L-glutamate and gamma-aminobutyric acid uptake in synaptosomes from the cerebral cortex of dogs with congenital chronic hepatic encephalopathy

Metab Brain Dis. 1995 Jun;10(2):135-41. doi: 10.1007/BF01991861.


High affinity [3H]gamma-aminobutyric acid (GABA) and [3H]L-glutamate uptake were determined in synaptosomes prepared from the cerebral cortex of dogs with congenital hepatic encephalopathy and control dogs. The Km value for GABA uptake was increased by 35% but there was a concomitant 34% increase in Vmax suggesting that GABA uptake capacity was not changed in HE dogs. In contrast, mean Vmax for glutamate uptake in HE dogs was 85% greater than mean Vmax in control dogs; mean Km was increased by 25% in HE dogs. Therefore, overall synaptosomal high affinity glutamate uptake capacity was increased in HE dogs compared to controls.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ammonia / blood
  • Animals
  • Cerebral Cortex / metabolism*
  • Cerebral Cortex / ultrastructure
  • Chronic Disease
  • Dogs
  • Glutamic Acid / metabolism*
  • Hepatic Encephalopathy / congenital
  • Hepatic Encephalopathy / metabolism*
  • In Vitro Techniques
  • Kinetics
  • Synaptosomes / metabolism*
  • gamma-Aminobutyric Acid / metabolism*


  • Glutamic Acid
  • gamma-Aminobutyric Acid
  • Ammonia