Reference : Thiamin and Derivatives as Modulators of Rat Brain Chloride Channels
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
http://hdl.handle.net/2268/4585
Thiamin and Derivatives as Modulators of Rat Brain Chloride Channels
English
Bettendorff, Lucien mailto [Université de Liège - ULiège > Département des sciences biomédicales et précliniques > Biochimie et physiologie humaine et pathologique >]
Hennuy, Benoît mailto [Université de Liège - ULiège > > GIGA-Management : Plate-forme transcriptomique >]
Wins, Pierre [> > > >]
Schoffeniels, Ernest [> > > >]
1993
Neuroscience
52
4
1009-1017
Yes (verified by ORBi)
International
0306-4522
[en] Several membrane fractions were prepared from rat brain by differential and sucrose density gradient centrifugation. Most fractions took up 36Cl- rapidly at a rate linear with time during the first 30-60 s, then the rate progressively slowed down. The lowest rate of uptake was found in the mitochondrial fraction. Oxythiamin partially inhibited 36Cl- uptake in all fractions. In P2 (crude synaptosomal fraction), oxythiamin decreased the initial rate of uptake by 32%, the apparent Ki being 1.5 mM. Thiamin and amprolium were less effective as inhibitors. 4,4'-Diisothiocyanostilbene-2,2'-disulfonic acid (0.1-1 mM) inhibited 36Cl- uptake by 40-50%. In the presence of this compound at a concentration > or = 5 x 10(-4) M, oxythiamin became ineffective. 36Cl- uptake was increased by GABA (0.1 mM) and this effect was antagonized by picrotoxin as expected, but not by oxythiamin. The rate of 36Cl- uptake did not appreciably depend on the external chloride concentration and was unaffected by bumetanide or by replacement of external Na+ by choline. Taken together, these data suggest that the oxythiamin-sensitive 36Cl- influx is essentially diffusional and is not related to the GABA receptor or the Na:K:2Cl co-transport. Partial replacement of external Na+ by K+ or treatment with 0.1 mM veratridine (which should both result in membrane depolarization) increased 36Cl- uptake by 50 and 30% respectively; the inhibitory effect of oxythiamin was enhanced to the same proportion.(ABSTRACT TRUNCATED AT 250 WORDS)
http://hdl.handle.net/2268/4585
10.1016/0306-4522(93)90547-S

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