Beyond Animal Research
By Jonathan Balcombe, Ph.D.
Migraine Research, Part 1
According the UK-based Migraine Trust Association (www.migrainetrust.org), migraine is the most common neurological condition in the developed world, affecting over 15 percent of the population of the UK, where it is more prevalent than diabetes, epilepsy and asthma combined. The National Institute for Neurological Disorders and Stroke reports some 28 million Americans as having migraine. There is no cure, but there are many available treatments.
Despite this, animals bear the brunt of scientific curiosity about migraine. Cats, monkeys, pigs, guinea pigs, and rats are all being used in headache research. These experimental subjects are not suffering from migraines (at least not that we can tell), but their skulls are opened up and their brains tweaked, probed and drugged in a parade of experiments designed, it seems, more to advance scientific careers than useful knowledge.
Here are some recent examples of migraine research using cats:
- The brains of seven anesthetized cats were stimulated to mimic the pain of human headache, then the animals were dosed with a known anti-migraine drug (topiramate) to try to understand how it works.1
- When the brains of anesthetized cats were stimulated for two hours, activity was observed in the hypothalamus, suggesting its role in headache. The authors mention prior studies in which stimulating another part of the brain has produced head pain in humans, and surmise that the hypothalamus is also involved.2
- Arteries were exposed and/or catheterized in anesthetized cats to study the effects of injections of the hormone serotonin on arteries. Observed effects were concluded not to be of likely importance to the pathophysiology of migraine.3
And here is one that used monkeys:
- Researchers attempted (unsuccessfully) to induce spreading depression (SD, a brain activity symptom associated with migraines) in nine macaque monkeys, by applying potassium chloride to their brains.4
These studies illustrate how little justification may be required for animal experiments. Not only is such research compromised by interspecies differences in physiology and drug metabolism, and by the inability of animals to communicate symptoms to us, but these experiments are mostly attempts to confirm already known aspects of the human condition.
Migraine is a uniquely human disorder, and studying it in humans is the way to make meaningful progress towards helping sufferers. Ethical methods abound. Brain imaging is a powerful non-invasive tool that allows researchers to observe brain activity while symptoms occur. A particularly fertile area of study has been prevention research. Several studies have shown that migraines often have a specific dietary or environmental trigger. A future column will examine migraine research in the human clinical setting.
Jonathan Balcombe, Ph.D., is a PCRM research consultant with background in ethology. He is the author of The Use of Animals in Higher Education, as well as many articles on humane life science education and scientific papers on animal behavior. He is the author of a recent scientific review showing that animal experiments are more stressful than previously understood.
1. Storer RJ, Goadsby PJ. Topiramate inhibits trigeminovascular neurons in the cat. Cephalalgia. 2004;24:1049-1056.
2. Benjamin L, Levy MJ, Lasalandra MP, Knight YE, Akerman S, Classey JD, Goadsby PJ. the cat: a Fos study. Neurobiol Dis. 2004;16:500-505.
3. Lambert GA, Donaldson C, Hoskin KL, Boers PM, Zagami AS. Dilatation induced by 5-HT in the middle meningeal artery of the anaesthetised cat. Naunyn Schmiedebergs Arch Pharmacol. 2004;369:591-601.
4. Yokota C, Kuge Y, Hasegawa Y, Tagaya M, Abumiya T, Ejima N, Tamaki N, Yamaguchi T, Minematsu K. Unique profile of spreading depression in a primate model. J Cereb Blood Flow Metab. 2002;22:835-842.