title: Age-related changes of glycine receptor at the rat hippocampus: from the embryo to the adult.
abstract: Glycinergic inhibitory transmission has been described in spinal cord, but rather disregarded in the brain. The spatial-temporal characterization of glycine receptors (GlyR) in the hippocampus over development is herein reported. GlyR expression increases from late embryonic stage (E18) to 7 days postnatal (P7) and decreases from P7 on. Quantitative real-time PCR showed that GlyR subunit expression changes over neuronal maturation with a preponderance of α2 and α3, over α1 and β. In immature stages, GlyR delineate the cell body of neurons at the Dentate Gyrus and Cornus Ammonis 1 and 3 (CA1/CA3) and are composed of α2 and α3 subunits. At P7, synaptic GlyRα2β can already be observed in the dendritic areas of Dentate Gyrus and of CA1/CA3. In the mature hippocampus, synaptic GlyR decrease and, although a few synaptic GlyRα1β can still be detected in the dendritic layers, extrasynaptic α2/α3-containing GlyR and somatic localized GlyRα3 are the most abundant. Our results point towards an important function of a slow tonic activation of extrasynaptic GlyR, over a fast phasic activation of synaptic GlyRα1β. We clearly show that GlyR are widely expressed in hippocampus and that their subcellular localization and subunit composition change over development.
authors.affiliation: Institute of Pharmacology and Neurosciences, Faculty of Medicine, and Unit of Neurosciences, Institute of Molecular Medicine, University of Lisbon, Portugal.
authors.forename: Rita I
authors.initials: RI
authors.lastname: Aroeira
authors.forename: Joaquim A
authors.initials: JA
authors.lastname: Ribeiro
authors.forename: Ana M
authors.initials: AM
authors.lastname: Sebastião
authors.forename: Cláudia A
authors.initials: CA
authors.lastname: Valente
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism; D003712:Dendrites / Q000378:metabolism; D005260:Female; D006624:Hippocampus / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism*; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000378:metabolism; D009841:Oligonucleotides / Q000378:metabolism; D011247:Pregnancy; D017729:Presynaptic Terminals / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D018009:Receptors, Glycine / Q000378:metabolism / Q000502:physiology*; D017661:Receptors, Presynaptic / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013116:Spinal Cord / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D016707:Tissue Fixation; D050495:Vesicular Inhibitory Amino Acid Transport Proteins / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; C501174:Glra2 protein, rat; D008565:Membrane Proteins; D009841:Oligonucleotides; D012333:RNA, Messenger; D018009:Receptors, Glycine; D017661:Receptors, Presynaptic; D050495:Vesicular Inhibitory Amino Acid Transport Proteins; C073441:gephyrin