People with migraines also may be suffering from some brain damage as brain cells swell and become starved of oxygen -- a finding that may help explain why migraine sufferers have a higher risk of stroke, researchers reported. Similar brain damage can occur with concussions and after strokes, the researchers said in this week's issue of the journal Nature Neuroscience.
They said yesterday their findings suggest that migraine sufferers should not simply get pain relief but should take drugs that prevent the migraine, which is often preceded by "aura" - a series of visual disturbances that can include flashes of light or black spots.
The research, which was done in mice, also suggests giving oxygen may help reduce the damage, said Takahiro Takano, Maiken Nedergaard and colleagues at the University of Rochester in New York, working with a team at the Danish pharmaceutical group Novo Nordisk.
They studied a process called cortical spreading depression, known as CSD, a wave of changes in cells associated with migraine, stroke and head trauma.
They used a precise two-photon microscopic and oxygen sensor microelectrodes to look at the brains of live mice while they caused this process. They saw a swelling occur and the brain cells became starved of oxygen. The nerve cells were damaged -- specifically the dendrites, the long, thin spikes that stretch from one nerve cell to another.
28 MILLION SUFFERERS IN U.S. "This observation may have direct clinical implications, as several lines of work support the notion that cortical spreading depression constitutes the neurological basis of migraine with aura, and spontaneous waves of CSD may contribute to secondary injury in stroke and traumatic brain injury," the researchers wrote. Migraine is a severe and debilitating form of headache, affecting 28 million people in the United States alone.
Two studies, including one published last week in the Archives in Internal Medicine, show that people who have migraines are more likely to have heart attacks. A 2004 study in the British Medical Journal found that migraine sufferers are twice as likely to suffer a stroke as people who do not have the headaches.
Women are much more likely to suffer the characteristic pain of a migraine. Usual pain medication often has little effect on migraine but a class of drugs called triptans, also called serotonin agonists, and ergotamine drugs, can be used to prevent the worst effects if patients take them at the first sign.
Giving the mice rich doses of oxygen seemed to shorten the duration of the wave of brain effects seen in CSD, the researchers said. They noted that migraine and cluster headache patients are sometimes treated with high-pressure oxygen.
It is not clear if the effects of migraine are permanent, the researchers said. Some studies have suggested they are while others have shown no difference in memory and other cognitive effects in migraine patients.