Quercetin, a bioflavonoid, attenuates haloperidol-induced orofacial dyskinesia.

Chronic treatment with neuroleptics leads to the development of abnormal orofacial movements described as vacuous chewing movements (VCMs) in rats. Vacuous chewing movements in rodents are widely accepted as one of the animal models of tardive dyskinesia. Oxidative stress and the products of lipid peroxidation are implicated in the pathophysiology of various neurological disorders including tardive dyskinesia. In the present study chronic haloperidol (1.0 mg kg(-1) for 21 days) treatment induced vacuous chewing movements and tongue protrusions in rats. Co-administration of quercetin, a bioflavonoid, dose dependently (25-100 mg kg(-1)) reduced haloperidol-induced vacuous chewing movements and tongue protrusions. Biochemical analysis revealed that chronic haloperidol treatment induces lipid peroxidation and decreases the glutathione (GSH) levels in the forebrains of rats. The antioxidant defense enzymes, superoxide dismutase (SOD) and catalase were also decreased due to chronic haloperidol treatment. Co-administration of quercetin (25-100 mg kg(-1)) significantly reduced the lipid peroxidation and restored the decreased glutathione levels in these animals. Further quercetin (50-100 mg kg(-1)) also reversed the haloperidol-induced decrease in forebrain SOD and catalase levels in rats. The major findings of the present study suggested that oxidative stress plays a significant role in neuroleptic-induced orofacial dyskinesia and quercetin co-administration reverses these behavioral and biochemical changes. Quercetin, a naturally occurring bioflavonoid could prove to be a useful agent in neuroleptic-induced orofacial dyskinesia.