This article about a promising new treatment for MS seems to me to be potentially relevant to PD as well.

http://www.sciencedaily.com/releases...1118131017.htm

I tried to understand the action of this new research and I believe the following about Adenosine is the relevant part (from Wiki)

Action in the central nervous system

Generalized, adenosine has an inhibitory effect in the central nervous system (CNS). Caffeine's stimulatory effects, on the other hand, are primarily (although not entirely) credited to its inhibition of adenosine by binding to the same receptors, and therefore effectively blocking adenosine receptors in the CNS. This reduction in adenosine activity leads to increased activity of the neurotransmitters dopamine and glutamate.

HAPPY THANKSGIVING ALL!!!!