Platelet-bound and free serotonin levels in jugular and forearm venous blood during migraine.

The level of serotonin in platelets and free in plasma has been determined in jugular and forearm venous blood before and during migraine attacks in six women. A significant fall in platelet serotonin was observed in five subjects and was accompanied by a significant fall in plasma free serotonin in the four subjects for whom data concerning free serotonin levels were available. There was no significant difference between jugular and forearm blood in respect to either platelet-bound or free serotonin in the headache-free phase, and during migraine, the values for jugular and forearm blood were parallel. The significance of these findings in relationship to the serotonin theory of migraine is discussed.