Question

The mechanism of action for relieving migraine by ergotamine is due to _______

• A. \( \text{Blocking vascular } \alpha \text{ adrenergic receptors} \)
• B. \( \text{Blocking vascular 5-HT}_2 \text{ receptors} \)
• C. \( \text{Dilating cranial arterio-venous shunt channels} \)
• D. \( \text{Constricting cranial vessels and reducing perivascular neurogenic inflammation} \)

Hint:

Think of ergotamine as a "vessel constrictor" for the head during a migraine. Targeting serotonin receptors is key to this action.

Answer 1

The Correct Option is D

Ergotamine is an ergot alkaloid used to treat migraine headaches. Its primary mechanism of action in relieving migraine pain involves the constriction of dilated cranial blood vessels. Migraine is thought to involve vasodilation of cranial arteries, which contributes to the headache pain. Ergotamine acts as a non-selective 5-HT$_1$ receptor agonist, particularly at 5-HT$_{1B}$ receptors located on intracranial blood vessels, causing vasoconstriction. Additionally, ergotamine can have complex effects on other receptors, including adrenergic and dopaminergic receptors, and may also help reduce perivascular neurogenic inflammation, further contributing to migraine relief.