title: A descending dopamine pathway conserved from basal vertebrates to mammals.
abstract: Dopamine neurons are classically known to modulate locomotion indirectly through ascending projections to the basal ganglia that project down to brainstem locomotor networks. Their loss in Parkinson's disease is devastating. In lampreys, we recently showed that brainstem networks also receive direct descending dopaminergic inputs that potentiate locomotor output. Here, we provide evidence that this descending dopaminergic pathway is conserved to higher vertebrates, including mammals. In salamanders, dopamine neurons projecting to the striatum or brainstem locomotor networks were partly intermingled. Stimulation of the dopaminergic region evoked dopamine release in brainstem locomotor networks and concurrent reticulospinal activity. In rats, some dopamine neurons projecting to the striatum also innervated the pedunculopontine nucleus, a known locomotor center, and stimulation of the dopaminergic region evoked pedunculopontine dopamine release in vivo. Finally, we found dopaminergic fibers in the human pedunculopontine nucleus. The conservation of a descending dopaminergic pathway across vertebrates warrants re-evaluating dopamine's role in locomotion.
authors.affiliation: Groupe de Recherche sur le Système Nerveux Central, Département de Neurosciences, Université de Montréal, Montreal, QC, Canada H3C 3J7;
authors.forename: Dimitri
authors.initials: D
authors.lastname: Ryczko
authors.affiliation: Department of Psychology, University of Illinois, Chicago, IL 60607;
authors.forename: Jackson J
authors.initials: JJ
authors.lastname: Cone
authors.affiliation: Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607;
authors.forename: Michael H
authors.initials: MH
authors.lastname: Alpert
authors.affiliation: Department of Psychiatry and Neuroscience, Faculty of Medicine, Centre de Recherche de l'Institut Universitaire en Santé Mentale de Québec, Université Laval, Quebec, QC, Canada G1J 2G3;
authors.forename: Laurent
authors.initials: L
authors.lastname: Goetz
authors.affiliation: Groupe de Recherche sur le Système Nerveux Central, Département de Neurosciences, Université de Montréal, Montreal, QC, Canada H3C 3J7;
authors.forename: François
authors.initials: F
authors.lastname: Auclair
authors.affiliation: Groupe de Recherche sur le Système Nerveux Central, Département de Neurosciences, Université de Montréal, Montreal, QC, Canada H3C 3J7;
authors.forename: Catherine
authors.initials: C
authors.lastname: Dubé
authors.affiliation: Department of Psychiatry and Neuroscience, Faculty of Medicine, Centre de Recherche de l'Institut Universitaire en Santé Mentale de Québec, Université Laval, Quebec, QC, Canada G1J 2G3;
authors.forename: Martin
authors.initials: M
authors.lastname: Parent
authors.affiliation: Department of Psychology, University of Illinois, Chicago, IL 60607;
authors.forename: Mitchell F
authors.initials: MF
authors.lastname: Roitman
authors.affiliation: Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607;
authors.forename: Simon
authors.initials: S
authors.lastname: Alford
authors.affiliation: Groupe de Recherche sur le Système Nerveux Central, Département de Neurosciences, Université de Montréal, Montreal, QC, Canada H3C 3J7; Département des Sciences de l'Activité Physique, Université du Québec à Montréal, Montreal, QC, Canada H3C 3P8 rejean.dubuc@gmail.com.
authors.forename: Réjean
authors.initials: R
authors.lastname: Dubuc
mesh_terms: D000368:Aged; D000818:Animals; D005075:Biological Evolution; D001933:Brain Stem / Q000502:physiology*; D003342:Corpus Striatum / Q000502:physiology; D004298:Dopamine; D059290:Dopaminergic Neurons / Q000502:physiology*; D005260:Female; D006801:Humans; D007798:Lampreys / Q000502:physiology; D008124:Locomotion / Q000502:physiology*; D008297:Male; D009044:Motor Cortex / Q000502:physiology; D045042:Pedunculopontine Tegmental Nucleus / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D055647:Rats, Transgenic; D014562:Caudata / Q000502:physiology
chemical_list: D004298:Dopamine
keywords: Parkinson disease; brainstem; conservation; dopamine; motor system