Michael,
I have written to Prof Leenders in Holland, who did the work showing all Parkies have a defective BBB. He did not reply. I have also told other researchers in London about the idea. They were not really interested. They have grants to investigate another idea entirely, and they focus only on their own work.
Birte,
You are right in all you say about methylprednisolone, but that was only an example. There must be a whole list of ways to tighten down the BBB.
Thelma has mentioned a compound I have not heard of, Marinol, and rightly points out that you can by-pass the BBB by a nasal route.
However, we need to list known ways of closing the pores, and where the method is not prescription based, to try try them, after checking safety. I have not had time to search for possible treatments yet.
Ron