Dopaminergic psychostimulants cause arousal from isoflurane-induced sedation without reversing memory impairment in rats.

BACKGROUND: Dopaminergic psychostimulants can restore arousal in anaesthetised animals, and dopaminergic signalling contributes to hippocampal-dependent memory formation. We tested the hypothesis that dopaminergic psychostimulants can antagonise the amnestic effects of isoflurane on visuospatial working memory. METHODS: Sixteen adult Sprague-Dawley rats were trained on a trial-unique nonmatching-to-location (TUNL) task which assessed the ability to identify a novel touchscreen location after a fixed delay. Once trained, the effects of low-dose isoflurane (0.3 vol%) on task performance and activity, assessed by infrared beam breaks, were assessed. We attempted to rescue deficits in performance and activity with a dopamine D1 receptor agonist (chloro-APB), a noradrenergic reuptake inhibitor (atomoxetine), and a mixed dopamine/norepinephrine releasing agent (dextroamphetamine). Anaesthetic induction, emergence, and recovery from anaesthesia were also investigated. RESULTS: Low-dose isoflurane impaired working memory in a sex-independent and intra-trial delay-independent manner as assessed by task performance, and caused an overall reduction in activity. Administration of chloro-APB, atomoxetine, or dextroamphetamine did not restore visuospatial working memory, but chloro-APB and dextroamphetamine recovered arousal to levels observed in the baseline awake state. Performance did not differ between induction and emergence. Animals recovered to baseline performance within 15 min of discontinuing isoflurane. CONCLUSIONS: Low-dose isoflurane impairs visuospatial working memory in a nondurable and delay-independent manner that potentially implicates non-hippocampal structures in isoflurane-induced memory deficits. Dopaminergic psychostimulants counteracted sedation but did not reverse memory impairments, suggesting that isoflurane-induced amnesia and isoflurane-induced sedation have distinct underlying mechanisms that can be antagonised independently.

Exploring peripheral biomarkers in psychostimulant use: A systematic review on neurotrophins, stress-related hormones, oxidative stress molecules and genetic factors.

BACKGROUND: This systematic review aims to comprehensively explore the impact of psychostimulant substances on neurotrophic and inflammatory pathways, including brain-derived neurotrophic factor (BDNF), pro-BDNF, cortisol, dehydroepiandrosterone sulfate (DHEAS), thiobarbituric acid reactive substances (TBARS), interleukins, and the role of genetic factors. The study seeks to address existing gaps in the literature by providing a thorough evaluation of neurotrophic and inflammatory system alterations associated with different stages of psychostimulant dependence for a more nuanced understanding of substance use disorder (SUD) neurobiology. METHODS: A systematic review was conducted in PubMed, Scopus, and Web of Science databases following the PRISMA guidelines. The research encompasses 50 studies with a participant pool totaling 6792 individuals using psychostimulant substances. RESULTS: Key findings include diverse impacts of cocaine on BDNF levels, mainly consisting of their significant increase during withdrawal. In contrast, NGF showed an opposite behavior, reducing during withdrawal. Cortisol and DHEAS levels exhibited relevant increases after psychostimulant use, while TBARS showed conflicting results. Genetic investigations predominantly focused on the Val66Met polymorphism of the BDNF gene, revealing associations with susceptibility to stimulant addiction. CONCLUSIONS: Neurotrophins and inflammatory molecules play a significant role in the pathophysiological mechanisms following psychostimulant use. A better understanding of their complex interplay could aid clinicians in identifying biomarkers of different disease stages. Moreover, clinical interventions designed to interfere with neurotrophic and inflammatory pathways could possibly lead to craving-modulatory strategies and reduce pathological neuronal and systemic consequences of psychostimulant use.

Hospitalized cocaine detoxification patients in Paris, France: Increased patient levels and changing population characteristics since 2011.

AIM OF THE STUDY: The past twenty years have seen a rise in cocaine-related statistics in France, including cocaine use in the general population, emergency ward presentations of acute cocaine intoxication, cocaine use disorders related outpatient appointments and cocaine-related deaths. This study's objectives were to describe trends in patients' admission for specific cocaine detoxification as well as changes in patients' characteristics in the Assistance publique-Hôpitaux de Paris (AP-HP) hospitals group located in Paris region, France. METHODS: We reviewed the international classification of diseases 10th edition (ICD-10) discharge codes of the AP-HP hospitals group between 2011 and 2021. In addition, medical reports of the largest addiction medicine ward were also analysed for changes across the years 2009, 2014, 2019 and 2022. RESULTS: The regional database showed an almost 3-fold increase in cocaine-related disorders discharge codes between 2011 and 2019. This occurred due to a rise in hospital stays for cocaine dependence or cocaine acute intoxication prior to the fall in levels of inpatient stays associated with the coronavirus disease 2019 (COVID-19) pandemic. The in-depth analysis of inpatients' stays in the specialized addiction medicine ward also showed an increase in admissions for cocaine detoxification programs, with a prevalence of 1.19% in 2009 to 15.73% in 2022 (P=1.44×10-20). Inpatient characteristics showed significant changes, especially in 2022, namely: more daily users, less intravenous administration and less comorbid illicit substances use disorders, with heightened levels of cured hepatitis C patients (P<0.05). Inpatient prescriptions were primarily dopaminergic antagonists with sedatives properties (cyamemazine, loxapine and chlorpromazine), dopamine-receptors partial agonist (aripiprazole) and serotonin reuptake inhibitors. CONCLUSION: The referral to hospital care for cocaine detoxification has increased in Paris region since 2011, coupled with changes in inpatients' characteristics. This trend has significant implications for the management of inpatient hospital services.

A systematic review and meta-analysis of synthetic cathinone use and psychosis.

RATIONALE: Synthetic cathinones (SC), commonly referred to as "bath salts", are stimulants resembling the natural alkaloid cathinone found in the khat plant. These substances have the potential to induce serious health risks such as hallucinations, delusions, paranoia and agitation which can lead to substance-induced psychotic disorders. Despite growing concerns, there is a limited understanding of the association between SC consumption and the devolvement of such psychopathologies. METHODS: We conducted a systematic review to investigate the frequency of substance-induced psychotic disorder (SIPD) and associated conditions in humans following synthetic cathinone consumption. We qualitatively and quantitatively analyzed SC exposure cases. RESULTS: A total of 32 studies were included, with a diverse range of demographics, synthetic cathinone types, and consumption patterns. The proportion of individuals developing psychotic symptoms was reported at 0.380 (Random-effects model, 95% CI 0.289 - 0.475). Additionally, the significant heterogeneity in diagnostic approaches limited our ability to provide a precise estimate of prevalence. CONCLUSIONS: Synthetic cathinone consumption is associated with the risk of developing psychotic symptoms as indicated by the prevalence of hallucinations and/or delusions. Due to the lack of information on classifying factors, particularly duration of symptoms, we are unable to conclude synthetic cathinone-induced psychosis. Further research is warranted to elucidate the underlying mechanism linking synthetic cathinone consumption and psychosis. This review underscores the urgency of addressing the growing health risks posed by synthetic cathinone use. Additionally, it highlights the necessity of proper quantification of psychotic symptoms through scales and reporting of classification criteria to accurately diagnose SIPD.

Armodafinil as a Potential Pharmacological Treatment for Attention Deficit Hyperactivity Disorder in Adults: A Review.

INTRODUCTION: Armodafinil is a psychostimulant that promotes alertness, and it has been shown to improve attention, memory, and fatigue in healthy adults and adults with neurodevelopmental conditions that share symptoms with Attention Deficit Hyperactivity Disorder (ADHD). It is generally well tolerated and safe, and most of the adverse events reported are considered not serious. However, the available evidence on the efficacy of armodafinil for the treatment of ADHD in adults is scarce. OBJECTIVE: The present review aims to perform a systematized search of the available evidence on the possible therapeutic benefit of armodafinil treatment in adult patients with ADHD. METHODS: A literature review using PubMed was conducted to compile and summarize the available clinical and scientific evidence on the possible use of armodafinil as a pharmacological treatment in adult patients with ADHD. RESULTS: From the 86 articles reviewed, the available evidence showed that both acute and chronic treatment with armodafinil can improve wakefulness, memory, impulse control, and executive functions in adults with sleep disorders and other conditions. In addition, evidence of improvement in cognitive functions and mood alterations in other neuropsychiatric conditions was shown. CONCLUSION: Armodafinil could be useful for the treatment of ADHD in adults, according to the review of the literature from both pre-clinical and clinical studies.

Psychostimulant Medications for Physical Function and Spasticity in Children With Cerebral Palsy: Protocol for a Randomized Controlled Trial.

BACKGROUND: Cerebral palsy (CP) is a prevalent nonprogressive disorder that leads to impaired movement (ie, spasticity), posture, and balance, which affects functions such as walking and upper extremity tasks. Current medical treatments show efficacy in improving motor performance but have considerable side effects. Emerging off-label use of central nervous system (CNS) medications for improving motor performance has shown promising results in children with CP and other populations. OBJECTIVE: The aim of this study is to describe a protocol for a pilot randomized controlled trial (RCT) to examine the safety, tolerability, and efficacy of methylphenidate (MPH) and modafinil on spasticity and motor performance in children with CP. METHODS: This will be a protocol study for a pilot, triple-masked, placebo-controlled RCT (a class I trial following the American Academy of Neurology criteria) with blinded patients, outcome assessors, and intervention delivery team. Eligible children should be diagnosed with CP levels I or II based on the Gross Motor Function Classification System and be aged between 7 and 12 years. Thirty-six children with CP will be randomized into 3 groups to receive (1) MPH (2.5 mg of MPH + 100 mg placebo), (2) modafinil (100 mg modafinil + 2.5 mg placebo), or (3) a placebo (2.5 mg placebo + 100 mg placebo), in addition to physical therapy for 12 weeks. Primary outcomes include the Gross Motor Function Measure-66 and the Modified Ashworth Scale. Secondary outcomes include the Timed Up and Go test, 5 Time Sit to Stand test, Modified Clinical Test for Sensory Interaction of Balance, and 10-Meter Walk Test. RESULTS: The protocol has been accepted by Kuwait University (VDR/EC-225) and the Ministry of Health of Kuwait (2022/2157). The inclusion of participants will start in June 2024. CONCLUSIONS: The combination of CNS stimulant medications and controlling for rehabilitation has not been studied yet. The findings of this study may determine if using CNS stimulant medications is beneficial for the reduction of spasticity and improvement of physical function in children with spastic CP. TRIAL REGISTRATION: ClinicalTrials.gov NCT05675098; https://clinicaltrials.gov/study/NCT05675098. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/53728.

Neuroimmune modulators as novel pharmacotherapies for substance use disorders.

One promising avenue of research is the use of neuroimmune modulators to treat substance use disorders (SUDs). Neuroimmune modulators target the interactions between the nervous system and immune system, which have been found to play a crucial role in the development and maintenance of SUDs. Multiple classes of substances produce alterations to neuroimmune signaling and peripheral immune function, including alcohol, opioids, and psychostimulants Preclinical studies have shown that neuroimmune modulators can reduce drug-seeking behavior and prevent relapse in animal models of SUDs. Additionally, early-phase clinical trials have demonstrated the safety and feasibility of using neuroimmune modulators as a treatment for SUDs in humans. These therapeutics can be used as stand-alone treatments or as adjunctive. This review summarizes the current state of the field and provides future directions with a specific focus on personalized medicine.

N-Isopropylbenzylamine-induced conditioned place preference, sensitization behaviour and self-administration in rodents.

N-Isopropylbenzylamine (N-ipb), a chain isomer of methamphetamine (METH) with similar physical properties, has been used as a substitute for METH in seized drug samples. However, the abuse potential of N-ipb remains unclear. Therefore, this study aimed to evaluate the abuse potential of N-ipb in comparison to METH, by using conditioned place preference (CPP), locomotor sensitization and intravenous self-administration tests. The results showed that N-ipb at a dose of 3 mg·kg-1 significantly induced CPP in mice, which was comparable to the effect of METH at 1 mg·kg-1 . Either acute or repeated N-ipb injections (1 or 3 mg·kg-1 ) failed to raise the locomotor activity. However, acute treatment with 10 mg·kg-1 N-ipb elevated the locomotor activity compared with saline, while chronic injection of 10 mg·kg-1 N-ipb induced a delayed and attenuated sensitization compared with 1 mg·kg-1 METH. Rats could acquire N-ipb self-administration at a dose of 1 mg·kg-1 ·infusion-1 , and a typical inverted U-shaped dose-response curve was obtained for N-ipb. The mean dose of N-ipb that maintained the maximum response was greater than that of METH, indicating that N-ipb is less potent for reinforcement than METH. In the economic behavioural analysis, comparison of essential values derived from the demand elasticity revealed that N-ipb is less efficacy as a reinforcer than METH. The present data demonstrate that N-ipb functions as a reinforcer and has a potential for abuse. However, the potency of psychomotor stimulation and the reinforcing effectiveness of N-ipb are lower than those of METH.

Drug poisoning deaths by occupation and drug type, Massachusetts 2010-2019.

OBJECTIVE: To investigate variation in drug poisoning mortality rates by drug type and occupation in Massachusetts. METHODS: Death certificates for deaths by drug poisonings occurring between 2010 and 2019 in Massachusetts were coded based on the decedent's occupation. Mortality rates and rate ratios (with all other occupations as the reference group) were calculated based on the occupation of the workers according to drug type. Poisson regression was used to determine significantly elevated mortality rates and trends in drug poisoning deaths by occupation and drug type. RESULTS: The rate of drug poisoning deaths increased from 2010 to 2016 after which they plateaued. With respect to specific substances, fentanyl- and cocaine-related deaths increased throughout the surveillance period. For drug poisoning deaths overall, workers in construction trades (3,017); food preparation and serving (1,116); transportation and material moving (1,062) occupations had the highest number of drug poisoning deaths. When adjusting for age, sex, race/ethnicity, and educational attainment, workers in 7 occupations had significantly elevated mortality rate ratios for drug poisonings overall: farming, fishing, and forestry (3.42, P < 0.001); construction trades (2.58, P < 0.001); health care support (1.61, P < 0.001); community and social service (1.60, P < 0.001); food preparation and serving related (1.54, P < 0.001); personal care and service (1.37, P < 0.001); and arts, design, entertainment, sports, and media (1.21, P = 0.010). In many cases, workers in these same occupations had elevated mortality rate ratios for poisonings from specific substances. Health care practitioners and technical occupation workers only had elevated rates for methadone-related poisonings (1.73, P = 0.010). CONCLUSIONS: These findings highlight that workers in certain occupations have an elevated risk for drug poisonings and that the patterns differ with respect to the drug type. These findings can be useful for providing services to workers in high-risk occupations and in identifying occupational factors that may be related to the risk of drug poisoning death. While previous research has begun to uncover work-related factors that may contribute to opioid use, further work is needed to identify occupational factors that may contribute to psychostimulant and benzodiazepine use.

Investigating Variations in Medicine Approvals for Attention-Deficit/Hyperactivity Disorder: A Cross-Country Document Analysis Comparing Drug Labeling.

OBJECTIVE: This study aimed to compare the approval of medicines for attention deficit/hyperactivity disorder (ADHD) for pediatric patients across five countries. METHOD: A document analysis was completed, using the drug labeling for ADHD medicines from five countries; United Kingdom, Australia, New Zealand, Canada and United States (US). Comparisons of available formulations and approval information for ADHD medicine use in pediatric patients were made. RESULTS: The US had the highest number of approved medicines and medicine forms across the studied countries (29 medicine forms for 10 approved medicines). Approved age and dosage variations across countries and missing dosage information were identified in several drug labeling. CONCLUSIONS: The discrepancies in approval information in ADHD medicine drug labeling and differing availability of medicine formulations across countries suggest variations in the management of ADHD across countries. The update of drug labeling and further research into reasons for variability and impact on practice are needed.

Could psychostimulant drug use among university students be related to ADHD symptoms? A preliminary study.

We aimed to explore if psychostimulant use among student could be linked to attention deficit-hyperactivity disorder (ADHD) symptoms using a self-administered questionnaire sent by email to French students in 2021. Participants were asked about their psychostimulant use and the presence of ADHD symptoms using the Wender Utah Rating Scale and the Adult Self-Report Scale. Among the 4431 respondents, the prevalence of psychostimulant use was concerning and significantly associated with ADHD symptoms. This association could be related to undiagnosed ADHD or to psychobehavioral impairments induced by psychostimulant use underlining the need of ADHD screening and targeted prevention measures.

Prescription psychostimulants for the treatment of amphetamine-type stimulant use disorder: A systematic review and meta-analysis of randomized placebo-controlled trials.

BACKGROUND AND AIMS: There is currently no standard of care for pharmacological treatment of amphetamine-type stimulant (ATS) use disorder (ATSUD). This systematic review with meta-analysis (PROSPERO CRD42022354492) aimed to pool results from randomized placebo-controlled trials (RCTs) to evaluate efficacy and safety of prescription psychostimulants (PPs) for ATSUD. METHODS: Major indexing sources and trial registries were searched to include records published before 29 August 2022. Eligible studies were RCTs evaluating efficacy and safety of PPs for ATSUD. Risk of bias (RoB) was assessed using the Cochrane RoB 2 tool. Risk ratio (RR) and risk difference were calculated for random-effect meta-analysis of dichotomous variables. Mean difference and standardized mean difference (SMD) were calculated for random-effect meta-analysis of continuous variables. RESULTS: Ten RCTs (n = 561 participants) were included in the meta-analysis. Trials studied methylphenidate (n = 7), with daily doses of 54-180 mg, and dextroamphetamine (n = 3), with daily doses of 60-110 mg, for 2-24 weeks. PPs significantly decreased end-point craving [SMD  -0.29; 95% confidence interval (CI) = -0.55, -0.03], while such a decrease did not reach statistical significance for ATS use, as evaluated by urine analysis (UA) (RR = 0.93; 95% CI = 0.85-1.01). No effect was observed for self-reported ATS use, retention in treatment, dropout following adverse events, early-stage craving, withdrawal and depressive symptoms. In a sensitivity analysis, treatment was associated with a significant reduction in UA positive for ATS (RR = 0.89; 95% CI = 0.79-0.99) after removing studies with a high risk of bias. In subgroup analyses, methylphenidate and high doses of PPs were negatively associated with ATS use by UA, while higher doses of PPs and treatment duration (≥ 20 weeks) were positively associated with longer retention. CONCLUSIONS: Among individuals with amphetamine-type stimulant use disorder, treatment with prescription psychostimulants may decrease ATS use and craving. While effect size is limited, it may increase with a higher dosage of medications.

Vilazodone, a Selective Serotonin Reuptake Inhibitor with Diminished Impact on Methylphenidate-Induced Gene Regulation in the Striatum: Role of 5-HT1A Receptor.

Selective serotonin reuptake inhibitors (SSRIs), including fluoxetine, are frequently combined with medical psychostimulants such as methylphenidate (Ritalin), for example, in the treatment of attention-deficit hyperactivity disorder/depression comorbidity. Co-exposure to these medications also occurs with misuse of methylphenidate as a recreational drug by patients on SSRIs. Methylphenidate, a dopamine reuptake blocker, produces moderate addiction-related gene regulation. Findings show that SSRIs such as fluoxetine given in conjunction with methylphenidate potentiate methylphenidate-induced gene regulation in the striatum in rats, consistent with a facilitatory action of serotonin on addiction-related processes. These SSRIs may thus increase methylphenidate's addiction liability. Here, we investigated the effects of a novel SSRI, vilazodone, on methylphenidate-induced gene regulation. Vilazodone differs from prototypical SSRIs in that, in addition to blocking serotonin reuptake, it acts as a partial agonist at the 5-HT1A serotonin receptor subtype. Studies showed that stimulation of the 5-HT1A receptor tempers serotonin input to the striatum. We compared the effects of acute treatment with vilazodone (10-20 mg/kg) with those of fluoxetine (5 mg/kg) on striatal gene regulation (zif268, substance P, enkephalin) induced by methylphenidate (5 mg/kg), by in situ hybridization histochemistry combined with autoradiography. We also assessed the impact of blocking 5-HT1A receptors by the selective antagonist WAY-100635 (0.5 mg/kg) on these responses. Behavioral effects of these drug treatments were examined in parallel in an open-field test. Our results show that, in contrast to fluoxetine, vilazodone did not potentiate gene regulation induced by methylphenidate in the striatum, while vilazodone enhanced methylphenidate-induced locomotor activity. However, blocking 5-HT1A receptors by WAY-100635 unmasked a potentiating effect of vilazodone on methylphenidate-induced gene regulation, thus confirming an inhibitory role for 5-HT1A receptors. Our findings suggest that vilazodone may serve as an adjunct SSRI with diminished addiction facilitating properties and identify the 5-HT1A receptor as a potential therapeutic target to treat addiction.

Understanding Regional Patterns of Overdose Deaths Related to Opioids and Psychostimulants.

BACKGROUND: As overdose rates increase for multiple substances, policymakers need to identify geographic patterns of substance-specific deaths. In this study, we describe county-level opioid and psychostimulant overdose patterns and how they correlate with county-level social vulnerability measures. METHODS: A cross-sectional observational study, we used nationwide 2016-2018 restricted access Centers for Disease Prevention and Control county-level mortality files for 1,024 counties. We estimated quartiles of opioid and psychostimulant overdose mortality and provided estimates of their association with county-level Social Vulnerability Index (SVI) percentile. RESULTS: There was high opioid and psychostimulant overdose mortality in the Middle Atlantic, South Atlantic, East North Central, and Mountain regions. The Central US had the lowest opioid and psychostimulant overdose mortality rates. Counties with higher SVI scores (i.e. higher social vulnerability) were significantly more likely to experience high opioid and high psychostimulant overdose (high-high) mortality. A 10-percentile increase in SVI score was associated with a 3.1 percentage point increase in the likelihood of being a high-high county (p < 0.001) in unadjusted models and a 1.5 percentage point increase (p < 0.05) in models adjusting for region. CONCLUSION: Our results illustrated the heterogenous geographic distribution of the growing concurrent opioid and psychostimulant overdose crisis. The substantial regional variation we identified highlights the need for local data to guide policymaking and treatment planning. The association of opioid-psychostimulant overdose mortality with social vulnerability demonstrates the critical need in impacted counties for tailored treatment that addresses the complex medical and social needs of people who use both opioids and psychostimulants.

Dopamine, Norepinephrine and Serotonin Participate Differently in Methylphenidate Action in Concomitant Behavioral and Ventral Tegmental Area, Locus Coeruleus and Dorsal Raphe Neuronal Study in Young Rats.

Methylphenidate (MPD), known as Ritalin, is a psychostimulant used to treat children, adults, and the elderly. MPD exerts its effects through increasing concentrations of dopamine (DA), norepinephrine (NE), and serotonin (5-HT) in the synaptic cleft. Concomitant behavioral and neuronal recording from the ventral tegmental area (VTA), locus coeruleus (LC), and from the dorsal raphe (DR) nucleus, which are the sources of DA, NE, and 5-HT to the mesocorticolimbic circuit, were investigated following acute and repetitive (chronic) saline, 0.6, 2.5, or 10.0 mg/kg MPD. Animals received daily saline or MPD administration on experimental days 1 to 6 (ED1-6), followed by a 3-day washout period and MPD rechallenge on ED10. Each chronic MPD dose elicits behavioral sensitization in some animals while inducing behavioral tolerance in others. The uniqueness of this study is in the evaluation of neuronal activity based on the behavioral response to chronic MPD. Neuronal excitation was observed mainly in brain areas of animals exhibiting behavioral sensitization, while neuronal attenuation following chronic MPD was observed in animals expressing behavioral tolerance. Different ratios of excitatory/inhibitory neuronal responses were obtained from the VTA, LC, or DR following chronic MPD. Thus, each brain area responds differently to each MPD dose used, suggesting that DA, NE, and 5-HT in the VTA, LC, and DR exert different effects.

Effects of cannabidiol on reward contextual memories induced by cocaine in male and female mice.

OBJECTIVE: Preclinical studies suggest that cannabidiol (CBD), a non-intoxicating phytocannabinoid, may reduce addiction-related behaviours for various drug classes in rodents, including ethanol, opiates, and psychostimulants. CBD modulates contextual memories and responses to reward stimuli. Nonetheless, research on the impact of CBD on cocaine addiction-like behaviors is limited and requires further clarification. This study tested the hypothesis that CBD administration inhibits the acquisition and retrieval of cocaine-induced conditioned place preference (CPP) in adult male and female C57BL6/J mice. We also ought to characterise a 5-day CPP protocol in these animals. METHODS: Male and female C57BL/6J mice were administered CBD (3, 10, and 30 mg/kg) 30 minutes before cocaine (15 mg/kg) acquisition of expression of CPP. RESULTS: Cocaine induces a CPP in both female and male mice in the 5-day CPP protocol. CBD failed to prevent the acquisition or retrieval of place preference induced by cocaine. CBD did not decrease the time spent on the side paired with cocaine at any of the doses tested in male and female mice, in either acquisition or expression of contextual memory. CONCLUSION: This study found no support for the hypothesis that CBD decreases reward memory involved in the formation of cocaine addiction. Further research is necessary to investigate the involvement of CBD in other behavioural responses to cocaine and other psychostimulant drugs. This study, however, characterised a 5-day CPP protocol for both female and male C57BL/6J mice.

Effects of repeated binge intake of the pyrovalerone cathinone derivative 3,4-methylenedioxypyrovalerone on prefrontal cytokine levels in rats - a preliminary study.

Drugs of abuse activate neuroimmune signaling in addiction-related regions of the brain, including the prefrontal cortex (PFC) which mediates executive control, attention, and behavioral inhibition. Traditional psychostimulants including methamphetamine and cocaine are known to induce PFC inflammation, yet the effects of synthetic cathinone derivatives are largely unexplored. In this study, we examined the ability of repeated binge-like intake of the pyrovalerone cathinone derivative 3,4-methylenedioxypyrovalerone (MDPV) to alter cytokine profiles in the PFC. Male and female rats were allowed to intravenously self-administer MDPV (0.05 mg/kg/infusion) or saline as a control under conditions of prolonged binge-like access, consisting of three 96 h periods of drug access interspersed with 72 h of forced abstinence. Three weeks following cessation of drug availability, PFC cytokine levels were assessed using antibody arrays. Employing the unsupervised clustering and regression analysis tool CytoMod, a single module of co-signaling cytokines associated with MDPV intake regardless of sex was identified. With regards to specific cytokines, MDPV intake was positively associated with PFC levels of VCAM-1/CD106 and negatively associated with levels of Flt-3 ligand. These findings indicate that prolonged MDPV intake causes changes in PFC cytokine levels that persist into abstinence; however, the functional ramifications of these changes remain to be fully elucidated.

Immunotherapeutic treatment of inflammation in mice exposed to methamphetamine.

Introduction: Currently, there are no FDA-approved medications to treat methamphetamine addiction, including the inflammatory, neurotoxic, and adverse neuropsychiatric effects. We have shown that partial (p)MHC class II constructs (i.e., Recombinant T-cell receptor Ligand - RTL1000), comprised of the extracellular α1 and ß1 domains of MHC class II molecules linked covalently to myelin oligodendrocyte glycoprotein (MOG)-35-55 peptide, can address the neuroimmune effects of methamphetamine addiction through its ability to bind to and down-regulate CD74 expression, block macrophage migration inhibitory factor (MIF) signaling, and reduce levels of pro-inflammatory chemokine ligand 2 (CCL2). The present study evaluated the effects of our third-generation pMHC II construct, DRmQ, on cognitive function and concentration of inflammatory cytokines in the frontal cortex, a region critical for cognitive functions such as memory, impulse control, and problem solving. Methods: Female and male C57BL/6J mice were exposed to methamphetamine (or saline) via subcutaneous (s.c.) injections administered four times per day every other day for 14 days. Following methamphetamine exposure, mice received immunotherapy (DRmQ or ibudilast) or vehicle s.c. injections daily for five days. Cognitive function was assessed using the novel object recognition test (NORT). To evaluate the effects of immunotherapy on inflammation in the frontal cortex, multiplex immunoassays were conducted. ANOVA was used to compare exploration times on the NORT and immune factor concentrations. Results: Post hoc analysis revealed increased novel object exploration time in MA-DRmQ treated mice, as compared to MA-VEH treated mice (non-significant trend). One-way ANOVA detected a significant difference across the groups in the concentration of macrophage inflammatory protein-2 (MIP-2) (p = 0.03). Post hoc tests indicated that mice treated with methamphetamine and DRmQ or ibudilast had significantly lower levels of MIP-2 in frontal cortex, as compared to mice treated with methamphetamine and vehicle (p > 0.05). Discussion: By specifically targeting CD74, our DRQ constructs can block the signaling of MIF, inhibiting the downstream signaling and pro-inflammatory effects that contribute to and perpetuate methamphetamine addiction.

Psychostimulant Misuse Among American Indian, Alaskan Native, or Native Hawaiian College Students in the U.S. From 2015 to 2019.

Introduction: This study examines factors associated with psychostimulant misuse, including polysubstance use and social factors, among the understudied American Indian/Alaska Native/Native Hawaiian (AI/AN/NH) college student population. Methods: Data were from the 2015 to 2019 American College Health Association-National College Health Assessment IIc (ACHA-NCHA IIc) survey. Multivariable logistic regression models and odds ratios were used to estimate associations between psychostimulant misuse and potential risk and protective factors among AI/AN/NH college students, including licit and illicit substance use, social support, relationship factors, exposure to violence or abuse, mental health symptoms, drug and alcohol education, and sample demographics. Results: Opioid misuse among AI/AN/NH college students significantly increased the odds of using psychostimulants. Specifically, for cocaine use, the adjusted odds ratio (aOR) was 3.17 with a 95% confidence interval (C.I.) of 2.17 to 4.63; for methamphetamine use, the aOR was 38.87 (95% C.I. 19.24-78.52). For amphetamine misuse among non-Tobacco users, the aOR was 5.47 (95% C.I. 3.49-8.55), while among Tobacco users, the aOR was 2.65 (95% C.I. 2.07-3.41). For cocaine and other stimulant misuse, the aOR was 3.64 (95% C.I. 2.30-5.67). Additionally, the use of other types of licit and illicit substances was associated with greater odds of psychostimulant use and misuse. Conversely, factors such as age, living on campus, and residing in parental/guardian housing were linked with lower odds of psychostimulant use and misuse. Conclusion: Substance use prevention and treatment interventions targeting AI/AN/NH college students should address polysubstance use, including the combined use of opioids and psychostimulants. Substance use interventions should not be siloed to focus narrowly on single substances but rather should leverage potential protective factors against substance use, such as promoting supportive campus and family living conditions and other social support networks, in broad efforts to reduce multiple forms of substance use among AI/AN/NH students.