Tardive dyskinetic syndrome in rats infected with Borna disease virus.

Tardive Dyskinesia (TD) is a hyperkinetic movement disorder caused by chronic treatment of psychiatric patients with dopamine (DA) receptor blocking drugs (Stacy & Jankovic 1991). Although TD is one of the most important and frequently encountered iatrogenic disorders in clinical medicine, its pathophysiology is poorly understood. We have observed a hyperkinetic movement disorder in rats experimentally infected with a neurotropic RNA virus, Borna disease virus, that may provide important insights into the pathophysiology of TD. Like TD patients, infected rats show prominent orofacial dyskinesias. In keeping with the dopamine (Goetz & Klawans 1982) and anatomic (Fibiger & Lloyd 1984) hypotheses of TD, the Borna disease rat model shows enhanced behavioural sensitivity to DA agonists and selective striatal cell damage. There is also evidence of DA deafferentation and heterogeneous reduction of D2 binding in the caudate-putamen, particularly from sites implicated in oral behaviour. These observations on a virus-induced movement disorder offer novel approaches to TD pathogenesis.