..interesting questions AlbertKLloyd, i admit i read this thread a few times without forming any coherent answer, and i'm tempted to respond to the questions with questions (e.g. what does spiritual mean, and does that mean the same thing to everyone?)
..but i'll have a go..
beyond a certain dose, DMT will usually elicit 'out of body' , 'contact with discarnate entity', or 'singularity of consciousness' experiences..i take 'spirit' to imply the non-material or the 'universal', non-rational concepts based on perception,..someone who doesn't believe they have 'spiritual experiences' may experience all of the above and still not describe it in spiritual terms, instead looking for a rational scientific basis..but others would still call that experience 'spiritual'..
and if you usually have spiritual experiences, you may not have one on DMT because the dose is low, or your mind is busy/cluttered, you are not mentally prepared, or you temporarily don't realize that everything you're seeing has a spiritual origin..
..as for DMT as a neuro-transmitter, the evidence seems fairly good that it is one, or is a 'hormone', or plays a function in CNS activity
(seconding Hyperspace Fool) ..smoked, it achieves it's effects once it has entered the blood stream..this indicates it gets past the blood-brain-barrier..so if it is in the blood/cerebrospinal fluid/urine it is probably in the brain, doing something..the fact that there are 12 or more kinds of '5HT 'receptor suggests that the system is looking to upload a wider range of tryptamines than serotonin..
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