RESUMO
BACKGROUND AND PURPOSE: Stroke survivors often have permanent deficits that are only partially addressed by physical therapy. This study evaluated the effects of dalfampridine, a potassium channel blocker, on persistent sensorimotor deficits in rats with treatment initiated 4 or 8 weeks after stroke. METHODS: Rats underwent permanent middle cerebral artery occlusion. Sensorimotor function was measured using limb-placing and body-swing symmetry tests, which normally show a partial recovery from initial deficits that plateaus ≈4 weeks after permanent middle cerebral artery occlusion. Dalfampridine was administered starting at 4 or 8 weeks after permanent middle cerebral artery occlusion in 2 blinded, vehicle-controlled studies. Plasma samples were collected and brain tissue was processed for histologic assessment. RESULTS: Dalfampridine treatment (0.5-2.0 mg/kg) improved forelimb- and hindlimb-placing responses and body-swing symmetry in a reversible and dose-dependent manner. Plasma dalfampridine concentrations correlated with dose. Brain infarct volumes showed no differences between treatment groups. CONCLUSIONS: Dalfampridine improves sensorimotor function in the rat permanent middle cerebral artery occlusion model. Dalfampridine extended-release tablets (prolonged release fampridine outside the United States) are used to improve walking in patients with multiple sclerosis, and these preclinical data provide a strong rationale for examining the potential of dalfampridine to treat chronic stable deficits in stroke patients. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT01605825.