Hallucinogens as discriminative stimuli: a comparison of 4-OMe DMT and 5-OMe DMT with their methythio counterparts

The molecular basis of the antidepressant action of the magic mushroom extract, psilocin

Magic mushrooms, and their extract psilocybin, are well-known for their psychedelic properties and recreational use. Psilocin, the bio-active form of psilocybin, can potentially treat various psychiatric diseases. Psilocin putatively exerts its psychedelic effect as an agonist to the serotonin 2A receptor (5-HT2AR), which is also the receptor for the neurological hormone serotonin. The two key chemical differences between the two molecules are first, that the primary amine in serotonin is replaced with a tertiary amine in psilocin, and second, the hydroxyl group is substituted differently on the aromatic ring. Here, we find that psilocin can bind to 5-HT2AR with an affinity higher than serotonin, and provide the molecular logic behind the higher binding affinity of psilocin using extensive molecular dynamics simulations and free energy calculations. The binding free energy of psilocin is dependent upon the protonation states of the ligands, as well as that of the key residue in the binding site: Aspartate 155. We find that the tertiary amine of psilocin, and not the altered substitution of the hydroxyl group in the ring is responsible for the increased affinity of psilocin. We propose design rules for effective antidepressants based on molecular insights from our simulations.

A narrative synthesis of research with 5-MeO-DMT

BACKGROUND

5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a naturally occurring, short-acting psychedelic tryptamine, produced by a variety of plant and animal species. Plants containing 5-MeO-DMT have been used throughout history for ritual and spiritual purposes. The aim of this article is to review the available literature about 5-MeO-DMT and inform subsequent clinical development.

METHODS

We searched PubMed database for articles about 5-MeO-DMT. Search results were cross-checked against earlier reviews and reference lists were hand searched. Findings were synthesised using a narrative synthesis approach. This review covers the pharmacology, chemistry and metabolism of 5-MeO-DMT, as well epidemiological studies, and reported adverse and beneficial effects.

RESULTS

5-MeO-DMT is serotonergic agonist, with highest affinity for 5-HT1A receptors. It was studied in a variety of animal models, but clinical studies with humans are lacking. Epidemiological studies indicate that, like other psychedelics, 5-MeO-DMT induces profound alterations in consciousness (including mystical experiences), with potential beneficial long-term effects on mental health and well-being.

CONCLUSION

5-MeO-DMT is a potentially useful addition to the psychedelic pharmacopoeia because of its short duration of action, relative lack of visual effects and putatively higher rates of ego-dissolution and mystical experiences. We conclude that further clinical exploration is warranted, using similar precautions as with other classic psychedelics.

Indolealkylamine and phenalkylamine hallucinogens: a brief overview

Various indolealkylamine and phenalkylamine derivatives are hallucinogenic in man and/or are behaviorally active in animals. This overview is divided into two parts. The first part attempts to bring together information concerning the activity of indolealkylamines (i.e., tryptamines, alpha-methyltryptamines, N,N-dimethyltryptamines, N-alkyltryptamines, lysergic acid derivatives and beta-carbolines) and phenalkylamines (i.e., phenethylamines, phenylisopropylamines) along with major key references, and with emphasis on those agents not recently reviewed. The latter portion of this overview describes some of the work being conducted in our laboratories in an effort to elucidate the role of the neurotransmitter serotonin in the mechanism of action of various indolealkylamine and phenalkylamine hallucinogens.