Linked Life Data

8102581

Source:http://linkedlifedata.com/resource/pubmed/id/8102581

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1993-9-23
pubmed:abstractText
There is now convincing evidence that excessive accumulation of the excitatory amino acid glutamate (Glu) in the extracellular space is toxic to neurons. However, the regulation of the release and uptake of Glu in producing this toxic concentration has not been adequately ascertained. The authors report that in hippocampal slices, the output of Glu significantly increased under in vitro ischemic states. Glu in the extracellular space increased fivefold. Since daurisoline, a drug that blocks N-type Ca2+ channels, or Ca(2+)-free solution potently and effectively lowered this stimulated output, it was hypothesized that the Glu output is mediated by Ca2+ influx in nerve terminals. When the slices were incubated for 30 minutes under ischemic state, daurisoline caused only small alterations in the postischemic accumulation of Glu. However, Glu accumulation was markedly attenuated by H-7, but not by calmidazolium, facilitated by PDB whereas 8-bromo-cAMP was without effect. It appears therefore that during a 30-minute ischemic insult, protein kinase C (PKC) was involved in the Glu accumulation of supernatant. A direct demonstration of this concept was obtained by showing significant increases in PKC activation in presynaptic nerve terminals (from 1.34 +/- 0.1 to 9.34 +/- 0.89 U) following 30 minutes of ischemia. DNQX, a non-NMDA receptor antagonist, potently reduced PKC activities and decreased extra Glu accumulation. Also observed was the inhibition of 1-[3H]-Glu uptake into synaptosomes by PDB. These results provide direct evidence that Ca2+ influx enhances Glu release, which in turn leads to inhibition of its reuptake, and is coupled with PKC activities in presynaptic nerve terminals.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1050-9631
pubmed:author
pubmed:issnType
Print
pubmed:volume
3
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
221-7
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Accumulation of glutamate is regulated by calcium and protein kinase C in rat hippocampal slices exposed to ischemic states.
pubmed:affiliation
Division of Molecular Pharmacology, Naval Neurobiology Research Centre, Nanjing, China.
pubmed:publicationType
Journal Article, In Vitro