Glutamine synthetase activity and glutamate uptake in hippocampus and frontal cortex in portal hypertensive rats

ACOSTA, GABRIELA B; FERNÁNDEZ, MARÍA A; ROSELLO, DIEGO M; TOMARO, MARÍA L.; BALESTRASSE, KARINA B.; LEMBERG, ABRAHAM

World Journal of Gastroenterology

The WJG Press and Baishideng.

Año: 2009 vol. 15 p. 2893 - 2899

1007-9327

AIM: To study glutamine synthetase (GS) activity and glutamate uptake in the hippocampus and frontal cortex (FC) from rats with prehepatic portal vein hypertension.METHODS: Male Wistar rats were divided into shamoperated group and a portal hypertension (PH) group with a regulated stricture of the portal vein. Animals were sacrificed by decapitation 14 d after portal vein stricture. GS activity was determined in the hippocampus and FC. Specific uptake of radiolabeled L-glutamate was studied using synaptosome-enriched fractions that werefreshly prepared from both brain areas.RESULTS: We observed that the activity of GS increased in the hippocampus of PH rats, as compared to control animals, and decreased in the FC. A significant decrease in glutamate ptake was found in both brain areas, and was more marked in the hippocampus. The decrease  glutamate uptake might have been caused by a deficient transport function, significantly and persistent increase in this excitatory neurotransmitter activity.CONCLUSION: The presence of moderate ammonia blood levels may add to the toxicity of  excitotoxic glutamate in the brain, which causes alterations in brain function. Portal vein stricture that causes portal hypertension modifies the normal function in some brain regions.