Document Detail

Ammonia downregulates GLAST mRNA glutamate transporter in rat astrocyte cultures.
MedLine Citation:
PMID:  10612626     Owner:  NLM     Status:  MEDLINE    
Abnormalities in glutamate metabolism and glutamatergic neurotransmission appear to play an important role in the pathogenesis of hyperammonemia and hepatic encephalopathy. Previous studies from our laboratory have shown that treatment of cultured astrocytes with NH4Cl result in decreased glutamate uptake. To extend these observations, we performed a Northern blot analysis of the astroglial glutamate transporter GLAST (EAAT1) in NH4Cl-treated primary rat astrocyte cultures. Following treatment with 2, 5, 10 mM NH4Cl for 3 days, cortical astrocytes showed a 22, 29, 36% decrease in GLAST mRNA, respectively. Striatal astrocytes showed 25, 51, 50% reduction, while cerebellar cultures showed decrements of 18, 37, 38%. Similar decreases in GLAST mRNA were also observed after 1 day of ammonia treatment. These findings, together with recent reports on the reduction of the GLT-1 glutamate transporter in in vivo models of acute liver failure and hyperammonemia, strongly suggest that an abnormality in astroglial glutamate uptake constitutes a critical aspect in the pathogenesis of hepatic encephalopathy and other hyperammonemic conditions.
B G Zhou; M D Norenberg
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Neuroscience letters     Volume:  276     ISSN:  0304-3940     ISO Abbreviation:  Neurosci. Lett.     Publication Date:  1999 Dec 
Date Detail:
Created Date:  2000-01-05     Completed Date:  2000-01-05     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7600130     Medline TA:  Neurosci Lett     Country:  IRELAND    
Other Details:
Languages:  eng     Pagination:  145-8     Citation Subset:  IM    
Laboratory of Neuropathology, Veterans Administration Medical Center, University of Miami School of Medicine, Miami, FL 33101, USA.
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MeSH Terms
ATP-Binding Cassette Transporters / genetics*
Amino Acid Transport System X-AG
Ammonia / pharmacology*
Astrocytes / drug effects,  metabolism*
Blotting, Northern
Cells, Cultured
Cerebellum / cytology,  metabolism
Cerebral Cortex / cytology,  metabolism
Corpus Striatum / cytology,  metabolism
RNA, Messenger / antagonists & inhibitors,  metabolism*
Grant Support
Reg. No./Substance:
0/ATP-Binding Cassette Transporters; 0/Amino Acid Transport System X-AG; 0/RNA, Messenger; 7664-41-7/Ammonia

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