NMR measurements of the diffusional permeability of water in cultured colonic epithelial cancer cells.
The water residence time and diffusional water permeability in colonic epithelial T84 cancer cells was measured using (1)H NMR spectroscopy; the values estimated were 35.2+/-2.8 ms and (7.4+/-0.6)x10(-3)cms(-1), respectively. Water permeability was inhibited to approximately 10% of its original value by the mercurial diuretic, p-chloromercuribenzenesulfonate (PCMBS; 1mM), and fully restored by dithiothreitol (DTT; 1mM). The permeability was also inhibited reversibly to approximately 55%, by extracellular glibenclamide (1mM), an inhibitor of some ATP-binding cassette (ABC) transporters, including the cystic fibrosis transmembrane conductance regulator (CFTR). Addition of the phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine (IMBX; 0.1-1mM) and the adenylate cyclase activator, forskolin (0.1-1mM) did not alter water permeability. It is concluded that in T84 cells water diffuses through the membrane lipid bilayer and via channels that are inhibited by PCMBS, including the channels that are known to be inhibited by glibenclamide.
Nouri-Sorkhabi
M H
MH
James Fairfax Institute of Paediatric Nutrition, Children's Hospital at Westmead, Westmead, NSW 2145, Australia.
Chapman
B E
BE
O'Loughlin
E V
EV
Li
Z
Z
Kuchel
P W
PW
Gaskin
K J
KJ
D002731:4-Chloromercuribenzenesulfonate / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D027682:Cation Transport Proteins / Q000235:genetics; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability; D003110:Colonic Neoplasms / Q000473:pathology*; D004058:Diffusion / Q000187:drug effects; D004229:Dithiothreitol / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D005905:Glyburide / Q000494:pharmacology; D006801:Humans; D033862:Iron-Binding Proteins / Q000235:genetics; D009682:Magnetic Resonance Spectroscopy; D013997:Time Factors; D014867:Water / Q000378:metabolism*; D000099236:Solute Carrier Family 11, Member 2
D002731:4-Chloromercuribenzenesulfonate; D027682:Cation Transport Proteins; D004229:Dithiothreitol; D005905:Glyburide; D033862:Iron-Binding Proteins; D014867:Water; D000099236:Solute Carrier Family 11, Member 2