The role of serotonin in the pathogenesis and clinical presentations of migraine attacks.

The Fontana-Masson method was used in 63 migraine patients to stain peripheral blood thrombocytes and measure the numbers of serotonin granules within them during the interictal period and, in 33 patients, during and 24, 48, and 72 h after migraine attacks. Enzyme-linked immunosorbent assay (ELISA) was used in 19 patients during attacks to study dissolved serotonin concentrations in serum. During the interictal period, high contents of serotonin granules per 100 blood thrombocytes were found (469.3 +/- 22.4), which was not significantly different from the level in healthy subjects (447.9 +/- 19.6). At the peak of attacks, serotonin contents decreased to 47.7 +/- 7.4, while the dissolved serotonin concentration, conversely, increased to 345.5 +/- 39.1 ng/ml (compared with serum serotonin levels of 184.2 +/- 12.3 ng/ml in healthy subjects). During the first and subsequent time points after migraine attacks, thrombocyte serotonin levels returned to baseline. These data provide evidence of impairment of serotonin stored in thrombocytes during migraine attacks and its release into the plasma, which may provide a laboratory method for monitoring the development of migraine attacks.