Sorry for the necromancy, and it appears that the OP is no longer with us; but I just wanted to update anyone who was unawares about the substance mentioned in the post. It has been found that this (rather interesting, on some levels) substance that was assumed for years to be exerting its antidepressant effect via the potential mechanisms of action listed above -- and indeed these are certainly related to the putative neurogenesis associated with tianeptine -- is in actuality through some quirk of chemistry to be an atypical mu-opioid receptor agonist (this despite it being a structural analogue to and member of the "tricyclic" class). This being the case, it can be said I think that rather than tianeptine being an antidepressant with a "novel mechanism of action", it is more accurately thought of as a "grandfathered-in" member of that earliest class of medicines to be used for their antidepressant actions: the Opioids.
I find the whole saga of this substance's discovery and the long road to the elucidation of its true pharmacology to be a fascinating tale. This is to say nothing of what I think of the drug itself when used in that dubious area between "medical" and "recreational" use, and the anecdotal reports coming in seem to point *very* strongly to this being a powerful psychoactive agent that should be used wisely, if at all.
Here is a study related to what I am describing above. I do find it interesting that the authors refer to the M.O.R. as a "novel" mechanism in fighting depression. [edit] meant to say that it is interesting because if you look at the historical literature (and I mean going
way back, MOR agonists were by far the earliest drugs used for their antidepressant action. The example of the Persian tradition of drinking Poppy tea before and during funerals comes to mind.
EDIT: I think I should add that the substance, while certainly interesting and potentially promising for some people with depression when used responsibly and at the recommended doses. However, I can speak from personal experience that at much higher doses the stuff is more-or-less just another MOR, with all the same liabilities that go along with that. If you've ever had a problem with opioids, steer far clear of this one. Part of my opioid addiction at the end was with this stuff, and it can, does, and will cause opioid w/d's just the same as any of the rest. However, in addition to regular MOR w/d effects, myself and one other person close to me who also has danced with it have noted a uniquely emotional aspect to its cessation syndrome, manifesting as marked anxiety and a tendency towards sadness/emotional distress (even more so than with a normal one). An interesting point on this (from a pharmacological point of view) is that when I'd use tianeptine for several days and then cycle to kratom, the hyperalgesic effects were ameliorated, but these funny emotional ones weren't (seeming to indicate some other activity than that at the MOR, as described above by the OP).
Anyway, I know this is really sort of beyond the purview of this forum but I just thought since the question was out there and people seem to be looking at the thread I'd add what I could on this still generally obscure one.