Regional skin temperature changes in a rat model for the menopausal hot flush

Area of Science:

• Pharmacology
• Neuroscience
• Physiology

Background:

• Opioid withdrawal can manifest with autonomic dysregulation, including temperature fluctuations.
• Flushing episodes are common in women and can also occur in men, often linked to hormonal changes or other physiological events.

Purpose of the Study:

• To investigate the effects of naloxone on thermoregulation in morphine-dependent rats.
• To compare the temperature responses between male and female rats.
• To evaluate the morphine-dependent rat as a model for human flushing episodes.

Main Methods:

• Morphine-dependent male and female rats were administered naloxone.
• Skin (tail and foot) and colonic temperatures were continuously monitored.
• Control groups received saline or naloxone without prior morphine dependence.
• Castration was performed on some male rats to assess hormonal influences.

Main Results:

• Naloxone induced significant increases in tail and foot skin temperatures, preceding a drop in colonic temperature in both sexes.
• The magnitude and pattern of skin temperature surges were similar in male and female rats, resembling human hot flashes.
• Female rats exhibited a more pronounced fall in colonic temperature compared to males.
• Castration did not alter the observed temperature responses in males.

Conclusions:

• The thermoregulatory pattern observed in morphine-dependent rats following naloxone administration closely mimics human hot flashes.
• The morphine-dependent rat serves as a valid model for studying flushing episodes, particularly in women.
• This study also suggests a potential model for investigating flushing episodes in men.