title: Dependence of the histofluorescently reactive zinc pool on zinc transporter-3 in the normal brain.
abstract: In the brain, free zinc levels are under the exquisite control of a variety of zinc-regulating systems, in which zinc transporter (ZnT) proteins play a central role. ZnT3, which is prominently expressed in the brain, facilitates the concentration of free zinc in pre-synaptic vesicles. In addition to histochemical staining methods, a variety of zinc-specific fluorescence dyes has been developed to image or analyze zinc in brain tissue. In this study, we demonstrate the close correlations between histofluorescently reactive zinc and ZnT3. We examined the overlapping distribution of the zinc-specific fluorescent dye, N-(6-methoxy-8-quinolyl)-p-toluenesulfonamide (TSQ)-, and ZnT3-immunoreactive fluorescence throughout the normal brain. TSQ and ZnT3-antibody intensely stained the hippocampus, cortex and amygdala, highlighting the characteristic laminar organization of these regions by variably staining the different layers. TSQ fluorescence and ZnT3 immunoreactivity were roughly co-localized with synaptophysin along the neuropil, but were absent in the neuronal soma. However, albeit relatively faint, TSQ fluorescence was also found throughout the brains of ZnT3-knockout mice. Although these results may indicate the presence of very small cerebral free zinc pools distinct from synaptic vesicle zinc, the synaptic vesicle zinc pool is predominant, accounting for more than 95% of the entire histofluorescently reactive zinc pool in the hippocampus and cortex. Thus, the physiological activity of free zinc in the normal brain might largely depend on the pool of synaptic vesicle zinc that is determined by ZnT3.
authors.affiliation: Asan Institute for Life Sciences, Asan Medical Center, Seoul 138-736, Republic of Korea. jlee@amc.seoul.kr
authors.forename: Joo-Yong
authors.initials: JY
authors.lastname: Lee
authors.forename: Jong S
authors.initials: JS
authors.lastname: Kim
authors.forename: Hye-Ran
authors.initials: HR
authors.lastname: Byun
authors.forename: Richard D
authors.initials: RD
authors.lastname: Palmiter
authors.forename: Jae-Young
authors.initials: JY
authors.lastname: Koh
mesh_terms: D000634:Aminoquinolines / Q000378:metabolism*; D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D027682:Cation Transport Proteins / Q000378:metabolism; D002614:Chelating Agents / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005029:Ethylenediamines / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000378:metabolism; D005786:Gene Expression Regulation / Q000235:genetics; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000172:deficiency / Q000378:metabolism*; D026901:Membrane Transport Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009474:Neurons / Q000378:metabolism; D013572:Synaptic Vesicles / Q000187:drug effects / Q000378:metabolism; D016708:Synaptophysin / Q000378:metabolism; D014018:Tissue Distribution / Q000187:drug effects / Q000235:genetics; D014105:Tosyl Compounds / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism*
chemical_list: D000634:Aminoquinolines; D002352:Carrier Proteins; D027682:Cation Transport Proteins; D002614:Chelating Agents; D005029:Ethylenediamines; D005456:Fluorescent Dyes; D005904:Glial Fibrillary Acidic Protein; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C485803:Slc30a1 protein, mouse; C491177:Slc30a3 protein, mouse; D016708:Synaptophysin; D014105:Tosyl Compounds; C061730:N-(6-methoxy-8-quinolyl)-4-toluenesulfonamide; D015032:Zinc; C044387:N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine