Attenuation of haloperidol induced orofacial dyskinesia by ginkgo biloba extract

Tardive dyskinesia is one of the major side effects of long-term neuroleptic treatment. Increased reactive oxygen species and oxidative stress has been proposed as possible etiopathologic mechanisms. Ginkgo biloba extract (EGB) is a natural antioxidant. We investigated the effects of ginkgo biloba extract on neuroleptic-induced orofacial dyskinesia in rats, a potential animal model for tardive dyskinesia. Orofacial dyskinesia was induced by chronic administration of haloperidol (1 mg/kg i.p) for a period of 21 days. On 22nd day, animals were assessed for development of oral dyskinesia. Malon di aldehyde (MDA), glutathione (GSH), superoxide dismutase (SOD) and catalase levels were evaluated in animal forebrain homogenate. Chronic haloperidol (1 mg/kg) treatment significantly increased the vacuous chewing movement’s frequency, increased MDA and decreased SOD and catalase levels. Co-administration of EGB 25 mg/kg along with haloperidol suppressed the haloperidol induced vacuous chewing movements (Pvalue < 0.05). EGB 100 mg/kg reversed haloperidol induced reduction in SOD level. It also reversed the increment in MDA level observed in haloperidol treated rats. The present study suggested that oxidative stress plays a significant role in neuroleptic-induced orofacial dyskinesia and EGB co-administration reverses these behavioral and biochemical changes.