This is another link I found and has more details which are very interesting, it seems this is not a drug and doesn’t seem to fit the category of intoxication mentioned in precepts and I believe in Jhanas (2nd onwards when all the 5 senses stop and it’s like dying) DMT are released from this gland producing profound experiences, though I may be wrong.
“One of the active ingredient in Ayahuasca is N,N-Dimethyltryptamine or DMT but there are many alkaloids in the medicine that have not been “studied” by Western Science. While humans produce DMT in the pineal gland, there are only a few times in your life when your body is naturally flooded with DMT. In the womb at around 45 days the fetus is flooded with DMT. This is thought to facilitate the new soul entering the fetus for the first time. At childbirth a woman’s body is also flooded with DMT. And at death a huge dose of DMT is released into the body which is thought to facilitate the soul’s departure from the body.
Ayahuasca is the bridge between the cerebral cortex – the part of the brain that makes us human – and the spiritual world. It is the human/spirit “interface.” It allows humans to enter the realm of spirits. Ayahuasca “lights up” your cerebral cortex and facilitates the journey.”