title: Homeostatic regulation of synaptic GlyR numbers driven by lateral diffusion.
abstract: In the spinal cord, most inhibitory synapses have a mixed glycine-GABA phenotype. Using a pharmacological approach, we report an NMDAR activity-dependent regulation of the mobility of GlyRs but not GABA(A)Rs at inhibitory synapses in cultured rat spinal cord neurons. The NMDAR-induced decrease in GlyR lateral diffusion was correlated with an increase in receptor cluster number and glycinergic mIPSC amplitude. Changes in GlyR diffusion properties occurred rapidly and before the changes in the number of synaptic receptors. Regulation of synaptic GlyR content occurred without change in the amount of gephyrin. Moreover, NMDAR-dependent regulation of GlyR lateral diffusion required calcium influx and calcium release from stores. Therefore, excitation may increase GlyR levels at synapses by a calcium-mediated increase in postsynaptic GlyR trapping involving regulation of receptor-scaffold interactions. This provides a mechanism for a rapid homeostatic regulation of the inhibitory glycinergic component at mixed glycine-GABA synapses in response to increased NMDA excitatory transmission.
authors.affiliation: Biologie Cellulaire de la Synapse, INSERM U789, Ecole Normale Supérieure, 46 rue d'Ulm, 75005 Paris, France.
authors.forename: Sabine
authors.initials: S
authors.lastname: Lévi
authors.forename: Claude
authors.initials: C
authors.lastname: Schweizer
authors.forename: Hiroko
authors.initials: H
authors.lastname: Bannai
authors.forename: Olivier
authors.initials: O
authors.lastname: Pascual
authors.forename: Cécile
authors.initials: C
authors.lastname: Charrier
authors.forename: Antoine
authors.initials: A
authors.lastname: Triller
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004058:Diffusion; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D005998:Glycine / Q000502:physiology; D006706:Homeostasis / Q000502:physiology*; D053444:Inhibitory Postsynaptic Potentials / Q000502:physiology; D009474:Neurons / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018009:Receptors, Glycine / Q000502:physiology*; D013569:Synapses / Q000502:physiology*
chemical_list: D018009:Receptors, Glycine; D005998:Glycine