Linked Life Data

7914220

Source:http://linkedlifedata.com/resource/pubmed/id/7914220

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1994-9-8
pubmed:abstractText
The time course of changes in extracellular glutamic acid levels and their Ca2+ dependency were studied in the rat striatum during focal cerebral ischaemia, using microdialysis. Ischaemia-induced changes were compared with those produced by high K(+)-evoked local depolarization. To optimize time resolution, glutamate was analysed continuously as the dialysate emerged from the microdialysis probe by either enzyme fluorimetry or biosensor. The Ca2+ dependency of glutamate changes was examined by perfusing the probe with Ca(2+)-free medium. With normal artificial CSF, ischaemia produced a biphasic increase in extracellular glutamate, which started from the onset of ischaemia. During the first phase lasting approximately 10 min, dialysate glutamate level increased from 5.8 +/- 0.9 microM.min-1 to 35.8 +/- 6.2 microM where it stabilized for approximately 3 min. During the second phase dialysate glutamate increased progressively to its maximum (82 +/- 8 microM), reached after 55 min of ischaemia, where it remained for as long as it was recorded (3 h). The overall changes in extracellular glutamate were similar when Ca2+ was omitted from the perfusion medium, except that the first phase was no longer detectable and, early in ischaemia, extracellular glutamate increased at a significantly slower rate than in the control group (2.2 +/- 1 microM.min-1; p < 0.05). On the basis of these data, we propose that most of the glutamate released in the extracellular space in severe ischaemia is of metabolic origin, probably originating from both neurons and glia, and caused by altered glutamate uptake mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0022-3042
pubmed:author
pubmed:issnType
Print
pubmed:volume
63
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1003-11
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Extracellular glutamate during focal cerebral ischaemia in rats: time course and calcium dependency.
pubmed:affiliation
Gough-Cooper Department of Neurological Surgery, Institute of Neurology, London, England.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't