Effects of age on reserpine-induced orofacial dyskinesia and possible protection of diphenyl diselenide

Abstract

Acute reserpine administration produces persistent oral dyskinesia in rats, an alleged animal model of tardive dyskinesia. The pathophysiology of the syndrome remains unclear, but experimental evidence suggests that neurodegeneration in the basal ganglia caused by oxidative stress plays a pivotal role in TD development. In this paper, the authors examined whether diphenyl diselenide, an organochalcogen with antioxidant properties, changes the behavioral and neurochemical effect of acute reserpine administration in old rats. The basal vacuous chewing movements (VCMs) and facial twitching (FT) duration was higher in old rats (15 months of age), when compared with adult rats (3 months of age; 0.01). Basal thiobarbituric acid-reactive species (TBARS) levels were increased only in the cortex of old rats, when compared to adult animals ( p < .05). Reserpine injection (1 mg/kg, s.c. for 3 days every other day) caused a significant increase on the tongue protusion (TP) frequency ( p < .01) and facial twitching duration ( p < .01) in old rats. Diphenyl diselenide (10 mg/kg, i.p. for 4 days, starting the day before reserpine) reversed only reserpine-induced TP increase ( p < .01). Reserpine caused a significant increase in striatal TBARS levels ( p < .01) and diselenide reversed ( p < .01) the effect of reserpine on TBARS levels in the striatum. In subcortical parts, isolated reserpine or diselenide administration significantly increased ( p < .01) the levels of TBARS, while simultaneous treatment with reserpine and diselenide reverted this effect ( p < .01). The results of the present study confirmed the effects of age on orofacial dyskinesia. Diphenyl diselenide, an organochalcogen with antioxidant properties, showed modest effects on reserpine-induced orofacial dyskinesia. However, additional studies are still necessary to establish whether this compound can be considered an effective antioxidant in other models of neurotoxicity.