Résumé
The effects of a series of chloride transport blockers (ethacrynate, furosemide, torasemide, 4,4′-diisothiocyano-2,2′-disulfonic acid stilbene and diphenylcarboxylate) on Cl
−-dependent
l-[
3H]glutamate (Glu) binding were tested in rat brain membranes. Cl
− transport blockers inhibit the
Ca
2+
Cl
−-
induced
increase in
l-[
3H]Glu binding, some of them without affecting the
Ca
2+
Cl
−-
independent
l-[
3H]Glu binding. Increasing the medium osmolarity by augmenting the sucrose concentration also inhibited the
Ca
2+
Cl
−-
induced
increase in
l-[
3H]Glu binding. The effects of both sucrose and Cl
− transport blockers were not additive, suggesting that they acted on the same type of mechanism. We recently suggested that
l-[
3H]Glu binding to brain membranes corresponds to Glu uptake in membrane vesicles. Therefore we propose that the Cl
− transport blockers inhibit a Cl
−-dependent Glu accumulation into these vesicles.