Stress hyperthermia: physiological arguments that it is a fever.

Area of Science:

• Physiology
• Neuroscience
• Behavioral Science

Background:

• Stress and emotional states can alter body temperature.
• The precise thermoregulatory mechanisms underlying stress-induced temperature changes are not fully understood.
• Distinguishing between fever and hyperthermia is crucial for understanding physiological responses.

Purpose of the Study:

• To test the hypothesis that stress-induced rise in central temperature (Tc) in rats is a regulated fever with an upward set-point shift.
• To investigate the role of skin vasomotor responses in emotional thermoregulation.
• To differentiate emotional fever from prostaglandin-induced fever.

Main Methods:

• Measuring tail skin temperature and central temperature (Tc) during stress.
• Assessing the impact of ambient temperature on stress-induced Tc changes.
• Comparing emotional Tc rise during day and night cycles.

Main Results:

• Skin vasomotor responses supported Tc increase and regulation at a higher level.
• Cold ambient temperatures did not reduce the emotional Tc rise, unlike in hyperthermia.
• Emotional fever was higher at night than during the day, suggesting distinct mechanisms from prostaglandin-induced fever.

Conclusions:

• The rise in Tc induced by handling or disturbance in rats is a regulated response.
• This stress-induced temperature increase is caused by a set-point shift, analogous to fever.
• Emotional fever appears to be a distinct physiological process from prostaglandin-mediated fever.