Higher Rate Of Fibromyalgia In Women Linked To Sex Differences In Brain Activity


A recent study showed that resident immune cells in brain areas involved with pain processing are more active in women than men.

When these resident immune cells, called microglia were blocked in female test subjects, the subjects' response to opioid pain medication (e.g. morphine) improved to the level of relief typically experienced by males.

This is significant since there is a greater incidence of inflammatory pain conditions, such as fibromyalgia, among women, and the drugs used to treat pain are frequently less effective for them. “Indeed, both clinical and preclinical studies report that females require almost twice as much morphine as males to produce comparable pain relief,” said Hillary Doyle, a graduate student at the Neuroscience Institute of Georgia State University.

To determine how sex differences in brain microglia affect morphine response, the researchers used a drug to inhibit microglia activation in male and female lab animals.

Microglia are responsible, in healthy individuals, for locating pathogens, or signs of infection in the brain. In the absence of pain, morphine is viewed as a pathogen and activates microglia, triggering a release of inflammatory chemicals.

“The results of the study have important implications for the treatment of pain, and suggests that microglia may be an important drug target to improve opioid pain relief in women,” said study coauthor Dr. Anne Murphy, associate professor in the Neuroscience Institute at Georgia State.

The research team’s finding that microglia are more active in pain processing brain regions may partly explain why women have substantially higher rates than men of several chronic pain syndromes.

Source: Georgia State University News
Photo credit: Patrick Denker


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Fibromyalgia is a prevalent condition that affects many people in the United States. Approximately 3.7 million Americans have Fibromyalgia. That is 1 in every 73 people.

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