L-glutamate and gamma-aminobutyric acid uptake in synaptosomes from the cerebral cortex of dogs with congenital chronic hepatic encephalopathy.
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.
Maddison
J E
JE
Department of Pharmacology, University of Sydney, NSW, Australia.
Watson
W E
WE
Johnston
G A
GA
D000641:Ammonia / Q000097:blood; D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism* / Q000648:ultrastructure; D002908:Chronic Disease; D004285:Dogs; D018698:Glutamic Acid / Q000378:metabolism*; D006501:Hepatic Encephalopathy / Q000151:congenital / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D013574:Synaptosomes / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D000641:Ammonia