Topiramate inhibits cortical spreading depression in rat and cat: impact in migraine aura

Cortical spreading depression is thought to be the pathophysiological correlate of the neurological symptoms in migraine with aura. Topiramate is an anti-epileptic drug that is also used as a migraine preventive. Ion homeostasis and excitatory amino acid efflux are major components of cortical spreading depression; so given the broad range of actions of topiramate, we examined its effect on cortical spreading depression. Cortical spreading depression was elicited by a needle stick in the cortex in surgically prepared rats and cats; laser Doppler probes were used to measure the cerebral blood flow and a recording electrode was used to measure electrical nerve cell activity. Topiramate at 30 mg kg(-1) was able to inhibit regional cerebral blood flow changes and cortical depolarization and spreading depression in all rats, and in 8 of 13 cats. We conclude that topiramate may act on mechanisms involved in the initiation and propagation of spreading depression, and that these mechanisms may be similar to those involved in the therapeutic role.