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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
3
|
| pubmed:dateCreated |
1977-9-22
|
| pubmed:abstractText |
Extracellular K+ activity (Ke), local tissue blood flow and the cortical evoked potential (EP) were measured concurrently in the cerebral cortex of baboons anaesthetised with a-chloralose. Flows were progressively reduced from normal by occlusion of the middle cerebral artery and controlled steps of exsanguination. Our data suggest that 3 stages may be identified in the disturbance of K+ homeostasis produced by progressive ischaemia. In the first stage, at flow levels similar to those sufficient to abolish the EP (12-16 ml/100 g/min), small, self-limiting increases in Ke occur, probably reflecting K+ efflux into the extracellular space (ECS) with partial impairment of K+ clearance from the ECS. The second stage occurs at distinctly lower (P less than 0.01) levels of flow (8-11 ml/100 g/min), and is characterized by a massive (30-80 mM) increase in Ke, which we attribute to an increase in ionic permeability of cell membranes with further impairment or overloading of K+ clearance mechanisms. In the third stage, at flows below about 6-8 ml/100 g/min, the data indicate an inverse relationship between flow and Ke with persisting high Ke levels, suggesting complete loss of K+ clearance. Transient increases of Ke also occur in the flow range 4-13 ml/100 g/min, the rate of recovery of Ke in their decay phase being positively corelated with flow (P less than 0.005).
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Jul
|
| pubmed:issn |
0022-510X
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
32
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
305-21
|
| pubmed:dateRevised |
2003-11-14
|
| pubmed:meshHeading |
pubmed-meshheading:407332-Animals,
pubmed-meshheading:407332-Cerebral Cortex,
pubmed-meshheading:407332-Evoked Potentials,
pubmed-meshheading:407332-Extracellular Space,
pubmed-meshheading:407332-Haplorhini,
pubmed-meshheading:407332-Ischemia,
pubmed-meshheading:407332-Male,
pubmed-meshheading:407332-Papio,
pubmed-meshheading:407332-Potassium,
pubmed-meshheading:407332-Regional Blood Flow
|
| pubmed:year |
1977
|
| pubmed:articleTitle |
Extracellular potassium activity, evoked potential and tissue blood flow. Relationships during progressive ischaemia in baboon cerebral cortex.
|
| pubmed:publicationType |
Journal Article
|