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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2010-9-3
pubmed:abstractText
The functionality of human erythrocyte nucleoside transporter ENT1 was examined at ice-cold temperatures (ICT; measured temperature, 0.5-0.7 degrees C) using rightside-out membrane vesicles (ROVs). The uptake of uridine, an ENT1 substrate, showed saturation kinetics and was inhibited by S-(4-nitrobenzyl)-6-thioinosine (NBMPR), a specific ENT1 inhibitor, at both 23 degrees C and ICT. [3H]Uridine uptake was markedly trans-stimulated by preloading ROVs with unlabeled uridine or ribavirin, another ENT1 substrate, and the overshoot phenomenon was observed at ICT. Similarly, [3H]ribavirin uptake was markedly trans-stimulated by unlabeled ribavirin or uridine at ICT. The trans-stimulated uptake of [3H]uridine at ICT was inhibited by ENT1 inhibitors/substrates such as NBMPR, dipyridamole, adenosine, and ribavirin in a concentration-dependent manner. The inhibition of [3H]uridine uptake by NBMPR and dipyridamole at ICT was also observed in intact red blood cells. Like uridine uptake, [3H]D-glucose uptake by ROVs, which is mediated by facilitative glucose transporter GLUT1, was trans-stimulated by unlabeled D-glucose at ICT, and the overshoot phenomenon was observed. In contrast, the ability of ATP-dependent transport of 5-(and-6)-carboxy-2',7'-dichlorofluorescein via multidrug resistance-associated protein 5 in inside-out membrane vesicles disappeared at ICT. These results clearly indicate that human erythrocyte transporters such as ENT1 function even at very low temperatures near 0 degrees C. The significance of these findings in transporter research is discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
1880-0920
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
25
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
351-60
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Human erythrocyte nucleoside transporter ENT1 functions at ice-cold temperatures.
pubmed:affiliation
Department of Pharmaceutics and Therapeutics, Graduate School of Biomedical Sciences, Hiroshima University. takanom@hiroshima-u.ac.jp
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't