A smattering of articles on what caffeine does.

http://www.ncbi.nlm.nih.gov/pubmed/20164568

http://worldofcaffeine.com/caffeine-...otransmitters/

http://www.ncbi.nlm.nih.gov/pubmed/7154859

http://www.news-medical.net/health/C...rmacology.aspx

And an article on why they are still arguing over whether Mestinon crosses the BBB (particularly the hypothalamus). But, of course, we aren't mice.

http://www.jmedcbr.org/issue_0601/Cool/Cool_10_08.html

Lots of variables can probably effect both.

Annie