Looks like an interesting thread. Unfortunately, I'm pretty much swamped right now, so I won't have the free time to read through a beast like that for at least a few weeks.
I did read the first post, and I'll make a few quick comments.
1. Be warned that increasing VMAT2 -- e.g. by taking lithium -- is also going to blunt the effects of amphetamine. The amphetamine/VMAT2 interaction is complex and not fully elucidated, but there's reason to think that a significant part of amphetamine's mechanism of action is mediated through. In other words, while VMAT2 inhibition almost certain contributes to neurotoxicity, it may not be a good functional target.
2. Be aware that only methamphetamine is going to alter tryptophan hydroxylase expression, as methamphetamine -- but not amphetamine -- has significant affinity for the SERT. Also note that recent research has pointed to methamphetamine being intrinsically more neurotoxic than amphetamine.
3. Don't forget the trace amine receptor (TAAR). There are major species differences in TAAR expression, and TAARs seem somehow involved in amphetamine neurotoxicity in an important way. This may be one of the reasons that translating results between rodents and humans is so difficult.
4. I haven't had time to research it extensively, but nAChRs are likely involved more in amphetamine neurotoxicity than is commonly realized. Amphetamine has nontrivial activity at the alpha7 nAChR in particular, and blocking the alpha7 nAChR has somewhat fascinating effect on the results of amphetamine administration. This is a hugely important target in the coming decade.
5. Be careful in suggesting supplements to attenuate amphetamine neurotoxicity. For one, we don't know the extent to which neurotoxicity occurs in healthy humans at therapeutic dosing, so it may not even be necessary. But more importantly, compounds (e.g. NAC) that have been shown to attenuate neurotoxicity with acute administration (i.e. NAC administered acutely before amphetamine insult) may not do so with chronic administration, and may even paradoxically inhibit long-term resistance to oxidative stress.
6. Parkinson's disease prevention research is promising, but based on postmoterm studies in methamphetamine addicts, the region of the basal ganglia most severely impacted by [meth]amphetamine abuse is the caudate nucleus, whereas the region most severely affected in PD is the putamen. This may explain why [meth]amphetamine abuse leads to cognitive disturbance (controlled, in part, by the caudate) before it leads to motor disturbance (more controlled by the putamen). As a result, caution must be used in extrapolating these models.
7. Don't lose sight of the fact that nothing has been shown, in humans or even in primates, to prevent Parkinson's disease or to prevent chronic amphetamine neurotoxicity. We can speculate a great deal, but the species differences makes it very, very hard to be conclusive.
8. Finally, be careful with DAT transporter inhibitors. Methylphenidate, for example, prevents Parkinsonism and DA neurotoxicity in models of amphetamine neurotoxicity exclusively because it blocks amphetamine from getting into DA neurons and doing its job. Methylphenidate isn't really neuroprotective, it just essentially antagonizes the effects of amphetamine.
9. The notion of using curcumin is intriguing, and I've been researching curcumin for such purposes -- and others -- for a while now, but there's just not enough decent research on curcumin's ability to produce such results in vivo. There is some evidence for curcumin attenuating morphine tolerance, so it's possible, but the magnitude of effect is unclear. It's also complicated because curcumin is much more bioavailable in rodents than in humans. And then this is further complicated by the fact that high enough doses of curcumin actually induce oxidative stress and may be toxic in the long-term.
That's all I've got off the top of my head. Feel free to reproduce this (i.e. quote me) in the thread, if you want. I don't have a Bluelight username, so I figured I'd just reply in a PM.
If you have specific questions, I'm happy to answer -- or at least try to answer -- those.
-Ex