“…Injection of adeno/lenti-associated virus that expresses wild-type or mutant a-syn into rat, mice or non-human primate SN produced loss of dopaminergic neurons, but the effect is not easily reproduced in transgenic mice overexpressing alpha-synuclein Rationale for the role of autophagy: Early dendritic and axonal dystrophy, reduction of striatal dopamine content, and the formation of somatic and dendritic ubiquitinated inclusions in DA neurons were prevented by ablation of Atg7 (an essential autophagy gene ) Rationale for the role of UPS/ALP: Protection from DA neuronal death was also observed in multiple experiments through the pharmacological modulation of the UPS, ALP system; however, there are also contradicting data in the literature Zhu et al, 2007; However, although many lines of evidence exist to support essentiality of impaired proteostasis, a single molecular chain of events cannot be established Clinical and experimental evidences show that the pharmacological replacement of the DA neurofunction by allografting fetal ventral mesencephalic tissues is successfully replacing degenerated DA neurons resulting in the total reversibility of motor deficit in animal model and partial effect is observed in human patient for PD Lopez-Lozano et al, 1991; Also, administration of L-DOPA or DA agonists results in an improvement of motor deficits . The success of these therapies in man as well as in experimental animal models clearly confirms the causal role of dopamine depletion for PD motor symptoms (Cotzias et al, 1969;Matsumoto et al, 1976;Narabayashi et al, 1984;Kelly et al, 1987;Lopez-Lozano et al, 1991;Uitti et al, 1996Uitti et al, , 1997Silva et al, 1997;Lang et al 1998;Scott et al, 1998;De Bie et al, 1999;Walter et al, 2004;...…”