title: Zinc uptake into synaptosomes.
abstract: Zinc uptake was studied in synaptosomes, isolated by the Ficoll flotation technique, using the radiotracer 65Zn. True uptake of zinc could be discriminated from binding to the outside of the synaptosomes by the absence of accumulation at 0 degree C and the dependency of the rate of uptake on the medium osmolarity. The zinc uptake, studied in the presence of various zinc-complexing agents, showed saturation kinetics when analyzed in terms of [Zn]free, yielding Km = 0.25 microM. The zinc uptake was independent of both ATP and the Na+ gradient. No efflux of zinc could be demonstrated from preloaded synaptosomes due to the formation of insoluble zinc complexes inside the synaptosomes. The results are discussed in terms of the modulation of diverse neurochemical processes by zinc.
authors.affiliation: Department of Radiochemistry, Interuniversity Reactor Institute, Delft, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Wensink
authors.forename: A J
authors.initials: AJ
authors.lastname: Molenaar
authors.forename: U D
authors.initials: UD
authors.lastname: Woroniecka
authors.forename: C J
authors.initials: CJ
authors.lastname: Van den Hamer
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000378:metabolism / Q000648:ultrastructure; D002614:Chelating Agents / Q000494:pharmacology; D008297:Male; D009994:Osmolar Concentration; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000494:pharmacology; D013347:Subcellular Fractions / Q000201:enzymology; D013574:Synaptosomes / Q000378:metabolism*; D013997:Time Factors; D015032:Zinc / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D002614:Chelating Agents; D000255:Adenosine Triphosphate; D012964:Sodium; D015032:Zinc