Rabbit's ear in cold acclimation studied on the change in ear temperature

Area of Science:

• Physiology
• Animal Biology
• Thermoregulation

Background:

• The rabbit's ear is a significant site for thermoregulation.
• Understanding cold acclimation is crucial for animal physiology research.

Purpose of the Study:

• To investigate the role of the rabbit's ear in cold acclimation.
• To determine if changes in ambient temperature affect ear skin temperature.
• To establish a method for assessing cold acclimation in rabbits.

Main Methods:

• Ambient temperatures were varied from -10 to +30 degrees C in a climatic room.
• Non-anesthetized rabbit ear skin temperatures were recorded.
• The effect of norepinephrine on isolated rabbit ear pressure-flow was analyzed before and after cold acclimation.

Main Results:

• Rabbit ear skin temperature exhibited an S-shaped curve in response to ambient temperature.
• Cold acclimation (7 weeks at -10 degrees C) shifted the curve's inflection point from 13 degrees C to 8 degrees C.
• Norepinephrine sensitivity in ear vascular beds remained largely unchanged post-acclimation.

Conclusions:

• The shift in the ear temperature's S-shaped curve serves as a qualitative index of cold acclimation.
• Changes in thermoregulation, not norepinephrine sensitivity, are likely responsible for the observed shift.
• This study provides a novel method for evaluating an animal's acclimated state to cold.