title: Activity- and development-dependent down-regulation of TARPγ8 and GluA1 in cultured rat hippocampal neurons.
abstract: OBJECTIVE
  Transmembrane AMPA receptor regulatory proteins (TARPs) regulate the trafficking and expression of AMPA receptors that are essential for the fast excitatory synaptic transmission and plasticity in the brain. This study aimed to investigate the activity-dependent regulation of TARPγ8 in cultured rat hippocampal neurons.
  
  
  METHODS
  Rat hippocampal neurons cultured for 7-8 DIV or 17-18 DIV were exposed to the AMPA receptor agonist AMPA at a non-toxic concentration (100 μmol/L) for 4 h. The protein levels of TARPγ8 and AMPA receptor subunits (GluA1 and GluA2) were measured using Western blotting analysis. AMPA-induced currents were recorded in the neurons using a whole-cell recording method.
  
  
  RESULTS
  Four-hour exposure to AMPA significantly decreased the protein levels of TARPγ8 and GluA1 in the neurons at 17-18 DIV, but did not change the protein level of TARPγ8 in the neurons cultured at 7-8 DIV. AMPA-induced down-regulation of TARPγ8 and GluA1 was largely blocked by the calpain inhibitor calpeptin (50 μmol/L), but not affected by the caspase inhibitor zVAD (50 μmol/L). Four-hour exposure to AMPA significantly decreased AMPA-induced currents in the neurons at 17-18 DIV, which was blocked by co-exposure to calpeptin (50 μmol/L).
  
  
  CONCLUSIONS
  The down-regulation of TARPγ8 and GluA1 protein levels and AMPA-induced currents in cultured rat hippocampal neurons is activity- and development-dependent, and mediated by endogenous calpain.
authors.affiliation: Key Laboratory of Brain Research of Henan Province, Xinxiang Medical University, Xinxiang 453003, China.|Department of Pathophysiology, Xinxiang Medical University, Xinxiang 453003, China.
authors.forename: Jian-gang
authors.initials: JG
authors.lastname: Wang
authors.affiliation: Key Laboratory of Brain Research of Henan Province, Xinxiang Medical University, Xinxiang 453003, China.|Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang 453003, China.
authors.forename: Ya-li
authors.initials: YL
authors.lastname: Wang
authors.affiliation: Key Laboratory of Brain Research of Henan Province, Xinxiang Medical University, Xinxiang 453003, China.|Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang 453003, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Xu
authors.affiliation: Key Laboratory of Brain Research of Henan Province, Xinxiang Medical University, Xinxiang 453003, China.|Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang 453003, China.
authors.forename: Jing-xi
authors.initials: JX
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Brain Research of Henan Province, Xinxiang Medical University, Xinxiang 453003, China.|Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang 453003, China.
authors.forename: Si-yuan
authors.initials: SY
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Brain Research of Henan Province, Xinxiang Medical University, Xinxiang 453003, China.|Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang 453003, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yu
authors.affiliation: School of Biological and Biomedical Science, Durham University, Durham DH13LE, UK.
authors.forename: Paul L
authors.initials: PL
authors.lastname: Chazot
authors.affiliation: Key Laboratory of Brain Research of Henan Province, Xinxiang Medical University, Xinxiang 453003, China.
authors.forename: Xiao-fang
authors.initials: XF
authors.lastname: Wang
authors.affiliation: Key Laboratory of Brain Research of Henan Province, Xinxiang Medical University, Xinxiang 453003, China.|Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang 453003, China.
authors.forename: Cheng-biao
authors.initials: CB
authors.lastname: Lu
mesh_terms: D000818:Animals; D015220:Calcium Channels / Q000378:metabolism*; D002154:Calpain / Q000378:metabolism; D002478:Cells, Cultured; D006624:Hippocampus / Q000166:cytology* / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000378:metabolism*; D009435:Synaptic Transmission
chemical_list: D015220:Calcium Channels; D002154:Calpain; D018091:Receptors, AMPA; C588152:cacng8 protein, rat; C104722:glutamate receptor ionotropic, AMPA 2