[Role of platelet serotonin in common migraine. Concentrations and uptake]

Concentrations and uptake of platelet conjugated and unconjugated serotonin were measured in 15 healthy subjects and in 19 patients with common migraine. Venous blood was taken between migrainous attacks in all patients and during attacks in 8 of them. A significant decrease in unconjugated serotonin concentrations was observed during the attacks, whereas conjugated serotonin concentrations were the same as in controls. In addition, migrainous attacks were accompanied by a significant decrease in serotonin uptake by the platelets, with fall in Km, Vmax and -y. This abnormality was corrected when platelets removed from patients during attacks were incubated in plasma from controls, but it persisted when platelets from controls were incubated in plasma taken from patients during attacks. These findings suggest that one or several factors present in plasma are responsible for the decrease in serotonin uptake observed during migrainous attacks. Finally a study of correlations between these changes and the time elapsed since the last migrainous attacks demonstrated cyclic variations in abnormalities between attacks.