Physical activity promotes expression of neurotrophic factors, as well as neurogenesis in adult rats. Exogenous neurotrophic factors protect against nigrostriatal dopamine (DA) cell loss and functional impairment in rats. We have recently shown that exclusive use of the impaired forelimb by immobilizing the non-impaired forelimb during the first 7 days after partial, unilateral 6-OHDA lesions results in long-term protection of striatal DA tissue content and limb use. Additionally, we have shown partial damage to DA neurons yields an increase in expression of the neurotrophic and neuroprotective factor, FGF-2, in SN and VTA (Moroz & Stewart, SFN Abst. 2000). Here, we examined the effects of forced limb use for 7 days before infusion of 6-OHDA. Compared to control animals, the animals forced to use the to-be impaired limb showed no behavioral asymmetries in a battery of sensorimotor tests. In addition, forcing SHAM-operated animals to use one forelimb exclusively for 7 days caused an increase in the number o...