Brown adipose tissue thermogenesis heats brain and body as part of the brain-coordinated ultradian basic rest-activity cycle

Y. Ootsuka, R. C. de Menezes, D. V. Zaretsky, A. Alimoradian, J. Hunt, A. Stefanidis, B. J. Oldfield, W. W. Blessing

Research output: Contribution to journalArticle

63 Scopus citations

Abstract

Brown adipose tissue (BAT), body and brain temperatures, as well as behavioral activity, arterial pressure and heart rate, increase episodically during the waking (dark) phase of the circadian cycle in rats. Phase-linking of combinations of these ultradian (<24 h) events has previously been noted, but no synthesis of their overall interrelationships has emerged. We hypothesized that they are coordinated by brain central command, and that BAT thermogenesis, itself controlled by the brain, contributes to increases in brain and body temperature. We used chronically implanted instruments to measure combinations of bat, brain and body temperatures, behavioral activity, tail artery blood flow, and arterial pressure and heart rate, in conscious freely moving Sprague-Dawley rats during the 12-h dark active period. Ambient temperature was kept constant for any particular 24-h day, varying between 22 and 27 °C on different days. Increases in BAT temperature (≥0.5 °C) occurred in an irregular episodic manner every 94±43 min (mean±SD). Varying the temperature over a wider range (18-30 °C) on different days did not change the periodicity, and neither body nor brain temperature fell before BAT temperature episodic increases. These increases are thus unlikely to reflect thermoregulatory homeostasis. Episodic BAT thermogenesis still occurred in food-deprived rats. Behavioral activity, arterial pressure (18±5 mmHg every 98±49 min) and heart rate (86±31 beats/min) increased approximately 3 min before each increase in BAT temperature. Increases in BAT temperature (1.1±0.4 °C) were larger than corresponding increases in brain (0.8±0.4 °C) and body (0.6±0.3 °C) temperature and the BAT episodes commenced 2-3 min before body and brain episodes, suggesting that BAT thermogenesis warms body and brain. Hippocampal 5-8 Hz theta rhythm, indicating active engagement with the environment, increased before the behavioral and autonomic events, suggesting coordination by brain central command as part of the 1-2 h ultradian basic rest-activity cycle (BRAC) proposed by Kleitman.

Original languageEnglish (US)
Pages (from-to)849-861
Number of pages13
JournalNeuroscience
Volume164
Issue number2
DOIs
StatePublished - Dec 1 2009

Keywords

  • arterial blood pressure
  • hippocampal theta rhythm
  • sleep
  • temperature
  • thermoregulation
  • wavelet mathematics

ASJC Scopus subject areas

  • Neuroscience(all)

Fingerprint Dive into the research topics of 'Brown adipose tissue thermogenesis heats brain and body as part of the brain-coordinated ultradian basic rest-activity cycle'. Together they form a unique fingerprint.

  • Cite this

    Ootsuka, Y., de Menezes, R. C., Zaretsky, D. V., Alimoradian, A., Hunt, J., Stefanidis, A., Oldfield, B. J., & Blessing, W. W. (2009). Brown adipose tissue thermogenesis heats brain and body as part of the brain-coordinated ultradian basic rest-activity cycle. Neuroscience, 164(2), 849-861. https://doi.org/10.1016/j.neuroscience.2009.08.013