Brain differences could explain why males and females experience pain relief differently

The finding, reported in the April 13 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 Murphy 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 Murphy 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 Murphy 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.

Source: Georgia State University

Why Women Get More Migraines Than Men
For every man with a migraine, three women are struck by the severe headaches that often come with nausea, sensitivity to light and sound, and aura. That means a staggering 18 to 25 percent of women suffer from migraines, making it one of the most common disabling conditions faced by women around the globe.
A new hand -- and signs of sensory recovery
Four months after a successful hand transplant -- 35 years after amputation in an industrial accident at age 19 -- a 54-year-old man's emerging sense of touch is registered in the former "hand area" of the his brain, says a University of Oregon neuroscientist.
Steroid treatment offers no benefit in preemies, study suggests
Results of a multicenter study led by Johns Hopkins Children's Center challenge the longstanding practice of treating premature babies with hydrocortisone, a steroid believed to fight inflammation and prevent lung disease. The researchers found that such treatment offers little or no benefit and that low cortisol levels are not even necessarily harmful. High cortisol levels, on the other hand, appeared to increase the risk of dangerous bleeding in the brain and require that babies be monitored aggressively to ward off life-threatening complications, according to the study published in the October issue of Pediatrics.
Occasional memory loss tied to lower brain volume
People who occasionally forget an appointment or a friend's name may have a loss of brain volume, even though they don't have memory deficits on regular tests of memory or dementia, according to a study published in the October 7, 2008, issue of Neurology, the medical journal of the American Academy of Neurology.
Calming your thoughts through mindfulness
Our worries. They're crescendoing like the finale of Beethoven's "Ninth": Bailouts, buyouts. Recession, depression.
Strippers, armadillos inspire Ig Nobel winners
(AP) -- Deborah Anderson had heard the urban legends about the contraceptive effectiveness of Coca-Cola products for years. So she and her colleagues decided to put the soft drink to the test. In the lab, that is.
New study proves that pain is not a symptom of arthritis, pain causes arthritis
Pain is more than a symptom of osteoarthritis, it is an inherent and damaging part of the disease itself, according to a study published today in journal Arthritis and Rheumatism. More specifically, the study revealed that pain signals originating in arthritic joints, and the biochemical processing of those signals as they reach the spinal cord, worsen and expand arthritis. In addition, researchers found that nerve pathways carrying pain signals transfer inflammation from arthritic joints to the spine and back again, causing disease at both ends.
MS patients have higher spinal fluid levels of suspicious immune molecule
A protein that helps keep immune cells quiet is more abundant in the spinal fluid of patients with multiple sclerosis (MS), further boosting suspicion that the protein, TREM-2, may be an important contributor to the disease.

Brain differences could explain why males and females experience pain relief differently

Related stories:

News discussion: