Mizuno_1997_Nihon.Shinkei.Seishin.Yakurigaku.Zasshi_17_17

The effects of carbamazepine (CBZ) and zonisamide (ZNS) on acetylcholine (ACh) release and ACh metabolism in rat striatum were investigated. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were also determined in vitro. CBZ and ZNS did not inhibit either type of AChE or BChE activity. Acute administration of CBZ (25 mg/kg) and ZNS (20 mg/kg) increased ACh release as well as ACh metabolism, while CBZ (100 mg/kg) and ZNS (100 mg/kg) inhibited ACh release and metabolism. Chronic administration of CBZ and ZNS showed the same effects on ACh metabolism. These results indicate that effective doses of CBZ and ZNS enhance ACh turnover and extracellular levels of ACh, while toxic doses of CBZ and ZNS (100 mg/kg) decrease them without affecting cholinesterase activity. The effects of CBZ and ZNS on ACh levels may, at least partly, explain the antiepileptic and mood stabilizing effects of these drugs.