Circadian organization is governed by extra-SCN pacemakers.
In mammals, a pacemaker in the suprachiasmatic nucleus (SCN) is thought to be required for behavioral, physiological, and molecular circadian rhythms. However, there is considerable evidence that temporal food restriction (restricted feedisng [RF]) and chronic methamphetamine (MA) can drive circadian rhythms of locomotor activity, body temperature, and endocrine function in the absence of SCN. This indicates the existence of extra-SCN pacemakers: the Food Entrainable Oscillator (FEO) and Methamphetamine Sensitive Circadian Oscillator (MASCO). Here, we show that these extra-SCN pacemakers control the phases of peripheral oscillators in intact as well as in SCN-ablated PER2::LUC mice. MA administration shifted the phases of SCN, cornea, pineal, pituitary, kidney, and salivary glands in intact animals. When the SCN was ablated, disrupted phase relationships among peripheral oscillators were reinstated by MA treatment. When intact animals were subjected to restricted feeding, the phases of cornea, pineal, kidney, salivary gland, lung, and liver were shifted. In SCN-lesioned restricted-fed mice, phases of all of the tissues shifted such that they aligned with the time of the meal. Taken together, these data show that FEO and MASCO are strong circadian pacemakers able to regulate the phases of peripheral oscillators.
Department of Biology, University of Virginia, Charlottesville, VA, USA.
Pinar
P
Pezuk
Jennifer A
JA
Mohawk
Tomoko
T
Yoshikawa
Michael T
MT
Sellix
Michael
M
Menaker
D000818:Animals; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D002940:Circadian Rhythm / Q000502:physiology*; D003315:Cornea / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology; D005260:Female; D007668:Kidney / Q000502:physiology; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology; D051379:Mice; D008822:Mice, Transgenic; D009043:Motor Activity / Q000502:physiology*; D056950:Period Circadian Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010870:Pineal Gland / Q000502:physiology; D010902:Pituitary Gland / Q000502:physiology; D012469:Salivary Glands / Q000502:physiology; D013493:Suprachiasmatic Nucleus / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*
D000697:Central Nervous System Stimulants; C513312:Per2 protein, mouse; D056950:Period Circadian Proteins; D008694:Methamphetamine; D008156:Luciferases