Migraine Pathology:

Migraines that are involved in the release of peptide neurotransmitters, a peptide that is associated with CGRP (from the nerve through the cerebral arteries). Therefore, this neurotransmitter induces vasodilation and extravasation of blood plasma and plasma protein into the perivascular oedema, as a result causing mechanical stretching in the dura and the pain nerve endings are activated. 

Migraine treatment:

• Anticonvulsants have prophylactic efficacy for migraines since they suppress excessive activation of the trigeminal nerve endings.
• Anti-inflammatory pain relievers have high efficacy as well.  
• Calcium blockers  and beta blockers are also effective for treating migraine prophylaxis in many patients. 
• Triptans are considered therapy for migraine and the partial agonists of serotonin 1B/1D receptors. It increases intercranial vasoconstriction which prevents vasodilation, which causes pain by stretching the sensory nerve endings. These agents also play a role in decreasing  the release from CGRP and as a result will reduce perivascular oedema in the intercranial circulation. 
• Lastly, ergot alkaloids have a mixed partial agonist effect on alpha-adrenoceptors and serotonin-2-receptors. They therefore block the alpha-agonist vasoconstriction and cause a noticeable contraction of smooth muscle (thus preventing vasodilation which leads to the pain)