Linked Life Data

6263713

Source:http://linkedlifedata.com/resource/pubmed/id/6263713

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1981-8-20
pubmed:abstractText
Ionophore use an illustrated by a description of experiments in which the K+ ionophore valinomycin and the uncoupler, carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) were employed to investigate Na+ transport pathways in renal microvillus membrane vesicles. First, the potential-dependence of solute transport was examined by using valinomycin and K+ gradients to alter the membrane potential. Whereas Na+-glucose cotransport was voltage-sensitive, the transport of Na+ in the absence of glucose was found to occur via a voltage-insensitive process, likely Na+-H+ exchange. Second, FCCP short-circuiting of the membrane vesicles was used to examine possible electrical interactions among Na+ transport pathways. The alanine inhibition of Na+-dependent glucose transport was abolished by FCCP, indicating that the effect of the amino acid on sugar flux was indirect and mediated by an alteration in the membrane potential. Third, aspects of the molecular mechanism of Na+-glucose cotransport were evaluated by using ionophores to study the potential-dependence of phlorizin binding to the Na+-coupled sugar carrier. Whereas the rate of phlorizin association was potential-dependent, the rate of release of bound phlorizin was insensitive to variation in the transmembrane voltage, suggesting that the potential-dependence of Na+-glucose cotransport arises from potential-dependent behavior of the free carrier rather than from potential-dependence of Na+-glucose translocation per se. These studies demonstrate that the use of ionophores augments the value of employing isolated plasma membrane vesicles to investigate mechanisms of epithelial solute transport.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0014-9446
pubmed:author
pubmed:issnType
Print
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2213-7
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1981
pubmed:articleTitle
Use of ionophores to study Na+ transport pathways in renal microvillus membrane vesicles.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.