title: Activation of muscarinic receptors inhibits glutamate-induced GSK-3β overactivation in PC12 cells.
abstract: OBJECTIVE
  To investigate the actions of the muscarinic agonist carbachol on glutamate-induced neurotoxicity in PC12 cells, and the underlying mechanisms.
  
  
  METHODS
  PC12 cells were treated with different concentrations of glutamate for 24 or 48 h. The cell viability was measured using MTT assay, and the expression and activation of GSK-3β were detected with Western blot. β-Catenin translocation was detected using immunofluorescence. Luciferase reporter assay and real-time PCR were used to analyze the transcriptional activity of β-catenin.
  
  
  RESULTS
  Glutamate (1, 3, and 10 mmol/L) induced PC12 cell death in a dose-dependent manner. Moreover, treatment of the cells with glutamate (1 mmol/L) caused significant overactivation of GSK-3β and prevented β-catenin translocation to the nucleus. Pretreatment with carbachol (0.01 μmol/L) blocked glutamate-induced cell death and GSK-3β overactivation, and markedly enhanced β-catenin transcriptional activity.
  
  
  CONCLUSIONS
  Activation of muscarinic receptors exerts neuroprotection in PC12 cells by attenuating glutamate-induced GSK-3β overactivation, suggesting potential benefits of muscarinic agonists for Alzheimer's disease.
authors.affiliation: Department of Pharmacy, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Ma
authors.forename: Li-min
authors.initials: LM
authors.lastname: Yang
authors.forename: Hong-zhuan
authors.initials: HZ
authors.lastname: Chen
authors.forename: Yang
authors.initials: Y
authors.lastname: Lu
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D018698:Glutamic Acid / Q000494:pharmacology*; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D016716:PC12 Cells; D051381:Rats; D011976:Receptors, Muscarinic / Q000378:metabolism*
chemical_list: D011976:Receptors, Muscarinic; D018698:Glutamic Acid; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D038362:Glycogen Synthase Kinase 3