Glyceryl trinitrate induces attacks of migraine without aura in sufferers of migraine with aura

Migraine with aura and migraine without aura have the same pain phase, thus indicating that migraine with aura and migraine without aura share a commo n pathway of nociception. In recent years, increasing evidence has suggeste d that the messenger molecule nitric oxide (NO) is involved in pain mechani sms of migraine without aura. In order to clarify whether the same is true for migraine with aura, in the present study we examined the headache respo nse to intravenous infusion of glyceryl trinitrate (GTN) (0.5 mu g/kg/min f or 20 min) in 12 sufferers of migraine with aura. The specific aim was to e lucidate whether an aura and/or an attack of migraine without aura could be induced. Fourteen healthy subjects served as controls. Aura symptoms were not elicited in any subject. Headache was more severe in migraineurs than i n the controls during and immediately after GTN infusion (p = 0.037) as wel l as during the following 11 h (p = 0.008). In the controls, the GTN-induce d headache gradually disappeared, whereas in migraineurs peak headache inte nsity occurred at a mean time of 240 min post-infusion. At this time the in duced headache in 6 of 12 migraineurs fulfilled the diagnostic criteria for migraine without aura of the International Headache Society. The results t herefore suggest that NO is involved in the pain mechanisms of migraine wit h aura. Since cortical spreading depression has been shown to liberate NO i n animals, this finding may help our understanding of the coupling between cortical spreading depression and headache in migraine with aura.