Thelma-

Stress is a major player (perhaps THE major player) in PD deriving from our imbalanced neuroendocrine system and our screwed up cortisol levels. They are typically high for PWP. More importantly, where a normal production cycle peaks in the morning to help us wake up and drops as much as 90% over the course of the day, PWP have a steady rate of production without the morning peak. Bottom line is we have chronically elevated levels.

And that isn't good. One of the obvious things is that hypercortisolism sets us up for systemic inflammation which, among other things, opens the BBB and lets in toxins such as the bacterial LPS i have mentioned earlier. The reaction of the microglia then leads to the destruction of the substantia nigra and so on.

We have never received a good answer from our docs as to just why we are so sensitive to stress. Shake at the drop of a hat. Why? The answer lies here and it may be a clue as to part of the action of the dextromethorphan. As RLSmi pointed out, femtomolar concentrations are pretty darned tiny. Not what one would expect as effective sedation for something as "weak" as DM. Something more is at work and this may be close to it.

Notice that Steve felt calm, not groggy or sedated or similar feelings. And he woke up feeling good, not hung over or anything.

Getting more interesting by the day. -Rick