Effects of a Unilateral Injection of Botulinum Neurotoxin Subtype-A in the Subthalamic Nucleus of a Parkinsonian Rat Model
Abstract
Dopaminergic degeneration in Parkinson’s disease (PD) leads to altered functional activity within the basal ganglia (BG) circuitry, including hyperactivity of the subthalamic nucleus (STN). Treatments restoring the BG functional circuitry often result in improvements in parkinsonian symptoms in patients and animal models. A recent study from our laboratory identified that infusing botulinum toxin (BoNT-A) into the internal globus pallidus provided a transient restoration of motor asymmetry and goal-directed locomotion in a rat model of PD. We hypothesized that infusions of BoNT-A into the STN in a parkinsonian rat model will improve motor asymmetry and locomotor abnormalities. Infusions of BoNT-A into the ipsilateral STN in unilaterally 6-hydroxydopamine lesioned rats assessed in the apomorphine rotation task, rotarod, or CatWalk apparatus revealed a dose-dependent amelioration of pathological rotations, while failing to affect spontaneous locomotion. The present results suggest that spontaneous locomotion may not dependent on the integrity of the BG functional circuitry.