Neuropsychopharmacology
October 1, 2007
Martina Ballmaier, Marco Bortolato, Cristina Rizzetti et al.
Clinical and laboratory findings suggest that cannabinoids and their receptors are implicated in schizophrenia. The role of cannabinoids in schizophrenia remains however poorly understood, as data are often contradictory. The primary aim of this study was to investigate whether the cannabinoid CB1 receptor antagonists rimonabant and AM251 are able to reverse deficits of sensorimotor gating...
Neuropsychopharmacology
September 2007
Tiziana Rubino, Mariaelvina Sala, Daniela Viganò et al.
We investigated the effect of low doses of intraperitoneal Delta(9)-tetrahydrocannabinol (THC) on anxiety behavior in rats using the elevated plus maze (EPM). An anxiolytic effect was obtained in a range of doses between 0.075 and 1.5 mg/kg, the 0.75 dose being the most effective. Pretreatment with the CB1 receptor antagonist AM251 fully reversed THC's effect, suggesting CB1 receptors were...
Neuropsychopharmacology
June 2007
Margaret Haney
In non-human animals, opioid antagonists block the reinforcing and discriminative-stimulus effects of Delta(9)-tetrahydrocannabinol (THC), while in human marijuana smokers, naltrexone (50 mg) enhances the reinforcing and subjective effects of THC. The objective of this study was to test a lower, more opioid-selective dose of naltrexone (12 mg) in combination with THC. The influence of...
Neuropsychopharmacology
May 2007
Cheng Z Wang, Kenneth M Johnson
This study determined the role of caspase-3 in phencyclidine (PCP)-induced neurodegeneration in postnatal rats. PCP administration to postnatal day 7 rats induced a dose-dependent increase in caspase-3 enzymatic activity in frontal cortex, striatum, and hippocampus. Enzymatic activation was present at 4 h, peaked between 6 and 12 h, and disappeared by 24 h. Further, cleaved...
Neuropsychopharmacology
March 2007
Maria Ellgren, Sabrina M Spano, Yasmin L. Hurd
Cannabis use is a hypothesized gateway to subsequent abuse of other drugs such as heroin. We currently assessed whether Delta-9-tetrahydrocannabinol (THC) exposure during adolescence modulates opiate reinforcement and opioid neural systems in adulthood. Long-Evan male rats received THC (1.5 mg/kg intraperitoneally (i.p.)) or vehicle every third day during postnatal days (PNDs) 28-49. Heroin...
Neuropsychopharmacology
February 14, 2007
Franz X. Vollenweider, Philipp A Csomor, Bernhard Knappe et al.
194 citations
Schizophrenia patients exhibit impairments in prepulse inhibition (PPI) of the startle response. Hallucinogenic 5-HT(2A) receptor agonists are used for animal models of schizophrenia because they mimic some symptoms of schizophrenia in humans and induce PPI deficits in animals. Nevertheless, one report indicates that the 5-HT(2A) receptor agonist psilocybin increases PPI in healthy humans....
Neuropsychopharmacology
July 2006
Michael John Morgan, Lara Chiara Impallomeni, Alessandro Pirona et al.
Ecstasy (MDMA; 3,4-methylenedioxymethamphetamine) has a well-recognized neurotoxic effect on central serotonergic (5-HT) systems in animals, and there is some evidence of persistent serotonergic dysregulation in human ecstasy users. Serotonin is believed to mediate impulsive behavior and effective decision-making. Thus, the aim of the present study was to investigate impulsive behavior and...
Neuropsychopharmacology
February 2006
Euphrosyne Gouzoulis‐mayfrank, Karsten Heekeren, Anna Neukirch et al.
Patients with schizophrenia exhibit disturbances of orienting of attention. However, findings have been inconsistent. Pharmacologic challenges with hallucinogens have been used as models for psychosis. The NMDA antagonist state (PCP, ketamine) resembles undifferentiated psychoses with positive and negative symptoms, while the 5-HT(2A) agonist state (LSD, dimethyltryptamine (DMT)) is thought to...
Neuropsychopharmacology
February 2006
Annis O. Mechan, Jie Yuan, George Hatzidimitriou et al.
A large body of data indicates that (+/-)3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') can damage brain serotonin neurons in animals. However, the relevance of these preclinical data to humans is uncertain, because doses and routes of administration used in animals have generally differed from those used by humans. Here, we examined the pharmacokinetic profile of MDMA in squirrel monkeys...
Neuropsychopharmacology
August 2005
June M Young, Iain S. Mcgregor, Paul E Mallet
3,4-Methylenedioxymethamphetamine (MDMA, 'Ecstasy') and cannabis are two of the most commonly used illicit drugs in the western world, and are often used in combination. Very little research has examined their effect on cognitive function or behavior when combined, The present study used a double Y-maze task to examine the acute effect of MDMA and delta9-tetrahydrocannabinol (THC, the principal...
Neuropsychopharmacology
June 2005
Grégory Conductier, Cyril Crosson, René Hen et al.
3,4-Methylenedioxy-N-methamphetamine (MDMA or 'ecstasy') is a psychoactive substance, first described as an appetite suppressant in humans, inducing side effects and even death. MDMA increases serotonin (5-HT) levels, and 5-HT inhibits food intake, but the 5-HT receptors involved in MDMA-induced changes in feeding behavior are unknown. We examined whether a systemic MDMA injection would reduce...
Neuropsychopharmacology
April 2005
Scott D Lane, Don R Cherek, Oleg V Tcheremissine et al.
Previous studies have established a relationship between marijuana use and risky behavior in natural settings. A limited number of laboratory investigations of marijuana effects on human risk taking have been conducted. The present study was designed to examine the acute effects of smoked marijuana on human risk taking, and to identify behavioral mechanisms that may be involved in drug-induced...
Neuropsychopharmacology
March 9, 2005
Paul J Gresch, Randy L Smith, Robert J. Barrett et al.
62 citations
Tolerance is defined as a decrease in responsiveness to a drug after repeated administration. Tolerance to the behavioral effects of hallucinogens occurs in humans and animals. In this study, we used drug discrimination to establish a behavioral model of lysergic acid diethylamide (LSD) tolerance and examined whether tolerance to the stimulus properties of LSD is related to altered serotonin...
Neuropsychopharmacology
January 26, 2005
Olivia Carter, John D. Pettigrew, Felix Hasler et al.
122 citations
Binocular rivalry occurs when different images are presented simultaneously to corresponding points within the left and right eyes. Under these conditions, the observer's perception will alternate between the two perceptual alternatives. Motivated by the reported link between the rate of perceptual alternations, symptoms of psychosis and an incidental observation that the rhythmicity of...
Neuropsychopharmacology
August 2004
Deepak Cyril D'Souza, Edward Perry, Lisa Macdougall et al.
Recent advances in the understanding of brain cannabinoid receptor function have renewed interest in the association between cannabinoid compounds and psychosis. In a 3-day, double-blind, randomized, and counterbalanced study, the behavioral, cognitive, and endocrine effects of 0, 2.5, and 5 mg intravenous delta-9-tetrahydrocannabinol (Delta-9-THC) were characterized in 22 healthy individuals,...
Neuropsychopharmacology
June 1, 2004
Janne Damm Andersen, Bruno Pouzet
It has been suggested that perinatal treatment with the noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist phencyclidine (PCP) induces transient neurodegeneration in the limbic and cortical structures of rats. Since dysfunction of these structures is associated with cognitive deficits in patients with schizophrenia, we studied the effects of subchronic treatment with PCP in...
Neuropsychopharmacology
May 2004
Boris B. Quednow, Kai‐uwe Kühn, Klaus Hoenig et al.
Chronic administration of 3,4-methylenedioxymethamphetamine (MDMA) is associated with long-term depletion of serotonin (5-HT) and loss of 5-HT axons in the brains of rodents and nonhuman primates. Despite the broad database concerning the selective serotonergic neurotoxicity of recreational MDMA consumption by humans, controversy still exists with respect to the question of whether the...
Neuropsychopharmacology
March 2004
Christopher D. Verrico, J David Jentsch, Robert H Roth et al.
The residual neuropsychological effects of marijuana abuse in man indicate a dysfunction of the attentional/executive systems. Moreover, experimental investigations suggest that repeated, intermittent (subchronic) Delta(9)-tetrahydrocannabinol (THC), the main psychoactive ingredient of marijuana, alters neurotransmission in the frontal cortex of rats and humans, a key neural site mediating...
Neuropsychopharmacology
July 2003
Jennifer S. McDonald, Laura Schleifer, Jerry B Richards et al.
This study investigated the acute effects of delta(9)-tetrahydrocannabinol (THC) on four behavioral measures of impulsivity in recreational marijuana users. Although impulsive behavior has been studied using several different measures of impulsivity, few studies have utilized more than one of these measures on a single cohort. In this study, 37 healthy men and women participated in three...
Neuropsychopharmacology
February 1, 2003
Susan M Cochran, Matthew D Kennedy, Clare E McKerchar et al.
Numerous human imaging studies have revealed an absolute or relative metabolic hypofunction within the prefrontal cortex, thalamus and temporal lobes of schizophrenic patients. The former deficit correlates with cognitive deficits and negative symptoms, whereas the latter correlates with positive symptomologies. There is also general consensus that schizophrenia is associated with decreased...
Neuropsychopharmacology
February 1, 2003
Y. Qu, Lisa Chang, J. Klaff et al.
Incorporation coefficients k* of intravenously injected [3H]arachidonic acid from blood into brain reflect the release from phospholipids of arachidonic acid by receptor-initiated activation of phospholipase A2 (PLA2). In unanesthetized adult rats, 2.5 mg/kg intraperitoneally (i.p.) (±)2,5-dimethoxy-4-iodophenyl-2-aminopropane (DOI), which is a 5-HT2A/2C receptor agonist, has been reported to...
Neuropsychopharmacology
2003
Daniel Umbricht, Franz X. Vollenweider, Liselotte Schmid et al.
192 citations
Previously the NMDA (N-methyl-D-aspartate) receptor (NMDAR) antagonist ketamine was shown to disrupt generation of the auditory event-related potential (ERP) mismatch negativity (MMN) and the performance of an 'AX'-type continuous performance test (AX-CPT)--measures of auditory and visual context-dependent information processing--in a similar manner as observed in schizophrenia. This...
Neuropsychopharmacology
2003
Andrea Balla, Henry Sershen, Michael Serra et al.
Functional dopaminergic hyperactivity is a key feature of schizophrenia. Etiology of this dopaminergic hyperactivity, however, is unknown. We have recently demonstrated that subchronic phencyclidine (PCP) treatment in rodents induces striatal dopaminergic hyperactivity similar to that observed in schizophrenia. The present study investigates the ability of PCP to potentiate amphetamine-induced...
Neuropsychopharmacology
June 2002
Daniel S O'Leary, Robert I Block, Julie A Koeppel et al.
The effects of smoking marijuana on regional cerebral blood flow (rCBF) and cognitive performance were assessed in 12 recreational users in a double-blinded, placebo-controlled study. PET with [(15)Oxygen]-labeled water ([(15)O]H(2)O) was used to measure rCBF before and after smoking of marijuana and placebo cigarettes, as subjects repeatedly performed an auditory attention task. Smoking...
Neuropsychopharmacology
May 1, 2002
C Nichols
165 citations
Hallucinogenic drugs such as lysergic acid diethylamide (LSD) have profound effects on humans including hallucinations and detachment from reality. These remarkable behavioral effects have many similarities to the debilitating symptoms of neuropsychiatric disorders such as schizophrenia. The effects of hallucinogens are thought to be mediated by serotonin receptor activation; however, how these...