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Rafael de la Torre

Universitat Pompeu Fabra, Neurosciences Institute

38 papers in the library · 2,947 citations · publishing 2000-2022

Papers

Combined immunomodulating properties of 3,4‐methylenedioxymethamphetamine (MDMA) and cannabis in humans

Addiction May 22, 2007 Roberta Pacifici, Piergiorgio Zuccaro, Magı́ Farré et al. 39 citations

People who use both MDMA (ecstasy) and cannabis show long-term changes in immune function, including lower levels of interleukin-2 and higher levels of anti-inflammatory transforming growth factor beta-1, along with fewer total lymphocytes, CD4 cells, and natural killer cells. These immune alterations persisted over one year. Regular users of both drugs had a higher rate of mild infections compared to occasional users and those who used only cannabis or neither drug. Cannabis-only users showed intermediate immune changes. The findings suggest that sustained disruption of immune balance may lead to poorer general health and greater susceptibility to infections.

MDMA-Induced Dissociative State not Mediated by the 5-HT2A Receptor

Frontiers in Pharmacology July 11, 2017 Drew J. Puxty, Johannes G. Ramaekers, Rafael de la Torre et al. 33 citations

A single 75 mg dose of MDMA produces a dissociative state, marked by feelings of depersonalization and derealization, in healthy recreational users. Blocking the 5-HT2 receptor with ketanserin did not prevent this effect, indicating that the 5-HT2 receptor does not mediate MDMA-induced dissociation. Heart rate correlated with the dissociative state after MDMA alone, but not when ketanserin was given, suggesting heart rate changes do not directly cause dissociation. Cortisol levels and MDMA blood concentrations showed no clear relationship with dissociation. The exact neurobiological mechanism remains unknown and may be relevant to MDMA's therapeutic use.

Acute Pharmacological Effects of Oral and Intranasal Mephedrone: An Observational Study in Humans

Pharmaceuticals January 28, 2021 Esther Papaseit, Eulàlia Olesti, Clara Pérez‐mañá et al. 30 citations

Mephedrone, a synthetic cathinone and popular new psychoactive substance, produces euphoria and well-being and increases cardiovascular effects when self-administered orally or intranasally by healthy experienced drug users. In this observational study, ten participants took a single dose orally (100–200 mg, mean 150 mg) or intranasally (50–100 mg, mean 70 mg). Although the oral route sometimes produced greater subjective effects, concentrations of mephedrone in oral fluid and total amounts in urine were considerably higher after intranasal administration. Controlled clinical trials are needed to confirm these results.

Mephedrone and Alcohol Interactions in Humans

Frontiers in Pharmacology January 28, 2020 Esther Papaseit, Clara Pérez-mañá, Elizabeth B. de Sousa Fernandes Perna et al. 27 citations

Combining mephedrone with alcohol amplifies cardiovascular effects and intensifies euphoria and well-being compared to either drug alone, while mephedrone reduces the sedative effects of alcohol. In a double-blind, placebo-controlled trial with 11 male volunteers, the combination increased blood pressure, heart rate, and subjective feelings of euphoria. Mephedrone alone and alcohol alone were also tested. The results suggest that the abuse liability of mephedrone is greater when taken with alcohol, similar to other psychostimulants like amphetamines and MDMA.

A Comparison of Acute Pharmacological Effects of Methylone and MDMA Administration in Humans and Oral Fluid Concentrations as Biomarkers of Exposure

Biology August 17, 2021 Lourdes Poyatos, Esther Papaseit, Eulàlia Olesti et al. 26 citations

Methylone, a synthetic cathinone and beta-keto analogue of MDMA, produces acute subjective and physiological effects similar to MDMA but less intense. In an observational-naturalistic study of 14 healthy poly-drug users who self-administered oral doses (methylone 100-300 mg, mean 187.5 mg; MDMA 75-100 mg, mean 87.5 mg), methylone showed a prototypical psychostimulant and empathogenic profile. Oral fluid concentrations of both substances peaked at 2 hours, with MDMA levels matching those from controlled studies. The findings indicate that methylone's abuse potential is comparable to MDMA's in recreational users.

Neurocognitive performance following acute mephedrone administration, with and without alcohol

Journal of Psychopharmacology August 25, 2016 EB de Sousa Fernandes Perna, Esther Papaseit, Clara Pérez‐mañá et al. 26 citations

Mephedrone, a recreational drug similar to MDMA, impairs short-term spatial memory one hour after intake but improves critical tracking performance four hours later. When combined with alcohol, mephedrone reduces reaction time compared to alcohol alone, but does not counteract alcohol's impairing effects on divided attention or spatial memory. Alcohol alone impairs both short- and long-term spatial memory and divided attention. The findings suggest mephedrone enhances psychomotor performance while harming memory, and its stimulatory effects are insufficient to offset alcohol-induced deficits on most cognitive tasks.

MDMA-induced indifference to negative sounds is mediated by the 5-HT2A receptor

Psychopharmacology July 22, 2017 Kim P. C. Kuypers, Rafael de la Torre, Magı́ Farré et al. 24 citations

MDMA reduced the arousal normally elicited by negative sounds, and this effect was blocked by pre-treatment with ketanserin, a 5-HT2 receptor antagonist, indicating the involvement of the serotonin 2A receptor. The drug did not produce a bias toward emotional or social stimuli in the tasks used. MDMA increased both positive and negative mood ratings and elevated oxytocin plasma concentrations. The reduction in arousal to negative sounds was unrelated to subjective arousal levels. This decrease in defensive arousal may contribute to MDMA's therapeutic effects.

Inhibition ofMDMA‐induced increase in cortisol does not prevent acute impairment of verbal memory

British Journal of Pharmacology September 4, 2012 Kim P. C. Kuypers, Rafael de la Torre, Magı́ Farré et al. 23 citations

MDMA acutely impairs memory, but this effect is not caused by the rise in cortisol that MDMA also triggers. In a placebo-controlled, within-subject experiment with 17 polydrug MDMA users, blocking the cortisol increase with metyrapone (a cortisol synthesis inhibitor) did not prevent the memory deficit produced by a 75 mg dose of MDMA. Memory was tested at peak drug concentrations. The finding suggests that the neuropharmacological mechanism behind MDMA-induced memory impairment is independent of cortisol.

Acute Effects of 2C-E in Humans: An Observational Study

Frontiers in Pharmacology March 18, 2020 Esther Papaseit, Marta Torrens, Mireia Ventura et al. 20 citations

2C-E, a psychedelic phenylethylamine similar to mescaline, acts as a partial agonist at serotonin 2A, 2B, and 2C receptors and inhibits norepinephrine and serotonin uptake. In an observational study, ten recreational psychedelic users self-administered single oral doses of 2C-E (6.5–25 mg). The drug induced alterations in perception, hallucinations, and euphoric mood, with saliva concentrations peaking 2 hours after administration. The effects resembled those of 2C-B and other serotonin-acting drugs.

Metabolomics and integrated network analysis reveal roles of endocannabinoids and large neutral amino acid balance in the ayahuasca experience

Biomedicine & Pharmacotherapy March 24, 2022 Francisco Madrid-Gambin, Àlex Gomez‐gómez, Arnau Busquets-García et al. 14 citations

Consumption of ayahuasca increases N-acyl-ethanolamine endocannabinoids, decreases 2-acyl-glycerol endocannabinoids, and alters several large-neutral amino acids (LNAAs) in human plasma. Most LNAAs were inversely associated with nine of eleven subscales of the 5-Dimension Altered States of Consciousness Rating Scale, except tryptophan, which was positively associated. Several endocannabinoids and hexosylceramides were directly associated with ayahuasca alkaloids. Enrichment analysis confirmed dysregulation in pathways involved in serotonin and dopamine synthesis. A crosstalk between circulating LNAAs and subjective effects is suggested, independent of alkaloid concentrations, providing insights into the metabolic fingerprint and mechanism of action underlying ayahuasca experiences.

Depressive mood ratings are reduced by MDMA in female polydrug ecstasy users homozygous for the l-allele of the serotonin transporter

Scientific Reports January 12, 2018 Kim P. C. Kuypers, Rafael de la Torre, Magı́ Farré et al. 12 citations

MDMA's mood effects depend partly on a genetic variation in the serotonin transporter gene (5-HTTLPR). People with the short variant of this gene typically show more anxiety and negative mood, while those with two long alleles (l-group) tend to be less anxious. In a pooled analysis of four placebo-controlled studies with 63 polydrug ecstasy users, MDMA (75 mg) generally improved mood but also increased anxiety and confusion. Unexpectedly, the l-group reported higher anxiety regardless of MDMA or placebo. MDMA reduced depressive feelings only in females from the l-group, suggesting a sex- and genotype-dependent effect.

Peripheral endocannabinoid concentrations are not associated with verbal memory impairment during MDMA intoxication

Psychopharmacology November 16, 2017 Eline Haijen, Magı́ Farré, Rafael de la Torre et al. 9 citations

MDMA impaired verbal memory 90 minutes after administration in a word learning task, replicating earlier findings with the same dose (75 mg). Contrary to expectations, MDMA did not affect endocannabinoid concentrations (anandamide and 2-AG) in blood, and the 5-HT2 receptor blocker ketanserin did not block MDMA-induced memory impairment. Ketanserin alone increased AEA concentrations 180 minutes after administration. The findings suggest that peripherally measured endocannabinoids are not involved in the verbal memory deficit during MDMA intoxication.

Non‐linear pharmacokinetics of MDMA (‘ecstasy’) in humans

British Journal of Clinical Pharmacology February 1, 2000 Rafael de la Torre, Magı́ Farré, Jordi Ortuño et al.

MDMA (ecstasy) shows nonlinear pharmacokinetics in humans: as the dose increases, plasma concentrations rise disproportionately, meaning small dose increases lead to much higher drug levels. In a controlled trial with 14 healthy volunteers given 50–150 mg, urinary recovery of the metabolite HMMA stayed constant while MDMA recovery rose, suggesting saturation or inhibition of the demethylenation metabolic step. Nonrenal clearance was dose-dependent while urinary clearance remained constant. This nonlinearity occurs regardless of CYP2D6 genotype, implying that even moderate dose increases in recreational use can produce unexpectedly high plasma concentrations, raising the risk of acute toxicity for all users, not just the 10% genetically deficient in CYP2D6.