Document Detail


Continuous monitoring of intracerebral glutamate levels in awake monkeys using microdialysis and enzyme fluorometric detection.
MedLine Citation:
PMID:  12814842     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A technique for continuous on-line detection of glutamate using brain microdialysis in awake primates is described. The method is based on an enzymatic assay using fluorescence detection of glutamate. The time resolution of the continuous fluorescent readout compares favorably with that of most published studies, which have used standard high-pressure liquid chromatography detection methods for glutamate. Exposure of the system to other amino acids (GABA, aspartate, glutamine, ascorbate, taurine, valine, alanine, and D-glutamate) revealed that this method is highly specific for L-glutamate. In vitro, the system detects reliably glutamate levels as low as 0.5 micromol/l. In vivo testing in the striatum of Rhesus macaques showed that glutamate levels were enhanced after reverse microdialysis with a glutamate uptake blocker. Stimulation with high potassium increased substantially the levels of glutamate, an effect that was calcium-dependent. Glutamate levels were also increased when the microdialysis solution contained the blocker of voltage-gated potassium channels, 4-aminopyridine. This technique effectively detects short-term changes in glutamate levels evoked by physiologic or pharmacologic manipulations in the primate brain.
Authors:
Adriana Galvan; Yoland Smith; Thomas Wichmann
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:  Journal of neuroscience methods     Volume:  126     ISSN:  0165-0270     ISO Abbreviation:  J. Neurosci. Methods     Publication Date:  2003 Jun 
Date Detail:
Created Date:  2003-06-19     Completed Date:  2003-08-21     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7905558     Medline TA:  J Neurosci Methods     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  175-85     Citation Subset:  IM    
Affiliation:
Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA.
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MeSH Terms
Descriptor/Qualifier:
4-Aminopyridine / pharmacology
Animals
Calcium / metabolism
Electrodes
Fluorescence
Glutamate Dehydrogenase
Glutamic Acid / metabolism*
Macaca mulatta
Male
Microdialysis / instrumentation,  methods*
Monitoring, Physiologic / instrumentation,  methods*
Potassium / pharmacology
Potassium Channel Blockers / pharmacology
Putamen / metabolism*
Sensitivity and Specificity
Synaptic Transmission / drug effects,  physiology
Wakefulness
Grant Support
ID/Acronym/Agency:
NS38399/NS/NINDS NIH HHS; R01-NS42937/NS/NINDS NIH HHS; RR00165/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
0/Potassium Channel Blockers; 504-24-5/4-Aminopyridine; 56-86-0/Glutamic Acid; 7440-09-7/Potassium; 7440-70-2/Calcium; EC 1.4.1.2/Glutamate Dehydrogenase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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