I read this today:

It's about Alzheimer disease and how exercise slows (and prevents) Alzheimer's disease. Apparently they discovered that during exercise CRF is released and this slows down progression.

So I went to search whether they did some experiments with CRF in Parkinson's disease. I found following article from 2007:

So yes, they did and results were very very good. Usually people treat rodents with some substance and then they poison their brains. However, in this research they gave CRF 7 days after poisoning and still it was shown to reverse lesions. So very promising, but I don't know whether there are clinical research done with this or whether there are meds based on this. I will try to find out and post here if I manage to find.
I yet didn't find anything about CRF treatments. Apparently it is a peptide that doesn't pass the BBB. So you need neurosurgery to treat the brain with it. But Exendin-4 seems promising too:

I will keep searching and hope I find something more about CRF.
A Korean group showed the mode of action of urocortin is via a cyclic AMP/protein kinase interaction in 2010:
I cant find anything recent by the group (at UCL) that wrote the original papers (2007,2009). In one part of the experiments the urocortin was administered 7 days after the toxin, still giving beneficial results.........but given that recent paper from Astra Zeneca I am very dubious until the experiment is repeated with the overexpressing alpha-sync model.