Human psychopharmacology of N,N-dimethyltryptamine

[pHarmacist]

Behavioural Brain Research (73) 1996 121-124

(http://pharmacist8.tripod.com/NN-DMT.pdf)
Strassman R.J.

Abstract: We generated dose-response data for the endogenous and ultra-short-acting hallucinogen, N,N-dimethyltryptamine (DMT), in a cohort of experienced hallucinogen users, measuring multiple biological and psychological outcome measures. Subjective responses were quantified with a new rating scale, the HRS, which provided better resolution of dose effects than did the biological variables.A tolerance study then was performed, in which volunteers received four closely spaced hallucinogenic doses of DMT. Subjective responses demonstrated no tolerance, while biological measures were inconsistently reduced over the course of the sessions. Thus, DMT remains unique among classic hallucinogens in its inability to induce tolerance to its psychological effects. To assess the role of the 5-HT1A site in mediating DMT's effects, a pindolol pre-treatment study was performed. Pindolol significantly increased psychological responses to DMT, suggesting a buffering effect of 5-HT1A agonism on 5-HT2-mediated psychedelic effects. These data are opposite to those described in lower animal models of hallucinogens' mechanisms of action. 

This study can confirm my own research on 5-MeO-DMT where my own subjective response didn't demonstrate any tolerance to the material. I can't fully agree with the author who claims that DMT remains unique in its inability to induce tolerance to its psychological effects simply because same holds true for 5-MeO-DMT.

P.S The author of this paper (Rick Strassman) also wrote "DMT: The Spirit Molecule". Sometimes when rading papers you can see that certain people that do research in this area have a real bee in them, it's so obvious in their way of expressing themselves...

EDIT:

Here is a sample-chapter from the book DMT: The Spirit Molecule ->

Contact Through The Veil

(http://www.rickstrassman.com/dmt/contact.pdf)

[Dextrose]

Very interesting article, thank you very much.

With multiple trials of 5-MeO-DMT (including redosing), and some with n,n-DMT, i've been wondering about the previous postulated rapid tolerance-developement, i've read in numerous (elder) FAQs.

Nothing i too haven't experienced at all.

[pHarmacist]

Differential Tolerance to Biological and Subjective Effects of Four Closely Spaced Doses of N,N-Dimethyltryptamine in Humans
Strassman R.J. ; Qualls C.R. ; Berg L.M.

Biological Psychiatry 1996;39:784-795

(http://pharmacist.the-hive.tripod.com/tolerance-dmt.pdf)

Abstract: Tolerance to the behavioral effects of the short-acting, endogenous hallucinogen, N,N-dimethyltryptamine (DMT) is seen inconsistently in animals, and has not been produced in humans. The nature and time course of responses to repetitive, closely spaced administrations of an hallucinogenic dose of DMT were characterized. Thirteen experienced hallucinogen users received intravenous 0.3 mg/kg DMT fumarate, or saline placebo, four times, at 30 min intervals, on 2 separate days, in a randomized, double-blind, design. Tolerance to ''psychedelic'' subjective effects did not occur according to either clinical interview or Hallucinogen Rating Scale scores. Adrenocorticotropic hormone (ACTH), prolactin, cortisol, and heart rate responses decreased with repeated DMT administration, although blood pressure did not. These data demonstrate the unique properties of DMT relative to other hallucinogens and underscore the differential regulation of the multiple processes mediating the effects of DMT.