title: Role of orexin-A in the ventrolateral preoptic area on components of total energy expenditure.
abstract: Identifying whether components of total energy expenditure (EE) are affected by orexin receptor (OXR1 and OXR2) stimulation or antagonism with dual orexin receptor antagonists (DORAs) has relevance for obesity treatment. Orexin receptor stimulation reduces weight gain by increasing total EE and EE during spontaneous physical activity (SPA).
  
  
  
  The purpose of this study was to determine if a DORA (TCS-1102) in the ventrolateral preoptic area (VLPO) reduced orexin-A-induced arousal, SPA, total EE and EE during sleep, rest, wake and SPA and whether the DORA alone reduced total EE and its components. We hypothesized that: (1) a DORA would reduce orexin-A induced increases in arousal, SPA, components of total EE, reductions in sleep and the EE during sleep and (2) the DORA alone would reduce baseline (non-stimulated) SPA and total EE.
  
  
  
  Sleep, wakefulness, SPA and EE were determined after microinjection of the DORA (TCS-1102) and orexin-A in the VLPO of male Sprague-Dawley rats with a unilateral cannula targeted towards the VLPO. Individual components of total EE were determined based on time-stamped data.
  
  
  
  The DORA reduced orexin-A-induced increases in arousal, SPA, total EE and EE during SPA, wake, rest and sleep 1 h post injection (P<0.05). Orexin-A significantly reduced sleep and significantly increased EE during sleep 1 h post injection (P<0.05). Furthermore, the DORA alone significantly reduced total EE, EE during sleep (NREM and REM) and resting EE 2 h post injection (P<0.05).
  
  
  
  These data suggest that orexin-A reduces weight gain by stimulating total EE through increases in EE during SPA, rest and sleep. Residual effects of the DORA alone include decreases in total EE and EE during sleep and rest, which may promote weight gain.
authors.affiliation: Department of Nutritional Sciences, University of Arizona, Tucson, AZ, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Coborn
authors.affiliation: Department of Nutritional Sciences, University of Arizona, Tucson, AZ, USA.
authors.forename: D P
authors.initials: DP
authors.lastname: DePorter
authors.affiliation: Minneapolis VA Health Care System, Minneapolis, MN, USA.
authors.forename: V
authors.initials: V
authors.lastname: Mavanji
authors.affiliation: Arizona Respiratory Center, University of Arizona, Tucson, AZ, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Sinton
authors.affiliation: Minneapolis VA Health Care System, Minneapolis, MN, USA.|Geriatric Research Education and Clinical Center, Minneapolis, MN, USA.|Minnesota Obesity Center, Saint Paul, MN, USA.|Department of Food Science and Nutrition, University of Minnesota, Saint Paul, MN, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Kotz
authors.affiliation: Minneapolis VA Health Care System, Minneapolis, MN, USA.|Minnesota Obesity Center, Saint Paul, MN, USA.|Department of Food Science and Nutrition, University of Minnesota, Saint Paul, MN, USA.|Department of Medicine, University of Minnesota, Minneapolis, MN, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Billington
authors.affiliation: Department of Nutritional Sciences, University of Arizona, Tucson, AZ, USA.|Minneapolis VA Health Care System, Minneapolis, MN, USA.|Minnesota Obesity Center, Saint Paul, MN, USA.|Department of Food Science and Nutrition, University of Minnesota, Saint Paul, MN, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Teske
mesh_terms: D000818:Animals; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008297:Male; D009765:Obesity / Q000188:drug therapy / Q000378:metabolism; D000068796:Orexin Receptor Antagonists / Q000494:pharmacology; D000068797:Orexins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011301:Preoptic Area / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012890:Sleep / Q000187:drug effects / Q000502:physiology; D014851:Wakefulness / Q000187:drug effects / Q000502:physiology; D015430:Weight Gain / Q000187:drug effects
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D000068796:Orexin Receptor Antagonists; D000068797:Orexins