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The physiological signature of daily torpor is not orexin dependent
- Publication Year :
- 2020
-
Abstract
- Under conditions of scarce food availability and cool ambient temperature, the mouse (Mus Musculus) enters into torpor, a state of transient metabolic suppression mediated in part by the autonomic nervous system. Hypothalamic orexins are involved in the coordination of behaviors and autonomic function. We tested whether orexins are necessary for the coordinated changes in physiological variables, which underlie torpor and represent its physiological signature. We performed simultaneous measurements of brain temperature, electroencephalographic, and electromyographic activity allowing objective assessment of wake-sleep behavior, and cardiovascular, respiratory, and metabolic variables in orexin knockout mice (ORX-KO) and wild-type mice (WT) during torpor bouts elicited by caloric restriction and mild cold stress. We found that torpor bouts in WT are characterized by an exquisitely coordinated physiological signature. The characteristics of torpor bouts in terms of duration and rate of change of brain temperature and electromyographic activity at torpor entrance and exit did not differ significantly between ORX-KO and WT, and neither did the cardiovascular, respiratory, and metabolic characteristics of torpor. ORX-KO and WT also had similar wake-sleep state changes associated with torpor bouts, with the exception of a significantly higher rapid-eye movement sleep time in ORX-KO at torpor entrance. Our results demonstrate that orexins are not necessary either for the normal physiological adaptations occurring during torpor in mice or for their coordination, suggesting that mechanisms different from orexin peptide signaling may be involved in the regulation and the coordination of these physiological responses.
- Subjects :
- 030110 physiology
0106 biological sciences
0301 basic medicine
medicine.medical_specialty
Physiology
Torpor
Biology
Metabolic rate
Cardiovascular
010603 evolutionary biology
01 natural sciences
Biochemistry
03 medical and health sciences
Oxygen Consumption
Endocrinology
Internal medicine
Orexins/hypocretin
medicine
Animals
Wakefulness
Respiratory system
Ecology, Evolution, Behavior and Systematics
Cold stress
Mice, Knockout
Orexins
Electromyography
Brain
Electroencephalography
Sleep in non-human animals
Ventilation
Orexin
Mice, Inbred C57BL
Autonomic nervous system
Knockout mouse
Breathing
Female
Animal Science and Zoology
Sleep
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....00e225ff9c1b93247f9fb524b854640b