title: Sigma-1 receptor knockout impairs neurogenesis in dentate gyrus of adult hippocampus via down-regulation of NMDA receptors.
abstract: OBJECTIVE
  This study investigated the influence of sigma-1 receptor (σ1 R) deficiency on adult neurogenesis.
  
  
  METHODS
  We employed 8-week-old male σ1 R knockout (σ1 R(-/-) ) mice to examine the proliferation and differentiation of progenitor cells, and the survival and neurite growth of newborn neurons in hippocampal dentate gyrus (DG).
  
  
  RESULTS
  In comparison with wild-type (WT) littermates, the numbers of 24-h-old BrdU(+) cells and Ki67(+) cells in σ1 R(-/-) mice increased, while the number of 28-day-old BrdU(+) cells decreased without changes in proportion of BrdU(+) /NeuN(+) cells and BrdU(+) /GFAP(+) cells. The neurite density of newborn neurons was slightly reduced in σ1 R(-/-) mice. In DG granular cells, N-methyl-d-aspartate (NMDA)-activated current (INMDA ) and phosphorylation of NMDA receptor (NMDAr) NR2B were reduced in σ1 R(-/-) mice without the alteration of NR2B expression and membrane properties compared to WT mice. The NR2B antagonist abolished the difference in INMDA between σ1 R(-/-) mice and WT mice. The application of NMDAr agonist in σ1 R(-/-) mice prevented the over-proliferation of cells and reduction in newborn neurons, but it had no effects on the hypoplastic neurite. The administration of NMDAr antagonist in WT mice enhanced the cell proliferation and depressed the survival of newborn neurons.
  
  
  CONCLUSIONS
  The σ1 R deficiency impairs neurogenesis in DG through down-regulation of NMDArs.
authors.affiliation: State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing, China.
authors.forename: Sha
authors.initials: S
authors.lastname: Sha
authors.forename: Wei-Jun
authors.initials: WJ
authors.lastname: Qu
authors.forename: Lin
authors.initials: L
authors.lastname: Li
authors.forename: Zi-Hong
authors.initials: ZH
authors.lastname: Lu
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.forename: Wen-Feng
authors.initials: WF
authors.lastname: Yu
authors.forename: Ling
authors.initials: L
authors.lastname: Chen
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation; D049109:Cell Proliferation; D018891:Dentate Gyrus / Q000502:physiology*; D015536:Down-Regulation; D008297:Male; D051379:Mice; D016202:N-Methylaspartate / Q000494:pharmacology; D016501:Neurites / Q000502:physiology; D055495:Neurogenesis; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D017480:Receptors, sigma / Q000502:physiology*; D000097605:Sigma-1 Receptor
chemical_list: D016202:N-Methylaspartate; D016194:Receptors, N-Methyl-D-Aspartate; D017480:Receptors, sigma; D000097605:Sigma-1 Receptor
keywords: Hippocampus; N-methyl-d-aspartate receptor; Neurogenesis; Sigma-1 receptor; γ-Aminobutyric acid