorescent probes and recently available
genetically-encoded optical nanosensors, this Technology Report shows how it is
now possible to monitor the concentration of metabolites in real-time and in
single cells. In combination with ad hoc inhibitor-stop protocols, these probes
have revealed a key role for K(+) in the acute stimulation of astrocytic
glycolysis by synaptic activity. They have also permitted detection of the
Warburg effect in single cancer cells. Genetically-encoded nanosensors currently
exist for glucose, lactate, NADH and ATP, and it is envisaged that other
metabolite nanosensors will soon be available. These optical tools together with
improved expression systems and in vivo imaging, herald an exciting era of
single-cell metabolic analysis.