Daily changes of cytochrome oxidase activity within the suprachiasmatic nucleus of the Syrian hamster.
Cytochrome oxidase (CO) activity was studied over a 24-h period in the Syrian hamster suprachiasmatic nucleus (SCN) (site of the biological clock), anterior hypothalamic area (AHA), and motor cortex. The SCN CO activity was highest at the middle of the day (Zeitgeber time (ZT) 05), decreased at the end of the light period (ZT 10) and continued at a low level during the night (ZT 13, 16, 21.5 and 24). AHA and motor cortex showed a similar profile of CO activity and no changes of CO activity were found in animals maintained under darkness (DD). We propose that photic input plays a role in the SCN neuronal activity that modulates metabolic activity on this area.
Ximenes da Silva
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A
Laboratoire de Neurobiologie des Fonctions Végétatives, INRA 78350, Jouy en Josas, France. ximenes@jouy.inra.fr
Gendrot
G
G
Servière
J
J
Lavialle
M
M
D000818:Animals; D007025:Anterior Hypothalamic Nucleus / Q000166:cytology / Q000378:metabolism; D015415:Biomarkers; D002940:Circadian Rhythm / Q000502:physiology*; D006224:Cricetinae; D003576:Electron Transport Complex IV / Q000378:metabolism*; D004734:Energy Metabolism / Q000502:physiology; D008297:Male; D009044:Motor Cortex / Q000166:cytology / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D010775:Photic Stimulation; D013493:Suprachiasmatic Nucleus / Q000166:cytology / Q000378:metabolism*; D013997:Time Factors
D015415:Biomarkers; D003576:Electron Transport Complex IV