NGF and Parkinson disease: Given that we have recently published that pharmacological-mediated enhancement of PKA signaling via intraperitoneal delivery of Forskolin is sufficient to ameliorate Parkinson’s pathology in 10-month-old PINK1-KO rats [46], in this study, we hypothesized that intranasal delivery of more than one nootropic agent that can enhance both PKA and neurotrophic support (BDNF + NGF) could yield neuroprotective effects in PINK1-KO rats in an additive manner compared to intraperitoneal administration of Forskolin alone [46].