title: Norepinephrine directly activates adult hippocampal precursors via beta3-adrenergic receptors.
abstract: Adult hippocampal neurogenesis is a critical form of cellular plasticity that is greatly influenced by neural activity. Among the neurotransmitters that are widely implicated in regulating this process are serotonin and norepinephrine, levels of which are modulated by stress, depression and clinical antidepressants. However, studies to date have failed to address a direct role for either neurotransmitter in regulating hippocampal precursor activity. Here we show that norepinephrine but not serotonin directly activates self-renewing and multipotent neural precursors, including stem cells, from the hippocampus of adult mice. Mechanistically, we provide evidence that beta(3)-adrenergic receptors, which are preferentially expressed on a Hes5-expressing precursor population in the subgranular zone (SGZ), mediate this norepinephrine-dependent activation. Moreover, intrahippocampal injection of a selective beta(3)-adrenergic receptor agonist in vivo increases the number of proliferating cells in the SGZ. Similarly, systemic injection of the beta-adrenergic receptor agonist isoproterenol not only results in enhancement of proliferation in the SGZ but also leads to an increase in the percentage of nestin/glial fibrillary acidic protein double-positive neural precursors in vivo. Finally, using a novel ex vivo "slice-sphere" assay that maintains an intact neurogenic niche, we demonstrate that antidepressants that selectively block the reuptake of norepinephrine, but not serotonin, robustly increase hippocampal precursor activity via beta-adrenergic receptors. These findings suggest that the activation of neurogenic precursors and stem cells via beta(3)-adrenergic receptors could be a potent mechanism to increase neuronal production, providing a putative target for the development of novel antidepressants.
authors.affiliation: The Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: Dhanisha J
authors.initials: DJ
authors.lastname: Jhaveri
authors.forename: Eirinn W
authors.initials: EW
authors.lastname: Mackay
authors.forename: Adam S
authors.initials: AS
authors.lastname: Hamlin
authors.forename: Swananda V
authors.initials: SV
authors.lastname: Marathe
authors.forename: L Sanjay
authors.initials: LS
authors.lastname: Nandam
authors.forename: Vidita A
authors.initials: VA
authors.lastname: Vaidya
authors.forename: Perry F
authors.initials: PF
authors.lastname: Bartlett
mesh_terms: D000322:Adrenergic Agonists / Q000494:pharmacology; D018674:Adrenergic Antagonists / Q000494:pharmacology; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D058667:Adrenergic beta-3 Receptor Agonists; D058673:Adrenergic beta-3 Receptor Antagonists; D053687:Adult Stem Cells / Q000187:drug effects*; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D005434:Flow Cytometry / Q000379:methods; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics; D006624:Hippocampus / Q000166:cytology*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D004676:Myelin Basic Protein / Q000378:metabolism; D009638:Norepinephrine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D022702:Receptors, Adrenergic, beta-3 / Q000235:genetics / Q000502:physiology*; D018709:Statistics, Nonparametric; D014404:Tubulin / Q000378:metabolism
chemical_list: D000322:Adrenergic Agonists; D018674:Adrenergic Antagonists; D000316:Adrenergic alpha-Agonists; D058667:Adrenergic beta-3 Receptor Agonists; D058673:Adrenergic beta-3 Receptor Antagonists; D005904:Glial Fibrillary Acidic Protein; D004676:Myelin Basic Protein; D022702:Receptors, Adrenergic, beta-3; D014404:Tubulin; D049452:Green Fluorescent Proteins; D009638:Norepinephrine