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Zinc Uptake into Synaptosomes
Author(s) -
Wensink Jan,
Molenaar Adriaan J.,
Woroniecka Urszula D.,
Van den Hamer Cornells J. A.
Publication year - 1988
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1988.tb02982.x
Subject(s) - zinc , chemistry , efflux , biochemistry , ficoll , osmotic concentration , synaptosome , isotopes of zinc , biophysics , kinetics , nuclear chemistry , membrane , biology , in vitro , organic chemistry , peripheral blood mononuclear cell , physics , quantum mechanics
Zinc uptake‘was studied in synaptosomes, isolated by the Ficoll flotation technique, using the radiotracer 65 Zn. True uptake of zinc could be discriminated from binding to the outside of the synaptosomes by the absence of accumulation at 0°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 K m = 0.25 μ M . 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.