Linked Life Data

7860667

Source:http://linkedlifedata.com/resource/pubmed/id/7860667

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1995-3-17
pubmed:abstractText
Brain and CSF potassium concentrations are well regulated during acute and chronic alterations of plasma potassium. In a previous study, we have shown that during chronic perturbations, regulation is achieved by appropriate adaptation of potassium influx, but that the degree of such adaptation during acute perturbations is much less. To elucidate further potential regulatory mechanisms, rats were rendered acutely or chronically hyper- or hypokalemic (range 2.7-7.6 mM). Measurements were made of brain and CSF water and ion contents to examine whether regulation occurred by modulation of K+ uptake into parenchymal cells. Furthermore, the permeability-surface area products (PSs) of 22Na+ were determined, because changes in K+ efflux fia Na+,K(+)-ATPase on the brain-facing side of the blood-brain barrier might be reflected in modified Na+ permeability. Brain and CSF K+ concentrations and Na PS were all independent of chronic changes in plasma K+ and acute hypokalemia, suggesting that neither modulation of parenchymal K+ uptake nor K+ efflux via the Na+,K(+)-ATPase is involved in extracellular K+ regulation in these conditions. In contrast, Na PSs were increased by 40% (p < 0.05) in acute hyperkalemia. This was accompanied by a slight loss of tissue K+ and water from the intracellular space. These results suggest that increased potassium influx in acute hyperkalemia is compensated by stimulation of K+ efflux via Na+,K(+)-ATPase. A slight degree of overstimulation, as indicated by a net loss of tissue K+, leads us to hypothesize that other factors, apart from the kinetic characteristics of Na+,K(+)-ATPase, may regulate this enzyme at the blood-brain barrier.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0271-678X
pubmed:author
pubmed:issnType
Print
pubmed:volume
15
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
336-44
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Mechanisms of brain ion homeostasis during acute and chronic variations of plasma potassium.
pubmed:affiliation
Department of Surgery, University of Michigan, Ann Arbor 48109-0532.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't