Regulation of ion uptake in membrane vesicles from rat brain by thiamine compounds.
We examined the effects of thiamine derivatives on ion uptake in rat brain membrane vesicles. Thiamine triphosphate (1 mM) and pyrithiamine (0.1 mM) increase chloride uptake. Preincubation of crude homogenate with thiamine or pyrithiamine increases chloride uptake while oxythiamine has the reverse effect. Thiamine and oxythiamine also affect 22Na+ and 86Rb+ uptake in the same way as for 36Cl- but to a lesser extent. Thiamine-dependent 36Cl- uptake is activated by sodium bicarbonate (10 mM) and partially inhibited by bumetanide (0.1 mM) and 2,4-dinitrophenol (0.1 mM). Preincubation with thiamine increases the thiamine triphosphate content of the vesicles. The hypothesis that TTP is the activator of a particular chloride uptake mechanism is discussed.
Bettendorff
L
L
Laboratory of General and Comparative Biochemistry, University of Liège, Belgium.
Wins
P
P
Schoffeniels
E
E
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism*; D005260:Female; D007700:Kinetics; D010119:Oxythiamine / Q000494:pharmacology; D011745:Pyrithiamine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012413:Rubidium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D013831:Thiamine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D013833:Thiamine Monophosphate / Q000494:pharmacology; D013835:Thiamine Pyrophosphate / Q000494:pharmacology; D013838:Thiamine Triphosphate / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D002712:Chlorides; D010119:Oxythiamine; D013838:Thiamine Triphosphate; D013833:Thiamine Monophosphate; D005680:gamma-Aminobutyric Acid; D011745:Pyrithiamine; D012964:Sodium; D012413:Rubidium; D013835:Thiamine Pyrophosphate; D013831:Thiamine