Variations in the Platelet Arginine/Nitric Oxide Pathway during the Ovarian Cycle in Females Affected by Menstrual Migraine

Previous studies have reported the existence of an arginine/nitric oxide (NO) pathway and the involvement of a Ca²⁺, NADPH-dependent nitric oxide synthase enzyme (NOS) in the generation of NO in human platelets. In the present research, we determined the rate of production of NO and cGMP in the cytosol of platelets stimulated by collagen in 20 females with menstrual migraine (MM), (age range 2440 years), assessed in the follicular and luteal phases, interictally and ictally in the latter period. The same patients were also assessed at mid-cycle. At the same time, the variations in the collagen response of platelets were evaluated. Moreover, these parameters were determined in the same periods in 20 age-matched control females and in 20 females affected by non-menstrually related migraine (nMM). The collagen-stimulated production of NO in the cytosol of the platelet cytosol was significantly higher in migraine patients with MM than in the control subjects. In MM patients, the increase was greater in the luteal phase of the cycle than during the follicular phase (p<0.005). A rise in NO production in platelets was also present, although to a lesser extent, in females affected by nMM compared to the healthy females, but this rise was most evident at ovulation (p<0.001). A slight but significant increase was also observed at mid-cycle in control women, but this increase did not reach the values determined in the migraine groups (p<0.02). NO production in platelets stimulated by collagen was significantly increased during attacks with respect to the interictal period in both patient groups. Similar variations were observed in the production of cGMP in MM and nMM patients. The increase in NO production was accompanied by a decrease in platelet aggregation in the migraine groups compared with the control group; this decrease was most evident at mid-cycle in nMM patients and in the luteal phase in MM patients. These data suggest an activation of the L-arginine/ NO pathway in MM and nMM patients which could explain the modifications in the platelet response to collagen evidenced in migraine-free periods and during attacks. The activation of this pathway is more accentuated in the luteal phase in MM patients, and this could be the cause of the increased susceptibility to migraine attacks in premenstrual and menstrual periods in these patients.