Influence of Selective Norepinephrine Reuptake Inhibition on Motor Function Recovery after Focal Cortical Brain Infarction

Earlier studies suggested that the neurotransmitter norepinephrine (NE) plays a major role in motor function recovery. Stimulation of central norepinephrine was postulated to enhance cortical excitability. This, in turn, is thought to influence functional recovery after focal cortical infarction. Reboxetine is a selective norepinephrine (NE) reuptake inhibitor and a clinically efficacious antidepressant drug. Thus, Reboxetine might facilitate functional recovery and cortical reorganization after ischemic stroke, and it might potentiate the benefit of other neurorehabilitation strategies. The objective of this study was to investigate whether Reboxetine promotes motor function recovery after focal cortical brain infarction in adult rats housed in an enriched environment. Twenty-four adult male Wistar rats were pre-trained in a skilled reaching task to grasp and retrieve food pellets. They then received a unilateral focal ischemic lesion of the sensorimotor cortex induced by photothrombosis. After the infarction the animals were assigned to one of the following treatments: standard housing condition/no reboxetine; enriched environment/no reboxetine; enriched environment/reboxetine (15mg/kg i.p. once daily up to four weeks after lesion). The animals were tested daily in the reaching task (20 food pellets/day) until asymptotic levels in motor performance were reached. The endpoint measures at day 28 after lesion revealed improved reaching success in animals treated with Reboxetine as compared to non-treated animals suggesting that Reboxetine promotes improvement of skilled motor function. Further analysis of reaching movement performance and processing of histological data is currently being performed. The findings of this study bear implications to improve rehabilitation strategies in stroke patients in combination with other rehabilitative therapy. Support contributed by The Center for Interdisciplinary Medical Research of Germany (IZKF).