Abstract
Muscarinic acetylcholine receptor (mAChR), a member of the G-protein-coupled receptors (GPCRs) gene superfamily, has been shown to mediate the effects of acetylcholine on differentiation and proliferation in the CNS. However, the mechanism or mechanisms whereby mAChRs regulate cell proliferation remain poorly understood. Here we show that in vitro bFGF-expanded neural progenitor cells dissociated from rat cortical neuroepithelium express muscarinic acetylcholine receptor subtype mRNAs. We demonstrate that stimulation of these mAChRs with carbachol, a muscarinic agonist, activated extracellular-regulated kinases (Erk1/2) and phosphatidylinositol-3 kinase (PI-3K). This, in turn, stimulated DNA synthesis in neural progenitor cells. MEK inhibitor PD98059 and PI-3K inhibitors wortmannin and LY294002 inhibited a carbachol-induced increase in DNA synthesis. These findings indicate that the activation of both PI-3 kinase and MEK signaling pathways via muscarinic receptors is involved in stimulating DNA synthesis in the neural progenitor cells during early neurogenesis.
MeSH terms
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Animals
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Cell Division / drug effects
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Cell Division / physiology
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Cell Survival / drug effects
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Cells, Cultured
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DNA / biosynthesis*
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Enzyme Activation / drug effects
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Enzyme Inhibitors / pharmacology
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Fibroblast Growth Factor 2 / pharmacology
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Intermediate Filament Proteins / biosynthesis
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Mitogen-Activated Protein Kinase 1 / antagonists & inhibitors
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Mitogen-Activated Protein Kinase 1 / metabolism
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Mitogen-Activated Protein Kinase 3
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Mitogen-Activated Protein Kinases / antagonists & inhibitors
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Mitogen-Activated Protein Kinases / metabolism*
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Muscarinic Agonists / pharmacology
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Nerve Tissue Proteins*
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Nestin
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Neurons / cytology
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Neurons / metabolism
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Phosphatidylinositol 3-Kinases / metabolism*
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RNA, Messenger / metabolism
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Rats
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Rats, Sprague-Dawley
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Receptors, Muscarinic / genetics
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Receptors, Muscarinic / metabolism*
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Stem Cells / cytology
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Stem Cells / drug effects
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Stem Cells / metabolism*
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Telencephalon / cytology
Substances
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Enzyme Inhibitors
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Intermediate Filament Proteins
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Muscarinic Agonists
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Nerve Tissue Proteins
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Nes protein, rat
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Nestin
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RNA, Messenger
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Receptors, Muscarinic
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Fibroblast Growth Factor 2
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DNA
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Phosphatidylinositol 3-Kinases
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Mitogen-Activated Protein Kinase 1
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Mitogen-Activated Protein Kinase 3
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Mitogen-Activated Protein Kinases