treated displayed complete neuroprotection fig7 a regardless of the degree of functional recovery in lenti gal treated monkeys intracarotid injections of mptp resulted in an 89 decrease in the number fig7 a and an 81 6 decrease in the density of th immunoreactive nigral neurons on the side ipsilateral to the toxin injection p lt 0 001 in contrast lenti gdnf treated monkeys displayed 32 more th immunoreactive nigral neurons p lt 0 001 and an 11 increase in th immunoreactive neuronal density p lt 0 05 relative to the intact side in lenti gal treated animals mptp significantly reduced 32 the volume of residual th immunoreactive nigral neurons on the lesion side relative to the intact side p lt 0 001 fig7 b the volume of th immunoreactive neurons in lenti gdnf treated animals was significantly larger 44 3 on the lesioned side relative to the intact side p lt 0 001 finally the optical density of th mrna was quantified bilaterally in all animals fig7 c in lenti gal treated animals there was a significant decrease 24 0 in the relative optical density of th mrna within residual neurons on the mptp lesioned side relative to the intact side p lt 0 03 in.