Chronic administration of THC prevents the behavioral effects of intermittent adolescent MDMA administration and attenuates MDMA-induced hyperthermia and neurotoxicity in rats

Detrimental effects of adolescent escalating low-dose Δ9 -tetrahydrocannabinol leads to a specific bio-behavioural profile in adult male rats

BACKGROUND AND PURPOSE

Adolescent cannabis use is associated with adult psychopathology. When Δ⁹ -tetrahydrocannabinol (THC), mainly in high doses, is administered to adolescence rats there are also long lasting effects in adults. This study aims to determine the specific adult bio-behavioural profile after adolescent low-dose THC, which better mirrors adolescent recreational cannabis use.

EXPERIMENTAL APPROACH

Adolescent male Sprague-Dawley rats were treated with escalating low-dose of THC. In adulthood, they were evaluated for their spontaneous locomotion, sensorimotor gating, higher order and spatial cognitive functions. Dopaminergic activity and cannabinoid receptor expression were measured in distinct brain regions. Hippocampal neurogenic activity of neural stem cells was determined and protein levels of neuroplasticity-related biomarkers were quantified. Adolescent low-dose THC exposure increased spontaneous open-field activity, without affecting prepulse inhibition and attentional set-shifting performance. Region-specific dopaminergic alterations and CB₁ receptor up-regulation in the prefrontal cortex were observed. Impaired spatial memory, as assessed with the object location task and Morris water maze test, was associated with significantly decreased proliferative activity (SOX2-positive cells), neurogenic potential (decreased doublecortin-positive cells) in the adult hippocampus and defective neuroplasticity, including reduced BDNF expression in the hippocampus and prefrontal cortex.

KEY RESULTS

Our findings reveal the adverse impact of adolescent low-dose THC on the psychomotor profile, dopaminergic neurotransmission, compensatory cannabinoid receptor response, cognition-related neurobiological and behavioural functions.

CONCLUSION AND IMPLICATIONS

Our adolescent low-dose THC animal model does not induce tangible psychotic-like effects, such as those reported in high-dose THC studies, but it impairs cognitive functions and points to hippocampal vulnerability and disrupted neurogenesis.

A Systematic Review of the MDMA Model to Address Social Impairment in Autism

BACKGROUND

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterised by repetitive behaviours, cognitive rigidity/inflexibility, and social-affective impairment. Unfortunately, no gold-standard treatments exist to alleviate the core socio-behavioural impairments of ASD. Meanwhile, the prosocial empathogen/entactogen 3,4-methylene-dioxy-methamphetamine (MDMA) is known to enhance sociability and empathy in both humans and animal models of psychological disorders.

OBJECTIVE

We review the evidence obtained from behavioural tests across the current literature, showing how MDMA can induce prosocial effects in animals and humans, where controlled experiments were able to be performed.

METHODS

Six electronic databases were consulted. The search strategy was tailored to each database. Only English-language papers were reviewed. Behaviours not screened in this review may have affected the core ASD behaviours studied. Molecular analogues of MDMA have not been investigated.

RESULTS

We find that the social impairments may potentially be alleviated by postnatal administration of MDMA producing prosocial behaviours in mostly the animal model.

CONCLUSION

MDMA and/or MDMA-like molecules appear to be an effective pharmacological treatment for the social impairments of autism, at least in animal models. Notably, clinical trials based on MDMA use are now in progress. Nevertheless, larger and more extended clinical studies are warranted to prove the assumption that MDMA and MDMA-like molecules have a role in the management of the social impairments of autism.

Escalating low-dose Δ9 -tetrahydrocannabinol exposure during adolescence induces differential behavioral and neurochemical effects in male and female adult rats

Cannabinoid administration during adolescence affects various physiological processes, such as motor and affective response, cognitive-related functions and modulates neurotransmitter activity. Literature remains scant concerning the parallel examination of the effects of adolescent escalating low-dose Δ⁹ -tetrahydrocannabinol (Δ⁹ -THC) on the behavioral and plasticity profile of adult rats in both sexes. Herein, we investigated the long-term behavioral, neurochemical and neurobiological effects of adolescent escalating low Δ⁹ -THC doses in adult male and female rats. In adult males, adolescent low-dose Δ⁹ -THC exposure led to increased spontaneous locomotor activity, impaired behavioral motor habituation and defective short-term spatial memory, paralleled with decreased BDNF protein levels in the prefrontal cortex. In this brain area, serotonergic activity was increased, as depicted by the increased serotonin turnover rate, while the opposite effect was observed in the hippocampus, a region where SERT levels were enhanced by Δ⁹ -THC, compared with vehicle. In adult females, adolescent Δ⁹ -THC treatment led to decreased spontaneous vertical activity and impaired short-term spatial memory, accompanied by increased BDNF protein levels in the prefrontal cortex. Present findings emphasize the key role of adolescent escalating low Δ⁹ -THC exposure in the long-term regulation of motor response, spatial-related cognitive functions and neuroplasticity indices in adulthood. In this framework, these changes could, at a translational level, contribute to clinical issues suggesting the development of psychopathology in a sex-differentiated manner following Δ⁹ -THC exposure during adolescence.

Long-term systemic administration with low dose of 3,4-methylenedioxymethamphetamine causes photoreceptor cell damage in CD1 mice

OBJECTIVE

As a powerful psychostimulant with high potential for abuse, 3,4-methylenedioxymethamphetamine (MDMA) causes long-lasting neurotoxicity. This study was to investigate the effects of systemic administration of MDMA on retinal damage in CD1 mice and its underlying mechanisms.

MATERIAL AND METHODS

CD1 mice were randomly divided into two groups (n = 10): group 1 receiving PBS by intraperitoneal injection daily; group 2 receiving 2 mg/kg MDMA by intraperitoneal injection daily for 3 months. The retinal function was tested by electroretinography (ERG). The retinal morphology and histology was evaluated by Toluidine blue staining and TUNEL assay, respectively. Inflammatory cytokines were measured by ELISA assays. Gene and protein expression was detected by real-time PCR and western blot.

RESULTS

Results demonstrated that retinal damage was caused by MDMA after 3-month treatment, evidenced by retinal dysfunction through photoreceptor cell apoptosis induced by inflammatory response and oxidative stress.

CONCLUSION

Our study indicated that systemic administration of MDMA increased inflammatory response in photoreceptor cells to cause retinal dysfunction on CD1 mice, providing the scientific rationale for the photoreceptor cell damage caused by the MDMA abuse.

Is the recreational use of 3,4-methylenedioxy-methamphetamine safe?

3,4-methylenedioxy-methamphetamine is taken recreationally by thousands of people, especially the young, across the globe. It is highly associated with electronic music and its use in the UK remains high at around 4.5% of 16-24 year olds. This review discusses both the short- and long-term effects of 3,4-methylenedioxy-methamphetamine including methods by which some of these adverse effects can be prevented or even reversed to increase the safety of the commonly used drug.

3,4-Methylenedioxymethamphetamine causes cytotoxicity on 661W cells through inducing macrophage polarization

The abuse of 3,4-methylenedioxymethamphetamine (MDMA), a psychedelic drug, can lead to a variety of disorders in neural system, including the death of retinal neural cells. MDMA at lower doses does not cause obvious cytotoxicity to photoreceptor cells, indicating potential indirect mechanisms which have not yet been elucidated. This study investigated the effect of MDMA at nontoxic concentration on macrophage activation state and its resultant toxicity to photoreceptor cells. Using a co-culture system, cytotoxicity was caused by MDMA on 661W cells after co-culturing with RAW264.7 macrophage. Results showed that MDMA induced the macrophages to M1 polarization, releasing more pro-inflammatory cytokines, upregulating the M1-related gene and protein expression. The phenotype, secretion pattern, and cytotoxicity of the macrophages treated by MDMA are comparable to those of the ones stimulated by IFNγ and LPS. Our study demonstrated that MDMA promoted macrophage polarization to M1 and induced inflammatory response, providing the scientific rationale for the photoreceptor cell damage caused by the MDMA abuse.

Cannabis and adolescent brain development

Heavy cannabis use has been frequently associated with increased rates of mental illness and cognitive impairment, particularly amongst adolescent users. However, the neurobiological processes that underlie these associations are still not well understood. In this review, we discuss the findings of studies examining the acute and chronic effects of cannabis use on the brain, with a particular focus on the impact of commencing use during adolescence. Accumulating evidence from both animal and human studies suggests that regular heavy use during this period is associated with more severe and persistent negative outcomes than use during adulthood, suggesting that the adolescent brain may be particularly vulnerable to the effects of cannabis exposure. As the endocannabinoid system plays an important role in brain development, it is plausible that prolonged use during adolescence results in a disruption in the normative neuromaturational processes that occur during this period. We identify synaptic pruning and white matter development as two processes that may be adversely impacted by cannabis exposure during adolescence. Potentially, alterations in these processes may underlie the cognitive and emotional deficits that have been associated with regular use commencing during adolescence.

Adolescent MDMA exposure diminishes the physiological and neurotoxic consequences of an MDMA binge in female rats

Intermittent MDMA pretreatment blocked the reductions in serotonin transporter (SERT) binding induced by an MDMA binge in a prior study in adolescent male rats. The objective of this investigation was to determine if the physiological, behavioral, and neurochemical responses to MDMA are sexually dimorphic. Female Sprague-Dawley rats received MDMA (10 mg/kg × 2) or Saline on every fifth day from postnatal day (PD) 35-60 and an MDMA binge (5 mg/kg × 4) on PD 67. The MDMA binge induced a pronounced temperature dysregulation in MDMA-naïve, but not MDMA-pretreated, groups. Similarly, MDMA-pretreated animals were resistant to the binge-induced SERT reductions, especially in the hippocampus. Motor activity at PD 68 was not reduced by the binge, unlike the responses found in males. These results show that female rats differ from males in their responses to an MDMA binge but are similar with respect to preconditioning from prior MDMA exposure.

Sex-dependent long-term effects of adolescent exposure to THC and/or MDMA on neuroinflammation and serotoninergic and cannabinoid systems in rats

BACKGROUND AND PURPOSE

Many young people consume ecstasy as a recreational drug and often in combination with cannabis. In this study, we aimed to mimic human consumption patterns and investigated, in male and female animals, the long-term effects of Δ(9) -tetrahydrocannabinol (THC) and 3,4-methylenedioxymethamphetamine (MDMA) on diverse neuroinflammation and neurotoxic markers.

EXPERIMENTAL APPROACH

Male and female Wistar rats were chronically treated with increasing doses of THC and/or MDMA during adolescence. The effects of THC and/or MDMA on glial reactivity and on serotoninergic and cannabinoid systems were assessed by immunohistochemistry in the hippocampus and parietal cortex.

KEY RESULTS

THC increased the area staining for glial fibrilar acidic protein in both sexes. In males, both drugs, either separately or in combination, increased the proportion of reactive microglia cells [ionized calcium binding adaptor molecule 1 (Iba-1)]. In contrast, in females, each drug, administered alone, decreased of this proportion, whereas the combination of both drugs resulted in a 'normalization' to control values. In males, MDMA reduced the number of SERT positive fibres, THC induced the opposite effect and the group receiving both drugs did not significantly differ from the controls. In females, MDMA reduced the number of SERT positive fibres and the combination of both drugs counteracted this effect. THC also reduced immunostaining for CB1 receptors in females and this effect was aggravated by the combination with MDMA.

CONCLUSIONS AND IMPLICATIONS

Adolescent exposure of rats to THC and/or MDMA induced long-term, sex-dependent neurochemical and glial alterations, and revealed interactions between the two drugs.

LINKED ARTICLES

This article is part of a themed section on Cannabinoids 2013. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-6.

Depression, impulsiveness, sleep, and memory in past and present polydrug users of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy)

RATIONALE

Ecstasy (3,4-methylenedioxymethamphetamine, MDMA) is a worldwide recreational drug of abuse. Unfortunately, the results from human research investigating its psychological effects have been inconsistent.

OBJECTIVES

The present study aimed to be the largest to date in sample size and 5HT-related behaviors; the first to compare present ecstasy users with past users after an abstinence of 4 or more years, and the first to include robust controls for other recreational substances.

METHODS

A sample of 997 participants (52 % male) was recruited to four control groups (non-drug (ND), alcohol/nicotine (AN), cannabis/alcohol/nicotine (CAN), non-ecstasy polydrug (PD)), and two ecstasy polydrug groups (present (MDMA) and past users (EX-MDMA). Participants completed a drug history questionnaire, Beck Depression Inventory, Barratt Impulsiveness Scale, Pittsburgh Sleep Quality Index, and Wechsler Memory Scale-Revised which, in total, provided 13 psychometric measures.

RESULTS

While the CAN and PD groups tended to record greater deficits than the non-drug controls, the MDMA and EX-MDMA groups recorded greater deficits than all the control groups on ten of the 13 psychometric measures. Strikingly, despite prolonged abstinence (mean, 4.98; range, 4-9 years), past ecstasy users showed few signs of recovery. Compared with present ecstasy users, the past users showed no change for ten measures, increased impairment for two measures, and improvement on just one measure.

CONCLUSIONS

Given this record of impaired memory and clinically significant levels of depression, impulsiveness, and sleep disturbance, the prognosis for the current generation of ecstasy users is a major cause for concern.

Sex-dependent psychoneuroendocrine effects of THC and MDMA in an animal model of adolescent drug consumption

Ecstasy is a drug that is usually consumed by young people at the weekends and frequently, in combination with cannabis. In the present study we have investigated the long-term effects of administering increasing doses of delta-9-tetrahydrocannabinol [THC; 2.5, 5, 10 mg/kg; i.p.] from postnatal day (pnd) 28 to 45, alone and/or in conjunction with 3,4-methylenedioxymethamphetamine [MDMA; two daily doses of 10 mg/kg every 5 days; s.c.] from pnd 30 to 45, in both male and female Wistar rats. When tested one day after the end of the pharmacological treatment (pnd 46), MDMA administration induced a reduction in directed exploration in the holeboard test and an increase in open-arm exploration in an elevated plus maze. In the long-term, cognitive functions in the novel object test were seen to be disrupted by THC administration to female but not male rats. In the prepulse inhibition test, MDMA-treated animals showed a decrease in prepulse inhibition at the most intense prepulse studied (80 dB), whereas in combination with THC it induced a similar decrease at 75 dB. THC decreased hippocampal Arc expression in both sexes, while in the frontal cortex this reduction was only evident in females. MDMA induced a reduction in ERK1/2 immunoreactivity in the frontal cortex of male but not female animals, and THC decreased prepro-orexin mRNA levels in the hypothalamus of males, although this effect was prevented when the animals also received MDMA. The results presented indicate that adolescent exposure to THC and/or MDMA induces long-term, sex-dependent psychophysiological alterations and they reveal functional interactions between the two drugs.

Cannabis-induced impairment of learning and memory: effect of different nootropic drugs

Cannabis sativa preparations are the most commonly used illicit drugs worldwide. The present study aimed to investigate the effect of Cannabis sativa extract in the working memory version of the Morris water maze (MWM; Morris, 1984[43]) test and determine the effect of standard memory enhancing drugs. Cannabis sativa was given at doses of 5, 10 or 20 mg/kg (expressed as Δ(9)-tetrahydrocannabinol) alone or co-administered with donepezil (1 mg/kg), piracetam (150 mg/ kg), vinpocetine (1.5 mg/kg) or ginkgo biloba (25 mg/kg) once daily subcutaneously (s.c.) for one month. Mice were examined three times weekly for their ability to locate a submerged platform. Mice were euthanized 30 days after starting cannabis injection when biochemical assays were carried out. Malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide, glucose and brain monoamines were determined. Cannabis resulted in a significant increase in the time taken to locate the platform and enhanced the memory impairment produced by scopolamine. This effect of cannabis decreased by memory enhancing drugs with piracetam resulting in the most-shorter latency compared with the cannabis. Biochemically, cannabis altered the oxidative status of the brain with decreased MDA, increased GSH, but decreased nitric oxide and glucose. In cannabis-treated rats, the level of GSH in brain was increased after vinpocetine and donepezil and was markedly elevated after Ginkgo biloba. Piracetam restored the decrease in glucose and nitric oxide by cannabis. Cannabis caused dose-dependent increases of brain serotonin, noradrenaline and dopamine. After cannabis treatment, noradrenaline is restored to its normal value by donepezil, vinpocetine or Ginkgo biloba, but increased by piracetam. The level of dopamine was significantly reduced by piracetam, vinpocetine or Ginkgo biloba. These data indicate that cannabis administration is associated with impaired memory performance which is likely to involve decreased brain glucose availability as well as alterations in brain monoamine neurotransmitter levels. Piracetam is more effective in ameliorating the cognitive impairments than other nootropics by alleviating the alterations in glucose, nitric oxide and dopamine in brain.

Cannabis and Δ9-tetrahydrocannabinol (THC) for weight loss?

Obesity is one of the highest preventable causes of morbidity and mortality in the developed world [1]. It has been well known for a long time that exposure to cannabis produces an increase of appetite (a phenomenon referred to as the 'munchies'). This phenomenon led to an exploration of the role of the endocannabinoid system in the regulation of obesity and associated metabolic syndrome. This effort subsequently led to the development of a successful therapeutic approach for obesity that consisted of blocking the cannabinoid CB1 receptors using ligands such as Rimonabant in order to produce weight loss and improve metabolic profile [2]. Despite being efficacious, Rimonabant was associated with increased rates of depression and anxiety and therefore removed from the market. We recently discovered that the prevalence of obesity is paradoxically much lower in cannabis users as compared to non-users and that this difference is not accounted for by tobacco smoking status and is still present after adjusting for variables such as sex and age. Here, we propose that this effect is directly related to exposure to the Δ(9)-tetrahydrocannabinol (THC) present in cannabis smoke. We therefore propose the seemingly paradoxical hypothesis that THC or a THC/cannabidiol combination drug may produce weight loss and may be a useful therapeutic for the treatment of obesity and its complications.

Δ9-Tetrahydrocannabinol attenuates MDMA-induced hyperthermia in rhesus monkeys

BACKGROUND

Cannabis is commonly consumed by Ecstasy (3,4-methylenedioxymethamphetamine; MDMA) users, including as an intentional strategy to manipulate the drug experience. The most active psychoactive constituent in cannabis, Δ(9)-tetrahydrocannabinol (THC), and other drugs with partial or full agonist activity at the CB(1) receptor, produces a reduction of body temperature in rodents. Reports show that administration of THC can attenuate temperature increases caused by MDMA in mice or rats; however, a recent study in humans shows that THC potentiates MDMA-induced temperature elevations. Relatively little scientific evidence on the thermoregulatory effects of THC in monkeys is available.

METHODS

The body temperature of male rhesus macaques was recorded after challenge with THC (0.1-0.3 mg/kg, i.m.) or combined challenge of THC with the CB(1) receptor antagonist SR141716 (Rimonabant; 0.3 mg/kg, i.m.) or combined challenge of THC (0.1, 0.3 mg/kg, i.m.) with MDMA (1.78 mg/kg p.o.) using minimally-invasive, implanted radiotelemetry techniques.

RESULTS

THC reduced the body temperature of monkeys in a dose-dependent manner with the nadir observed 3-5 h post-injection; however, an attenuation of normal circadian cooling was also produced overnight following dosing. Hypothermia induced by THC (0.3 mg/kg, i.m.) was prevented by Rimonabant (0.3 mg/kg, i.m.). Finally, 0.3 mg/kg THC (i.m.) attenuated the elevation of body temperature produced by MDMA for about 4 h after oral dosing.

CONCLUSIONS

As with rodents THC produces a robust and lasting decrement in the body temperature of rhesus monkeys; this effect is mediated by the CB(1) receptor. THC also protects against the immediate hyperthermic effects of MDMA in monkeys in a dose-dependent manner. Nevertheless, a paradoxical attenuation of circadian cooling overnight after the THC/MDMA combination cautions that longer-term effects may be critical in assessing risks for the recreational user of cannabis in combination with MDMA.