Opiate-based painkillers prescribed for patients suffering from
fibromyalgia, a condition that causes widespread pain, nausea, and fatigue,
are often ineffective. Now, researchers at the University of Michigan have
found out why.
Patients with fibromyalgia were found to have reduced binding ability of a
type of receptor in the brain that is the target of opioid painkiller drugs
such as morphine.
The study led by Richard E. Harris, PhD, University of Michigan, compared a
sample of 17 fibromyalgia patients and 17 age- and sex-matched healthy
controls, using µ-opioid receptor (MOR) positron emission tomography.
“The fibromyalgia patients displayed reduced MOR binding potential (BP)
within several regions known to play a role in pain modulation, including
the nucleus accumbens, the amygdala, and the dorsal cingulated,” stated an
abstract of the study. “MOR BP in the accumbens of fibromyalgia patients was
negatively correlated with affective pain ratings.”
The findings indicate altered endogenous opioid analgesic activity in
fibromyalgia, suggesting a possible reason for why exogenous opiates (i.e.,
synthetic analgesics such as pills) appear to have reduced efficacy for
sufferers of the disease.
The research appears in the September 12 issue of the Journal of
Neuroscience. To read the abstract, click here.
