Anticonvulsant activity of quinine in rat models of seizure in comparison with valproate and phenytoin

Background: Presently available anti-seizure drugs cannot control seizures in 20-40% epilepsy patients who develop refractory epilepsy. None of the currently available anti-seizure drugs targets hypersynchronization of epileptogenic impulses. Process of hypersynchronization involves gap junction (GJ) activity. Quinine blocks GJs, and prevents seizures in animal models. Since comparative studies were lacking, this animal study compared anticonvulsant activity of quinine with that of valproate and phenytoin. Materials and Methods: Seizures were induced in adult albino Sprague/Dawley rats (n = 72) using pentylenetetrazole (PTZ) and maximum electroshock (MES) methods, comparator drugs being valproate (90 mg/kg) and phenytoin (27 mg/kg), respectively. Quinine was given in three doses (28, 35 and 42 mg/kg). Results: Higher doses of quinine (35 and 42 mg/kg) controlled PTZ seizures; efficacy was similar to valproate. MES seizures were not suppressed. Conclusion: Quinine has in-vivo anticonvulsant activity in rats in PTZ model at higher doses, but not in MES model in the doses tested.