COPENHAGEN, Denmark—Glutamate, the major excitatory neurotransmitter in the central nervous system (CNS) is abnormal in fibromyalgia (FM) patients in brain areas that mediate pain perception and emotional processing, according to data reported at the 2009 EULAR meeting.1,2 1. Harris RE. Glutamate levels in the insula and pain perception in fibromyalgia, Presented at the 2009 EULAR meeting, Copenhagen, June 11, 2009. Presentation no. SP0077.
Richard E. Harris, PhD, of the University of Michigan's Chronic Pain and Fatigue Research Program (Ann Arbor, MI) reported that FM patients have significantly elevated glutamate and glutamate/glutamine levels in the right posterior insula, compared with non-FM controls. Dr. Harris also found that higher levels of glutamate and glutamine were associated with lower pain thresholds both in FM patients and in non-FM controls.
“The elevated levels of glutamate were associated with pain sensitivity. The higher a participant's glutamate levels were, the more tender they were to pressure pain,” Dr. Harris told Musculoskeletal Report.
Dr. Harris said that since functional magnetic resonance imaging (fMRI) studies implicate the insula as a region of heightened neuronal activity in FM, and since glutamate is a major cortical excitatory neurotransmitter that functions in pain neurotransmission, his group suspected that increased levels of insular glutamate might be present in FM patients and might correlate with reported pain. They used proton magnetic resonance spectroscopy (H-MRS) to examine the right anterior and right posterior insula at rest in 19 FM patients and 14 age- and sex-matched pain free controls, who also underwent pressure pain testing.
2. Collado A, Valdes M, Bargallo N, et al. Increased glutamate compounds in the brain of patients with fibromyalgia: a MR spectroscopy study. Presented at the 2009 EULAR meeting, Copenhagen, June 11, 2009. Presentation no. OP-0142.
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