Autonomic nervous activity in migraine

: The autonomic nervous function in patients with migraine was studied during headache free intervals. (I) Hemodynamic test. The following observations were made: (1) a decrease in overshoot in Valsalva's maneuver; (2) orthostatic hypotension; (3) low levels of plasma norepinephrine; (4) failure in elevation of the plasma norepinephrine level after head-up tilting; (5) dilatation of the pupils after instillation in the eyes of 1.25% epinephrine; (6) a long recovery time in test by bolus injection of l-norepinephrine. These data suggest that patients with migraine show sympathetic hypofunction together with denervation hypersensitivity of the iris and arteries. (II) Neuropeptides. Blood samples were taken after 30 minutes supine rest in a quiet room and the level of substance-P (SP), calcitonin gene-related peptide (CGRP), endothelin-1 (ET-1), and human atrial natriuretic peptide (hANP) were determined by radioimmunoassay. The level of SP, CGRP, and hANP in classic migraineurs during headache-free intervals were significantly lower than that of controls. There was no significant difference in the level of ET-1 between migraineurs and controls. These data suggest that neuropeptides such as SP, CGRP and hANP are closely related to the pathophysiology of migraine. (III) L-arginine infusion test. To examine whether or not NO is involved in the pathophysiology of migraine, L-arginine, a precursor of NO, was administered. The magnitude of blood pressure decrease in migraineurs was significantly greater than that of controls. Although plasma levels of CGRP decreased significantly in controls following L-arginine infusion, those of CGRP did not change in migraine patients. These data suggest that NO and CGRP may be involved in pathophysiology in migraine.