Addiction Biology最新文献

Heinz et al. (2024) recently criticised habit/compulsion theory of human addiction but nevertheless concluded that ‘habit formation plays a significant role in drug addiction’. To challenge this causal claim, the current article develops four further methodological criticisms, that publications supporting the habit/compulsion account of human addiction: (1) under-report contradictory observations; (2) exaggerate the process purity of positive observations; (3) under-emphasise the low quality of epidemiological support for a causal hypothesis; (4) recapitulate the social injustice of racial intelligence era by prematurely attributing lower task performance to drug user group membership (endophenotype) without having adequately tested social, psychological, economic and environmental inequalities. Methodological guidelines are recommended to address each concern, which should raise evidence standards, incorporate social justice and improve accuracy of estimating any specific effect of addiction history on task performance. Given that construing drug users as intellectually impaired could promote stigma and reduce their recovery potential, it is recommended that scientific discourse about habit/compulsive endophenotypes underpinning addiction is avoided until these higher evidence standards are met.

Murillo Gonzalez, DJ, Hernandez Granados, BA, Sabandal, PR, Han, K-A. Social setting interacts with hyper dopamine to boost the stimulant effect of ethanol. Addiction Biology. 2024; 29(6):e13420, doi:10.1111/adb.13420.

The footnote, “Dilean J. Murillo Gonzalez and Bryan A. Hernandez Granados contributed equally to this work”, is incorrect and should be removed. Dilean J. Murillo Gonzalez is the sole first author.

There are three institutions listed in the affiliations, which is incorrect. All works reported in the paper were done entirely at the “Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX, USA”. The other institutions are the authors' present addresses as noted below.

D.M.G.’s present address: Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA.

B.H.G.’s present address: Department of Biochemistry, Vanderbilt University, Nashville, TN, USA.

We apologize for these errors.

Approximately 50 million Americans suffer from chronic pain, and nearly a quarter of chronic pain patients have reported misusing opioid prescriptions. Repeated drug seeking is associated with reactivation of an ensemble of neurons sparsely scattered throughout the dorsomedial prefrontal cortex (dmPFC). Prior research has demonstrated that chronic pain increases intrinsic excitability of dmPFC neurons, which may increase the likelihood of reactivation during drug seeking. We tested the hypothesis that chronic pain would increase oxycodone-seeking behaviour and that the pain state would differentially increase intrinsic excitability in dmPFC drug-seeking ensemble neurons. TetTag mice self-administered intravenous oxycodone. After 7 days of forced abstinence, a drug-seeking session was performed, and the ensemble was tagged. Mice received spared nerve injury (SNI) to induce chronic pain during the period between the first and second seeking session. Following the second seeking session, we performed electrophysiology on individual neurons within the dmPFC to assess intrinsic excitability of the drug-seeking ensemble and non-ensemble neurons. SNI had no impact on sucrose seeking or intrinsic excitability of dmPFC neurons from these mice. In females, SNI increased oxycodone seeking and intrinsic excitability of non-ensemble neurons. In males, SNI had no impact on oxycodone seeking or neuron excitability. Data from females are consistent with clinical reports that chronic pain can promote drug craving and relapse and support the hypothesis that chronic pain itself may lead to neuroadaptations which promote opioid seeking.

While previous research has shown that compulsivity is related to an imbalance between goal-directed and habitual learning systems, very little is known about whether this effect is due to the impairment of a single system or the impairment of the arbitration mechanism that determines which system controls behaviour at any given moment; the current study aims to address this disagreement. Nineteen alcohol use disorder, 30 obsessive-compulsive disorder (OCD) and 20 major depressive disorder patients and corresponding sex- and age-matched controls performed two-choice, three-stage Markov decision-making paradigm. Model-based and mode-free reinforcement learning models were used to independently fitted their behavioural data. Alcohol use disorder and OCD patients showed less model-based strategy choice than healthy controls in task conditions where the model-based strategy was optimal. Only OCD patients showed higher behavioural control system switching in task conditions where model-free use was optimal. Major depressive disorder patients did not differ from the matched control in both. These findings suggest that dysfunction in arbitration control between dual systems may be the basis for diverse disorders involving compulsivity.

The endocannabinoid system interacts with the reward system to modulate responsiveness to natural reinforcers, as well as drugs of abuse. Previous preclinical studies suggested that direct blockade of CB1 cannabinoid receptors (CB1R) could be leveraged as a potential pharmacological approach to treat substance use disorder, but this strategy failed during clinical trials due to severe psychiatric side effects. Alternative strategies have emerged to circumvent the side effects of direct CB1 binding through the development of allosteric modulators. We hypothesized that negative allosteric modulation of CB1R signalling would reduce the reinforcing properties of morphine and decrease behaviours associated with opioid misuse. By employing intravenous self-administration in mice, we studied the effects of GAT358, a functionally-biased CB1R negative allosteric modulator (NAM), on morphine intake, relapse-like behaviour and motivation to work for morphine infusions. GAT358 reduced morphine infusion intake during the maintenance phase of morphine self-administration under a fixed ratio 1 schedule of reinforcement. GAT358 also decreased morphine-seeking behaviour after forced abstinence. Moreover, GAT358 dose dependently decreased the motivation to obtain morphine infusions under a progressive ratio schedule of reinforcement. Strikingly, GAT358 did not affect the motivation to work for food rewards in an identical progressive ratio task, suggesting that the effect of GAT358 in decreasing opioid self-administration was reward specific. Furthermore, GAT58 did not produce motor ataxia in the rotarod test. Our results suggest that CB1R NAMs reduced the reinforcing properties of morphine and could represent a viable therapeutic route to safely decrease misuse of opioids.

Inflammation appears to be a critical mechanism in the development of alcohol use disorder (AUD) and a consequence of chronic alcohol use. The potential anti-inflammatory properties of cannabis may modulate the proinflammatory effects of alcohol. This study sought to extend previous work investigating the relationship between alcohol consumption, cannabis use and circulating interleukin (IL)-6 levels in a sample with AUD. One hundred and thirty-three individuals with an AUD provided blood samples to assess IL-6 and answered questions regarding alcohol and cannabis use. An ordinary least squares multiple regression analysis was conducted to assess the effect of alcohol and cannabis use on IL-6. A moderation analysis examined cannabis use as a potential moderator of the relationship between alcohol use and circulating IL-6 levels. Alcohol use was predictive of higher log IL-6 levels (standardized β = 0.16, p = 0.03), while cannabis use was not predictive of log IL-6 levels (p = 0.36). Days of cannabis use moderated the relationship between alcohol use and IL-6 levels, such that the relationship between alcohol use and IL-6 levels was only significant in individuals with AUD without recent cannabis use. This study extends previous work to a clinical sample with an AUD and underscores the importance of considering cannabis use in studies on alcohol use and inflammation. This study also indicates the need for in-depth analyses on cannabinoids and inflammation and the interaction between cannabinoids and alcohol use on inflammation.

The increasing rates of drug misuse highlight the urgency of identifying improved therapeutics for treatment. Most drug-seeking behaviours that can be modelled in rodents utilize the repeated intravenous self-administration (SA) of drugs. Recent studies examining the mesolimbic pathway suggest that K_v7/KCNQ channels may contribute to the transition from recreational to chronic drug use. However, to date, all such studies used noncontingent, experimenter-delivered drug model systems, and the extent to which this effect generalizes to rats trained to self-administer drugs is not known. Here, we tested the ability of retigabine (ezogabine), a K_v7 channel opener, to regulate instrumental behaviour in male Sprague Dawley rats. We first validated the ability of retigabine to target experimenter-delivered cocaine in a conditioned place preference (CPP) assay and found that retigabine reduced the acquisition of place preference. Next, we trained rats for cocaine-SA under a fixed-ratio or progressive-ratio reinforcement schedule and found that retigabine pretreatment attenuated the SA of low to moderate doses of cocaine. This was not observed in parallel experiments, with rats self-administering sucrose, a natural reward. Compared with sucrose-SA, cocaine-SA was associated with reductions in the expression of the K_v7.5 subunit in the nucleus accumbens, without alterations in K_v7.2 and K_v7.3. Therefore, these studies reveal a reward-specific reduction in SA behaviour and support the notion that K_v7 is a potential therapeutic target for human psychiatric diseases with dysfunctional reward circuitry.

Benzodiazepine (BZD) dependence poses a significant challenge in mental health, prompting the exploration of treatments like repetitive transcranial magnetic stimulation (rTMS). This research aims to assess the impact of rTMS on alleviating symptoms of BZD dependence. A randomized control trial was employed to study 40 BZD-dependent inpatients. Their symptoms were quantified using the Hamilton Anxiety Rating Scale (HAMA), Montgomery–Åsberg Depression Rating Scale (MADRS) and Pittsburgh Sleep Quality Index (PSQI). Participants were divided into a conventional treatment group (daily diazepam with gradual tapering) with supportive psychotherapy and another group receiving the same treatment supplemented with rTMS (five weekly sessions for 2 weeks). Significant improvements were observed in both groups over baseline in MADRS, HAMA and PSQI scores at the 2nd, 4th, 8th and 12th week assessments (p < 0.05). The group receiving rTMS in addition to conventional treatment exhibited superior improvements in all measures at the 8th and 12th weeks. The addition of rTMS to conventional treatment methods for BZD dependence significantly betters the recovery in terms of depression, anxiety and sleep quality, highlighting the role of rTMS as an effective adjunct therapy.

The addictive use of nicotine contained in tobacco is associated with stressor-like emotional and cognitive effects such as anxiety and working memory impairment, and the involvement of epigenetic mechanisms such as histone acetylation has recently been reported. Although the precise nature of behavioural plasticity remains unclear, both anxiogenic- and working memory impairment-like effects were observed in the present experimental model of mice treated with repeated subcutaneous nicotine and/or immobilization stress, and these effects were commonly attenuated by the histone deacetylase (HDAC) inhibitors that induce histone acetylation. Such HDAC inhibitor-induced resilience was mimicked by ligands for the endocannabinoid (ECB) system, a neurotransmitter system that is closely associated with nicotine-induced addiction-related behaviours: the anxiogenic-like effects were mitigated by the cannabinoid type 1 (CB1) agonist arachidonylcyclopropylamide (ACPA), whereas the working memory impairment-like effects were mitigated by the CB1 antagonist SR 141716A. Moreover, the effects of the HDAC inhibitors were also mimicked by ligands for the endovanilloid (transient receptor potential vanilloid 1 [TRPV1]) system, a system that shares common characteristics with the ECB system: the anxiogenic-like effects were mitigated by the TRPV1 antagonist capsazepine, whereas the working memory impairment-like effects were mitigated by the TRPV1 agonist olvanil. Notably, the HDAC inhibitor-induced anxiolytic-like effects were attenuated by SR 141716A, which were further counteracted by capsazepine, whereas the working memory improvement-like effects were attenuated by capsazepine, which were further counteracted by SR 141716A. These results suggest the contribution of interrelated control of the ECB/TRPV1 systems and epigenetic processes such as histone acetylation to novel therapeutic approaches.