[davekm (OP)]

Caffeine increases BDNF, and prevents stress induced decreases in BDNF.

However, chronic BDNF downregulates the TrkB receptor. - http://www.ncbi.nlm.nih.gov/pubmed/8752592 [nofollow]

This is true of caffeine as well. -http://www.ncbi.nlm.nih.gov/pubmed/22841916

Does downregulation of TrkB stops BDNF from performing it's functions, like neuroprotection and neurogenesis?