Psychopharmacology
January 2007
Manuel E. Tancer, Chris‐ellyn Johanson
The purpose of this study was to investigate the role of serotonin (5-HT) in the effects of oral 3,4-methylenedioxymethamphetamine (MDMA) in humans. The subjective and physiological effects of 1.5 mg/kg MDMA were evaluated after 20 mg fluoxetine in eight recreational MDMA users in a double-blind, placebo-controlled study. During phase 1, participants were maintained on placebo for at least 5...
Psychopharmacology
January 2007
Daniel Kueh, Lisa E Baker
Relatively few studies have compared the discriminative stimulus effects of 3,4-methylenedioxymethamphetamine (MDMA) and cocaine, and findings from different laboratories are somewhat inconsistent. One possible reason for discrepant results may be the use of different reinforcement schedules during discrimination training. The present study compared fixed ratio (FR) 20 and variable interval...
Psychopharmacology
January 2007
Jonathan P. Roiser, Robert D Rogers, Barbara J. Sahakian
A number of studies have compared ecstasy users to control groups on various measures of neuropsychological function in order to determine whether ecstasy use results in lasting cognitive deficits. However, few of those studies controlled adequately for non-ecstasy illicit drug use. The aim of this study was to investigate neuropsychological function in chronic ecstasy users while controlling...
Psychopharmacology
December 1, 2006
Kirsten Krebs-Thomson, Erbert M Ruiz, Virginia L Masten et al.
96 citations
The hallucinogen 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is structurally similar to other indoleamine hallucinogens such as LSD. The present study examined the effects of 5-MeO-DMT in rats using the Behavioral Pattern Monitor (BPM), which enables analyses of patterns of locomotor activity and exploration, and the prepulse inhibition of startle (PPI) paradigm. A series of interaction...
Psychopharmacology
October 2006
Jonathan P. Roiser, Robert D Rogers, Lynnette J Cook et al.
3, 4-Methylenedioxymethamphetamine (MDMA or "ecstasy") is a popular drug of abuse known to result in depletions of the serotonin (5-HT) system. A number of studies have reported that ecstasy users differ from controls on a variety of measures of cognitive function. However, the literature is not consistent and many negative findings were also reported. One reason for such inconsistency might be...
Psychopharmacology
July 7, 2006
Roland R. Griffiths, William A. Richards, U. Mccann et al.
1,684 citations
RationaleAlthough psilocybin has been used for centuries for religious purposes, little is known scientifically about its acute and persisting effects.ObjectivesThis double-blind study evaluated the acute and longer-term psychological effects of a high dose of psilocybin relative to a comparison compound administered under comfortable, supportive conditions.Materials and methodsThe participants...
Psychopharmacology
June 2006
Stephen A Varvel, J L Wiley, R Yang et al.
Interest persists in characterizing potential interactions between Delta(9)-tetrahydocannabinol (THC) and other marijuana constituents such as cannabidiol (CBD). Such interactions may have important implications for understanding the long-term health consequences of chronic marijuana use as well as for attempts to develop therapeutic uses for THC and other CB(1) agonists. We investigated...
Psychopharmacology
March 30, 2006
Jordi Riba, Sergio Romero, Eva Grasa et al.
245 citations
RationaleAyahuasca is a South American psychoactive plant tea which contains the serotonergic psychedelic N,N-dimethyltryptamine (DMT) and monoamine-oxidase inhibitors that render DMT orally active. Previous investigations with ayahuasca have highlighted a psychotropic effect profile characterized by enhanced introspective attention, with individuals reporting altered somatic perceptions and...
Psychopharmacology
March 15, 2006
Michael H. Baumann, Xiaoying Wang, Richard B Rothman
269 citations
RATIONALE: 3,4-Methylenedioxymethamphetamine (MDMA) is a widely abused illicit drug. In animals, high-dose administration of MDMA produces deficits in serotonin (5-HT) neurons (e.g., depletion of forebrain 5-HT) that have been interpreted as neurotoxicity. Whether such 5-HT deficits reflect neuronal damage is a matter of ongoing debate. OBJECTIVE: The present paper reviews four specific issues...
Psychopharmacology
January 20, 2006
Boris B. Quednow, K. Kühn, C. Hoppe et al.
RationaleIn animal studies, the common club drug 3,4-methylendioxymethamphetamine (MDMA, “Ecstasy”) consistently caused a prolonged loss of presynaptic serotonergic neurons, and evidence suggests that MDMA consumption may also affect the human serotonergic system. Serotonin (5-HT) has been implicated in the regulation of impulsivity and such executive functions as decision-making cognition. In...
Psychopharmacology
January 2006
A G Romano, Jennifer L Quinn, R Liu et al.
Associative learning during Pavlovian eyeblink conditioning has been shown to be regulated by 5-HT2A receptors. The existence of inverse agonists that retard learning through an action at the 5-HT2A receptor suggests the existence of constitutive activity at that receptor and that depletion of serotonin should have minimal effects on learning. We examined whether depletion of serotonin would...
Psychopharmacology
December 2005
Paul J Fletcher, Catherine C Tenn, Zoë Rizos et al.
Repeated exposure to psychomotor stimulants can lead to sensitization to their effects, and sensitization has been implicated in the pathophysiology of schizophrenia and drug abuse. These disorders are characterized by cognitive deficits, particularly in prefrontally mediated executive function. The present experiments were conducted to investigate the effects of sensitizing regimens of...
Psychopharmacology
October 2005
Chad J Reissig, Justin R Eckler, R A Rabin et al.
It has been suggested that the 5-HT1A receptor plays a significant modulatory role in the stimulus effects of the indoleamine hallucinogen lysergic acid diethylamide (LSD). The present study sought to characterize the effects of several compounds with known affinity for the 5-HT1A receptor on the discriminative stimulus effects of LSD. Twelve male Fischer 344 rats were trained in a two-lever,...
Psychopharmacology
September 1, 2005
William E Fantegrossi, Andrew W Harrington, Justin R Eckler et al.
72 citations
Few studies have examined the effects of 2,5-dimethoxy-4-(n)-propylthiophenethylamine (2C-T-7) in vivo. 2C-T-7 was tested in a drug-elicited head twitch assay in mice and in several drug discrimination assays in rats; 2C-T-7 was compared to the phenylisopropylamine hallucinogen R(-)-1-(2,5-dimethoxy-4-methylphenyl)-2aminopropane (DOM) in both assays, with or without pretreatment with the...
Psychopharmacology
July 2005
Danuta Marona‐lewicka, Ronald A Thisted, David E Nichols
The effect of LSD in humans has been described as occurring in two temporal phases. The behavioral effects in rats also occur in two temporal phases: an initial suppression of exploration followed by increased locomotor activity. We decided to investigate this phenomenon from the perspective that the pharmacology might have relevance to the neurochemical mechanisms underlying psychosis....
Psychopharmacology
June 2005
Marcello Solinas, Steven R Goldberg
Many behavioral effects of delta-9-tetrahydrocannabinol (THC), including its discriminative-stimulus effects, are modulated by endogenous opioid systems. To investigate opioid receptor subtypes involved in the discriminative effects of THC. Rats trained to discriminate 3 mg/kg i.p. of THC from vehicle using a two-lever operant drug-discrimination procedure, were tested with compounds that bind...
Psychopharmacology
May 1, 2005
Yong Zhang, Eduardo R Butelman, Stefan D Schlussman et al.
198 citations
Salvinorin A is a naturally occurring hallucinogen derived from the plant Salvia divinorum. Salvinorin A is also a potent and selective kappa opioid receptor agonist in vitro. It has been shown that kappa agonists decrease dopamine levels in the caudate putamen and nucleus accumbens and cause conditioned place aversion in rodents. To study the effects of salvinorin A on basal dopamine levels in...
Psychopharmacology
May 2005
Styliani Vlachou, George G. Nomikos, George Panagis
Addictive drugs have a number of commonalities in animal behavioral models. They lower intracranial self-stimulation (ICSS) thresholds, support self-administration, and produce conditioned place preference (CPP). However, cannabinoids appear atypical as drugs of abuse, since there are controversial data in the literature concerning their reinforcing properties. The aim of the present study was...
Psychopharmacology
May 2005
Matthew Rizzo, C T J Lamers, C G Sauer et al.
Illicit drug use can increase driver crash risk due to loss of control over vehicle trajectory. This study asks, does recreational use of +/-3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) and tetrahydrocannabinol (THC; marijuana) impair cognitive processes that help direct our safe movement through the world? This study assesses the residual effects of combined MDMA/THC use, and of THC use...
Psychopharmacology
March 2005
Stephen A Varvel, E Anum, F Niyuhire et al.
The results of recent in vitro studies have underscored the important role that activation of CB(1) receptors has on GABAergic activity in brain areas associated with memory. The primary purpose of this study was to test the hypothesis that the memory disruptive effects of Delta(9)-tetrahydrocannabinol (Delta(9)-THC) in vivo are mediated through GABAergic systems. Conversely, we also evaluated...
Psychopharmacology
January 11, 2005
Michael A. Benneyworth, Randy L Smith, Robert J. Barrett et al.
38 citations
RationaleThe drug discrimination procedure is the most frequently used in vivo model of hallucinogen activity. Historically, most drug discrimination studies have been conducted in the rat. With the development of genetically modified mice, a powerful new tool has become available for investigating the mechanisms of drug-induced behavior. The current paper is part of an ongoing effort to...
Psychopharmacology
December 2004
F Gerard Moeller, Joel L. Steinberg, Donald M Dougherty et al.
Methylene-dioxymethamphetamine (MDMA) is known to cause degeneration of serotonin nerve terminals after acute doses in animals. Similarly, behavioral studies in human MDMA users regularly find abnormalities in memory, mood, and impulse control. However, studies of brain function using brain imaging in MDMA users have been less consistent. The purpose of this study was to determine, using...
Psychopharmacology
September 2004
Niels Alting Von Geusau, Pieter Stalenhoef, Mariette Huizinga et al.
Long-term users of ecstasy have shown impaired performance on a multitude of cognitive abilities (most notably memory, attention, executive function). Research into the pattern of MDMA effects on executive functions remains fragmented, however. To determine more systematically what aspects of executive function are affected by a history of MDMA use, by using a model that divides executive...
Psychopharmacology
May 2004
Jonathan P. Roiser, Barbara J. Sahakian
3,4-Methylenedioxymethamphetamine (MDMA or "ecstasy") causes serotonin neuron damage in laboratory animals. The serotonin system is known to be important in the regulation of mood. Previous research has shown that MDMA users score higher on self-report ratings of depression than controls. However, MDMA users commonly take other illicit substances and many studies do not fully control for...
Psychopharmacology
May 2004
A C Parrott
Not every tablet sold as "ecstasy" contains MDMA (3,4-methylenedioxymethamphetamine). The historical origins and evolution of this mismatch will be reviewed, in order to estimate the proportions of ecstasy tablets containing MDMA at different periods over the past 30 years. Surveys into the pharmacological constituents of ecstasy tablets, dosage levels, and empirical reports of their perceived...