Core to Surface Thermal Gradients in the Rat at Several Environmental Temperatures

Abstract

Clipped (restrained and nonrestrained) and nonclipped (restrained and nonrestrained) adult male rats were exposed to varying cold environments. Colonic, subcutaneous and cutaneous temperatures were measured. Restraint produced hypothermia at low temperatures (0 and 8°C) and at higher temperatures (16 and 28°C) it resulted in the virtual disappearance of the normal subcutaneous to skin surface temperature gradient. It was also observed that when the severity of stress was increased (e.g. by lowering the temperature of the cold room or adding clipping to the cold stress) the thermolability among the individuals of a group of restrained animals not only increased but also appeared to be more uniform. Thus with mild stress (e.g. clipping with severe cold or restraint with mild cold) only some of the animals showed thermolability but with a more severe stress all animals became hypothermic.