“…Extensive studies in both rodent and nonhuman primate models, as well as studies in humans, suggest a role for the striatal opioid system in the development of LIDs (Morissette et al, 1997,Cenci et al, 1998,Duty et al, 1998,Henry et al, 1999,Johansson et al, 2001,Quik et al, 2002,Tel et al, 2002,Winkler et al, 2002,Henry et al, 2003,Carta et al, 2005,Aubert et al, 2006. Evidence for this possibility stems from results showing that enhanced PPE-B transcript levels correlate well with LIDs in experimental parkinsonian models and Parkinson's disease (Duty et al, 1998,Henry et al, 1999,Tel et al, 2002,Henry et al, 2003,Aubert et al, 2006.…”