Effects of methysergide on platelets incubated with reserpine

Migraine and haemostasis

Migraine is a risk factor for cerebral infarction in young women. The nature of the connection between these diseases remains however essentially unknown. Abnormalities of haemostasis leading to an increased thrombotic risk would provide a logical link. Platelets, antiphospholipid antibodies and more recently congenital thrombophilia have thus successively been implicated. The different studies concerning these topics have been reviewed. Because of the conflicting results obtained and because of the numerous methodological shortcomings of many of these studies, no definite conclusion can be reached. It is possible that these 3 factors play a role in the ischemic risk of migraine, but it is as likely or even more likely that other factors (inside or outside the hemostatic system) play a more important role. Further studies are thus deeply needed.

Effects of reserpine and chlorpromazine on 5-hydroxytryptamine uptake of platelets from migrainous and control subjects

Platelet aggregation experiments confirm differences between the 5-hydroxytryptamine (5-HT) receptors of migrainous and control platelets. However, no differences have been found in 5-HT uptake, in the presence of reserpine or chlorpromazine, into migrainous and control platelets. The results support the hypothesis that receptors for 5-HT induced platelet aggregation provide a model for vascular receptors causing constriction and are distinct from those transferring 5-HT through the platelet membrane.

Effects of ergotamine and methysergide on blood platelet aggregation responses of migrainous subjects

Platelet aggregation responses to 5-hydroxytryptamine (5-HT) were measured in plasma from migrainous subjects taking either methysergide maleate or ergotamine tartrate and were found to be reduced. Blood 5-HT levels of subjects free of headache were not affected by these drugs. The results support the hypothesis that methysergide and ergotamine act by occupying 5-HT uptake sites in vessel walls, leaving 5-HT molecules available to occupy receptors concerned with vasoconstriction.

5-Hydroxytryptamine levels and platelet aggregation responses in subjects with acute migraine headache

Blood 5-hydroxytryptamine levels were reduced during migraine attacks in patients who had not taken any drugs but the aggregation responses to 5-hydroxytryptamine of the blood platelets from these patients were similar to responses of platelets from migrainous subjects between attacks. This confirms earlier findings that a permanent difference exists in the behaviour of platelets from migrainous subjects. Blood 5-hydroxytryptamine levels were reduced during migraine attacks in patients who had taken ergotamine. The aggregation responses of platelets taken from migrainous patients on ergotamine both during and between attacks were inhibited, which is in agreement with results previously found for aggregation responses following the in vitro pre-incubation of control platelets with ergotamine. Blood 5-hydroxytryptamine levels were maintained during migraine attacks in patients who had taken analgesics and there was no reduction in the aggregation responses of their platelets.