Mescaline, a hallucinogenic agent found in the Peyote cactus, has poorly understood psychoactive mechanisms despite being one of the oldest known such substances. Its effects are primarily due to interaction with serotonergic 5-HT2A-C receptors, producing euphoria, hallucinations, depersonalization, and psychoses similar to LSD and psilocybin, alongside sympathomimetic signs. The drug is mainly metabolized into trimethoxyphenylacetic acid, with several minor metabolites reported. Most intoxications are mild and unlikely to produce life-threatening symptoms; addiction and dependence are practically absent, supporting contemporary interest in therapeutic potential.
Ketamine and its metabolite (2R,6R)-hydroxynorketamine show rapid antidepressant effects in models of major depressive disorder. The review discusses how these compounds work differently from traditional antidepressants, potentially offering faster relief for treatment-resistant depression. The FDA-approved nasal spray Spravato (esketamine) is highlighted as a clinical application. The text suggests that understanding the mechanisms of these compounds could lead to better treatments for major depressive disorder.