CNTF and Parkinson disease: Expression of CNTF and CNTFRα can increase in the brain following injury [5–7]; however, the levels of CNTF are reduced in dopaminergic neurons in the substantia nigra (SN) of Parkinson’s disease (PD) patients [8] and treatment with recombinant human CNTF preventes the degeneration of dopaminergic neurons [9].