Kat Arney: Migraines can be extremely debilitating as any sufferer will know, but the trouble is we still don’t really know what causes them, and now researchers writing in the latest edition of the journal Neuron have made a step forward in understanding what may make the brain vulnerable to migraine attacks.

Chris Smith: What have they found?

Kat: This is work by Daniela Pietrobon and her colleagues in Italy and the Netherlands. Now, we know from previous research that the so-called aura in migraine, this is a visual disturbance, is caused by something called cortical spreading depression; this is an electrical wave that passes across the brain. Now, it was thought that this wave is basically what brings on the migraine, and in this work the researchers studied mice with a gene fault called FHM1. This is the same fault that causes a condition in humans called familial hemiplegic migraine, and these mice also showed cortical spreading depression, so they’re thought to be a pretty good model for human migraine.

Laboratory mouse Creative commons image Credit: Rick Eh? used under Creative Commons licence.
Laboratory mouse.

Now the scientists studied the brains of these mice in depth, and they discovered that the brains with the FHM mutation showed high levels of release of a neurotransmitter called glutamate, and this is the main chemical in the brain that excites or activates nerve cells, but when the researchers dropped the levels of glutamate in these FHM mice, the mice didn’t show cortical spreading depression, so presumably weren’t experiencing these migraines.

Chris: One thing to say, it’s true in mice though, what about in humans?

Kat: Well, the research does show that the overactive release of glutamate might explain why this cortical spreading depression is more likely in the mice with the mutation. It does suggest that perhaps migraines are down to imbalance between activation and suppression of nerve cell activity in the brain. Now, this idea does need following up with studies in humans, but it may also help to explain why some people are susceptible to migraines and could even point towards new avenues for treatment in the future.

Listen to the whole edition of Breaking Science, originally broadcast on Radio Five Live, March 2009

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