Synthetic cannabinoid JWH-018 and its halogenated derivatives JWH-018-Cl and JWH-018-Br impair Novel Object Recognition in mice: Behavioral, electrophysiological and neurochemical evidence

Effects of acute Δ9-tetrahydrocannabinol on behavior and the endocannabinoid system in HIV-1 Tat transgenic female and male mice

Cannabis use is highly prevalent especially among people living with HIV (PLWH). Activation of the anti-inflammatory and neuroprotective endocannabinoid system by phytocannabinoids, i.e. Δ9-tetrahydrocannabinol (THC), has been proposed to reduce HIV symptoms. However, THC's effects on HIV-related memory deficits are unclear. Using HIV-1 Tat transgenic mice, the current study investigates acute THC effects on various behavioral outcomes and the endocannabinoid system. For the rodent tetrad model, THC doses (1, 3, 10 mg/kg) induced known antinociceptive effects, with Tat induction increasing antinociceptive THC effects at 3 and 10 mg/kg doses. Only minor or no effects were noted for acute THC on body temperature, locomotor activity, and coordination. Increased anxiety-like behavior was found for females compared to males, but acute THC had no effect on anxiety. Object recognition memory was diminished by acute THC in Tat(-) females but not Tat(+) females, without affecting males. The endocannabinoid system and related lipids were not affected by acute THC, except for THC-induced decreases in CB1R protein expression levels in the spinal cord of Tat(-) mice. Female sex and Tat induction was associated with elevated 2-AG, AEA, AA, CB1R, CB2R, FAAH and/or MAGL expression in various brain regions. Further, AEA levels in the prefrontal cortex of Tat(+) females were negatively associated with object recognition memory. Overall, findings indicate that acute THC exerts differential effects on antinociception and memory, dependent on sex and HIV Tat expression, potentially in relation to an altered endocannabinoid system, which may be of relevance in view of potential cannabis-based treatment options for PLWH.

Cognitive dysfunction and impaired neuroplasticity following repeated exposure to the synthetic cannabinoid JWH-018 in male mice

BACKGROUND AND PURPOSE

Psychotic disorders have been reported in long-term users of synthetic cannabinoids. This study aims at investigating the long-lasting effects of repeated JWH-018 exposure.

EXPERIMENTAL APPROACH

Male CD-1 mice were injected with vehicle, JWH-018 (6 mg·kg-1 ), the CB1 -antagonist NESS-0327 (1 mg·kg-1 ) or co-administration of NESS-0327 and JWH-018, every day for 7 days. After 15 or 16 days washout, we investigated the effects of JWH-018 on motor function, memory, social dominance and prepulse inhibition (PPI). We also evaluated glutamate levels in dialysates from dorsal striatum, striatal dopamine content and striatal/hippocampal neuroplasticity focusing on the NMDA receptor complex and the neurotrophin BDNF. These measurements were accompanied by in vitro electrophysiological evaluations in hippocampal preparations. Finally, we investigated the density of CB1 receptors and levels of the endocannabinoid anandamide (AEA) and 2-arachidonoylglycerol (2-AG) and their main synthetic and degrading enzymes in the striatum and hippocampus.

KEY RESULTS

The repeated treatment with JWH-018 induced psychomotor agitation while reducing social dominance, recognition memory and PPI in mice. JWH-018 disrupted hippocampal LTP and decreased BDNF expression, reduced the synaptic levels of NMDA receptor subunits and decreased the expression of PSD95. Repeated exposure to JWH-018, reduced hippocampal CB1 receptor density and induced a long-term alteration in AEA and 2-AG levels and their degrading enzymes, FAAH and MAGL, in the striatum.

CONCLUSION AND IMPLICATIONS

Our findings suggest that repeated administration of a high dose of JWH-018 leads to the manifestation of psychotic-like symptoms accompanied by alterations in neuroplasticity and change in the endocannabinoid system.

Addictive drugs modify neurogenesis, synaptogenesis and synaptic plasticity to impair memory formation through neurotransmitter imbalances and signaling dysfunction

Drug abuse changes neurophysiological functions at multiple cellular and molecular levels in the addicted brain. Well-supported scientific evidence suggests that drugs negatively affect memory formation, decision-making and inhibition, and emotional and cognitive behaviors. The mesocorticolimbic brain regions are involved in reward-related learning and habitual drug-seeking/taking behaviors to develop physiological and psychological dependence on the drugs. This review highlights the importance of specific drug-induced chemical imbalances resulting in memory impairment through various neurotransmitter receptor-mediated signaling pathways. The mesocorticolimbic modifications in the expression levels of brain-derived neurotrophic factor (BDNF) and the cAMP-response element binding protein (CREB) impair reward-related memory formation following drug abuse. The contributions of protein kinases and microRNAs (miRNAs), along with the transcriptional and epigenetic regulation have also been considered in memory impairment underlying drug addiction. Overall, we integrate the research on various types of drug-induced memory impairment in distinguished brain regions and provide a comprehensive review with clinical implications addressing the upcoming studies.

Long-Term Treatment with Cannabidiol-Enriched Cannabis Extract Induces Synaptic Changes in the Adolescent Rat Hippocampus

The endocannabinoid system (eCS) is widely distributed in mammalian tissues and it is classically formed by cannabinoid receptors, endogenous bioactive lipids and its synthesis and degradation enzymes. Due to the modulatory role of eCS in synaptic activity in the Central Nervous System (CNS), phytocannabinoids have been increasingly used for the treatment of neurological disorders, even though little is known in terms of the long-term effect of these treatments on CNS development, mainly in the timeframe that comprises childhood and adolescence. Furthermore, an increased number of clinical trials using full-spectrum Cannabis extracts has been seen, rather than the isolated form of phytocannabinoids, when exploring the therapeutical benefits of the Cannabis plant. Thus, this study aims to evaluate the effect of cannabidiol (CBD)-enriched Cannabis extract on synaptic components in the hippocampus of rats from adolescence to early adulthood (postnatal day 45 to 60). Oral treatment of healthy male Wistar rats with a CBD-enriched Cannabis extract (3 mg/kg/day CBD) during 15 days did not affect food intake and water balance. There was also no negative impact on locomotor behaviour and cognitive performance. However, the hippocampal protein levels of GluA1 and GFAP were reduced in animals treated with the extract, whilst PSD95 levels were increased, which suggests rearrangement of glutamatergic synapses and modulation of astrocytic features. Microglial complexity was reduced in CA1 and CA3 regions, but no alterations in their phagocytic activity have been identified by Iba-1 and LAMP2 co-localization. Collectively, our data suggest that CBD-enriched Cannabis treatment may be safe and well-tolerated in healthy subjects, besides acting as a neuroprotective agent against hippocampal alterations related to the pathogenesis of excitatory and astrogliosis-mediated disorders in CNS.

Cognitive Alterations in Addictive Disorders: A Translational Approach

The cognitive decline in people with substance use disorders is well known and can be found during both the dependence and drug abstinence phases. At the clinical level, cognitive decline impairs the response to addiction treatment and increases dropout rates. It can be irreversible, even after the end of drug abuse consumption. Improving our understanding of the molecular and cellular alterations associated with cognitive decline could be essential to developing specific therapeutic strategies for its treatment. Developing animal models to simulate drug abuse-induced learning and memory alterations is critical to continue exploring this clinical situation. The main aim of this review is to summarize the most recent evidence on cognitive impairment and the associated biological markers in patients addicted to some of the most consumed drugs of abuse and in animal models simulating this clinical situation. The available information suggests the need to develop more studies to further explore the molecular alterations associated with cognitive impairment, with the ultimate goal of developing new potential therapeutic strategies.

MAM-2201 acute administration impairs motor, sensorimotor, prepulse inhibition, and memory functions in mice: a comparison with its analogue AM-2201

RATIONALE

1-[(5-fluoropentyl)-1H-indol-3-yl](4-methyl-1-naphthalenyl) methanone (MAM-2201) is a potent synthetic cannabinoid receptor agonist illegally marketed in "spice" products and as "synthacaine" for its psychoactive effects. It is a naphthoyl-indole derivative which differs from its analogue 1-[(5-Fluoropentyl)-1H-indol-3-yl](1-naphthylenyl) methanone (AM-2201) by the presence of a methyl substituent on carbon 4 (C-4) of the naphthoyl moiety. Multiple cases of intoxication and impaired driving have been linked to AM-2201 and MAM-2201 consumption.

OBJECTIVES

This study aims to investigate the in vitro (murine and human cannabinoid receptors) and in vivo (CD-1 male mice) pharmacodynamic activity of MAM-2201 and compare its effects with those induced by its desmethylated analogue, AM-2201.

RESULTS

In vitro competition binding studies confirmed that MAM-2201 and AM-2201 possess nanomolar affinity for both CD-1 murine and human CB₁ and CB₂ receptors, with preference for the CB₁ receptor. In agreement with the in vitro binding data, in vivo studies showed that MAM-2201 induces visual, acoustic, and tactile impairments that were fully prevented by pretreatment with CB₁ receptor antagonist/partial agonist AM-251, indicating a CB₁ receptor mediated mechanism of action. Administration of MAM-2201 also altered locomotor activity and PPI responses of mice, pointing out its detrimental effect on motor and sensory gating functions and confirming its potential use liability. MAM-2201 and AM-2201 also caused deficits in short- and long-term working memory.

CONCLUSION

These findings point to the potential public health burden that these synthetic cannabinoids may pose, with particular emphasis on impaired driving and workplace performance.

Ethanol enhances JWH-018-induced impairment of sensorimotor and memory functions in mice: From preclinical evidence to forensic implication in Driving Under the Influence of Drugs

BACKGROUND

Several new Synthetic Cannabinoids have appeared each year since their introduction into the illicit drug market as recreational drugs. Among these, naphtalen-1-yl-(1-pentylindol-3-yl) methanone (JWH-018) is one of the most detected compounds in biological samples from patients involved in intoxication or death cases. Furthermore, consumption of JWH-018 has been linked to several cases of Driving Under the Influence of Drugs (DUID) suggesting that effects induced by this compound can affect individuals' ability to drive.

METHODS

Given the high spread of polydrug consumption and the wide number of alcohol-related traffic accidents, this study aims to investigate the acute effects induced by co-administration of JWH-018 with ethanol on sensorimotor and motor responses, grip strength and memory functions in CD-1 male mice. Acute impairments induced by JWH-018 and ethanol alone have also been investigated, in order to compare their effects with that induced by their concurrent administration.

RESULTS

In vivo behavioral experiments revealed a worsening of the cognitive and sensorimotor disruption after the co-administration of JWH-018 with ethanol compared to single compounds.

CONCLUSIONS

These animal-based findings suggest a potential increased impairment on psychomotor performances which could be related to driving abilities posed by poly-drug consumption involving SCs and ethanol.

Chronic pain in Alzheimer's disease: Endocannabinoid system

Chronic pain, one of the most common reasons adults seek medical care, has been linked to restrictions in mobility and daily activities, dependence on opioids, anxiety, depression, sleep deprivation, and reduced quality of life. Alzheimer's disease (AD), a devastating neurodegenerative disorder (characterized by a progressive impairment of cognitive functions) in the elderly, is often co-morbid with chronic pain. AD is one of the most common neurodegenerative disorders in the aged population. The reported prevalence of chronic pain is 45.8% of the 50 million people with AD. As the population ages, the number of older people who experience AD and chronic pain will also increase. The current treatment options for chronic pain are limited, often ineffective, and have associated side effects. This review summarizes the role of the endocannabinoid system in pain, its potential role in chronic pain in AD, and addresses gaps and future directions.

Mepirapim, a novel synthetic cannabinoid, induces Parkinson's disease-related behaviors by causing maladaptation of the dopamine system in the brain

Mepirapim is a novel synthetic cannabinoid that first appeared on the illicit drug market in 2013. In recent years, recreational abuse of Mepirapim has caused serious emergencies, posing a threat to public health. However, there are no legal regulations to prohibit the use of Mepirapim, as there is no scientific evidence for the dangerous pharmacological effects of the drug. In the present study, we investigated the dangerous neurotoxic effects of Mepirapim through behavioral and molecular experiments in mice (ICR/CD1, male, 25-30 g). In particular, based on a previous study that Mepirapim activates the dopamine system, we evaluated whether high-dose Mepirapim [single (15, 30, or 60 mg·kg^-1, i.p.) or multiple (8, 15, or 30 mg·kg^-1, i.p. × 4 at 2 h intervals)] treatment causes Parkinson's disease-related symptoms through damage to the dopamine system. In the result, we found that Mepirapim treatment caused comprehensive Parkinson's disease-related symptoms, including motor impairment, cognitive deficits and mood disorders. Furthermore, we confirmed the maladaptation in dopamine-related neurochemicals, including decreased dopamine levels, decreased tyrosine hydroxylase expression, and increased α-synuclein expression, in the brains of mice treated with Mepirapim. Taken together, these results indicate that Mepirapim has dangerous neurotoxic effects that induces Parkinson's disease-related behaviors by causing maladaptation of the dopamine system in the brain. Based on these findings, we propose the strict regulation of recreational abuse and therapeutic misuse of Mepirapim.

Acute toxic effects of new synthetic cannabinoid on brain: Neurobehavioral and Histological: Preclinical studies

The psychoactive effects of new synthetic cannabinoids (SCs), MDMB-4en-PINACA, are being marketed as a blend of herbs and spices. This study aims to determine the behavioral, neurochemical, histopathological, and immunohistochemical alterations associated with the acute toxicity of MDMB-4en-PINACA compounds.

METHODS

Adult male albino rats were administered various toxic doses of the drug (1.5, 3, and 6 mg/kg), and behavioral studies were conducted 2 and 24 h later; animals were then sacrificed. Histopathological and neurochemical examinations were performed. Two hours after intraperitoneal.

RESULTS

Intraperitoneal injection of MDMB-4en-PINACA, horizontal movement, the number of stops, and mobility ratio were significantly impaired, along with coordination and balance. In addition, it led to a decline in spatial learning and memory, and neurotransmitter concentrations decreased significantly in a dose-dependent manner. Further examination of the cerebral cortex and hippocampus histopathology revealed pathological degeneration of small pyramidal cells.

CONCLUSION

Thus, these findings revealed that MDMB-4en-PINACA interferes with hippocampal function and impairs cognitive performance, highlighting the cognitive risk associated with SC abuse.

In Vivo Bio-Activation of JWH-175 to JWH-018: Pharmacodynamic and Pharmacokinetic Studies in Mice

3-(1-Naphthalenylmethyl)-1-pentyl-1H-indole (JWH-175) is a synthetic cannabinoid illegally marketed for its psychoactive cannabis-like effects. This study aimed to investigate and compare in vitro and in vivo pharmacodynamic activity of JWH-175 with that of 1-naphthalenyl (1-pentyl-1H-indol-3-yl)-methanone (JWH-018), as well as evaluate the in vitro (human liver microsomes) and in vivo (urine and plasma of CD-1 male mice) metabolic profile of JWH-175. In vitro binding studies showed that JWH-175 is a cannabinoid receptor agonist less potent than JWH-018 on mouse and human CB1 and CB2 receptors. In agreement with in vitro data, JWH-175 reduced the fESPS in brain hippocampal slices of mice less effectively than JWH-018. Similarly, in vivo behavioral studies showed that JWH-175 impaired sensorimotor responses, reduced breath rate and motor activity, and increased pain threshold to mechanical stimuli less potently than JWH-018. Metabolic studies demonstrated that JWH-175 is rapidly bioactivated to JWH-018 in mice blood, suggesting that in vivo effects of JWH-175 are also due to JWH-018 formation. The pharmaco-toxicological profile of JWH-175 was characterized for the first time, proving its in vivo bio-activation to the more potent agonist JWH-018. Thus, it highlighted the great importance of investigating the in vivo metabolism of synthetic cannabinoids for both clinical toxicology and forensic purposes.

Synthetic cannabinoid JWH-073 alters both acute behavior and in vivo/vitro electrophysiological responses in mice

JWH-073 is a synthetic cannabinoid (SCB) that is illegally marketed within an "herbal blend", causing psychoactive effects more intense than those produced by Cannabis. Users report that JWH-073 causes less harmful effects than other SCBs, misrepresenting it as a "safe JWH-018 alternative", which in turn prompts its recreational use. The present study is aimed to investigate the in vivo pharmacological activity on physiological and neurobehavioral parameters in male CD-1 mice after acute 1 mg/kg JWH-073 administration. To this aim we investigate its effect on sensorimotor (visual, acoustic, and tactile), motor (spontaneous motor activity and catalepsy), and memory functions (novel object recognition; NOR) in mice coupling behavioral and EEG data. Moreover, to clarify how memory function is affected by JWH-073, we performed in vitro electrophysiological studies in hippocampal preparations using a Long-Term Potentiation (LTP) stimulation paradigm. We demonstrated that acute administration of JWH-073 transiently decreased motor activity for up to 25 min and visual sensorimotor responses for up to 105 min, with the highest effects at 25 min (~48 and ~38%, respectively), while the memory function was altered up to 24 h (~33%) in treated-mice as compared to the vehicle. EEG in the somatosensory cortex showed a maximal decrease of α (~23%) and γ (~26%) bands at 15 min, β (~26%) band at 25 min, a maximal increase of θ (~14%) band at 25 min and δ (~35%) band at 2 h, and a significant decrease of θ (~18%), α (~26%), and β (~10%) bands during 24 h. On the other hand, EEG in the hippocampus showed a significant decrease of all bands from 10 min to 2 h, with the maximal effect at 30 min for θ (~34%) and γ (~26%) bands and 2 h for α (~36%), β (~29%), and δ (~15%) bands. Notably, the δ band significant increase both at 5 min (~12%) and 24 h (~19%). Moreover, in vitro results support cognitive function impairment (~60% of decrease) by interfering with hippocampal synaptic transmission and LTP generation. Our results suggest that JWH-073 deeply alters brain electrical responsiveness with minor behavioral symptoms. Thus, it poses a subtle threat to consumers who mistakenly consider it safer than other SCBs.

Effects of synthetic cannabinoids on psychomotor, sensory and cognitive functions relevant for safe driving

Recreational use of Synthetic Cannabinoids (SCs), one of the largest groups of New Psychoactive Substances (NPS), has increased globally over the past few years. Driving is a structured process requiring the cooperation of several cognitive and psychomotor functions, organized in different levels of complexity. Each of these functions can be affected when Driving Under the Influence (DUI) of SCs. In order to reduce the likelihood of SC-related road accidents, it is essential to understand which areas of psychomotor performance are most affected by these substances, as well as the severity of impairment. For this purpose, a multiple database- literature review of recent experimental studies in humans and animals regarding the psychomotor effects of SCs has been performed. Despite the many limitations connected to experimental studies on humans, results showed a consistency between animal and human data. SCs appear to impair psychomotor performance in humans, affecting different domains related to safe driving even at low doses. Cases of DUI of SC have been repeatedly reported, although the exact prevalence is likely to be underestimated due to current analytical and interpretative issues. For this reason, an accurate physical examination performed by trained and experienced personnel has a primary role in recognizing signs of impairment in case of strong suspicion of SC consumption. The identification of a suspected case should be followed by reliable laboratory examination.

Hypericin Ameliorates Maternal Separation-Induced Cognitive Deficits and Hippocampal Inflammation in Rats

BACKGROUND AND OBJECTIVE

Maternal separation as an epigenetic agent provokes a severe change in the brain, such as inflammation response, which is a key risk factor for the progression of autism spectrum disorders (ASD). This study evaluated the preventive effect of hypericin on maternal separation-induced cognitive deficits and hippocampal inflammation.

METHODS

Here, we reported that pups are subjected to maternal separations for 1 h per day from postnatal days (PND) 1-9 displayed apparent memory impairment in young rats (postnatal day 34) compared to controls group. Furthermore, maternal separation significantly increased inflammation factors in the hippocampus area. Anti-inflammation constituent shed light on treating ASD.

RESULTS

In this study, we found that treatment with hypericin (10 and 50 mg/kg) significantly suppresses expression of hippocampal interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α) in the maternal separation rat model. Also, we found that hypericin prevented the decrease of hippocampal dopamine levels in the offspring of maternal separation rats.

CONCLUSION

The data indicated that hypericin may play a neuroprotective role in hippocampal cell and ameliorates dysfunctions in memory and level of inflammation factor in this autism model. Thus, hypericin could be used as an intervention for treating ASD.

Potential and Limits of Cannabinoids in Alzheimer's Disease Therapy

Simple Summary

This review was aimed at exploring the potentiality of drugging the endocannabinoid system as a therapeutic option for Alzheimer’s disease (AD). Recent discoveries have demonstrated how the modulation of cannabinoid receptor 1 (CB1) and receptor 2 (CB2) can exert neuroprotective effects without the recreational and pharmacological properties of Cannabis sativa. Thus, this review explores the potential of cannabinoids in AD, also highlighting their limitations in perspective to point out the need for further research on cannabinoids in AD therapy.

Abstract

Alzheimer’s disease (AD) is a detrimental brain disorder characterized by a gradual cognitive decline and neuronal deterioration. To date, the treatments available are effective only in the early stage of the disease. The AD etiology has not been completely revealed, and investigating new pathological mechanisms is essential for developing effective and safe drugs. The recreational and pharmacological properties of marijuana are known for centuries, but only recently the scientific community started to investigate the potential use of cannabinoids in AD therapy—sometimes with contradictory outcomes. Since the endocannabinoid system (ECS) is highly expressed in the hippocampus and cortex, cannabis use/abuse has often been associated with memory and learning dysfunction in vulnerable individuals. However, the latest findings in AD rodent models have shown promising effects of cannabinoids in reducing amyloid plaque deposition and stimulating hippocampal neurogenesis. Beneficial effects on several dementia-related symptoms have also been reported in clinical trials after cannabinoid treatments. Accordingly, future studies should address identifying the correct therapeutic dosage and timing of treatment from the perspective of using cannabinoids in AD therapy. The present paper aims to summarize the potential and limitations of cannabinoids as therapeutics for AD, focusing on recent pre-clinical and clinical evidence.

Plasticity in the Hippocampus, Neurogenesis and Drugs of Abuse

Synaptic plasticity in the hippocampus assists with consolidation and storage of long-lasting memories. Decades of research has provided substantial information on the cellular and molecular mechanisms underlying synaptic plasticity in the hippocampus, and this review discusses these mechanisms in brief. Addiction is a chronic relapsing disorder with loss of control over drug taking and drug seeking that is caused by long-lasting memories of drug experience. Relapse to drug use is caused by exposure to context and cues associated with the drug experience, and is a major clinical problem that contributes to the persistence of addiction. This review also briefly discusses some evidence that drugs of abuse alter plasticity in the hippocampus, and that development of novel treatment strategies that reverse or prevent drug-induced synaptic alterations in the hippocampus may reduce relapse behaviors associated with addiction.

Sex and Gender Differences in the Effects of Novel Psychoactive Substances

Sex and gender deeply affect the subjective effects and pharmaco-toxicological responses to drugs. Men are more likely than women to use almost all types of illicit drugs and to present to emergency departments for serious or fatal intoxications. However, women are just as likely as men to develop substance use disorders, and may be more susceptible to craving and relapse. Clinical and preclinical studies have shown important differences between males and females after administration of “classic” drugs of abuse (e.g., Δ9-tetrahydrocannabinol (THC), morphine, cocaine). This scenario has become enormously complicated in the last decade with the overbearing appearance of the new psychoactive substances (NPS) that have emerged as alternatives to regulated drugs. To date, more than 900 NPS have been identified, and can be catalogued in different pharmacological categories including synthetic cannabinoids, synthetic stimulants (cathinones and amphetamine-like), hallucinogenic phenethylamines, synthetic opioids (fentanyls and non-fentanyls), new benzodiazepines and dissociative anesthetics (i.e., methoxetamine and phencyclidine-derivatives). This work collects the little knowledge reached so far on the effects of NPS in male and female animal and human subjects, highlighting how much sex and gender differences in the effects of NPS has yet to be studied and understood.

The medial prefrontal cortex - hippocampus circuit that integrates information of object, place and time to construct episodic memory in rodents: Behavioral, anatomical and neurochemical properties

Rats and mice have been demonstrated to show episodic-like memory, a prototype of episodic memory, as defined by an integrated memory of the experience of an object or event, in a particular place and time. Such memory can be assessed via the use of spontaneous object exploration paradigms, variably designed to measure memory for object, place, temporal order and object-location inter-relationships. We review the methodological properties of these tests, the neurobiology about time and discuss the evidence for the involvement of the medial prefrontal cortex (mPFC), entorhinal cortex (EC) and hippocampus, with respect to their anatomy, neurotransmitter systems and functional circuits. The systematic analysis suggests that a specific circuit between the mPFC, lateral EC and hippocampus encodes the information for event, place and time of occurrence into the complex episodic-like memory, as a top-down regulation from the mPFC onto the hippocampus. This circuit can be distinguished from the neuronal component memory systems for processing the individual information of object, time and place.

Genotoxic Properties of Synthetic Cannabinoids on TK6 Human Cells by Flow Cytometry

Novel Psychoactive Substances (NPS) include several classes of substances such as synthetic cannabinoids (SCBs), an emerging alternative to marijuana, easily purchasable on internet. SCBs are more dangerous than Δ⁹-Tetrahydrocannabinol as a consequence of their stronger affinities for the CB₁ and CB₂ receptors, which may result in longer duration of distinct effects, greater potency, and toxicity. The information on SCBs cytotoxicity, genotoxicity, mutagenicity, and long-term effects is scarce. This fact suggests the urgent need to increase available data and to investigate if some SCBs have an impact on the stability of genetic material. Therefore, the aim of the present study was the evaluation of the mutagenic effect of different SCBs belonging to indole- and indazole-structures. The analyzes were conducted in vitro on human TK6 cells and mutagenicity were measured as micronucleus fold increase by flow cytometry. Our results have highlighted, for the first time, the mutagenic capacity of four SCBs, in particular in terms of chromosomal damage induction. We underline the serious potential toxicity of SCBs that suggests the need to proceed with the studies of other different synthetic compounds. Moreover, we identified a method that allows a rapid but effective screening of NPS placed on the market increasingly faster.

CB1 Activity Drives the Selection of Navigational Strategies: A Behavioral and c-Fos Immunoreactivity Study

To promote efficient explorative behaviors, subjects adaptively select spatial navigational strategies based on landmarks or a cognitive map. The hippocampus works alone or in conjunction with the dorsal striatum, both representing the neuronal underpinnings of the navigational strategies organized on the basis of different systems of spatial coordinate integration. The high expression of cannabinoid type 1 (CB₁) receptors in structures related to spatial learning—such as the hippocampus, dorsal striatum and amygdala—renders the endocannabinoid system a critical target to study the balance between landmark- and cognitive map-based navigational strategies. In the present study, mice treated with the CB₁-inverse agonist/antagonist AM251 or vehicle were trained on a Circular Hole Board, a task that could be solved through either navigational strategy. At the end of the behavioral testing, c-Fos immunoreactivity was evaluated in specific nuclei of the hippocampus, dorsal striatum and amygdala. AM251 treatment impaired spatial learning and modified the pattern of the performed navigational strategies as well as the c-Fos immunoreactivity in the hippocampus, dorsal striatum and amygdala. The present findings shed light on the involvement of CB₁ receptors as part of the selection system of the navigational strategies implemented to efficiently solve the spatial problem.

Novel halogenated synthetic cannabinoids impair sensorimotor functions in mice

JWH-018-Cl, JWH-018-Br and AM-2201 (JWH-018 halogenated-derivatives; JWH-018-R compounds) are synthetic cannabinoid agonists illegally marketed as "Spice", "K2", "herbal blend" and research chemicals for their cannabis-like psychoactive effects. In rodents, JWH-018 and its halogenated derivatives reproduce the typical effects of Δ⁹-tetrahydrocannabinol (Δ⁹-THC), i.e. hypothermia, analgesia, hypolocomotion and akinesia. Yet, the effects of JWH-018-R compounds on sensorimotor functions are still unknown. This study was designed to investigate the effect of an acute intraperitoneal (i.p.) administration of JWH-018-R compounds (0.01-6 mg/kg) on sensorimotor functions in mice and to compare them to those caused by the reference compound JWH-018 and Δ⁹-THC. A well validated battery of behavioral tests was used to investigate the effects of these synthetic cannabinoids on the visual, auditory and tactile responses in mice, while the pre-pulse inhibition (PPI) test was used to investigate their effect on sensorimotor gating. The effect of the synthetic cannabinoids on spontaneous locomotion was also measured by a video tracking analysis to assess potential cannabinoid-induced motor impairment. Results showed that, similarly to JWH-018, systemic administration of JWH-018-R compounds inhibits sensorimotor and PPI responses at lower doses (0.01-0.1 mg/kg) and reduced spontaneous locomotion at intermediate/high doses (1-6 mg/kg). All effects were prevented by the administration of the selective cannabinoid CB₁ receptor antagonist/inverse agonist AM-251 thus confirming a CB₁ receptor-mediated action. Finding that lower doses of JWH-018-R compounds selectively impair sensorimotor and PPI responses without affecting locomotion should be carefully considered to better understand the potential danger that halogenated-derivatives of JWH-018 may pose to public health, with particular reference to decreased performance in driving and hazardous works.

Elevation of endocannabinoids in the brain by synthetic cannabinoid JWH-018: mechanism and effect on learning and memory

The impairment of learning and memory is a well-documented effect of both natural and synthetic cannabinoids. In the present study, we aimed to investigate the effect of acute administration of JWH-018, a synthetic cannabinoid, on the hippocampal metabolome to assess biochemical changes in vivo. JWH-018 elevated levels of the endocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG). The increase of endocannabinoid levels in response to JWH-018 could be inhibited by co-administration of AM251, a CB1 receptor antagonist. Biochemical analyses revealed that this was the result of suppression of two hydrolases involved in endocannabinoid degradation (fatty acid amide hydrolase [FAAH] and monoacylglycerol lipase [MAGL]). Additionally, we showed that JWH-018 causes a reduction in the levels of brain-derived neurotrophic factor (BDNF), which is known to modulate synaptic plasticity and adaptive processes underlying learning and memory. The decrease of BDNF following JWH-018 treatment was also rescued by co-administration of AM251. As both endocannabinoids and BDNF have been shown to modulate learning and memory in the hippocampus, the alteration of their levels in response to JWH-018 may explain the contribution of synthetic cannabinoids to impairment of memory.

Acute Cannabinoids Produce Robust Anxiety-Like and Locomotor Effects in Mice, but Long-Term Consequences Are Age- and Sex-Dependent

The rise in cannabinoid legalization and decriminalization in the US has been paired with an increase in adolescents that perceive marijuana as a “no risk” drug. However, a comprehensive review of human literature indicates that cannabinoid usage may have both beneficial and detrimental effects, with adolescent exposure being a critical window for harming cognitive development. Although the cannabinoids Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are often used together for recreational and medical purposes, no study has previously observed the acute and long-lasting effects of THC+CBD in a battery of behavioral assays analogous to subjective human reports. The current study observed the acute and long-term effects of THC, CBD, and THC+CBD on object recognition memory, anxiety-like behavior, and activity levels in adolescent and adult mice of both sexes. Acute THC alone and in combination with CBD resulted in robust effects on anxiety-like and locomotor behavior. A history of repeated cannabinoid treatment followed by a period without drug administration resulted in minimal effects in these behavioral assays. Most notably, the strongest effects of repeated cannabinoid treatment were seen in adult females administered THC+CBD, which significantly impaired their object recognition. No effects of repeated cannabinoid history were present on hippocampal protein expression. These studies represent a detailed examination of age- and sex-effects of acute and repeated cannabinoid administration. However, the acute and long-term effects of THC with and without CBD on additional behaviors in adolescents and adults will need to be examined for a more complete picture of these drug effects.

Potential Mechanisms Underlying the Deleterious Effects of Synthetic Cannabinoids Found in Spice/K2 Products

The chief psychoactive constituent of many bioactive phytocannabinoids (Δ⁹-tetrahydrocannabinol, Δ⁹-THC) found in hemp, cannabis or marijuana plants are scientifically denoted by the Latin term, Cannabis sativa, acts on cell surface receptors. These receptors are ubiquitously expressed. To date, two cannabinoid receptors have been cloned and characterized. Cannabinoid receptor type 1 (CB1R) is found to serve as the archetype for cannabinoid action in the brain. They have attracted wide interest as the mediator of all psychoactive properties of exogenous and endogenous cannabinoids and they are abundantly expressed on most inhibitory and excitatory neurons. Recent evidence established that cannabinoid receptor type 2 (CB2R) is also expressed in the neurons at both presynaptic and postsynaptic terminals and are involved in neuropsychiatric effects. Distinct types of cells in many regions in the brain express CB2Rs and the cellular origin of CB2Rs that induce specific behavioral effects are emerging. To mimic the bliss effects of marijuana, synthetic cannabinoids (SCBs) have been sprayed onto plant material, and this plant material has been consequently packaged and sold under brand name “Spice” or “K2”. These SCBs have been shown to maintain their affinity and functional activity for CB1R and CB2R and have been shown to cause severe harmful effects when compared to the effects of Δ⁹-THC. The present review discusses the potential brain mechanisms that are involved in the deleterious effects of SCBs.

Perinatal Glyphosate-Based Herbicide Exposure in Rats Alters Brain Antioxidant Status, Glutamate and Acetylcholine Metabolism and Affects Recognition Memory

Glyphosate-based herbicides (Gly-BHs) lead the world pesticide market. Although are frequently promoted as safe and of low toxicity, several investigations question its innocuousness. Previously, we described that oral exposure of rats to a Gly-BH during pregnancy and lactation decreased locomotor activity and anxiety in the offspring. The aim of the present study was to evaluate the mechanisms of neurotoxicity of this herbicide. Pregnant Wistar rats were supplied orally with 0.2 and 0.4% of Gly-BH (corresponding to 0.65 and 1.30 g/l of pure Gly, respectively) from gestational day (GD) 0, until weaning (postnatal day, PND, 21). Oxidative stress markers were determined in whole brain homogenates of PND90 offspring. The activity of acetylcholinesterase (AChE), transaminases, and alkaline phosphatase (AP) were assessed in prefrontal cortex (PFC), striatum, and hippocampus. Recognition memory was evaluated by the novel object recognition test. Brain antioxidant status was altered in Gly-BH-exposed rats. Moreover, AChE and transaminases activities were decreased and AP activity was increased in PFC, striatum and hippocampus by Gly-BH treatment. In addition, the recognition memory after 24 h was impaired in adult offspring perinatally exposed to Gly-BH. The present study reveals that exposure to a Gly-BH during early stages of rat development affects brain oxidative stress markers as well as the activity of enzymes involved in the glutamatergic and cholinergic systems. These alterations could contribute to the neurobehavioral variations reported previously by us, and to the impairment in recognition memory described in the present work.

The Effects of Cannabinoids on Executive Functions: Evidence from Cannabis and Synthetic Cannabinoids-A Systematic Review

Background—Cannabis is the most popular illicit drug in the Western world. Repeated cannabis use has been associated with short and long-term range of adverse effects. Recently, new types of designer-drugs containing synthetic cannabinoids have been widespread. These synthetic cannabinoid drugs are associated with undesired adverse effects similar to those seen with cannabis use, yet, in more severe and long-lasting forms. Method—A literature search was conducted using electronic bibliographic databases up to 31 December 2017. Specific search strategies were employed using multiple keywords (e.g., “synthetic cannabinoids AND cognition,” “cannabis AND cognition” and “cannabinoids AND cognition”). Results—The search has yielded 160 eligible studies including 37 preclinical studies (5 attention, 25 short-term memory, 7 cognitive flexibility) and 44 human studies (16 attention, 15 working memory, 13 cognitive flexibility). Both pre-clinical and clinical studies demonstrated an association between synthetic cannabinoids and executive-function impairment either after acute or repeated consumptions. These deficits differ in severity depending on several factors including the type of drug, dose of use, quantity, age of onset and duration of use. Conclusions—Understanding the nature of the impaired executive function following consumption of synthetic cannabinoids is crucial in view of the increasing use of these drugs.

Neurocognition and subjective experience following acute doses of the synthetic cannabinoid JWH-018: a phase 1, placebo-controlled, pilot study

BACKGROUND AND PURPOSE

Synthetic cannabinoids (often sold as Spice or K2) have become a very popular alternative to cannabis due to their easy access and portrayed safety. Controlled studies on the behavioural effects of synthetic cannabinoids are currently lacking, which hampers risk assessments of these compounds.

EXPERIMENTAL APPROACH

This is a first attempt to assess the influence of a synthetic cannabinoid, JWH-018, on neurocognition and subjective experience in humans after controlled administration. JWH-018, 2 and 3 mg, was administered to six healthy cannabis-experienced volunteers in a placebo-controlled, cross-over study following an escalating dosing schedule. Participants were monitored for 12 h after drug administration, and several neurocognitive measures and subjective questionnaires were taken.

KEY RESULTS

Serum concentrations of JWH-018 were highest after the 2 mg dose but generally low after administration of both doses. Both doses of JWH-018 were well tolerated, and no serious side effects were reported. Participants reported feeling more 'high' at 1 and 2 h after administration, particularly after the 2 mg dose. Behavioural impairments also emerged despite the low serum concentrations of JWH-018. The low dose of JWH-018 impaired performance on the tracking, divided attention and stop signal task.

CONCLUSION AND IMPLICATIONS

JWH-018 dosing in the present study resulted in drug concentrations that were generally low and not fully representative of common use. Yet initial impairments of neurocognitive function and subjective feelings of high did emerge despite low levels of JWH-018 in serum. Higher doses are needed to obtain a more representative risk profile of JWH-018.

Pharmaco-toxicological effects of the novel third-generation fluorinate synthetic cannabinoids, 5F-ADBINACA, AB-FUBINACA, and STS-135 in mice. In vitro and in vivo studies

INTRODUCTION

5F-ADBINACA, AB-FUBINACA, and STS-135 are 3 novel third-generation fluorinate synthetic cannabinoids that are illegally marketed as incense, herbal preparations, or research chemicals for their psychoactive cannabis-like effects.

METHODS

The present study aims at investigating the in vitro and in vivo pharmacological activity of 5F-ADBINACA, AB-FUBINACA, and STS-135 in male CD-1 mice, comparing their in vivo effects with those caused by the administration of Δ⁹ -THC and JWH-018. In vitro competition binding experiments revealed a nanomolar affinity and potency of the 5F-ADBINACA, AB-FUBINACA, and STS-135 on mouse and human CB₁ and CB₂ receptors. Moreover, these synthetic cannabinoids induced neurotoxicity in murine neuro-2a cells.

RESULTS

In vivo studies showed that 5F-ADBINACA, AB-FUBINACA, and STS-135 induced hypothermia; increased pain threshold to both noxious mechanical and thermal stimuli; caused catalepsy; reduced motor activity; impaired sensorimotor responses (visual, acoustic, and tactile); caused seizures, myoclonia, and hyperreflexia; and promoted aggressiveness in mice. Behavioral and neurological effects were fully prevented by the selective CB₁ receptor antagonist/inverse agonist AM 251. Differently, the visual sensory response induced by STS-135 was only partly prevented by the AM 251, suggesting a CB₁ -independent mechanism.

CONCLUSIONS

For the first time, the present study demonstrates the pharmaco-toxicological effects induced by the administration of 5F-ADBINACA, AB-FUBINACA, and STS-135 in mice and suggests their possible detrimental effects on human health.

Psychostimulant Effect of the Synthetic Cannabinoid JWH-018 and AKB48: Behavioral, Neurochemical, and Dopamine Transporter Scan Imaging Studies in Mice

JWH-018 and AKB48 are two synthetic cannabinoids (SCBs) belonging to different structural classes and illegally marketed as incense, herbal preparations, or chemical supply for theirs psychoactive cannabis-like effects. Clinical reports from emergency room reported psychomotor agitation as one of the most frequent effects in people assuming SCBs. This study aimed to investigate the psychostimulant properties of JWH-018 and AKB48 in male CD-1 mice and to compare their behavioral and biochemical effects with those caused by cocaine and amphetamine. In vivo studies showed that JWH-018 and AKB48, as cocaine and amphetamine, facilitated spontaneous locomotion in mice. These effects were prevented by CB₁ receptor blockade and dopamine (DA) D_1/5 and D_2/3 receptors inhibition. SPECT-CT studies on dopamine transporter (DAT) revealed that, as cocaine and amphetamine, JWH-018 and AKB48 decreased the [¹²³I]-FP-CIT binding in the mouse striatum. Conversely, in vitro competition binding studies revealed that, unlike cocaine and amphetamine, JWH-018 and AKB48 did not bind to mouse or human DAT. Moreover, microdialysis studies showed that the systemic administration of JWH-018, AKB48, cocaine, and amphetamine stimulated DA release in the nucleus accumbens (NAc) shell of freely moving mice. Finally, unlike amphetamine and cocaine, JWH-018 and AKB48 did not induce any changes on spontaneous [³H]-DA efflux from murine striatal synaptosomes. The present results suggest that SCBs facilitate striatal DA release possibly with different mechanisms than cocaine and amphetamine. Furthermore, they demonstrate, for the first time, that JWH-018 and AKB48 induce a psychostimulant effect in mice possibly by increasing NAc DA release. These data, according to clinical reports, outline the potential psychostimulant action of SCBs highlighting their possible danger to human health.

Effect of the novel synthetic cannabinoids AKB48 and 5F-AKB48 on "tetrad", sensorimotor, neurological and neurochemical responses in mice. In vitro and in vivo pharmacological studies

RATIONALE

AKB48 and its fluorinate derivate 5F-AKB48 are two novel synthetic cannabinoids belonging to a structural class with an indazole core structure. They are marketed as incense, herbal preparations or chemical supply for their psychoactive Cannabis-like effects.

OBJECTIVES

The present study was aimed at investigating the in vitro and in vivo pharmacological activity of AKB48 and 5F-AKB48 in male CD-1 mice and comparing their in vivo effects with those caused by the administration of Δ⁹-THC and JWH-018.

RESULTS

In vitro competition binding experiments performed on mouse and human CB₁ and CB₂ receptors revealed a nanomolar affinity and potency of the AKB48 and 5F-AKB48. In vivo studies showed that AKB48 and 5F-AKB48, induced hypothermia, increased pain threshold to both noxious mechanical and thermal stimuli, caused catalepsy, reduced motor activity, impaired sensorimotor responses (visual, acoustic and tactile), caused seizures, myoclonia, hyperreflexia and promoted aggressiveness in mice. Moreover, microdialysis study in freely moving mice showed that systemic administration of AKB48 and 5F-AKB48 stimulated dopamine release in the nucleus accumbens. Behavioural, neurological and neurochemical effects were fully prevented by the selective CB₁ receptor antagonist/inverse agonist AM 251.

CONCLUSIONS

For the first time, the present study demonstrates the overall pharmacological effects induced by the administration of AKB48 and 5F-AKB48 in mice and suggests that the fluorination can increase the power and/or effectiveness of SCBs. Furthermore, this study outlines the potential detrimental effects of SCBs on human health.