Study Finds Decreasing Dopamine Levels during Migraine
Researchers at the University of Michigan have uncovered some potentially treatment-changing information regarding dopamine levels and migraine. The study, published online and in print in this month’s issue of Neurology, points towards decreasing levels of dopamine during a migraine attack. The researchers, led by Alex DaSilva, DDS, DMedSc, Assistant Professor at the University of Michigan School of Dentistry and Center for Human Growth and Development at the University of Michigan, utilized PET scans of the brain, and various other measurements of brain activity and chemical composition to determine that dopamine levels demonstrate unusual patterns in migraineurs during an attack.
“Dopamine is one of the main neurotransmitters controlling sensory sensitivity. Therefore, a drop in dopamine could produce increased sensory sensitivity so that normally painless or imperceptible sensory signals from skin, muscle and blood vessels could become painful.”
– Study co-author Kenneth Casey, MD, University of Michigan Professor Emeritus of Neurology.
Essentially, the paper reports that dopamine levels can fluctuate, and eventually plummet, during a migraine. Dopamine is the brain’s main pleasure-related, and feel-good neurotransmitter, which also regulates motivation, sensory perception, and emotion. It makes sense that its depletion could lead to the pain and hypersensitivity migraineurs face. It has often been hypothesized that dopamine and migraines could be connected, however, this link hasn’t been fully investigated. This information could potential affect the way migraine is treated, aid in creating dopamine-based therapies, and explain symptoms and behaviors during a migraine attack.
The researchers performed the experiment using eight individuals with migraine, and eight control individuals without migraine, who were otherwise healthy. They measured dopamine levels and brain activity in each group during headaches, migraine attacks, and non-attack states. By comparing the individuals with migraine to each other, as well as to the control group, the researchers were able to observe a large decrease in dopamine levels for the migraine group, and only during a migraine attack. Dopamine levels were actually found to be stable, and almost identical, in both groups during the headache and non-attack states.
This information supports the hypothesis that migraine is periodic in nature, and is at least partially the result of sensory hypersensitivity. This is why sound, odors, and light can be painful or debilitating during or right before an attack. This phenomenon is often referred to as allodynia, in which something that wouldn’t normally cause an adverse reaction can cause extreme discomfort or debilitating pain.
One interesting result from the study was that while individuals with migraine were resting or sleeping during an attack, their brain experienced a small spike in dopamine levels. However, this spike is actually what may be responsible for some of the more adverse symptoms of an attack. For example, since the receptors are overly sensitive to dopamine once it’s depleted, one small spike could overwhelm the neurotransmitter system, leading to more nausea, vomiting, increased pain, isolation, and withdrawal symptoms.
Right now, a common treatment for someone who goes to the emergency room during a migraine attack is to give them dopamine antagonists, which further deplete the dopamine response system, and control overall fluctuations of the chemical. Hopefully, these results will help fine-tune this treatment and lead to better management of migraine symptoms overall.
“Brain scans show dopamine levels fall during migraine attacks.” EurekAlert! American Association for the Advancement of Science. 29 Mar 2017. Available here.
DaSilva AF, et al. “Dopamine D2/D3 imbalance during migraine attack and allodynia in vivo.” Neurology. 29 Mar 2017. Abstract available here.