Using thermal preference to understand mouse thermal biology

Area of Science:

• Physiology
• Neuroscience
• Animal Behavior

Background:

• Homeotherms maintain a stable core body temperature (Tb) through thermoregulation.
• Behavioral thermoregulation, such as moving to a preferred thermal environment, is an energy-efficient mechanism.

Purpose of the Study:

• To optimize a mouse binary thermal preference assay for studying thermoregulation.
• To investigate factors influencing thermal preference in mice, including sex, age, fasting, and genetic manipulations.
• To assess the utility of thermal preference assays in detecting physiological changes.

Main Methods:

• Optimized a binary thermal preference assay using specific floor plate temperatures for male and female mice.
• Investigated the effects of fasting, aging, genetic ablation (uncoupling protein 1, adenosine receptors, estrogen receptor α), and drug treatments (CL-316243, MRS5698) on thermal preference.
• Compared thermal preference data with core body temperature (Tb) measurements.

Main Results:

• Female mice exhibited increased warm preference compared to males.
• Warm preference increased with age and fasting.
• Ablation of uncoupling protein 1 (Ucp1) or all adenosine receptors (Adora1, Adora2a, Adora2b, Adora3) increased warm preference.
• Estrogen receptor α (Esr1) ablation reduced warm preference in females but not males.
• Specific agonists (CL-316243, MRS5698) induced a preference for cooler temperatures.
• Thermal preference assays were more sensitive than Tb measurements for detecting certain physiological changes.

Conclusions:

• Thermal preference assays provide valuable insights into thermoregulatory mechanisms.
• Factors such as sex, age, fasting, and specific genetic or pharmacological interventions significantly modulate thermal preference.
• Behavioral thermal preference is a sensitive indicator of altered thermoregulation, potentially reflecting changes in thermal setpoints.