title: Photoperiod programs dorsal raphe serotonergic neurons and affective behaviors.
abstract: The serotonergic raphe nuclei of the midbrain are principal centers from which serotonin neurons project to innervate cortical and sub-cortical structures. The dorsal raphe nuclei receive light input from the circadian visual system and indirect input from the biological clock nuclei. Dysregulation of serotonin neurotransmission is implicated in neurobehavioral disorders, such as depression and anxiety, and alterations in the serotonergic phenotype of raphe neurons have dramatic effects on affective behaviors in rodents. Here, we demonstrate that day length (photoperiod) during development induces enduring changes in mouse dorsal raphe serotonin neurons—programming their firing rate, responsiveness to noradrenergic stimulation, intrinsic electrical properties, serotonin and norepinephrine content in the midbrain, and depression/anxiety-related behavior in a melatonin receptor 1 (MT1)-dependent manner. Our results establish mechanisms by which seasonal photoperiods may dramatically and persistently alter the function of serotonin neurons.
authors.affiliation: Department of Biological Sciences, Vanderbilt University School of Medicine, Nashville, TN 37235, USA; Silvio O. Conte Center for Neuroscience Research, Vanderbilt University School of Medicine, Nashville, TN 37235, USA.
authors.forename: Noah H
authors.initials: NH
authors.lastname: Green
authors.affiliation: Department of Biological Sciences, Vanderbilt University School of Medicine, Nashville, TN 37235, USA; Silvio O. Conte Center for Neuroscience Research, Vanderbilt University School of Medicine, Nashville, TN 37235, USA.
authors.forename: Chad R
authors.initials: CR
authors.lastname: Jackson
authors.affiliation: Department of Biological Sciences, Vanderbilt University School of Medicine, Nashville, TN 37235, USA; Silvio O. Conte Center for Neuroscience Research, Vanderbilt University School of Medicine, Nashville, TN 37235, USA; Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37235, USA.
authors.forename: Hideki
authors.initials: H
authors.lastname: Iwamoto
authors.affiliation: Neuroscience Graduate Program, Vanderbilt University School of Medicine, Nashville, TN 37235, USA.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Tackenberg
authors.affiliation: Department of Biological Sciences, Vanderbilt University School of Medicine, Nashville, TN 37235, USA; Silvio O. Conte Center for Neuroscience Research, Vanderbilt University School of Medicine, Nashville, TN 37235, USA; Neuroscience Graduate Program, Vanderbilt University School of Medicine, Nashville, TN 37235, USA. Electronic address: douglas.g.mcmahon@vanderbilt.edu.
authors.forename: Douglas G
authors.initials: DG
authors.lastname: McMahon
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D058646:Adrenergic alpha-1 Receptor Agonists / Q000494:pharmacology; D000818:Animals; D065847:Dorsal Raphe Nucleus / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D008636:Mesencephalon / Q000502:physiology; D008809:Mice, Inbred C3H; D018345:Mice, Knockout; D009638:Norepinephrine / Q000502:physiology; D009924:Organ Culture Techniques; D010656:Phenylephrine / Q000494:pharmacology; D017440:Photoperiod; D044122:Receptor, Melatonin, MT1 / Q000235:genetics / Q000378:metabolism; D059326:Serotonergic Neurons / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000502:physiology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology
chemical_list: D058646:Adrenergic alpha-1 Receptor Agonists; D044122:Receptor, Melatonin, MT1; D017366:Serotonin Receptor Agonists; D010656:Phenylephrine; D012701:Serotonin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D009638:Norepinephrine