Brain Differences Could Explain Why Males & Females Experience Pain Relief Dif

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Brain Differences Could Explain Why Males And Females Experience Pain

Relief Differently

http://www.medicalnewstoday.com/medicalnews.php?newsid=41876

A study conducted by investigators at Georgia State University and

the Atlanta-based Center for Behavioral Neuroscience (CBN) reports

that anatomical and functional differences in the brain may explain

sex differences in the experience of pain and in the effects of

certain drugs on pain.

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.

A team led by Dr. Anne of the Georgia State Department of

Biology and the CBN showed that male and female rodents are

anatomically different in the area of the brain called the

periaqueductal gray (PAG). This region of the brain relays

information regarding pain to another brain region, the rostral

ventral medulla (RVM). This PAG-RVM circuit is the main pain circuit

in the brain, and is responsible for the sensation of pain. Both

narcotics and analgesics work by acting on these brain regions.

Interestingly, while thousands of studies have been conducted

examining the role of the PAG and the RVM in pain and analgesia,

these studies were conducted exclusively in males. The study by

is the very first to examine if these brain regions are

organized anatomically in a similar manner in females. In addition to

sex differences in how the PAG is organized anatomically, the team

went on to show that persistent pain activates this pathway

differently in males and females. Specifically, the scientists showed

that inflammatory pain activated the PAG-RVM circuit to a greater

degree in males than in females. Morphine - an opioid drug or

narcotic - reduced the response of this circuit to pain to in males,

but not females.

These results provide the first potential anatomical and functional

explanation for sex differences in the experience of pain and

responses to the drug morphine in the treatment of pain.

Morphine is currently the drug of choice for treating several types

of post-operative pain, and it is becoming increasingly clear that

morphine alleviates pain to a greater degree in males in comparison

to females. The results of the study by and Loyd provide

important details about how morphine might be used differently in

females and males to achieve maximum pain relief.

Pain is one of the most common reasons that people consult

physicians. Thus, the management of pain has become one of the

highest priorities in health care. Chronic pain from inflammatory

conditions such as arthritis and fibromyalgia are the most prevalent

and pervasive forms of chronic pain.

Clinical evidence suggests that women are much more likely to

experience chronic forms of pain than are men and that women report

feeling more pain than men following various medical procedures.

Recent recommendations from the American Academy of Pain Medicine and

the American Pain Society indicate that opioid drugs or " narcotics " ,

such as morphine, are essential in the management of chronic pain.

However, there is well-established clinical and nonclinical evidence

that males and females do not respond the same to the effects of

morphine. Specifically, females tend to require higher doses of

morphine than males for pain relief following various medical

procedures.

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The co-authors of 's study include graduate student Dayna Loyd,

doctoral candidate in the Dept. of Biology at GSU. These studies were

supported by a research grant from the National Institute of Health.

CBN, a National Science Foundation Science and Technology Center, is

a research and education consortium of eight metro Atlanta colleges

and universities. More than 90 neuroscientists lead the

interdisciplinary research program to understand the neurobiology of

complex social behaviors. CBN studies have led to breakthrough

treatment for anxiety-related disorders and new understanding of the

neurochemicals vasopressin and oxytocin in social behavior. In

addition to research, CBN has a comprehensive education program

designed to improve science literacy and attract more women and

underrepresented minorities to neuroscience programs. The center is

supported by more than $53 million in grants from NSF and the Georgia

Research Alliance.