Handling elevates the colonic temperature of mice.

Handling mice for repeatedly measuring their colonic temperature (Tc) resulted in a significant rise in their Tc. When the procedure was repeated day after day, this response diminished by habituation, showing the emotional origin of Tc rise. Salicylate lowered both the maximal Tc reached during handling and the Tc before handling without affecting the difference between the initial and the maximal Tc. During the first Tc measurement in a session, concomitant to the Tc rise, ear pinna temperature decreased. When Tc reached a plateau during the last measurements, ear temperature increased. This vasomotor response suggests that stress Tc rise is a regulated Tc change. However, since, contrary to what was reported in the rat, the salicylate did not diminish the magnitude of the Tc rise, it is doubtful that the emotional Tc rise in mice is a true fever.