[Plasma releasing factors in common migraine].

Many platelet abnormalities have been described in migraine, but they are now regarded as secondary phenomena rather than primary causative factors. In this study, we attempted to assess the presence of bioamine-releasing factors in the plasma of patients with common, non-dietary migraine. Blood samples were collected from 17 such patients, either during attacks (n = 9) or during attack-free periods (n = 8). Ten healthy volunteers served as controls. Release experiments were performed by adding 1 volume as controls. Release experiments were performed by adding 1 volume of migraineur's platelet-poor plasma to 1 volume of either control's whole blood (histamine release) or isolated platelets (catecholamines or serotonin release). Endogenous unconjugated bioamines were measured in whole blood and in isolated platelets from migraineurs' blood collected during and between attacks. We also measured plasma levels of histamine and of unconjugated and conjugated serotonin and catecholamines, as well as the inhibition of serotonin uptake and labelled serotonin release from controls' platelets in the presence of migraineurs' plasma collected during or between attacks. The results obtained suggest the presence of two plasma bioamine-releasing factors: a histamine-releasing factor present in migraineurs' blood during and between attacks, and a catecholamine and serotonin releasing factor present only during attacks in migraineurs' platelet-poor plasma. The latter factor is thermolabile and dialysable, with an apparent molecular weight lower than 16 kd. Gel-filtered fractions of semi-purified catecholamine-serotonin releasing factor induced the same events as the migraineurs' platelet-poor plasma from which they were obtained.