March 30 (UPI) -- Researchers at the University of Michigan found dopamine levels drop and fluctuate during a migraine headache, a discovery that could lead to better treatment.
Dopamine is a chemical in the brain that helps regulate emotion, motivation and sensory perception.
Current treatment for migraines often includes giving patients dopamine antagonists -- drugs that block overactive dopamine receptors to stave off dopamine fluctuations and ease migraine pain.
Michigan researchers used PET scans of the brain to measure brain activity and dopamine levels of eight migraine patients during migraine attacks and between headaches and eight healthy patients.
The team analyzed scans of participants with and without migraines and compared migraine patients with healthy patients. They found migraine patients had stable dopamine levels between headaches similar to healthy patients. However, during a migraine, dopamine levels dropped significantly.
"Dopamine is one of the main neurotransmitters controlling sensory sensitivity," Kenneth Casey, professor of neurology at the University of Michigan, said in a press release. "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."
Researchers found that when patients were resting during a migraine, they experienced a slight increase in dopamine levels and worse symptoms when warmth was applied to their forehead. This phenomenon is known as allodynia and occurs when a stimulus that would not normally cause pain does. It may be attributed to environmental stimulation.
The decrease in dopamine levels could be responsible for the isolation and withdrawal that migraine patients show during attacks.
"This dopamine reduction and fluctuation during the migraine attack is your brain telling you that something is not going well internally, and that you need time to heal by forcing you to slow down, go to a dark room and avoid any kind of stimulation," Alex DaSilva, assistant professor at the University of Michigan School of Dentistry and Center for Human Growth and Development, said.
The finding could lead to better treatments for migraines.
The study was published in the journal Neurology.