A recent study entitled “Differential dopamine function in fibromyalgia,” published in the Brain Imaging and Behavior journal, suggests that dopamine signaling may be altered in fibromyalgia patients, contributing to their enhanced pain experience.
Dopamine is an important neurotransmitter involved in cognitive functions and associated with the regulation of pain sensing processes, i.e., nociception. Fibromyalgia patients have altered dopamine function that may result in abnormal pain perception. Nonetheless, the neurobiological processes of dopamine signaling in fibromyalgia and its implications for patients’ pain experience and cognitive functions are still largely unknown.
Researchers studied dopamine activity in the brains of 12 FM patients and 12 healthy individuals using positron emission tomography (PET) combined with a radiotracer dopamine receptor agonist. Dopamine activity effects on pain sensing and cognitive functions were established by measuring radiotracer binding in different brain regions during specific assessment tests.
The team showed that fibromyalgia patients seem to have altered dopamine transmission, showing evidences of lower dopamine binding levels in the brain cortex compared to healthy individuals. This is associated with a higher spontaneous pain rating, increased sensitivity and decreased tolerance to experimental provoked pain. The brain cortical regions with lower dopamine activity in fibromyalgia are associated with the regulation and processing of the emotional and affective components of pain, which could explain the high incidence of emotional disturbance and enhanced pain perception in fibromyalgia. This could also lead to cognitive deficits commonly described by fibromyalgia patients, since these brain regions are also part of functional networks for memory and sensory information processing of the surrounding environment. However, these results need to be substantiated by larger cohort studies.
Overall, authors suggest that dopamine signaling might be important for nociception and cognitive processing in fibromyalgia and in other chronic pain syndromes as well. Future studies are needed to fully understand the implications of dopamine activity in chronic pain diseases.