A migraine is a disorder characterized by recurrent headaches that range from moderate to severe.
The physiology behind migraine is complex and the mechanisms are not yet fully understood.
Nitroglycerin is a chemical that is used for its vasodilating properties to induce a migraine in migraine patients. Vasodilation is the process by which a blood vessel expands. Due to this property, nitroglycerin can be used to test the cardiovascular system.
In a study published in Cephalalgia, researchers aimed to understand the cardiovascular effects of nitroglycerin in migraine patients compared to healthy controls (those who did not suffer from migraines).
Sixteen female migraine patients and ten healthy female patients participated in the study. After overnight fasting, all of the participants were given a nitroglycerin infusion. Cardiovascular and clinical parameters were measured before, during, and after the infusion. In particular, the researchers made note of blood pressure, heart rate, stroke volume, cardiac output, and peripheral resistance using a technique called photopletismography, which measures blood pressure in the finger.
Out of the 16 migraine patients, 13 patients developed a migraine. Of those who developed a migraine, six patients had a migraine within 270 minutes of the infusion, labeled the “early attack” group.
The remaining seven patients had a migraine more than 270 minutes after the infusion, labeled the “late attack” group. None of the healthy controls developed a migraine.
After analyzing the photopletismography results, the researchers found that the migraine group had different cardiovascular responses compared to the healthy participants. The researchers noted that the migraine patients had a higher heart rate compared to the healthy controls.
They also noted a faster and more pronounced reduction in stroke volume and cardiac output in the migraine group and a sharp increase in peripheral resistance prior to a sharp decrease.
Overall, blood pressure was higher in migraine patients compared to healthy participants.
Although the sample size of the study was quite small (there were only 26 participants in total), the researchers did note that the migraine group appeared to be more susceptible to nitroglycerin. This suggests that the cardiovascular system in migraine patients may be more prone to vasodilation and may not have the appropriate mechanisms to combat the effects of vasodilation.
Further research needs to be done to see if the mechanisms underlying migraines can be elucidated. Future studies will require a larger sample size and more gender representation.
References:
- van Oosterhout, W., Schoonman, G., Saal, D., Thijs, R., Ferrari, M. and van Dijk, J. (2019). Abnormal cardiovascular response to nitroglycerin in migraine. Cephalalgia, p.033310241988165.
- EurekAlert!. (2020). On nitroglycerin, cardiovascular homeostasis and…bam, migraine!. [online] Available at: https://www.eurekalert.org/pub_releases/2019-12/ihs-onc122719.php [Accessed 3 Jan. 2020].