Gender Difference In Pain Experience Explained By Brain Diversity

Functional and structural difference in the brain can explain why men and women experience pain differently and respond in unique ways to the effects of certain pain-relief drugs, reveals a new study conducted by researchers at Georgia State University and the Atlanta-based Center for Behavioral Neuroscience (CBN).

Although the study has been conducted on rat brains, the results highlight that similar differences occur in humans as well. The results of this study have several important clinical implications. It could lead to novel treatment strategies to treat pain in men and women.

The finding, reported in the April issue of the Journal of Comparative Neurology, is the first report of specific differences in the parts of the brain responsible for the transmission of pain sensations in the body. The study used rat brains, but a host of clinical evidence suggests that similar differences occur in humans - in other words, this finding could eventually lead to the development of differential treatments for pain in men versus women.

The researchers were able to demonstrate a structural difference in a specific area of the brain, commonly referred to as the periaqueductal gray (PAG). This area of the brain communicates pain information to another region referred to as the rostral ventral medulla (RVM). This PAG-RVM circuit plays a crucial role in the pain sensation.

This region of the brain is infact influenced by both narcotics and analgesics, commonly referred for pain relief. Although a number of studies have been conducted on the same subject, the major drawback is that it has been conducted only on males. This study is the first ever to establish sex-differences in pain perception.

In addition to an anatomic difference in the organization of the PAG between either sex, the researchers were able to find that persistent pain activated a totally different pathway in males and females. More specifically, pain associated with inflammation resulted in a greater activation of the PAG-RVM circuit, in males compared to females.

Additionally, morphine, an opioid drug or narcotic was found to reduce the response of this circuit to pain to in males. This effect however was not observed in the opposite sex. Morphine is being increasingly used in the treatment of post-operative pain. The results of the study provide important clues that morphine could be used differently in men and women to achieve maximum pain relief.

Pain is one of the most common reasons for patients to consult their physicians. Pain management, both acute and chronic has become one of the utmost priorities in the health care industry. Chronic pain associated with arthritis and fibromyalgia has been responsible for causing disability.

Women experience a greater chronic pain when compared to men and therefore require an increased dose of opioid drugs or narcotics, (morphine) for achieving the same amount of pain relief.

Clearly, more research is needed to better understand the sex-related difference in pain perception.