title: Role of the Suprachiasmatic and Arcuate Nuclei in Diurnal Temperature Regulation in the Rat.
abstract: In mammals, daily changes in body temperature (Tb) depend on the integrity of the suprachiasmatic nucleus (SCN). Fasting influences the Tb in the resting period and the presence of the SCN is essential for this process. However, the origin of this circadian/metabolic influence is unknown. We hypothesized that, not only the SCN but also the arcuate nucleus (ARC), are involved in the Tb setting through afferents to the thermoregulatory median preoptic nucleus (MnPO). Therefore, we investigated by neuronal tracing and microdialysis experiments the possible targeting of the MnPO by the SCN and the ARC in male Wistar rats. We observed that vasopressin release from the SCN decreases the temperature just before light onset, whereas α-melanocyte stimulating hormone release, especially at the end of the dark period, maintains high temperature. Both peptides have opposite effects on the brown adipose tissue activity through thermoregulatory nuclei such as the dorsomedial nucleus of the hypothalamus and the dorsal raphe nucleus. The present study indicates that the coordination between circadian and metabolic signaling within the hypothalamus is essential for an adequate temperature control.
  
  
  CONCLUSIONS
  When circadian and metabolic systems are not well synchronized, individuals may develop metabolic diseases. The underlying mechanisms are unknown. Here, we demonstrate that the balance between the releases of neuropeptides derived from the biological clock and from a metabolic sensory organ as the arcuate nucleus, are essential for an adequate temperature control. These observations show that brain areas involved in circadian and metabolic functions of the body need to interact to produce a coherent arrangement of physiological processes associated with temperature control.
authors.affiliation: Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, PC 04510 Mexico D.F., Mexico, and.
authors.forename: Mara Alaide
authors.initials: MA
authors.lastname: Guzmán-Ruiz
authors.affiliation: Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, PC 04510 Mexico D.F., Mexico, and.
authors.forename: Arlen
authors.identifier: http://orcid.org/0000-0001-6498-3948
authors.initials: A
authors.lastname: Ramirez-Corona
authors.affiliation: Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, PC 04510 Mexico D.F., Mexico, and.
authors.forename: Natali Nadia
authors.initials: NN
authors.lastname: Guerrero-Vargas
authors.affiliation: Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, PC 04510 Mexico D.F., Mexico, and.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Sabath
authors.affiliation: Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, PC 04510 Mexico D.F., Mexico, and.
authors.forename: Oscar Daniel
authors.identifier: http://orcid.org/0000-0002-6862-4974
authors.initials: OD
authors.lastname: Ramirez-Plascencia
authors.affiliation: Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, PC 04510 Mexico D.F., Mexico, and.
authors.forename: Rebecca
authors.identifier: http://orcid.org/0000-0002-0755-8651
authors.initials: R
authors.lastname: Fuentes-Romero
authors.affiliation: Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, PC 04510 Mexico D.F., Mexico, and.
authors.forename: Luis Abel
authors.initials: LA
authors.lastname: León-Mercado
authors.affiliation: Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, PC 04510 Mexico D.F., Mexico, and.
authors.forename: MariCarmen
authors.initials: M
authors.lastname: Basualdo Sigales
authors.affiliation: Facultad de Medicina, Departamento de Anatomía, Universidad Nacional Autónoma de México, Ciudad Universitaria, PC 04510 Mexico D.F., Mexico.
authors.forename: Carolina
authors.initials: C
authors.lastname: Escobar
authors.affiliation: Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, PC 04510 Mexico D.F., Mexico, and ruudbuijs@gmail.com.
authors.forename: Ruud Marinus
authors.identifier: http://orcid.org/0000-0003-3894-4632
authors.initials: RM
authors.lastname: Buijs
mesh_terms: D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists / Q000494:pharmacology; D001111:Arcuate Nucleus of Hypothalamus / Q000166:cytology / Q000502:physiology*; D001127:Arginine Vasopressin / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D002772:Cholera Toxin / Q000493:pharmacokinetics; D002940:Circadian Rhythm / Q000502:physiology*; D005968:Glutamate Decarboxylase / Q000378:metabolism; D009074:Melanocyte-Stimulating Hormones / Q000494:pharmacology; D017551:Microdialysis; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009479:Neuropeptides / Q000494:pharmacology; D010775:Photic Stimulation; D011301:Preoptic Area / Q000187:drug effects / Q000502:physiology; D016760:Proto-Oncogene Proteins c-fos; D051381:Rats; D013493:Suprachiasmatic Nucleus / Q000166:cytology / Q000502:physiology*; D013696:Temperature; D000521:alpha-MSH / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; D009479:Neuropeptides; D016760:Proto-Oncogene Proteins c-fos; C105974:acetyl-norleucyl(4)-(aspartyl(5)-histidyl(6)-phenylalanyl(7)-arginyl(8)-tryptophyl(9)-lysyl(10))cyclo-alpha-MSH(4-10)amide; C549395:vasopressin, deaminoPen(1)-O-Me-Tyr(2)-Arg(8)-; D001127:Arginine Vasopressin; C103272:SHU 9119; C107065:argipressin, Gly(OH9)-; D000521:alpha-MSH; D009074:Melanocyte-Stimulating Hormones; D002772:Cholera Toxin; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2
keywords: arcuate; body temperature; median preoptic nucleus; suprachiasmatic; vasopressin; α-melanocyte-stimulating hormone