Abstract

Although the vascular, neurogenic, and inflammatory theories are introduced as the pathomechanism of migraine, any single one is not enough for explaining the whole clinical manifestations of migraine. Accumulating evidences of nitric oxide(NO) involvement in migraine headache have been reported on the basis of the NO-cGMP pathway. Three hypotheses can be thought for explaining NO involvement in migraine. First, activation of the NO-cGMP pathway causes migraine attacks in migraineurs. Second, drugs that are effective in the treatment of migraine exert their activity by inhibiting one or more steps in the NO-cGMP pathway or by antagonizing the effects of products of this pathway. Third, substance which can cause an attack of migraine do so by stimulating one or more steps in the NO-cGMP pathway or by exerting effects which are agonistic to those of one or more effects in this pathway. The possible mechanisms whereby NO could cause migraine are by dilatation of cerebral and extracerebral blood vessels, by changes of cerebrovascular regulation following cortical spreading depression, by direct effect of perivascular sensory nerves, and so on. In this context, NO may play a key role in migraine, and the importance of NO as a potential initiator of the migraine attack indicates new direction for the phar- macological treatment of migraine. Korean Journal of Headache 1(1):25-31, 2000