How do mice handle sudden temperature changes? - briefly
Mice rapidly adjust to abrupt temperature shifts by initiating shivering thermogenesis, activating brown adipose tissue, and constricting peripheral blood vessels, while simultaneously seeking microhabitats with more suitable thermal conditions. These physiological and behavioral responses restore core temperature within minutes, averting hypothermia or hyperthermia.
How do mice handle sudden temperature changes? - in detail
Mice maintain core temperature through rapid physiological adjustments when ambient temperature shifts abruptly. Vasoconstriction of peripheral blood vessels reduces heat loss, while brown adipose tissue (BAT) activation increases non‑shivering thermogenesis. Sympathetic nervous system releases norepinephrine, stimulating uncoupling protein‑1 in BAT mitochondria, producing heat without muscular activity.
Behavioral strategies complement autonomic responses. Upon exposure to cold, mice seek shelter, cluster together, and increase locomotor activity to generate additional warmth. In hot conditions, they display reduced movement, adopt sprawled postures to enhance surface area, and increase licking of forepaws to promote evaporative cooling.
Neural circuitry governing these reactions involves the preoptic area of the hypothalamus, which integrates peripheral temperature signals from cutaneous thermoreceptors. The hypothalamus modulates autonomic output and triggers motor pathways that coordinate grooming and postural changes.
Key experimental observations include:
- Immediate drop in tail skin temperature within seconds of cold exposure, indicating vasoconstriction.
- Elevation of BAT oxygen consumption within minutes, measurable by indirect calorimetry.
- Up‑regulation of heat‑shock protein expression in brain and muscle tissue after repeated thermal shocks.
- Increased expression of TRPM8 channels in dorsal root ganglia, enhancing cold detection sensitivity.
- Reduced core temperature plateau after pharmacological blockade of β‑adrenergic receptors, confirming sympathetic involvement.
Acclimation to repeated temperature fluctuations leads to long‑term adaptations: enhanced BAT mass, altered expression of thermogenic genes, and modified behavioral thresholds for seeking thermal refuge. These mechanisms collectively enable mice to survive and function despite rapid environmental temperature changes.