ULTRASTRUCTRAL LOCALIZATION OF ZINC TRANSPORTER-3 (ZNT-3) TO SYNAPTICVESICLE MEMBRANES WITHIN MOSSY FIBER BOUTONS IN THE HIPPOCAMPUS OF MOUSE AND MONKEY
Hj. Wenzel et al., ULTRASTRUCTRAL LOCALIZATION OF ZINC TRANSPORTER-3 (ZNT-3) TO SYNAPTICVESICLE MEMBRANES WITHIN MOSSY FIBER BOUTONS IN THE HIPPOCAMPUS OF MOUSE AND MONKEY, Proceedings of the National Academy of Sciences of the United Statesof America, 94(23), 1997, pp. 12676-12681
Zinc transporter-3 (ZnT-3), a member of a growing family of mammalian
zinc transporters, is expressed in regions of the brain that are rich
in histochemically reactive zinc (as revealed by the Timm's stain), in
cluding entorhinal cortex, amygdala, and hippocampus. ZnT-3 protein is
most abundant in the zinc enriched messy fibers that project from the
dentate granule cells to hilar and CA3 pyramidal neurons. We show her
e by electron microscopy that ZnT-3 decorates the membranes of all cle
ar, small, round synaptic vesicles (SVs) in the messy fiber boutons of
both mouse and monkey, Furthermore, up to 60-80% of these SVs contain
Timm's-stainable zinc, The coincidence of ZnT-3 on the membranes of S
Vs that accumulate zinc, and its homology with known zinc transporters
, suggest that ZnT-3 is responsible for the transport of zinc into SVs
, and hence for the ability of these neurons to release zinc upon exci
tation.