title: Medullary Reticular Neurons Mediate Neuropeptide Y-Induced Metabolic Inhibition and Mastication.
abstract: Hypothalamic neuropeptide Y (NPY) elicits hunger responses to increase the chances of surviving starvation: an inhibition of metabolism and an increase in feeding. Here we elucidate a key central circuit mechanism through which hypothalamic NPY signals drive these hunger responses. GABAergic neurons in the intermediate and parvicellular reticular nuclei (IRt/PCRt) of the medulla oblongata, which are activated by NPY-triggered neural signaling from the hypothalamus, potentially through the nucleus tractus solitarius, mediate the NPY-induced inhibition of metabolic thermogenesis in brown adipose tissue (BAT) via their innervation of BAT sympathetic premotor neurons. Intriguingly, the GABAergic IRt/PCRt neurons innervating the BAT sympathetic premotor region also innervate the masticatory motor region, and stimulation of the IRt/PCRt elicits mastication and increases feeding as well as inhibits BAT thermogenesis. These results indicate that GABAergic IRt/PCRt neurons mediate hypothalamus-derived hunger signaling by coordinating both autonomic and feeding motor systems to reduce energy expenditure and to promote feeding.
authors.affiliation: Department of Integrative Physiology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi 371-8511, Japan.
authors.forename: Yuchio
authors.initials: Y
authors.lastname: Yanagawa
authors.affiliation: Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, USA.
authors.forename: Shaun F
authors.initials: SF
authors.lastname: Morrison
authors.affiliation: Department of Integrative Physiology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan. Electronic address: kazu@med.nagoya-u.ac.jp.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nakamura
mesh_terms: D002001:Adipose Tissue, Brown / Q000294:innervation / Q000378:metabolism; D000818:Animals; D005247:Feeding Behavior; D059330:GABAergic Neurons / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism; D008297:Male; D008409:Mastication; D008526:Medulla Oblongata / Q000378:metabolism*; D009046:Motor Neurons / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D009474:Neurons / Q000378:metabolism*; D009478:Neuropeptide Y / Q000378:metabolism*; D011903:Raphe Nuclei / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D013564:Sympathetic Nervous System / Q000378:metabolism; D013569:Synapses / Q000378:metabolism; D013610:Tachycardia / Q000378:metabolism / Q000473:pathology; D022722:Thermogenesis
chemical_list: D009478:Neuropeptide Y
keywords: brown adipose tissue; cardiovascular; feeding; hunger; medulla; metabolism; neural circuit; obesity; sympathetic; thermoregulation