Reference : Thiamin and Derivatives as Modulators of Rat Brain Chloride Channels
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
Thiamin and Derivatives as Modulators of Rat Brain Chloride Channels
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 [> > > >]
Yes (verified by ORBi)
[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)

There is no file associated with this reference.

Bookmark and Share SFX Query

All documents in ORBi are protected by a user license.