Topiramate is effective for migraine prophylaxis due to its multiple mechanisms. Which of the following mechanisms of topiramate contributes to its antimigraine effect by blocking cortical spreading depression?

• A Carbonic anhydrase inhibition
• B Voltage-gated sodium channel blockade
• C GABA-A receptor potentiation
• D AMPA/kainate receptor antagonism ✓

Explanation

Topiramate blocks AMPA/kainate glutamate receptors, which inhibits cortical spreading depression, the physiological mechanism underlying migraine aura and pain. While it also potentiates GABA-A receptors, blocks sodium channels, and inhibits carbonic anhydrase, the AMPA/kainate antagonism is specifically linked to its antimigraine efficacy. Carbonic anhydrase inhibition causes metabolic acidosis and paresthesias.

Reference: Katzung and Trevor's Pharmacology, 12th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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