GAT-3 Dysfunction Generates Tonic Inhibition in External Globus Pallidus Neurons in Parkinsonian Rodents

Cell Rep. 2018 May 8;23(6):1678-1690. doi: 10.1016/j.celrep.2018.04.014.


The external globus pallidus (GP) is a key GABAergic hub in the basal ganglia (BG) circuitry, a neuronal network involved in motor control. In Parkinson's disease (PD), the rate and pattern of activity of GP neurons are profoundly altered and contribute to the motor symptoms of the disease. In rodent models of PD, the striato-pallidal pathway is hyperactive, and extracellular GABA concentrations are abnormally elevated in the GP, supporting the hypothesis of an alteration of neuronal and/or glial clearance of GABA. Here, we discovered the existence of persistent GABAergic tonic inhibition in GP neurons of dopamine-depleted (DD) rodent models. We showed that glial GAT-3 transporters are downregulated while neuronal GAT-1 function remains normal in DD rodents. Finally, we showed that blocking GAT-3 activity in vivo alters the motor coordination of control rodents, suggesting that GABAergic tonic inhibition in the GP contributes to the pathophysiology of PD.

Keywords: GABA transporters; basal ganglia; electrophysiology; extrasynaptic GABA(A) receptors; tonic inhibition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Dopamine / deficiency
  • GABA Plasma Membrane Transport Proteins / metabolism*
  • GABAergic Neurons / drug effects
  • GABAergic Neurons / metabolism
  • Globus Pallidus / drug effects
  • Globus Pallidus / pathology*
  • Globus Pallidus / physiopathology*
  • Mice, Inbred C57BL
  • Motor Activity / drug effects
  • Neural Inhibition* / drug effects
  • Neuroglia / drug effects
  • Neuroglia / metabolism
  • Neurons / drug effects
  • Neurons / metabolism
  • Neurons / pathology*
  • Parkinson Disease / physiopathology*
  • Rats, Sprague-Dawley
  • Receptors, Dopamine / metabolism
  • Receptors, GABA / metabolism
  • Synapses / drug effects
  • Synapses / metabolism
  • gamma-Aminobutyric Acid / pharmacology


  • GABA Plasma Membrane Transport Proteins
  • Receptors, Dopamine
  • Receptors, GABA
  • Slc6a11 protein, rat
  • Slc6a13 protein, mouse
  • gamma-Aminobutyric Acid
  • Dopamine