Continuous exposure to a novel stressor based on water aversion induces abnormal circadian locomotor rhythms and sleep-wake cycles in mice

PLoS One. 2013;8(1):e55452. doi: 10.1371/journal.pone.0055452. Epub 2013 Jan 30.


Psychological stressors prominently affect diurnal rhythms, including locomotor activity, sleep, blood pressure, and body temperature, in humans. Here, we found that a novel continuous stress imposed by the perpetual avoidance of water on a wheel (PAWW) affected several physiological diurnal rhythms in mice. One week of PAWW stress decayed robust circadian locomotor rhythmicity, while locomotor activity was evident even during the light period when the mice are normally asleep. Daytime activity was significantly upregulated, whereas nighttime activity was downregulated, resulting in a low amplitude of activity. Total daily activity gradually decreased with increasing exposure to PAWW stress. The mice could be exposed to PAWW stress for over 3 weeks without adaptation. Furthermore, continuous PAWW stress enhanced food intake, but decreased body weight and plasma leptin levels, indicating that sleep loss and PAWW stress altered the energy balance in these mice. The diurnal rhythm of corticosterone levels was not severely affected. The body temperature rhythm was diurnal in the stressed mice, but significantly dysregulated during the dark period. Plasma catecholamines were elevated in the stressed mice. Continuous PAWW stress reduced the duration of daytime sleep, especially during the first half of the light period, and increased nighttime sleepiness. Continuous PAWW stress also simultaneously obscured sleep/wake and locomotor activity rhythms compared with control mice. These sleep architecture phenotypes under stress are similar to those of patients with insomnia. The stressed mice could be entrained to the light/dark cycle, and when they were transferred to constant darkness, they exhibited a free-running circadian rhythm with a timing of activity onset predicted by the phase of their entrained rhythms. Circadian gene expression in the liver and muscle was unaltered, indicating that the peripheral clocks in these tissues remained intact.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ARNTL Transcription Factors / metabolism
  • Analysis of Variance
  • Animals
  • Body Temperature Regulation / physiology
  • Catecholamines / blood
  • Circadian Rhythm / physiology*
  • Corticosterone / blood
  • DNA Primers / genetics
  • Electroencephalography
  • Enzyme-Linked Immunosorbent Assay
  • Gene Expression Regulation / physiology
  • Male
  • Mice
  • Motor Activity / physiology*
  • Period Circadian Proteins / metabolism
  • Real-Time Polymerase Chain Reaction
  • Sleep Disorders, Circadian Rhythm / etiology*
  • Stress, Psychological / complications
  • Stress, Psychological / physiopathology*
  • Water*


  • ARNTL Transcription Factors
  • Arntl protein, mouse
  • Catecholamines
  • DNA Primers
  • Per2 protein, mouse
  • Period Circadian Proteins
  • Water
  • Corticosterone

Grant support

This study was supported by operational subsidies from AIST, and a Grant-in Aid for Scientific Research KAKENHI 23607040 to K. Miyazaki from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan. The study was also partially funded by a Yamada Bee Farm Grant for Honeybee Research ( to K. Oishi. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.