This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epilepsy, Subject name: Pharmacology
[{'content': 'Which of the following antiepileptic drugs acts by affecting the levels of GABA? \nSelect and explain. \nA. Sodium valproate, B. Ethosuximide, C. Phenytoin sodium, D. Carbamazepine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (A) Sodium valproate(Ref: KDT 8/e p444)It acts by various mechanisms like increase in GABA, blockade of Na+ channels and inhibition of T-type Ca2+ currents. Valproate increases the formation of GABA (by stimulating glutamic acid decarboxylase) and inhibits the degradation of GABA (by inhibiting GABA transaminase and succinic semialdehyde dehydrogenase).Phenytoin and carbamazepine acts by affecting neuronal Na+ channels.Ethosuximide acts by affecting T-type Ca2+ currents.', 'role': 'assistant'}]