title: Suprachiasmatic Nucleus Interaction with the Arcuate Nucleus; Essential for Organizing Physiological Rhythms.
abstract: The suprachiasmatic nucleus (SCN) is generally considered the master clock, independently driving all circadian rhythms. We recently demonstrated the SCN receives metabolic and cardiovascular feedback adeptly altering its neuronal activity. In the present study, we show that microcuts effectively removing SCN-arcuate nucleus (ARC) interconnectivity in Wistar rats result in a loss of rhythmicity in locomotor activity, corticosterone levels, and body temperature in constant dark (DD) conditions. Elimination of these reciprocal connections did not affect SCN clock gene rhythmicity but did cause the ARC to desynchronize. Moreover, unilateral SCN lesions with contralateral retrochiasmatic microcuts resulted in identical arrhythmicity, proving that for the expression of physiological rhythms this reciprocal SCN-ARC interaction is essential. The unaltered SCN c-Fos expression following glucose administration in disconnected animals as compared to a significant decrease in controls demonstrates the importance of the ARC as metabolic modulator of SCN neuronal activity. Together, these results indicate that the SCN is more than an autonomous clock, and forms an essential component of a larger network controlling homeostasis. The present novel findings illustrate how an imbalance between SCN and ARC communication through circadian disruption could be involved in the etiology of metabolic disorders.
authors.affiliation: Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria , 04510 Mexico DF , Mexico.
authors.forename: Frederik N
authors.identifier: 0000-0003-3894-4632
authors.initials: FN
authors.lastname: Buijs
authors.affiliation: Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria , 04510 Mexico DF , Mexico.
authors.forename: Mara
authors.initials: M
authors.lastname: Guzmán-Ruiz
authors.affiliation: Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria , 04510 Mexico DF , Mexico.
authors.forename: Luis
authors.identifier: 0000-0001-6362-7968
authors.initials: L
authors.lastname: León-Mercado
authors.affiliation: Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria , 04510 Mexico DF , Mexico.
authors.forename: Mari Carmen
authors.identifier: 0000-0002-5932-9148
authors.initials: MC
authors.lastname: Basualdo
authors.affiliation: Departamento de Anatomia, Facultad de Medicina, UNAM, Ciudad Universitaria , 04510 Mexico DF , Mexico.
authors.forename: Carolina
authors.identifier: 0000-0002-2974-7875
authors.initials: C
authors.lastname: Escobar
authors.affiliation: Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences , Amsterdam 1105 BA, The Netherlands.
authors.forename: Andries
authors.identifier: 0000-0001-9606-8453
authors.initials: A
authors.lastname: Kalsbeek
authors.affiliation: Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria , 04510 Mexico DF , Mexico.
authors.forename: Ruud M
authors.identifier: 0000-0003-3894-4632
authors.initials: RM
authors.lastname: Buijs
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000473:pathology / Q000502:physiology* / Q000503:physiopathology; D001831:Body Temperature / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D003345:Corticosterone / Q000378:metabolism; D005947:Glucose / Q000008:administration & dosage / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D023421:Models, Animal; D009043:Motor Activity / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology / Q000503:physiopathology; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D056950:Period Circadian Proteins / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D017208:Rats, Wistar; D013493:Suprachiasmatic Nucleus / Q000473:pathology / Q000502:physiology* / Q000503:physiopathology
chemical_list: D056950:Period Circadian Proteins; D016760:Proto-Oncogene Proteins c-fos; D005947:Glucose; D003345:Corticosterone
keywords: circadian rhythm; clock genes; melatonin; network; oscillator coupling; temperature