Protective effect of melatonin against methamphetamine-induced attention deficits through miR-181/SIRT1 axis in the prefrontal cortex.

INTRODUCTION: Methamphetamine (METH) is an addictive psychostimulant with deleterious effects on the central nervous system. Chronic use of METH in high doses impairs cognition, attention and executive functions, but the underlying mechanisms are still unclear. Sirtuin 1 (SIRT1) is a post-translational regulator that is downregulated following METH neurotoxicity. Melatonin is a neuroprotective hormone that enhances mitochondrial metabolism. Here, we evaluated the effect of melatonin on METH-induced attention deficits disorder and the involvement of the miR-181/SIRT1 axis in melatonin neuroprotection. METHODS AND RESULTS: METH at a dose of 5 mg/kg was injected for 21 consecutive days. The animals were assigned to receive either melatonin or the vehicle after METH injections. Attention levels were evaluated with abject-based attention test. In the prefrontal cortex, the expression levels of miR-181a-5p, SIRT1, p53 and CCAR2, as well as the mtDNA copy numbers were evaluated using qRT-PCR and western blotting. The outcomes revealed that melatonin treatment following METH injections improved METH-induced attention deficits. METH toxicity can be associated with changes in the miR-181/SIRT1 axis, elevated levels of p53 and COXII, and decreased levels of mtDNA in the prefrontal cortex of adult rats. Interestingly, administration of melatonin can improve the expression of these molecules and reduces the toxic effects of METH. CONCLUSION: Melatonin ameliorated the neurotoxicity of METH in the prefrontal cortex and the miR-181/SIRT1 axis is involve in the protective effects of melatonin. However, melatonin can be potentially administrated to improve attention impairment in METH use disorders.

Distinct eLPBChAT projections for methamphetamine withdrawal anxiety and primed reinstatement of conditioned place preference.

Methamphetamine (METH) withdrawal anxiety symptom and relapse have been significant challenges for clinical practice, however, the underlying neuronal basis remains unclear. Our recent research has identified a specific subpopulation of choline acetyltransferase (ChAT+) neurons localized in the external lateral portion of parabrachial nucleus (eLPBChAT), which modulates METH primed-reinstatement of conditioned place preference (CPP). Here, the anatomical structures and functional roles of eLPBChAT projections in METH withdrawal anxiety and primed reinstatement were further explored. Methods: In the present study, a multifaceted approach was employed to dissect the LPBChAT+ projections in male mice, including anterograde and retrograde tracing, acetylcholine (Ach) indicator combined with fiber photometry recording, photogenetic and chemogenetic regulation, as well as electrophysiological recording. METH withdrawal anxiety-like behaviors and METH-primed reinstatement of conditioned place preference (CPP) were assessed in male mice. Results: We identified that eLPBChAT send projections to PKCδ-positive (PKCδ+) neurons in lateral portion of central nucleus of amygdala (lCeAPKCδ) and oval portion of bed nucleus of the stria terminalis (ovBNSTPKCδ), forming eLPBChAT-lCeAPKCδ and eLPBChAT-ovBNSTPKCδ pathways. At least in part, the eLPBChAT neurons positively innervate lCeAPKCδ neurons and ovBNSTPKCδ neurons through regulating synaptic elements of presynaptic Ach release and postsynaptic nicotinic acetylcholine receptors (nAChRs). METH withdrawal anxiety and METH-primed reinstatement of CPP respectively recruit eLPBChAT-lCeAPKCδ pathway and eLPBChAT-ovBNSTPKCδ pathway in male mice. Conclusion: Our findings put new insights into the complex neural networks, especially focusing on the eLPBChAT projections. The eLPBChAT is a critical node in the neural networks governing METH withdrawal anxiety and primed-reinstatement of CPP through its projections to the lCeAPKCδ and ovBNSTPKCδ, respectively.

Innovation and adaptation: The rise of a fentanyl smoking culture in San Francisco.

BACKGROUND: Illicitly manufactured fentanyls and stimulants are implicated in the escalating US mortality from drug overdose. San Francisco, California (SF) has seen declining fentanyl injection while smoking has increased. Beliefs and behaviors surrounding this development are not well understood. METHODS: The study used rapid ethnography to explore fentanyl and methamphetamine use in SF. The team conducted semi-structured interviews (n = 34) with participants recruited from syringe service programs. Video-recorded smoking sequences (n = 12), photography and daily field notes supplemented interview data. RESULTS: Difficulty injecting and fear of overdose motivated transitions from injecting to smoking. Fentanyl was extremely cheap-$10/gram-with variability in quality. Foil was the most commonly used smoking material but glass bubbles, bongs and dabbing devices were also popular. No reliable visible methods for determining fentanyl quality existed, however, participants could gauge potency upon inhalation, and developed techniques to regulate dosage. Several participants reported at least hourly use, some reporting one or more grams of daily fentanyl consumption. Smoking was also very social, with people sharing equipment, drugs and information. Participants raised concerns about hygiene and overdose risk to others arising from shared equipment. Reportedly potent fentanyl 'residue' accumulated on smoking materials and was commonly shared/traded/stolen or consumed accidentally with diverse preferences for its use. CONCLUSION: Our data highlight fentanyl residue as a new overdose risk with potential mismatch between the potency of the residual drug and the recipient's tolerance. Further, large doses of fentanyl are being consumed (estimated at approximately 50 mg of pure fentanyl/day). Smoking fentanyl has potential health benefits over injecting and may be protective against overdose, but substantial uncertainty exists. However, SF overdose mortality hit a record high in 2023. Recommendations to reduce fentanyl smoking overdose risks through pacing, greater awareness of dosages consumed and checking tolerance of residue recipients are potentially viable interventions deserving further exploration.

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.

Changes in injecting versus smoking heroin, fentanyl, and methamphetamine among people who inject drugs in San Diego, California, 2020-2023.

BACKGROUND: Amidst an increasingly toxic drug supply in North America, people who inject drugs may be transitioning to smoking them. We aimed to assess changes in injecting and smoking opioids and methamphetamine among a cohort of people who inject drugs from San Diego, California. METHODS: Over five six-month periods spanning October 2020-April 2023, we assessed prevalence of injecting and smoking opioids or methamphetamine and whether participants used these drugs more frequently by smoking than injecting. Multivariable Poisson regression via generalized estimating equations was used to examine time trends. RESULTS: Of 362 participants, median age was 40 years; a minority were female (29%), Hispanic/Latinx/Mexican (45%), and housed (33%). Among this cohort, of whom 100% injected (and 84% injected and smoked) in period one (October 2020-April 2021), by period five (November 2022-April 2023), 34% only smoked, 59% injected and smoked, and 7% only injected. By period five, the adjusted relative risk (aRR) of injecting opioids was 0.41 (95% Confidence Interval [CI]: 0.33, 0.51) and the aRR for injecting methamphetamine was 0.50 (95% CI: 0.39, 0.63) compared to period one. Risks for smoking fentanyl rose significantly during period three (aRR=1.44, 95% CI: 1.06, 1.94), four (aRR=1.65, 95% CI: 1.24, 2.20) and five (aRR=1.90, 95% CI: 1.43, 2.53) compared to period one. Risks for smoking heroin and methamphetamine more frequently than injecting these drugs increased across all periods. CONCLUSIONS: Opioid and methamphetamine injection declined precipitously, with notable increases in smoking these drugs. Research is needed to understand the health consequences of these trends.

Mesenchymal stem cell-derived exosomes improve neurogenesis and cognitive function of mice with methamphetamine addiction: A novel treatment approach.

BACKGROUND: Methamphetamine (METH) is a psychostimulant substance with highly addictive and neurotoxic effects, but no ideal treatment option exists to improve METH-induced neurocognitive deficits. Recently, mesenchymal stem cells (MSCs)-derived exosomes have raised many hopes for treating neurodegenerative sequela of brain disorders. This study aimed to determine the therapeutic potential of MSCs-derived exosomes on cognitive function and neurogenesis of METH-addicted rodents. METHODS: Male BALB/c mice were subjected to chronic METH addiction, followed by intravenous administration of bone marrow MSCs-derived exosomes. Then, the spatial memory and recognition memory of animals were assessed by the Barnes maze and the novel object recognition test (NORT). The neurogenesis-related factors, including NeuN and DCX, and the expression of Iba-1, a microglial activation marker, were assessed in the hippocampus by immunofluorescence staining. Also, the expression of inflammatory cytokines, including TNF-α and NF-κB, were evaluated by western blotting. RESULTS: The results showed that BMSCs-exosomes improved the time spent in the target quadrant and correct-to-wrong relative time in the Barnes maze. Also, NORT's discrimination index (DI) and recognition index (RI) were improved following exosome therapy. Additionally, exosome therapy significantly increased the expression of NeuN and DCX in the hippocampus while decreasing the expression of inflammatory cytokines, including TNF-α and NF-κB. Besides, BMSC-exosomes down-regulated the expression of Iba-1. CONCLUSION: Our findings indicate that BMSC-exosomes mitigated METH-caused cognitive dysfunction by improving neurogenesis and inhibiting neuroinflammation in the hippocampus.

High frequency deep brain stimulation of the dorsal raphe nucleus prevents methamphetamine priming-induced reinstatement of drug seeking in rats.

Drug addiction represents a multifaceted and recurrent brain disorder that possesses the capability to create persistent and ineradicable pathological memory. Deep brain stimulation (DBS) has shown a therapeutic potential for neuropsychological disorders, while the precise stimulation targets and therapeutic parameters for addiction remain deficient. Among the crucial brain regions implicated in drug addiction, the dorsal raphe nucleus (DRN) has been found to exert an essential role in the manifestation of addiction memory. Thus, we investigated the effects of DRN DBS in the treatment of addiction and whether it might produce side effects by a series of behavioral assessments, including methamphetamine priming-induced reinstatement of drug seeking behaviors, food-induced conditioned place preference (CPP), open field test and elevated plus-maze test, and examined brain activity and connectivity after DBS of DRN. We found that high-frequency DBS of the DRN significantly lowered the CPP scores and the number of active-nosepokes in the methamphetamine-primed CPP test and the self-administration model. Moreover, both high-frequency and sham DBS group rats were able to establish significant food-induced place preference, and no significant difference was observed in the open field test and in the elevated plus-maze test between the two groups. Immunofluorescence staining and functional magnetic resonance imaging revealed that high-frequency DBS of the DRN could alter the activity and functional connectivity of brain regions related to addiction. These results indicate that high-frequency DBS of the DRN effectively inhibits methamphetamine priming-induced relapse and seeking behaviors in rats and provides a new target for the treatment of drug addiction.

Hereditary and cortical morphological biomarker of sensitivity to reward in short-term withdrawal methamphetamine abusers.

Higher sensitivity to reward (SR) and weaker sensitivity to punishment (SP) construct the fundamental craving characteristics of methamphetamine abuse. However, few studies have appraised relationships between SR/SP (SR or SP) and cortical morphological alterations in methamphetamine abusers and whether hereditary factors take effects on SR/SP is unclear. Based on surface-based morphometric analysis, cortical discrepancy was investigated between 38 methamphetamine abusers and 37 healthy controls. Within methamphetamine abusers, correlation profiling was performed to discover associations among aberrant neuroimaging substrates, SR, SP, and craving. According to nine single nucleotide polymorphism sites of dopamine-related genes, we conducted univariate general linear model to find different effects of genotypes on cortical alterations and SR/SP/craving (SR, SP, or craving). Ultimately, mediation analyses were conducted among single nucleotide polymorphism sites, SR/SP/craving, and cortical morphological alterations to discover their association pathways. Compared to healthy controls, thinner cortices in inferior temporal gyrus, lateral orbitofrontal cortex, medial orbitofrontal cortex, inferior parietal lobule, and lateral occipital cortex in the left hemisphere were found in methamphetamine abusers (P < 0.05, family-wise error corrected). Cortical thickness in the inferior temporal gyrus was negatively correlated with SR scores. We found that rs1800497 A-containing genotypes had lower cortical thickness in the left inferior parietal lobule than the GG genotype. The rs5751876 had effects on SR scores. This study would provide convincing biomarkers for SR in methamphetamine abusers and offer potential genetic targets for personalizing relapse prevention.

An Investigation into the Prevalence of Methamphetamine Related Enquiries to Local Government Environmental Health Officers.

Methamphetamine contamination of residential properties remains a serious public health concern for members of the public. External stakeholders including Environmental Health Officers (EHOs) and testing and remediation technicians are engaged on investigating whether contamination has occurred from manufacturing or smoking processes. More specifically, local council EHOs are responsible for managing clandestine drug laboratories when notified by police and also for responding to public enquiries. However, the full scope of these contaminated properties is not seen by any single stakeholder, making it very challenging to quantify these situations. To evaluate the prevalence of methamphetamine related enquiries from the general public to EHOs, this study surveyed and interviewed officers from around Australia. It was found that public enquiries were infrequent with only 6% of respondents having received enquiries in the last month, which indicates that people are seeking information from other sources. Interestingly, there were case study scenarios that also mentioned issues with awareness and the flow of information. Concerns regarding difficult cases, police notifications, and site visits were also highlighted. The results of this study provide a benchmark of how methamphetamine related cases are managed and highlight the need for trustworthy information that is available to EHOs, governments, industry members, and the public in a unified location.

Combining brief recall and ketamine treatment prevents stress-primed methamphetamine memory reinstatement via heightening mPFC GABA activity.

This study aimed to assess whether brief recall of methamphetamine (MA) memory, when combined with ketamine (KE) treatment, may prevent stress-primed MA memory reinstatement. Combining 3-min recall and KE facilitated MA memory extinction and resistance to subsequent stress-primed reinstatement. Such combination also produced glutamate metabotropic receptor 5 (mGluR5) upregulation in animals' medial prefrontal cortex (mPFC) γ-amino-butyric acid (GABA) neuron. Accordingly, chemogenetic methods were employed to bi-directionally modulate mPFC GABA activity. Following brief recall and KE-produced MA memory extinction, intra-mPFC mDlx-Gi-coupled-human-muscarinic-receptor 4 (hM4Di)-infused mice receiving compound 21 (C21) treatment showed eminent stress-primed reinstatement, while their GABA mGluR5 expression seemed to be unaltered. Intra-mPFC mDlx-Gq-coupled-human-muscarinic-receptor 3 (hM3Dq)-infused mice undergoing C21 treatment displayed MA memory extinction and resistance to stress-provoked reinstatement. These results suggest that combining a brief recall and KE treatment and exciting mPFC GABA neuron may facilitate MA memory extinction and resistance to stress-primed recall. mPFC GABA neuronal activity plays a role in mediating brief recall/KE-produced effects on curbing the stress-provoked MA seeking.

Motivation and context of concurrent stimulant and opioid use among persons who use drugs in the rural United States: a multi-site qualitative inquiry.

BACKGROUND: In recent years, stimulant use has increased among persons who use opioids in the rural U.S., leading to high rates of overdose and death. We sought to understand motivations and contexts for stimulant use among persons who use opioids in a large, geographically diverse sample of persons who use drugs (PWUD) in the rural settings. METHODS: We conducted semi-structured individual interviews with PWUD at 8 U.S. sites spanning 10 states and 65 counties. Content areas included general substance use, injection drug use, changes in drug use, and harm reduction practices. We used an iterative open-coding process to comprehensively itemize and categorize content shared by participants related to concurrent use. RESULTS: We interviewed 349 PWUD (64% male, mean age 36). Of those discussing current use of stimulants in the context of opioid use (n = 137, 39%), the stimulant most used was methamphetamine (78%) followed by cocaine/crack (26%). Motivations for co-use included: 1) change in drug markets and cost considerations; 2) recreational goals, e.g., seeking stronger effects after heightened opioid tolerance; 3) practical goals, such as a desire to balance or alleviate the effects of the other drug, including the use of stimulants to avoid/reverse opioid overdose, and/or control symptoms of opioid withdrawal; and 4) functional goals, such as being simultaneously energized and pain-free in order to remain productive for employment. CONCLUSION: In a rural U.S. cohort of PWUD, use of both stimulants and opioids was highly prevalent. Reasons for dual use found in the rural context compared to urban studies included changes in drug availability, functional/productivity goals, and the use of methamphetamine to offset opioid overdose. Education efforts and harm reduction services and treatment, such as access to naloxone, fentanyl test strips, and accessible drug treatment for combined opioid and stimulant use, are urgently needed in the rural U.S. to reduce overdose and other adverse outcomes.

Point-of-care testing of methamphetamine and cocaine utilizing wearable sensors.

The imperative for the point-of-care testing of methamphetamine and cocaine in drug abuse prevention necessitates innovative solutions. To address this need, we have introduced a multi-channel wearable sensor harnessing CRISPR/Cas12a system. A CRISPR/Cas12a based system, integrated with aptamers specific to methamphetamine and cocaine, has been engineered. These aptamers function as signal-mediated intermediaries, converting methamphetamine and cocaine into nucleic acid signals, subsequently generating single-stranded DNA to activate the Cas12 protein. Additionally, we have integrated a microfluidic system and magnetic separation technology into the CRISPR system, enabling rapid and precise detection of cocaine and methamphetamine. The proposed sensing platform demonstrated exceptional sensitivity, achieving a detection limit as low as 0.1 ng/mL. This sensor is expected to be used for on-site drug detection in the future.

Neonatal brain inflammation enhances methamphetamine-induced reinstated behavioral sensitization in adult rats analyzed with explainable machine learning.

Neonatal brain inflammation produced by intraperitoneal (i.p.) injection of lipopolysaccharide (LPS) results in long-lasting brain dopaminergic injury and motor disturbances in adult rats. The goal of the present work is to investigate the effect of neonatal systemic LPS exposure (1 or 2 mg/kg, i.p. injection in postnatal day 5, P5, male rats)-induced dopaminergic injury to examine methamphetamine (METH)-induced behavioral sensitization as an indicator of drug addiction. On P70, subjects underwent a treatment schedule of 5 once daily subcutaneous (s.c.) administrations of METH (0.5 mg/kg) (P70-P74) to induce behavioral sensitization. Ninety-six hours following the 5th treatment of METH (P78), the rats received one dose of 0.5 mg/kg METH (s.c.) to reintroduce behavioral sensitization. Hyperlocomotion is a critical index caused by drug abuse, and METH administration has been shown to produce remarkable locomotor-enhancing effects. Therefore, a random forest model was used as the detector to extract the feature interaction patterns among the collected high-dimensional locomotor data. Our approaches identified neonatal systemic LPS exposure dose and METH-treated dates as features significantly associated with METH-induced behavioral sensitization, reinstated behavioral sensitization, and perinatal inflammation in this experimental model of drug addiction. Overall, the analysis suggests that the implementation of machine learning strategies is sensitive enough to detect interaction patterns in locomotor activity. Neonatal LPS exposure also enhanced METH-induced reduction of dopamine transporter expression and [3H]dopamine uptake, reduced mitochondrial complex I activity, and elevated interleukin-1ß and cyclooxygenase-2 concentrations in the P78 rat striatum. These results indicate that neonatal systemic LPS exposure produces a persistent dopaminergic lesion leading to a long-lasting change in the brain reward system as indicated by the enhanced METH-induced behavioral sensitization and reinstated behavioral sensitization later in life. These findings indicate that early-life brain inflammation may enhance susceptibility to drug addiction development later in life, which provides new insights for developing potential therapeutic treatments for drug addiction.

Chiral analysis of amphetamine, methamphetamine, MDMA and MDA enantiomers in human hair samples.

A novel analytical method was developed for the simultaneous quantification of the R/S-enantiomers of amphetamine, methamphetamine, MDA and MDMA in hair samples using liquid chromatography-tandem mass spectrometry (LC-MS-MS). This method involved a straightforward derivatization step with dansyl chloride and the use of a chiral column, enabling the separation and quantification of all eight enantiomers in a single analysis. The method exhibited excellent linearity across a concentration range of 0.03-3.00 ng/mg for each enantiomer. Precision and accuracy were within acceptable limits, with bias and relative standard deviation (RSD) values consistently below 6% and 9%, respectively. Selectivity and specificity assessments confirmed the absence of any interference from contaminants or co-extracted drugs. The method demonstrated high sensitivity, with limits of detection (LOD) below 8 pg/mg and limits of quantification (LOQ) below 19 pg/mg for all analytes. Extraction recovery exceeded 79%, and matrix effects were minimal for all analytes. Processed sample stability evaluations revealed consistent results with deviations below 11% for all analytes. Application of the method to 32 authentic human hair samples provided valuable insights into amphetamine use patterns, allowing differentiation between medical amphetamine consumption and illicit use based on enantiomeric composition. Additionally, the method detected co-use of methamphetamine, MDA or MDMA in some samples, highlighting its applicability in drug monitoring and real-life case scenarios within a forensic institute. This innovative analytical approach offers a sensitive and selective method for enantiomeric differentiation of amphetamine, methamphetamine, MDA and MDMA in human hair samples, providing a valuable tool for forensic and clinical investigations.

Co-administration of naloxone and dexmedetomidine to simultaneously reverse acute effects of fentanyl and methamphetamine in rats.

BACKGROUND: The incidence of combination methamphetamine (METH)-opioid overdose has substantially increased in recent years. While agitation is uncommon after the naloxone (NLX) reversal of opioids, it is a major clinical concern in acute METH intoxication and can be physiologically antagonized by opioid-induced sedation. This study aimed to perform initial preclinical analysis of the safety and efficacy of dexmedetomidine (DEXMED) co-administered with NLX to attenuate METH-induced locomotor activity, as a rat model of agitation, after the reversal of fentanyl (FENT)-induced sedation. METHODS: Male Sprague Dawley rats were administered subcutaneous (SC) 0.1mg/kg FENT ± 1mg/kg METH. Fifteen min later, SC 0.1mg/kg NLX ± an increasing (0, 0.032, 0.056, and 0.1mg/kg) DEXMED dose was administered prior to the measurement of locomotor activity. After a washout period, the FENT ± METH and NLX ± DEXMED administration with the highest dose of DEXMED was administered for measurement of blood oxygen saturation and heart rate. RESULTS: After the NLX reversal of FENT-induced sedation, adjunct DEXMED substantially and significantly reduced METH-induced locomotor activity (p<0.05) at all doses tested. While the addition of DEXMED did not significantly reduce blood oxygenation in METH treated rats, it did so in the absence of METH. Also, DEXMED significantly reduced heart rate compared to non-DEXMED treated groups and resulted in further significant reductions in the animals not exposed to METH (p<0.05). CONCLUSIONS: These data provide preclinical evidence that DEXMED may be a safe and effective chemical restraint for METH-induced agitation after NLX opioid reversal.

Effects of methamphetamine on actigraphy-based sleep parameters in female rhesus monkeys: Orexin receptor mechanisms.

BACKGROUND: The orexin system has been implicated as a mechanism underlying insomnia and methamphetamine-induced sleep disruptions, with a potential role for OX2 receptors in the sleep-modulating effects of orexin. The aim of the present study was to investigate the extent to which orexin receptors mediate the effects of acute methamphetamine administration on actigraphy-based sleep in female rhesus monkeys. METHODS: Actigraphy-based sleep measures were obtained in female rhesus monkeys (n=5) under baseline and acute test conditions. First, morning (10h) i.m. injections of methamphetamine (0.03 - 0.56mg/kg) were administered to determine the effects of methamphetamine alone. Then, saline or methamphetamine (0.3mg/kg) were administered at 10h, and evening (17h30) oral treatments with vehicle, the non-selective orexin receptor antagonist suvorexant (1 - 10mg/kg, p.o.), or the OX2-selective orexin receptor antagonist MK-1064 (1 - 10mg/kg, p.o.) were given. The ability of suvorexant and MK-1064 (10mg/kg, p.o.) to improve actigraphy-based sleep was also assessed in a group of female monkeys quantitatively identified with "short-duration sleep" (n=4). RESULTS: Methamphetamine dose-dependently disrupted actigraphy-based sleep parameters. Treatment with either suvorexant or MK-1064 dose-dependently improved actigraphy-based sleep in monkeys treated with methamphetamine. Additionally, both suvorexant and MK-1064 promoted actigraphy-based sleep in a group of monkeys with baseline short actigraphy-based sleep. CONCLUSIONS: These findings suggest that orexin-mediated mechanisms play a role in the effects of methamphetamine on actigraphy-based sleep in female monkeys. Targeting the orexin system, in particular OX2 receptors, could be an effective option for treating sleep disruptions observed in individuals with methamphetamine use disorder.

"Everything is kind of the same except my mind is with me": exploring cannabis substitution in a sample of adults in early recovery from an opioid or stimulant addiction.

BACKGROUND: Recovery from addiction is frequently equated with abstinence. However, some individuals who resolve an addiction continue to use substances, including via substitution (i.e., increased use of one substance after eliminating/ reducing another). Substitution may play a distinct role during early recovery (≤ 1 year), as this period is marked by dramatic change and adjustment. Cannabis is one of the most used substances and is legal for medical and recreational use in an increasing number of states. Consequently, cannabis an increasingly accessible substitute for substances, like fentanyl, heroin, cocaine and methamphetamine, with higher risk profiles (e.g., associated with risk for withdrawal, overdose, and incarceration). METHODS: Fourteen participants reported that they had resolved a primary opioid or stimulant addiction and subsequently increased their cannabis use within the previous 12 months. Using grounded theory, the interviewer explored their experiences of cannabis use during early recovery. Data were analyzed in three stages: line by line coding for all text related to cannabis use and recovery, focused coding, and axial coding to generate a theory about recovery with cannabis substitution. The motivational model of substance use provided sensitizing concepts. RESULTS & DISCUSSION: The final sample included eight men and six women ranging in age from 20 to 50 years old. Three participants resolved an addiction to methamphetamine and the remaining 11, an addiction to opioids. Participants explained that cannabis was appealing because of its less harmful profile (e.g., no overdose risk, safe supply, few side effects). Participants' primary motives for cannabis use included mitigation of psychiatric symptoms, withdrawal/ cravings, and boredom. While cannabis was effective toward these ends, participants also reported some negative side effects (e.g., decreased productivity, social anxiety). All participants described typical benefits of recovery (e.g., improved self-concept, better relationships) while continuing to use cannabis. Their experiences with and beliefs about substitution suggest it can be an effective strategy for some individuals during early recovery. CONCLUSIONS: Cannabis use may benefit some adults who are reducing their opioid or stimulant use, especially during early recovery. The addiction field's focus on abstinence has limited our knowledge about non-abstinent recovery. Longitudinal studies are needed to understand the nature of substitution and its impact on recovery over time.

Alterations in the fecal microbiota of methamphetamine users with bad sleep quality during abstinence.

BACKGROUND: Methamphetamine (MA) abuse has resulted in a plethora of social issues. Sleep disturbance is a prominent issue about MA addiction, which serve as a risk factor for relapse, and the gut microbiota could play an important role in the pathophysiological mechanisms of sleep disturbances. Therefore, improving sleep quality can be beneficial for treating methamphetamine addiction, and interventions addressing the gut microbiota may represent a promising approach. METHOD: We recruited 70 MA users to investigate the associations between sleep quality and fecal microbiota by the Pittsburgh Sleep Quality Index (PSQI), which was divided into MA-GS (PSQI score < 7, MA users with good sleep quality, n = 49) and MA-BS group (PSQI score ≥ 7, MA users with bad sleep quality, n = 21). In addition, we compared the gut microbiota between the MA-GS and healthy control (HC, n = 38) groups. 16S rRNA sequencing was applied to identify the gut bacteria. RESULT: The study revealed that the relative abundances of the Thermoanaerobacterales at the order level differed between the MA-GS and MA-BS groups. Additionally, a positive correlation was found between the relative abundance of the genus Sutterella and daytime dysfunction. Furthermore, comparisons between MA users and HCs revealed differences in beta diversity and relative abundances of various bacterial taxa. CONCLUSION: In conclusion, the study investigated alterations in the gut microbiota among MA users. Furthermore, we demonstrated that the genus Sutterella changes may be associated with daytime dysfunction, suggesting that the genus Sutterella may be a biomarker for bad sleep quality in MA users.

Moderate Salinity Stress Affects Rice Quality by Influencing Expression of Amylose- and Protein-Content-Associated Genes.

Salinity is an environmental stress that severely impacts rice grain yield and quality. However, limited information is available on the molecular mechanism by which salinity reduces grain quality. In this study, we investigated the milling, appearance, eating and cooking, and nutritional quality among three japonica rice cultivars grown either under moderate salinity with an electrical conductivity of 4 dS/m or under non-saline conditions in a paddy field in Dongying, Shandong, China. Moderate salinity affected rice appearance quality predominantly by increasing chalkiness rate and chalkiness degree and affected rice eating and cooking and nutritional quality predominantly by decreasing amylose content and increasing protein content. We compared the expression levels of genes determining grain chalkiness, amylose content, and protein content in developing seeds (0, 5, 10, 15, and 20 days after flowering) of plants grown under saline or non-saline conditions. The chalkiness-related gene Chalk5 was up-regulated and WHITE-CORE RATE 1 was repressed. The genes Nuclear factor Y and Wx, which determine amylose content, were downregulated, while protein-content-associated genes OsAAP6 and OsGluA2 were upregulated by salinity in the developing seeds. These findings suggest some target genes that may be utilized to improve the grain quality under salinity stress conditions via gene-pyramiding breeding approaches.