Hippocampal GABA transporter distribution in patients with temporal lobe epilepsy and hippocampal sclerosis

J Chem Neuroanat. 2015 Oct:68:39-44. doi: 10.1016/j.jchemneu.2015.07.004. Epub 2015 Jul 23.


Purpose: To determine hippocampal expression of neuronal GABA-transporter (GAT-1) and glial GABA-transporter (GAT-3) in patients with temporal lobe epilepsy (TLE) and hippocampal sclerosis (HS).

Methods: Hippocampal sections were immunohistochemically stained for GABA-transporter 1 and GABA-transporter-3, followed by quantification of the immunoreactivity in the hilus by optical density measurements. GABA-transporter 3 positive hilar cells were counted and GABA-transporter protein expression in sections that included all hippocampal subfields was quantified by Western blot.

Results: The hilar GABA-transporter 1 expression of patients with severe hippocampal sclerosis was about 7% lower compared to that in the mild hippocampal sclerosis/control group (p<0.001). The hilar GABA-transporter 3 expression was about 5% lower in the severe hippocampal sclerosis group than in the mild hippocampal sclerosis/control group (non-significant). Also, severe hippocampal sclerosis samples contained 34% less (non-significant) GABA-transporter 3 positive cells compared to that of controls. Protein expression as assessed by Western blot showed that GABA-transporter 1 was equally expressed in mild and severe hippocampal sclerosis samples, whereas GABA-transporter 3 was reduced by about 62% in severe hippocampal sclerosis samples (p<0.0001).

Conclusion: These data confirm that GABA-transporter expression is spatially and isoform-specific reduced and GABA-transporter 3 positive cell numbers are unchanged in hippocampal sclerosis. Implications for the use of GABAergic antiepileptic therapies in hippocampal sclerosis vs non-hippocampal sclerosis patients remain to be studied.

Keywords: GABA-transporter; Hilus; Hippocampal sclerosis; Temporal lobe epilepsy.

MeSH terms

  • Adolescent
  • Adult
  • Autopsy
  • Child
  • Child, Preschool
  • Epilepsy, Temporal Lobe / metabolism*
  • Epilepsy, Temporal Lobe / pathology
  • Epilepsy, Temporal Lobe / surgery
  • Female
  • GABA Plasma Membrane Transport Proteins / metabolism*
  • Hippocampus / metabolism*
  • Hippocampus / pathology
  • Hippocampus / surgery
  • Humans
  • Immunohistochemistry
  • Male
  • Middle Aged
  • Sclerosis
  • Synaptic Transmission
  • Treatment Outcome
  • Young Adult


  • GABA Plasma Membrane Transport Proteins
  • SLC6A1 protein, human
  • SLC6A11 protein, human