Suppression of exaggerated neuronal oscillations by oxytocin in a rat model of Parkinson's disease.

Abstract

Increased oscillatory activity has been demonstrated in the basal ganglia of Parkinson's disease (PD) patients. The aim of the present study was to evaluate the effects of oxytocin on local field potentials (LFPs) in a rotenone-induced rat model of PD. Adult male Sprague-Dawley rats were unilaterally injected with rotenone (3 &#xb5;g/&#xb5;l in DMSO) into the left substantia nigra pars compacta whereas vehicle group was received only DMSO. PD developed rats were then administered either oxytocin (160 &#xb5;g/kg/day, i.p.) or saline for three weeks. Following treatment period, LFPs were recorded from the left striatum of freely moving rats and neuronal cell loss was evaluated by Nissl staining. We found significant increase in all frequency bands except delta in saline group when compared with vehicle (p < 0.0005), while treatment of oxytocin prevented these alterations in EEG recordings. Besides, histopathological evaluation of the striatal sections revealed a significant cell loss (p < 0.005), whereas administration of rats with oxytocin significantly lessened the neuronal death. These findings suggest that injury of dopaminergic neurons triggers exaggerated neuronal oscillations in the striatum and oxytocin may have some inhibitory effects on neuronal activity in PD.