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900 Walnut St. (215)-955-0433 |
Michael L. Oshinsky, PhD|
What is the Pathophysiology of Migraine Headache and Other Recurrent Trigeminal Pain Disorders.
Recurrent episodic headache syndromes, such as migraine, are the most common pain-related complaint seen in medical practice, accounting for 18 million physician visits each year. These primary headache disorders are responsible for >$16 billion in lost productivity in the U.S. each year. Migraine is more than just episodic headache. Migraine is a neurologic disorder characterized by periodic attacks of head pain, as well as nausea, vomiting, phonophobia, photophobia, and allodynia. Even when migraine patients have not had an attack in weeks, physiological and biochemical abnormalities are present. Migraineurs also have significant sensory processing abnormalities, such as a lack of habituation to repeated stimuli, even when they do not have head pain. Our lab is investigating a new model of recurrent headache in rat. This model uses repeated inflammatory dural stimulation to mimic the repeated activation of dural afferents believed to occur in patients with recurrent migraine headache. After multiple inflammatory stimulations of the dura, there is an unique physiological state generated in the rats that is stable, and long outlasts the last stimulation. This state is characterized by sensory and physiological hyperresponsiveness of the trigeminal neurovascular system that significantly differs from the relatively short lasting and smaller magnitude changes induced by a single acute stimulation of the dura. Rats that have received many simulated headaches display behaviors and sensory changes similar to the associated symptoms and comorbid clinical conditions of migraine patients. We use electrophysiology, microdialysis, immunohistochemistry and behavior to quantify and assess the mechanism by which repeated trigeminal nociceptive stimulation causes long-lasting physiological changes that parallel the interictal physiological abnormalities of migraineurs. |
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