Perinatal hypoxia: different effects of the inhibitors of GABA transporters GAT1 and GAT3 on the initial velocity of [3H]GABA uptake by cortical, hippocampal, and thalamic nerve terminals

Croat Med J. 2014 Jun 1;55(3):250-8. doi: 10.3325/cmj.2014.55.250.

Abstract

AIM. To analyze the effects of highly selective blocker GAT1, NO-711, and substrate inhibitor GAT3, β-alanine, on the initial velocity of [(3)H]GABA uptake by cortical, hippocampal, and thalamic nerve terminals (synaptosomes) after perinatal hypoxia. METHODS. Animals were divided into two groups: control (n=17) and hypoxia (n=12). Rats in the hypoxia group underwent hypoxia and seizures (airtight chamber, 4% O2 and 96% N2) at the age of 10-12 postnatal days and were used in the experiments 8-9 weeks after hypoxia. RESULTS. In cortical synaptosomes, the effects of NO-711 (30 μΜ) and β-alanine (100 μΜ) on [(3)H]GABA uptake were similar in control and hypoxia groups. In hippocampal synaptosomes, NO-711 inhibited 84.3% of the initial velocity of [(3)H]GABA uptake in normal conditions and 80.1% after hypoxia, whereas the effect of β-alanine was increased after hypoxia from 14.4% to 22.1%. In thalamic synaptosomes, the effect of NO-711 was decreased by 79.6% in controls and by 70.9% in hypoxia group, whereas the effect of β-alanine was increased after hypoxia from 20.2% to 30.2%. CONCLUSIONS. The effectiveness of β-alanine to influence GABA uptake was increased in hippocampal and thalamic nerve terminals as a result of perinatal hypoxia and the effectiveness of NO-711 in thalamic nerve terminals was decreased. These results may indicate changes in the ratio of active GAT1/GAT3 expressed in the plasma membrane of nerve terminals after perinatal hypoxia. We showed a possibility to modulate non-GAT1 GABA transporter activity in different brain regions by exogenous and endogenous β-alanine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Cerebral Cortex / drug effects
  • Cerebral Cortex / metabolism
  • GABA Plasma Membrane Transport Proteins / metabolism*
  • GABA Uptake Inhibitors / pharmacology*
  • Hippocampus / drug effects*
  • Hippocampus / metabolism
  • Hypoxia / metabolism*
  • Male
  • Nipecotic Acids / pharmacology
  • Oximes / pharmacology
  • Rats
  • Rats, Wistar
  • Synaptosomes / drug effects*
  • Synaptosomes / metabolism
  • Thalamus / drug effects*
  • Thalamus / metabolism
  • beta-Alanine / pharmacology
  • gamma-Aminobutyric Acid / metabolism*

Substances

  • GABA Plasma Membrane Transport Proteins
  • GABA Uptake Inhibitors
  • Nipecotic Acids
  • Oximes
  • beta-Alanine
  • NNC 711
  • gamma-Aminobutyric Acid