Cannabidiol attenuates methamphetamine-induced conditioned place preference in male rats and viability in PC12 cells through the Sigma1R/AKT/GSK3β/CREB signaling pathway

Xenon gas as a potential treatment for opioid use disorder, alcohol use disorder, and related disorders

Xenon gas is considered to be a safe anesthetic and imaging agent. Research on its other potentially beneficial effects suggests that xenon may have broad efficacy for treating health disorders. A number of reviews on xenon applications have been published, but none have focused on substance use disorders. Accordingly, we review xenon effects and targets relevant to the treatment of substance use disorders, with a focus on opioid use disorder and alcohol use disorder. We report that xenon inhaled at subsedative concentrations inhibits conditioned memory reconsolidation and opioid withdrawal symptoms. We review work by others reporting on the antidepressant, anxiolytic, and analgesic properties of xenon, which could diminish negative affective states and pain. We discuss research supporting the possibility that xenon could prevent analgesic- or stress-induced opioid tolerance and, by so doing could reduce the risk of developing opioid use disorder. The rapid kinetics, favorable safety and side effect profiles, and multitargeting capability of xenon suggest that it could be used as an ambulatory on-demand treatment to rapidly attenuate maladaptive memory, physical and affective withdrawal symptoms, and pain drivers of substance use disorders when they occur. Xenon may also have human immunodeficiency virus and oncology applications because its effects relevant to substance use disorders could be exploited to target human immunodeficiency virus reservoirs, human immunodeficiency virus protein-induced abnormalities, and cancers. Although xenon is expensive, low concentrations exert beneficial effects, and gas separation, recovery, and recycling advancements will lower xenon costs, increasing the economic feasibility of its therapeutic use. More research is needed to better understand the remarkable repertoire of effects of xenon and its potential therapeutic applications.

Pharmacological modulation of Sigma-1 receptor ameliorates pathological neuroinflammation in rats with diabetic neuropathic pain via the AKT/GSK-3β/NF-κB pathway

Diabetic neuropathic pain (DNP) is a common complication of diabetes mellitus (DM) and is characterized by spontaneous pain and neuroinflammation. The Sigma-1 receptor (Sig-1R) has been proposed as a target for analgesic development. It is an important receptor with anti-inflammatory properties and has been found to regulate DNP. However, it is not known whether Sig-1R can ameliorate pathological neuroinflammation in DNP. The present study used a rat model of DNP and a highly selective agonist of Sig-1R to assess the effects of the protein on neuropathic pain in rats with type 2 diabetes mellitus. The rats were divided into Control, Model, Sig-1R agonist PRE-084 (0.3, 0.6, 1 mg/kg), and metformin (Met, 20 mg/kg) groups, with seven rats per group, and their body weight, fasting blood glucose, mechanical withdrawal threshold and thermal withdrawal latency were tested weekly for two weeks. After treatment with PRE-084, the pain thresholds in the DNP rats were significantly improved, together with pathological changes in the dorsal root ganglion, reductions in the serum levels of TNF-α, IL-1β, IL-6, MOD, and prostaglandin E2 (PGE2), and the activity of superoxide dismutase was increased. The mRNA levels of TNF-α, IL-1β, and cyclooxygenase 2 (COX-2) were reduced. Pharmacological inhibition of Sig-1R with BD1047 (10 μM) abolished Sig-1R-mediated activation of lipopolysaccharide-treated BV-2 microglial cells. It was also found that PRE-084 increased phosphorylation of serine/threonine protein kinase B (AKT) and glycogen synthase kinase 3β (GSK-3β) at Ser9, inhibiting nuclear factor kappa B (NF-κB)-mediated neuroinflammation in the dorsal root ganglion, thus reducing DNP. The findings suggest that the effect of Sig-1R agonist PRE-084 on DNP may reduce the level of inflammation through the up-regulation of AKT/GSK-3β and down-regulation of the NF-κB signaling, thereby contributing to the treatment of the disease.

Pharmacological Treatments for Methamphetamine Use Disorder: Current Status and Future Targets

The illicit use of the psychostimulant methamphetamine (METH) is a major concern, with overdose deaths increasing substantially since the mid-2010s. One challenge to treating METH use disorder (MUD), as with other psychostimulant use disorders, is that there are no available pharmacotherapies that can reduce cravings and help individuals achieve abstinence. The purpose of the current review is to discuss the molecular targets that have been tested in assays measuring the physiological, the cognitive, and the reinforcing effects of METH in both animals and humans. Several drugs show promise as potential pharmacotherapies for MUD when tested in animals, but fail to produce long-term changes in METH use in dependent individuals (eg, modafinil, antipsychotic medications, baclofen). However, these drugs, plus medications like atomoxetine and varenicline, may be better served as treatments to ameliorate the psychotomimetic effects of METH or to reverse METH-induced cognitive deficits. Preclinical studies show that vesicular monoamine transporter 2 inhibitors, metabotropic glutamate receptor ligands, and trace amine-associated receptor agonists are efficacious in attenuating the reinforcing effects of METH; however, clinical studies are needed to determine if these drugs effectively treat MUD. In addition to screening these compounds in individuals with MUD, potential future directions include increased emphasis on sex differences in preclinical studies and utilization of pharmacogenetic approaches to determine if genetic variances are predictive of treatment outcomes. These future directions can help lead to better interventions for treating MUD.

Mechanisms and treatments of methamphetamine and HIV-1 co-induced neurotoxicity: a systematic review

Combination antiretroviral therapy (cART) has dramatically reduced mortality in people with human immunodeficiency virus (HIV), but it does not completely eradicate the virus from the brain. Patients with long-term HIV-1 infection often show neurocognitive impairment, which severely affects the quality of life of those infected. Methamphetamine (METH) users are at a significantly higher risk of contracting HIV-1 through behaviors such as engaging in high-risk sex or sharing needles, which can lead to transmission of the virus. In addition, HIV-1-infected individuals who abuse METH exhibit higher viral loads and more severe cognitive dysfunction, suggesting that METH exacerbates the neurotoxicity associated with HIV-1. Therefore, this review focuses on various mechanisms underlying METH and HIV-1 infection co-induced neurotoxicity and existing interventions targeting the sigma 1 receptor, dopamine transporter protein, and other relevant targets are explored. The findings of this review are envisaged to systematically establish a theoretical framework for METH abuse and HIV-1 infection co-induced neurotoxicity, and to suggest novel clinical treatment targets.

Nrf2 expression, mitochondrial fission, and neuronal apoptosis in the prefrontal cortex of methamphetamine abusers and rats

Methamphetamine (MA), a representative amphetamine-type stimulant, is one of the most abused drugs worldwide. Studies have shown that MA-induced neurotoxicity is strongly associated with oxidative stress and apoptosis. While nuclear factor E2-related factor 2 (Nrf2), an antioxidant transcription factor, is known to exert neuroprotective effects, its role in MA-induced dopaminergic neuronal apoptosis remains incompletely understood. In the present study, we explored the effects of MA on the expression levels of Nrf2, dynamin-related protein 1 (Drp1), mitofusin 1 (Mfn1), cytochrome c oxidase (Cyt-c), and cysteine aspartate-specific protease 3 (Caspase 3), as well as the correlations between Nrf2 and mitochondrial dynamics and apoptosis. Brain tissue from MA abusers was collected during autopsy procedures. An MA-dependent rat model was also established by intraperitoneal administration of MA (10 mg/kg daily) for 28 consecutive days, followed by conditioned place preference (CPP) testing. Based on immunohistochemical staining and western blot analysis, the protein expression levels of Nrf2 and Mfn1 showed a decreasing trend, while levels of Drp1, Cyt-c, and Caspase 3 showed an increasing trend in the cerebral prefrontal cortex of both MA abusers and MA-dependent rats. Notably, the expression of Nrf2 was positively associated with the expression of Mfn1, but negatively associated with the expression levels of Drp1, Cyt-c, and Caspase 3. These findings suggest that oxidative stress and mitochondrial fission contribute to neuronal apoptosis, with Nrf2 potentially playing a critical role in MA-induced neurotoxicity.

Cannabidiol and addiction

Cannabidiol (CBD) has been investigated for several therapeutic applications, having reached the clinics for the treatment of certain types of epilepsies. This chapter reviews the potential of CBD for the treatment of substance use disorders (SUD). We will present a brief introduction on SUD and current treatments. In the second part, preclinical and clinical studies with CBD are discussed, focusing on its potential therapeutic application for SUD. Next, we will consider the potential molecular mechanism of action of CBD in SUD. Finally, we will summarize the main findings and perspectives in this field. There is a lack of studies on CBD and SUD in comparison to the extensive literature investigating the use of this phytocannabinoid for other neurological and psychiatric disorders, such as epilepsy. However, the few studies available do suggest a promising role of CBD in the pharmacotherapy of SUD, particularly related to cocaine and other psychostimulant drugs.

Identification of the circRNA-miRNA-mRNA network for treating methamphetamine-induced relapse and behavioral sensitization with cannabidiol

AIMS

This study aims to investigate the pharmacological effects and the underlying mechanism of cannabidiol (CBD) on methamphetamine (METH)-induced relapse and behavioral sensitization in male mice.

METHODS

The conditioned place preference (CPP) test with a biased paradigm and open-field test were used to assess the effects of CBD on METH-induced relapse and behavioral sensitization in male mice. RNA sequencing and bioinformatics analysis was employed to identify differential expressed (DE) circRNAs, miRNAs, and mRNAs in the nucleus accumbens (NAc) of mice, and the interaction among them was predicted using competing endogenous RNAs (ceRNAs) network analysis.

RESULTS

Chronic administration of CBD (40 mg/kg) during the METH withdrawal phase alleviated METH (2 mg/kg)-induced CPP reinstatement and behavioral sensitization in mice, as well as mood and cognitive impairments following behavioral sensitization. Furthermore, 42 DEcircRNAs, 11 DEmiRNAs, and 40 DEmRNAs were identified in the NAc of mice. The circMeis2-miR-183-5p-Kcnj5 network in the NAc of mice is involved in the effects of CBD on METH-induced CPP reinstatement and behavioral sensitization.

CONCLUSIONS

This study constructed the ceRNAs network for the first time, revealing the potential mechanism of CBD in treating METH-induced CPP reinstatement and behavioral sensitization, thus advancing the application of CBD in METH use disorders.