NITRIC-OXIDE, ENDOTHELIN-1, AND TRANSCRANIAL DOPPLER IN MIGRAINE - FINDINGS IN INTERICTAL CONDITIONS AND DURING MIGRAINE ATTACK

The role of vascular phenomena taking place during an attack of migrai ne are poorly understood. The aim of this study was to measure systemi c levels of nitric oxide and endothelin-1, two of the most potent vaso active mediators known, and to assess vasomotor responses through tran scranial Doppler ultrasound monitoring in patients suffering from migr aine without aura, both during the headache event and in headache-free periods as well as after pharmacologically induced pain relief. Seven patients (mean age 31.3 years, range 24 to 49 years), five women and two men, were enrolled in the pilot study. Transcranial Doppler record ings were performed according to conventional procedure. Endothelin-1 concentrations ware measured by means of radioimmunoassay, whereas nit ric oxide levels were estimated using electron paramagnetic resonance spectroscopy. ultrasound evaluation did not show significant changes d uring migraine attacks compared to the interictal condition. Nitric ox ide levels showed only slight differences between basal and attack con ditions (0.85 +/- 0.46 versus 1.56 +/- 0.88, expressed as arbitrary un its), and were raised after pharmacological intervention (2.91 +/- 1.9 3, P < 0.05). Plasma endothelin-1 concentrations decreased during migr aine attacks with respect to interictal conditions (3.99 +/- 1.21 pg/m l versus 4.23 +/- 1.19), and returned to basal values (4.44 +/- 1.08 p g/mL) after relief of pain. Coupling the measurements of systemic leve ls of nitric oxide and endothelin-1 with transcranial Doppler velocity results will provide useful information on the hemodynamic changes of cerebral blood flow regulation in migraineurs, thereby adding new ins ights into the mechanisms of the migraine attack.