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Nat Commun. 2016 Apr 7;7:11251. doi: 10.1038/ncomms11251.

Real-time imaging of glutamate clearance reveals normal striatal uptake in Huntington disease mouse models.

Author information

1
Brain Research Centre and Djavad Mowafaghian Centre for Brain Health, Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 1Z3.

Abstract

It has become well accepted that Huntington disease (HD) is associated with impaired glutamate uptake, resulting in a prolonged time-course of extracellular glutamate that contributes to excitotoxicity. However, the data supporting this view come largely from work in synaptosomes, which may overrepresent nerve-terminal uptake over astrocytic uptake. Here, we quantify real-time glutamate dynamics in HD mouse models by high-speed imaging of an intensity-based glutamate-sensing fluorescent reporter (iGluSnFR) and electrophysiological recordings of synaptically activated transporter currents in astrocytes. These techniques reveal a disconnect between the results obtained in synaptosomes and those in situ. Exogenous glutamate uptake is impaired in synaptosomes, whereas real-time measures of glutamate clearance in the HD striatum are normal or even accelerated, particularly in the aggressive R6/2 model. Our results highlight the importance of quantifying glutamate dynamics under endogenous release conditions, and suggest that the widely cited uptake impairment in HD does not contribute to pathogenesis.

PMID:
27052848
PMCID:
PMC4829692
DOI:
10.1038/ncomms11251
[Indexed for MEDLINE]
Free PMC Article

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