Enhanced GABAergic Inhibition of Cholinergic Interneurons in the zQ175+/− Mouse Model of Huntington's Disease

Sean Austin O. Lim, D. James Surmeier*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder that initially manifests itself in the striatum. How intrastriatal circuitry is altered by the disease is poorly understood. To help fill this gap, the circuitry linking spiny projection neurons (SPNs) to cholinergic interneurons (ChIs) was examined using electrophysiological and optogenetic approaches in ex vivo brain slices from wildtype mice and zQ175+/− models of HD. These studies revealed a severalfold enhancement of GABAergic inhibition of ChIs mediated by collaterals of indirect pathway SPNs (iSPNs), but not direct pathway SPNs (dSPNs). This cell-specific alteration in synaptic transmission appeared in parallel with the emergence of motor symptoms in the zQ175+/− model. The adaptation had a presynaptic locus, as it was accompanied by a reduction in paired-pulse ratio but not in the postsynaptic response to GABA. The alterations in striatal GABAergic signaling disrupted spontaneous ChI activity, potentially contributing to the network dysfunction underlying the hyperkinetic phase of HD.

Original languageEnglish (US)
Article number626412
JournalFrontiers in Systems Neuroscience
Volume14
DOIs
StatePublished - Jan 20 2021

Keywords

  • GABA uncaging
  • channelrhodopsin (ChR2)
  • dorsal striatum
  • giant aspiny interneurons
  • medium spiny neuron
  • pacemaker activity
  • paired-pulse ratio
  • striatal interneuron

ASJC Scopus subject areas

  • Neuroscience (miscellaneous)
  • Developmental Neuroscience
  • Cognitive Neuroscience
  • Cellular and Molecular Neuroscience

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