Yes, this is what I said, it's not that endogenous DMT is the source of NDE's, it's that the DMT experience is similar enough to an NDE or mystical experience that it's proposed that it may be used to "map the terrain"

But hold on, I will come back to that, first, Currently unknown psychedelic chemical produced by the brain?

Do you have a source on this or is this personal speculation?

Below is a Rick strassman interview which may clarify his position, a good deal of his speculations and conjecture are often taken as fact, and it always helps to be clear on the speakers intended meaning.

Below is some miscellaneous terence McKenna on the topic of psychedelics in relation to death, and while I sincerely apologize for the length of this post, these McKenna excerpts capture some of the currant hopes of psychedelic research in relation to spirituality and death:

terence McKenna : thoughts on death

-eg