Document Detail

Anomalously high concentrations of brain extracellular uric acid detected with chronically implanted probes: implications for in vivo sampling techniques.
MedLine Citation:
PMID:  2051164     Owner:  NLM     Status:  MEDLINE    
The height of peak 2, h2, recorded using linear sweep voltammetry with 350-micron-diameter carbon paste electrodes in rat striatum was measured from the day of implantation (day 0) to 4 months after surgery. The value of h2 was at a minimum on day 0 (0.6 +/- 0.2 nA; n = 20), rose sharply to a maximum on day 2 (6.3 +/- 0.9 nA; n = 12), and decreased to a stable level by day 7 (3.3 +/- 0.7 nA; n = 16), which lasted for 4 months (3.2 +/- 0.6 nA; n = 9). These changes were shown by microinfusion of uricase to be due to variations in the concentrations of extracellular uric acid, although h2 appears to have a small baseline contribution of approximately 0.3 nA from 5-hydroxyindoleacetic acid. The stable value of h2 recorded under chronic conditions was estimated to correspond to a minimal uric acid concentration of 50 mumol/L, which represents a 10-fold increase in the extracellular level of this purine metabolite compared with the initial (acute) value. Very similar results were obtained using a microdialysis technique that detected uric acid directly. These estimates of striatal uric acid concentration are in marked contrast to those obtained using 40-micron diameter carbon fiber electrodes, which showed a decrease from the acute preparation to less than 1 mumol/L under chronic conditions. Large values of h2 were also recorded with chronically implanted paste electrodes in the hippocampus and frontal cortex.(ABSTRACT TRUNCATED AT 250 WORDS)
R D O'Neill; J L Gonzalez-Mora; M G Boutelle; D E Ormonde; J P Lowry; A Duff; B Fumero; M Fillenz; M Mas
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of neurochemistry     Volume:  57     ISSN:  0022-3042     ISO Abbreviation:  J. Neurochem.     Publication Date:  1991 Jul 
Date Detail:
Created Date:  1991-07-23     Completed Date:  1991-07-23     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985190R     Medline TA:  J Neurochem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  22-9     Citation Subset:  IM    
Department of Chemistry, University College, Dublin, Ireland.
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MeSH Terms
Brain / metabolism*
Carbon / diagnostic use
Electrochemistry / methods*
Electrodes, Implanted
Extracellular Space / metabolism*
Osmolar Concentration
Rats, Inbred Strains
Time Factors
Uric Acid / metabolism*
Reg. No./Substance:
69-93-2/Uric Acid; 7440-44-0/Carbon
Comment In:
J Neurochem. 1992 Aug;59(2):784-6   [PMID:  1378492 ]
Erratum In:
J Neurochem 1991 Nov;57(5):1822

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

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