N,N-dimethyltryptamine (DMT) is neither formed nor retained in serotonin terminals in the rat brain.
Open Access CRIS of the University of Bern February 9, 2026 Mikael Palner, Elisabeth Kolesnik, Christina Baun et al.
The mammalian brain may contain an endogenous pool of the psychedelic N,N-dimethyltryptamine (DMT), possibly acting as a co-transmitter with serotonin. In rats, inhibiting monoamine oxidase with pargyline did not make endogenous DMT detectable, while probenecid slightly elevated the acidic metabolite 3-indoleacetic acid (3-IAA), suggesting formation from tryptamine, especially in the striatum. After administering DMT plus harmine, peak brain DMT occurred at 45 minutes and peak 3-IAA at 60 minutes, with nearly complete washout by 210 minutes. Escitalopram did not alter exogenous DMT or 3-IAA disposition, and dihydrotetrabenazine slightly increased 3-IAA in some regions. The results do not support an endogenous DMT pool or retention of exogenous DMT in serotonin terminals.