Document Detail

Potassium efflux from infant and adult rat choroid plexuses: effects of CSF anion substitution, N-ethylmaleimide and Cl transport inhibitors.
MedLine Citation:
PMID:  8047284     Owner:  NLM     Status:  MEDLINE    
To analyze interdependent transport of K and Cl, we investigated Rb (K) efflux from in vitro choroid plexus (CP) in isotonic artificial CSF (aCSF) medium containing anions or agents that alter KCl transport. Lateral ventricle CP was loaded with 86Rb for release to enable calculation of the efflux rate coefficient, k. With Cl as the main anion in control aCSF, the k value for 86Rb (K) in CP of 1 week infant rats (0.177 min-1) was 19% lower than in adults (0.218 min-1) (P < 0.005). Replacing CSF Cl with NO3 or SCN, respectively, reduced k for K in infant CP by 73% and 43%; similar anion selectivity was observed in adult tissues (P < 0.05). N-Ethylmaleimide (NEM), which stimulates KCI cotransport, significantly enhanced K efflux in infants and adults. In adult CP, the KCl cotransport inhibitor, furosemide (1 mM), decreased K efflux by 23% or 65%, respectively, when aCSF had Cl or NO3 as the main anion. In infant rat CP, 0.1 mM bumetanide (another KCl cotransport inhibitor), reduced k for K by 65%, whereas the Cl channel blocker diphenylamine carboxylate (1 mM) did not significantly alter K efflux. The collective findings for rat CP indicate a substantial component of K efflux that is associated with Cl concentration and the Cl transport protein sensitive to loop diuretics and NEM. The Cl-dependent K efflux is present in infants.
C E Johanson; J E Preston
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Neuroscience letters     Volume:  169     ISSN:  0304-3940     ISO Abbreviation:  Neurosci. Lett.     Publication Date:  1994 Mar 
Date Detail:
Created Date:  1994-09-01     Completed Date:  1994-09-01     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7600130     Medline TA:  Neurosci Lett     Country:  IRELAND    
Other Details:
Languages:  eng     Pagination:  207-11     Citation Subset:  IM    
Department of Clinical Neurosciences, Brown University/Rhode Island Hospital, Providence 02903.
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MeSH Terms
Aging / metabolism
Anions / cerebrospinal fluid*
Benzoates / pharmacology
Bumetanide / pharmacology
Chlorides / cerebrospinal fluid,  metabolism*
Choroid Plexus / drug effects,  metabolism*
Ethylmaleimide / pharmacology*
Furosemide / pharmacology
Nitrous Oxide / cerebrospinal fluid
Potassium / metabolism*
Rats, Sprague-Dawley
Rubidium Radioisotopes / diagnostic use
Thiocyanates / cerebrospinal fluid
Grant Support
Reg. No./Substance:
0/Anions; 0/Benzoates; 0/Chlorides; 0/Rubidium Radioisotopes; 0/Thiocyanates; 10024-97-2/Nitrous Oxide; 128-53-0/Ethylmaleimide; 28395-03-1/Bumetanide; 302-04-5/thiocyanate; 54-31-9/Furosemide; 7440-09-7/Potassium; 93-99-2/diphenylcarboxylate

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

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