title: Capture of extracellular zinc ions by astrocytes.
abstract: Synaptic zinc ions released during synaptic transmission interact with pre- and postsynaptic neuroreceptors, thus modulating neurotransmission. It is likely that they have to be efficiently cleared from the extracellular milieu to assure subsequent synaptic events. Both neurons and glia are assumed to participate in this clearance by mechanisms that are not fully understood. In this study, electron microscopic zinc cytochemistry has shown zinc-electrondense particles associated with hippocampal astrocytic membranes frequently found accumulated in stacked lamellae. In cultured astrocytes, the use of zinc fluorochromes and endocytic markers allowed the simultaneous imaging of the capture of extracellular zinc simultaneously to plasma membrane markers; this endocytic process was inhibited by high sucrose concentrations. Finally, electron microscopy of zinc-loaded and fluorochrome photoconverted cells demonstrated some early events of extracellular zinc capture as well as its late accumulation in lysosome-like organelles.
authors.affiliation: Cell Biology Department, Universitat de Valencia, Valencia, Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Varea
authors.forename: Gregori
authors.initials: G
authors.lastname: Alonso-Llosà
authors.forename: Asunción
authors.initials: A
authors.lastname: Molowny
authors.forename: Carlos
authors.initials: C
authors.lastname: Lopez-Garcia
authors.forename: Xavier
authors.initials: X
authors.lastname: Ponsoda
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D011992:Endosomes / Q000502:physiology / Q000648:ultrastructure; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006706:Homeostasis; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D015388:Organelles / Q000502:physiology / Q000648:ultrastructure; D011817:Rabbits; D013395:Sucrose / Q000494:pharmacology; D015032:Zinc / Q000378:metabolism*
chemical_list: D005904:Glial Fibrillary Acidic Protein; D013395:Sucrose; D015032:Zinc