Circadian Clock and Body Temperature.

Area of Science:

• Chronobiology
• Physiology
• Molecular Biology

Background:

• Circadian rhythms govern daily physiological cycles, with body temperature oscillation being a key output.
• This daily temperature fluctuation (1-3°C) synchronizes peripheral clocks and maintains energy homeostasis.
• Thermal entrainment involves factors like heat shock transcription factor and cold-inducible RNA-binding protein influencing clock gene expression.

Purpose of the Study:

• To review the intricate relationship between circadian clock mechanisms and body temperature regulation.
• To highlight conserved molecular pathways involved in thermoregulation across species.
• To synthesize current knowledge on how body temperature influences and is influenced by the circadian system.

Main Methods:

• Literature review of studies on circadian rhythms and body temperature.
• Analysis of molecular mechanisms underlying thermal entrainment in the circadian clock.
• Comparative analysis of thermoregulation and clock gene expression in different animal models (poikilotherms, flies, mice).

Main Results:

• Body temperature exhibits a stable circadian oscillation vital for energy homeostasis.
• Specific molecular players, including heat shock transcription factor, cold-inducible RNA-binding protein, and calcitonin receptors, mediate thermal entrainment.
• Conserved molecular circuits, particularly involving calcitonin receptors in clock neurons, regulate body temperature rhythms in both flies and mice.

Conclusions:

• Body temperature regulation and the circadian clock are deeply interconnected, with reciprocal influences.
• Understanding these relationships is key to comprehending physiological synchrony and energy balance.
• Shared molecular pathways underscore the evolutionary importance of circadian thermoregulation.