Platelet serotonin measures in migraine

Serotonergic mechanisms play an important role in the pathogenesis of headache. To search for potential indicators of altered serotonin homeostasis in migraine, we have investigated three parameters of the platelet serotonin (5HT) system, platelet serotonin level (PSL), platelet serotonin uptake (PSU), and monoamine oxidase (MAO-B) activity, in a group of 55 patients with migraine and in 81 healthy controls.

After platelet separation, PSL was determined fluorimetrically; PSU was measured by incubating aliquots of platelet-rich plasma with six concentrations of 14C-5-HT for 60 seconds at 37 degrees C, followed by vacuum filtration; platelet MAO-B activity (toward kynuramine as a substrate) was determined fluorimetrically.

Values of the investigated measures, in patients versus controls, amounted to (mean +/- SD) 608 +/- 166 vs. 591 +/- 184 ng/10(9) platelets for PSL, 139 +/- 25 vs. 142 +/- 25 pmol 5HT/10(8) platelets/minute for Vmax of PSU, 376 +/- 62 vs. 404 +/- 72 nM for Km of PSU, and 15.8 +/- 5.1 vs. 14.3 +/- 5.7 nmol product/10(8) platelets/60 minutes for velocity of MAO-B. Mentioned parameters did not show statistical differences between patients and controls, with exception of a small difference in Km of PSU, reaching significance (P<0.01). After subgrouping of patients according to diagnosis (migraine with aura, migraine without aura, and migraine attack) and gender, no differences retained significance.

Our results indicate the absence of a measurable disturbance in 5HT homeostasis in migraine, as shown by platelet 5HT parameters, and they question the suitability of the use of mentioned blood elements in this regard.