For clarification of possible platelet activation in migraine and chronic muscle contraction headache (MCH) under stress, plasma platelet factor 4 (PF4), norepinephrine (NE), and free fatty acids (FFA) were investigated during the cold pressor test. Both PF4 and NE increased significantly, whereas FFA showed no remarkable changes. The increases of PF4 in MCH and migraine during this test were significantly greater than in healthy controls. The increase of PF4, however, was independent of NE increase and FFA changes. On the other hand, we observed decreased NE levels in both MCH and migraine, which might suggest peripheral sympathetic hypofunction. The platelets of MCH or migraine patients seem to be impaired, and the impairment may be caused by continuous sympathetic hypofunction. The behaviour of the above three substances in MCH was similar to that in migraine throughout the present study.

To evaluate the change of the neurotransmitter function in migraine, a neuroendocrinological study was performed in eleven female migraineurs and nine female controls. Thyrotropin releasing hormone, luteinizing hormone releasing hormone, and insulin were simultaneously loaded (the Triple test). Before and after loading, serum glucose, prolactin (PRL), thyroid stimulating hormone (TSH), luteinizing hormone, follicle stimulating hormone, adrenocorticotropic hormone, cortisol, human growth hormone and beta-endorphin were measured. The Triple test produced an increase of PRL in both migraine and control groups, but in migraineurs the increase was significantly larger than in controls. TSH also increased in response to the test, but the TSH response in patients was less than in controls, although not significantly so. The responses of other substances showed no significant differences between the two groups. Although dopaminergic hypofunction in migraine has been proposed by some authors, the present findings rather suggest a serotonergic hyperfunction.