5HT1F- and 5HT7-receptor agonists for the treatment of migraines.

Serotonin was the first neurotransmitter believed to be involved in cephalic pain transfer forward to the cortex, but the precise mechanism was confirmed only after sumatriptan, a 5-HT(1B/1D0) high affinity agonist, was introduced in the acute treatment of migraine. Although very efficient for migraine relief, activation of 5-HT(1B) receptor may also cause vasoconstriction outside brain, within the heart arteries for example. Unlike 5-HT(1B), the 5-HT(1D) receptor is not located in vascular tissues but exclusively within neuronal, but high affinity agonists for 5-HT(1D) failed to prove clinical significance in randomized trials. The recent clone of 5-HT(1F) receptor together with data showing that sumatriptan exerts high affinity for this receptor subtype generated high expectations. Potent agonists for 5-HT(1F) receptors were effective in animal models for migraine and later clinical trials showed efficacy even in humans, introducing the first line future anti-migraine drugs. Apart from 5-HT(1F), another new cloned 5-HT subtype receptor, the 5-HT(7) also attracts attention. Recently developed and clinically tested selective 5HT(7) antagonists SB-269970-A and SB-656104-A suggest that the receptor may play a role in other CNS disorders including anxiety and cognitive disturbances, suggesting a potential role for the migraine prophylaxis. These data and speculations are discussed in details in this paper with special references.