Concurrent and robust regulation of feeding behaviors and metabolism by orexin neurons

Orexin neurons in the hypothalamus regulate energy homeostasis by coordinating various physiological responses. Past studies have shown the role of the orexin peptide itself; however, orexin neurons contain not only orexin but also other neurotransmitters such as glutamate and dynorphin. In this study, we examined the physiological role of orexin neurons in feeding behavior and metabolism by pharmacogenetic activation and chronic ablation. We generated novel orexin-Cre mice and utilized Cre-dependent adeno-associated virus vectors to express Gq-coupled modified GPCR, hM3Dq or diphtheria toxin fragment A in orexin neurons. By intraperitoneal injection of clozapine-N oxide in orexin-Cre mice expressing hM3Dq in orexin neurons, we could selectively manipulate the activity of orexin neurons. Pharmacogenetic stimulation of orexin neurons simultaneously increased locomotive activity, food intake, water intake and the respiratory exchange ratio (RER). Elevation of blood glucose levels and RER persisted even after locomotion and feeding behaviors returned to basal levels. Accordantly, 83% ablation of orexin neurons resulted in decreased food and water intake, while 70% ablation had almost no effect on these parameters. Our results indicate that orexin neurons play an integral role in regulation of both feeding behavior and metabolism. This regulation is so robust that greater than 80% of orexin neurons were ablated before significant changes in feeding behavior emerged.

[1]  R. Huerta,et al.  Mechanism for Hypocretin-mediated sleep-to-wake transitions , 2012, Proceedings of the National Academy of Sciences.

[2]  R. Leak,et al.  The suprachiasmatic nucleus projects to posterior hypothalamic arousal systems , 2001, Neuroreport.

[3]  Jon T. Willie,et al.  Orexin (Hypocretin) Neurons Contain Dynorphin , 2001, The Journal of Neuroscience.

[4]  Takuya Sasaki,et al.  Optogenetic Countering of Glial Acidosis Suppresses Glial Glutamate Release and Ischemic Brain Damage , 2014, Neuron.

[5]  Edward S Boyden,et al.  Acute Optogenetic Silencing of Orexin/Hypocretin Neurons Induces Slow-Wave Sleep in Mice , 2011, The Journal of Neuroscience.

[6]  F E Bloom,et al.  The hypocretins: hypothalamus-specific peptides with neuroexcitatory activity. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[7]  Russell S. Ray,et al.  Impaired Respiratory and Body Temperature Control Upon Acute Serotonergic Neuron Inhibition , 2011, Science.

[8]  Jon T. Willie,et al.  Genetic Ablation of Orexin Neurons in Mice Results in Narcolepsy, Hypophagia, and Obesity , 2001, Neuron.

[9]  A. Inutsuka,et al.  The physiological role of orexin/hypocretin neurons in the regulation of sleep/wakefulness and neuroendocrine functions , 2013, Front. Endocrinol..

[10]  Ramón Huerta,et al.  Hypocretin (orexin) regulation of sleep-to-wake transitions , 2014, Front. Pharmacol..

[11]  M. Nicolelis,et al.  Remote Control of Neuronal Activity in Transgenic Mice Expressing Evolved G Protein-Coupled Receptors , 2009, Neuron.

[12]  Jon T. Willie,et al.  Narcolepsy in orexin Knockout Mice Molecular Genetics of Sleep Regulation , 1999, Cell.

[13]  N. Oppenheimer,et al.  Diphtheria toxin. Site and configuration of ADP-ribosylation of diphthamide in elongation factor 2. , 1981, The Journal of biological chemistry.

[14]  Sebastiaan Overeem,et al.  Hypocretin (orexin) deficiency in human narcolepsy , 2000, The Lancet.

[15]  B. Roth,et al.  Evolving the lock to fit the key to create a family of G protein-coupled receptors potently activated by an inert ligand , 2007, Proceedings of the National Academy of Sciences.

[16]  A. Yamanaka,et al.  Chronic intracerebroventricular administration of orexin-A to rats increases food intake in daytime, but has no effect on body weight , 1999, Brain Research.

[17]  Takeshi Sakurai,et al.  Distribution of orexin neurons in the adult rat brain 1 Published on the World Wide Web on 17 March 1999. 1 , 1999, Brain Research.

[18]  A. N. van den Pol,et al.  Neurons Containing Hypocretin (Orexin) Project to Multiple Neuronal Systems , 1998, The Journal of Neuroscience.

[19]  O. Paulsen,et al.  Cholinergic induction of network oscillations at 40 Hz in the hippocampus in vitro , 1998, Nature.

[20]  A. Lang,et al.  Parkinson's disease. First of two parts. , 1998, The New England journal of medicine.

[21]  C. Davies,et al.  Orexins induce increased Excitability and Synchronisation of Rat Sympathetic Preganglionic Neurones , 2003, Journal of Physiology.

[22]  Burton S. Rosner,et al.  Neuropharmacology , 1958, Nature.

[23]  A. Yamanaka,et al.  Orexins/hypocretins regulate drinking behaviour 1 Published on the World Wide Web on 4 August 1999. 1 , 1999, Brain Research.

[24]  T. Sakurai,et al.  The Human Prepro-orexin Gene Regulatory Region That Activates Gene Expression in the Lateral Region and Represses It in the Medial Regions of the Hypothalamus* , 2002, The Journal of Biological Chemistry.

[25]  A. Yamanaka,et al.  Orexin Directly Excites Orexin Neurons through Orexin 2 Receptor , 2010, The Journal of Neuroscience.

[26]  Sebastiaan Overeem,et al.  A mutation in a case of early onset narcolepsy and a generalized absence of hypocretin peptides in human narcoleptic brains , 2000, Nature Medicine.

[27]  S. Carr,et al.  Orexins and Orexin Receptors: A Family of Hypothalamic Neuropeptides and G Protein-Coupled Receptors that Regulate Feeding Behavior , 1998, Cell.

[28]  Wiklund Ra,et al.  First of two parts , 1997 .

[29]  B. Roth,et al.  Pharmacogenetic Modulation of Orexin Neurons Alters Sleep/Wakefulness States in Mice , 2011, Neuroscience Research.

[30]  Michael J Krashes,et al.  Rapid versus delayed stimulation of feeding by the endogenously released AgRP neuron mediators GABA, NPY, and AgRP. , 2013, Cell metabolism.

[31]  C. Saper,et al.  Fos Expression in Orexin Neurons Varies with Behavioral State , 2001, The Journal of Neuroscience.

[32]  S. Morrison,et al.  An orexinergic projection from perifornical hypothalamus to raphe pallidus increases rat brown adipose tissue thermogenesis , 2011, The Journal of Neuroscience.

[33]  Takeshi Sakurai,et al.  The neural circuit of orexin (hypocretin): maintaining sleep and wakefulness , 2007, Nature Reviews Neuroscience.

[34]  A. Yamanaka,et al.  Cholecystokinin Activates Orexin/Hypocretin Neurons through the Cholecystokinin A Receptor , 2005, The Journal of Neuroscience.

[35]  S. Carr,et al.  Orexins and orexin receptors: a family of hypothalamic neuropeptides and G protein-coupled receptors that regulate feeding behavior. , 1998, Cell.

[36]  T. Sakurai,et al.  Structure and Function of Human Prepro-orexin Gene* , 1999, The Journal of Biological Chemistry.

[37]  S. Sternson,et al.  A FLEX Switch Targets Channelrhodopsin-2 to Multiple Cell Types for Imaging and Long-Range Circuit Mapping , 2008, The Journal of Neuroscience.

[38]  Michael Aldrich,et al.  Reduced Number of Hypocretin Neurons in Human Narcolepsy , 2000, Neuron.

[39]  K. Deisseroth,et al.  Neural substrates of awakening probed with optogenetic control of hypocretin neurons , 2007, Nature.

[40]  Houeto Jean-Luc.  [Parkinson's disease]. , 2022, La Revue du praticien.

[41]  Jian Hua Li,et al.  A chemical-genetic approach to study G protein regulation of β cell function in vivo , 2009, Proceedings of the National Academy of Sciences.

[42]  A. Kalsbeek,et al.  A Major Role for Perifornical Orexin Neurons in the Control of Glucose Metabolism in Rats , 2009, Diabetes.

[43]  Smaroula Dilioglou,et al.  Correction of multi-gene deficiency in vivo using a single 'self-cleaving' 2A peptide–based retroviral vector , 2004, Nature Biotechnology.

[44]  Raphaelle Winsky-Sommerer,et al.  Arousal Effect of Caffeine Depends on Adenosine A2A Receptors in the Shell of the Nucleus Accumbens , 2011, The Journal of Neuroscience.