Relationship between autonomic and behavioral thermoregulation in the mouse

Area of Science:

• Physiology
• Thermoregulation
• Animal Behavior

Background:

• Understanding thermoregulation is crucial for physiological studies.
• Mice (BALB/c strain) are common models for mammalian physiology research.
• Preferred ambient temperature (Ta) influences metabolic rate and thermal balance.

Purpose of the Study:

• To determine the preferred ambient temperature (Ta) for BALB/c mice.
• To investigate the physiological parameters associated with the preferred Ta.
• To understand the trade-offs between energy expenditure and evaporative heat loss in mice.

Main Methods:

• Measurement of preferred ambient temperature (Ta) using a temperature gradient in BALB/c mice.
• Assessment of metabolic rate, evaporative water loss, and colonic temperature across a range of Ta (18-34°C).
• Calculation of whole-body thermal conductance.

Main Results:

• The mean preferred Ta for BALB/c mice was 30.9°C.
• This preferred Ta was near the lower critical temperature, indicating increased metabolic rate below this point.
• At the preferred Ta, evaporative water loss was 57% higher (per O2 consumed) and thermal conductance was 92% above baseline, while maintaining normothermic colonic temperature (37.0-37.5°C).

Conclusions:

• BALB/c mice select an ambient temperature that minimizes energy expenditure for thermoregulation.
• This preferred temperature involves a higher rate of evaporative heat loss and increased thermal conductance.
• The findings highlight a strategy in mice to balance metabolic cost with heat dissipation.