title: [ERK activation effects on GABA secretion inhibition induced by SDF-1 in hippocampal neurons of rats].
abstract: OBJECTIVE
  To investigate the effect of extracellular regulating kinase (ERK) signaling pathway on the secretion of gamma-aminobutyric acid (GABA) in cultured rat hippocampal neurons induced by stromal cell derived factor-1 (SDF-1).
  
  
  METHODS
  The hippocampal neurons of newborn SD rats were cultured and identified in vitro; the phosphorylation level of ERK1/2 was examined by Western blot; ELISA was used to detect the effect of PD98059, a ERK1/2 specific blocker on GABA secretion of cultured hippocampal neurons and Western blot were adopted to measure the protein expression levels of glutamate decarboxylase (GAD65/67) and gamma aminobutyric acid transporter (GAT); after blocking ERK1/2 signaling pathway with PD98059; RT-PCR was used to detect the mRNA expression levels of GAT-1 and GAD65 after treated with PD98059.
  
  
  RESULTS
  The levels of ERKl/2 phosphorylation were increased significantly by SDF1 acting on hippocampal neurons, and CX-CR4 receptor blocker AMD3100, could inhibit SDF-1 induced ERK1/2 activation; SDF-1 could inhibit the secretion of GABA in cultured hippocampal neurons, and ERK1/2 specific inhibitor PD98059, could partly reverse the inhibition of GABA secretion by SDF-1. The effects of SDF-1 on cultured hippocampal neurons was to decrease the mRNA genesis of glutamic acid decarboxylase GAD65 and GABA transporter GAT-1, besides, ERK inhibitor PD98059 could effectively flip the effect of SDF-1. The results of Western blot showed that SDF-1 could inhibit the protein expression of GAT-1 and GAD65/67 in hippocampal neurons and the inhibition of GAT-1 and GAD65/67 protein expression could be partially restored by ERK1/2 blocker.
  
  
  CONCLUSIONS
  SDF-1 acts on the CXCR4 of hippocampal neurons in vitro, and inhibits the expression of GAD by activating the ERK1/2 signaling pathway, and this may represent one possible pathway of GABA secretion inhibition.
authors.forename: Zi-juan
authors.initials: ZJ
authors.lastname: Zhang
authors.forename: Mei-xia
authors.initials: MX
authors.lastname: Guo
authors.forename: Ying
authors.initials: Y
authors.lastname: Xing
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D054377:Chemokine CXCL12 / Q000494:pharmacology*; D005419:Flavonoids / Q000494:pharmacology; D005968:Glutamate Decarboxylase / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology; D020935:MAP Kinase Signaling System; D009474:Neurons / Q000378:metabolism*; D010766:Phosphorylation; D012333:RNA, Messenger; D051381:Rats; D017207:Rats, Sprague-Dawley; D019718:Receptors, CXCR4 / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D054377:Chemokine CXCL12; D005419:Flavonoids; D012333:RNA, Messenger; D019718:Receptors, CXCR4; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one