Acute Aerobic Exercise Ameliorates Cravings and Inhibitory Control in Heroin Addicts: Evidence From Event-Related Potentials and Frequency Bands

Forced wheel running pre-conditioning diminishes reward learning induced by methamphetamine: Involvement of orexin 1 receptor in the hippocampus

Methamphetamine (METH) is a highly addictive drug that leads to neurobehavioral changes related to the brain's reward circuit. Orexin and orexinergic receptors, found in crucial brain areas involved in reward processing, may play a significant role in reward mechanisms and addiction. Studies have shown that physical exercise can be an effective non-pharmacological approach to controlling drug use but limited research explores its role as pre-conditioning to prevent dependency on narcotics. In this study, 48 male Wistar rats were assigned into six groups: exercise training+saline (EX-SA), exercise training+METH 1mg/kg (EX-METH1), exercise training + METH 2 mg/kg (EX-METH2), control+saline (CON), control+METH 1 mg/kg (CON-METH1), control+METH 2 mg/kg (CON-METH2). The pre-conditioning groups underwent forced wheel-running training (five days a week, at 65 % Vmax) for eight weeks. Following pre-conditioning with exercise training, the METH groups received intraperitoneal (IP) METH injections using the conditioned place preference (CPP) model. After the post-test, the animals were dissected, and hippocampal tissue was collected to measure orexin receptor1 (OXR1) expression levels. The results showed that long-term, moderate-intensity forced exercise pre-conditioning prevented METH-induced CPP. However, CPP was observed only in the EX-METH2 group, receiving a double dose of the drug. Molecular analysis also revealed a significant increase in OXR1 expression in the hippocampus following METH injections, while physical exercise caused suppression in OXR1 increment. Seemingly, prior exercise influences this pathway and effectively prevents conditioning to METH, probably through OXR1, indicating an adaptation in the mesolimbic reward pathway that helps protect against METH addiction.

Environmental enrichment attenuates reinstatement of heroin seeking and reverses heroin-induced upregulation of mesolimbic ghrelin receptors

We have shown that environmental enrichment (EE) can effectively reduce reinstatement and facilitate true abstinence in animal models of drug use. Here, we investigated whether EE is effective against reinstatement of heroin seeking in long access (LA) model, which has been argued to capture the compulsive features of human drug addiction. We also explored the neurobiology by which EE produces its anti-drug addiction effects. In particular, we focused here on the ghrelin system, which is known for its involvement in reward-motivated behaviors and upregulation following intravenous drug self-administration. Following LA to heroin, rats were housed in either non-EE or EE conditions. During extinction and cue-induced reinstatement test, EE rats showed a significant reduction in active lever responding compared to non-EE rats, suggesting that EE facilitates extinction of drug seeking and reduces the capacity of drug-associated stimuli to elicit and maintain drug seeking. Using Western Blotting, we found that rats with LA to heroin IVSA showed a significant increase in ghrelin receptor (GHS-R1a) expression in the ventral tegmental area and nucleus accumbens, the brain regions implicated in resumption of drug use . Exposure to EE attenuated heroin-induced upregulation of GHS-R1a receptor in these regions but produced no significant changes other brain regions. Our findings suggest that EE can be an effective behavioral approach to diminish drug seeking even following LA to heroin. Compulsive drug taking and seeking seem to be correlated with an upregulation of GHS-R1a expression in the limbic regions, and EE can reverse these neuroadaptations, potentially contributing to a reduction in drug seeking.

Impact of exercise on drug cravings: mediating role of cardiorespiratory fitness and inhibitory control

Background

Contemporary research has consistently demonstrated a link between physical exercise, inhibition, and drug cravings, with several hypotheses proposed to explain how exercise enhances inhibition. However, few studies have explored the mechanisms underlying this effect. This study investigates the pivotal role of cardiorespiratory fitness in mediating the impact of physical exercise on inhibition and drug cravings.

Methods

In this study, the researchers selected participants who had completed physical detoxification in China's compulsory isolation drug rehabilitation centers. Moreover, we conducted surveys and assessed cardiorespiratory fitness using tools such as the Physical Exercise Rating Scale, Inhibition Scale, Drug Craving Scale, and Queen College Step Test. Additionally, we employed exploratory and confirmatory factor analyses, correlation analysis, regression analysis, and structural equation model (SEM) to analyze the study's data.

Results and findings

The findings of this study reveal that physical exercise significantly reduces drug craving by improving cardiorespiratory fitness and enhancing inhibition. Furthermore, it showed that men had better physical exercise levels, cardiorespiratory fitness, and inhibition compared to women, while women exhibited higher psychological cravings. Besides, the study also highlighted that longer years of drug use were associated with lower physical exercise, reduced cardiorespiratory fitness, and weaker inhibition, leading to higher drug cravings. In addition, cardiorespiratory fitness and inhibition acted as mediators between physical exercise and drug craving, with the combination of both factors serving as a chain mediator in reducing cravings. These findings suggest that physical exercise, particularly through improving cardiorespiratory fitness, plays a key role in mitigating drug cravings and supporting rehabilitation efforts for drug dependence.

Treadmill exercise training inhibits morphine CPP by reversing morphine effects on GABA neurotransmission in D2-MSNs of the accumbens-pallidal pathway in male mice

Relapse is a major challenge in the treatment of drug addiction, and exercise has been shown to decrease relapse to drug seeking in animal models. However, the neural circuitry mechanisms by which exercise inhibits morphine relapse remain unclear. In this study, we report that 4-week treadmill training prevented morphine conditioned place preference (CPP) expression during abstinence by acting through the nucleus accumbens (NAc)-ventral pallidum (VP) pathway. We found that neuronal excitability was reduced in D2-dopamine receptor-expressing medium spiny neurons (D2-MSNs) following repeated exposure to morphine and forced abstinence. Enhancing the excitability of NAc D2-MSNs via treadmill training decreased the expression of morphine CPP. We also found that the effects of treadmill training were mediated by decreasing enkephalin levels and that restoring opioid modulation of GABA neurotransmission in the VP, which increased neurotransmitter release from NAc D2-MSNs to VP, decreased morphine CPP. Our findings suggest the inhibitory effect of exercise on morphine CPP is mediated by reversing morphine-induced neuroadaptations in the NAc-to-VP pathway.

Potential Link Between Exercise and N-Methyl-D-Aspartate Glutamate Receptors in Alcohol Use Disorder: Implications for Therapeutic Strategies

Alcohol use disorder (AUD) is a significant risk factor, accounting for approximately 13% of all deaths in the US. AUD not only destroys families but also causes economic losses due to reduced productivity, absenteeism, and healthcare expenses. Statistics revealing the sustained number of individuals affected by AUD over the years underscore the need for further understanding of the underlying pathophysiology to advance novel therapeutic strategies. Previous research has implicated the limbic brain regions N-methyl-D-aspartate glutamate receptors (NMDAR) in the emotional and behavioral effects of AUD. Given that aerobic exercise can modulate NMDAR activity and sensitivity to alcohol, this review presents a summary of clinical and basic science studies on NMDAR levels induced by alcohol consumption, as well as acute and protracted withdrawal, highlighting the potential role of aerobic exercise as an adjunctive therapy for AUD. Based on our findings, the utility of exercise in the modulation of reward-linked receptors and AUD may be mediated by its effects on NMDA signaling. These data support further consideration of the potential of aerobic exercise as a promising adjunctive therapy for AUD.

Understanding physical exercise among individuals with substance use disorders using an integrated theoretical perspective of the health action process approach and theory of planned behavior

Introduction

Physical exercise is considered a useful non-pharmacological adjunctive treatment for promoting recovery from substance use disorders (SUD). However, adherence to physical exercise treatments is low, and little is known about what factors are associated with the initiation and maintenance of physical exercise behaviors. The aim of this study was to explore the psychosocial factors underlying these behaviors in individuals with SUD using an integrated theoretical model based on the health action process approach (HAPA) and the theory of planned behavior (TPB).

Methods

A total of 1,197 individuals with SUDs (aged 37.20 ± 8.62 years) were recruited from 10 compulsory isolation drug rehabilitation centers in Zhejiang Province via convenience sampling according to a set of inclusion criteria. Self-reported data were collected to assess task self-efficacy (TSE), maintenance self-efficacy (MSE), recovery self-efficacy (RSE), outcome expectations (OE), action planning (AP), coping planning (CP), social support (SS), subjective norms (SN), attitude behavior (AB), behavioral intention (BI), perceived behavioral control (PBC), risk perception (RP), exercise stage, and exercise behavior in this integrated model. ANOVA and structural equation modeling (SEM) were used to evaluate this model.

Results

One-way ANOVA revealed that the majority of the moderating variables were significantly different in the exercise phase. Further SEM showed that the model fit the data and revealed several important relationships. TSE, RP, SS, AB, and SN were indirectly associated with physical exercise behavior in individuals with SUD through the BI in the SUD initiation stage. In addition, PBC was directly related to physical exercise behavior in individuals with SUD. In the maintenance stage, MSE, AP, CP and exercise behavior were significantly related. Moreover, AP and CP were mediators of BI and MSE.

Conclusion

This study is the first attempt to integrate patterns of physical exercise behavior in individuals with SUD. The HAPA-TPB integration model provides a useful framework for identifying determinants of physical exercise behavioral intentions and behaviors in individuals with SUD and for explaining and predicting the initiation and maintenance of physical exercise behaviors in these individuals. Moreover, the model provides scientific guidance for the enhancement of physical exercise adherence in individuals with SUD.

Effects of a Two-Month Exercise Training Program on Concurrent Non-Opiate Substance Use in Opioid-Dependent Patients during Substitution Treatment

BACKGROUND

This randomized controlled trial aimed to evaluate the effects of a two-month exercise intervention on the concurrent non-opiate substance use (alcohol, cocaine, cannabis, and benzodiazepines) in opioid users during their medication treatment.

METHODS

Ninety opioid users (41 females) in methadone and buprenorphine medication treatment were randomly divided into four groups: (a) buprenorphine experimental (BEX; n = 26, aged 41.9 ± 6.1 yrs); (b) buprenorphine control (BCON; n = 25, aged 41.9 ± 5.6 yrs); (c) methadone experimental (MEX; n = 20, aged 46.7 ± 6.6 yrs); and (d) methadone control (MCON; n = 19, aged 46.1 ± 7.5 yrs). The experimental groups (BEX and MEX) followed an aerobic exercise training program on a treadmill for 20 min at 70% HRmax, 3 days/week for 8 weeks. Socio-demographic, anthropometric, and clinical characteristics, as well as non-opioid drug use in days and quantity per week, were assessed before and after the intervention period.

RESULTS

Following the exercise training, the weekly non-opioid substance consumption (days) decreased (p < 0.05) in both exercise groups and was lower in BEX compared to MEX, while no differences were observed (p > 0.05) between the control groups (BCON vs. MCON) or compared to their baseline levels. Similarly, the daily amount of non-opiate substance intake was reduced (p < 0.05) post-training in BEX and MEX, whereas it did not differ (p > 0.05) in BCON and MCON compared to the baseline.

CONCLUSIONS

The two-month exercise intervention reduced the non-opioid drug use in both the methadone and buprenorphine substitution groups compared to the controls, suggesting that aerobic exercise training may be an effective strategy for treating patients with OUDs.

Functional neuroanatomy of craving in heroin use disorder: voxel-based meta-analysis of functional magnetic resonance imaging (fMRI) drug cue reactivity studies

Background: The neuroanatomy of craving, typically investigated using the functional magnetic resonance imaging (fMRI) drug cue reactivity (FDCR) paradigm, has been shown to involve the mesocorticolimbic, nigrostriatal, and corticocerebellar systems in several substances. However, the neuroanatomy of craving in heroin use disorder is still unclear.Objective: The current meta-analysis examines previous research on the neuroanatomy of craving in abstinent individuals with opioid use disorder (OUD).Method: Seven databases were searched for studies comparing abstinent OUD versus healthy controls on drug > neutral contrast interaction at the whole-brain level. Voxel-based meta-analysis was performed using seed-based d mapping with permuted subject images (SDM-PSI). Thresholds were set at a family-wise error rate of less than 5% with the default pre-processing parameters of SDM-PSI.Results: A total of 10 studies were included (296 OUD and 187 controls). Four hyperactivated clusters were identified with Hedges' g of peaks that ranged from 0.51 to 0.82. These peaks and their associated clusters correspond to the three systems identified in the previous literature: a) mesocorticolimbic, b) nigrostriatal, and c) corticocerebellar. There were also newly revealed hyperactivation regions including the bilateral cingulate, precuneus, fusiform gyrus, pons, lingual gyrus, and inferior occipital gyrus. The meta-analysis did not reveal areas of hypoactivation.Conclusion: Recommendations based on the functional neuroanatomical findings of this meta-analysis include pharmacological interventions such as buprenorphine/naloxone and cognitive-behavioral treatments such as cue-exposure combined with HRV biofeedback. In addition, research should utilize FDCR as pre- and post-measurement to determine the effectiveness and mechanism of action of such interventions.

Effects of Acute Exercise on Affect, Anxiety, and Self-Esteem in Poly-Substance Dependent Inpatients

INTRODUCTION

Negative affect and anxiety frequently precede the onset of drug use in those with substance use disorder (SUD). Low self-esteem may increase the risk of relapse. We examined the short-term effects of exercise on affect, anxiety, and self-esteem in inpatients with poly-SUD.

METHODS

This is a multicenter randomized control trial (RCT) with a crossover design. Thirty-eight inpatients (37.3 ± 6.4 years; 84% male) from three clinics participated in 45 min of soccer, circuit training, and control condition (psychoeducation) in a random order. Positive and negative affect (PANAS), state anxiety (single item), and self-esteem (Rosenberg SE-scale) were measured immediately before, immediately after, 1-h, 2-h, and 4-h post-exercise. Heart rate and ratings of perceived exertion were taken. Effects were assessed using linear mixed effects models.

RESULTS

Compared to the control condition, there were significant post-exercise improvements in positive affect (β = 2.99, CI = 0.39: 5.58), self-esteem (β = 1.84, CI = 0.49: 3.20), and anxiety (β = -0.69, CI = -1.34: -0.04) after circuit training (shown) and soccer. Effects persisted 4-h post-exercise. Reductions in negative affect were observed 2-h (circuit training: β = -3.39, CI = -6.35: -1.51) and 4-h (soccer: β = -3.71, CI = -6.03: -1.39) post-exercise, respectively.

CONCLUSION

Moderately strenuous exercise undertaken in naturalistic settings may improve mental health symptoms in poly-SUD inpatients for up to 4-h post-exercise.

The Role of Physical Exercise in Opioid Substitution Therapy: Mechanisms of Sequential Effects

It is generally accepted that chronic opioid use is associated with structural and functional changes in the human brain that lead to an enhancement of impulsive behavior for immediate satisfaction. Interestingly, in recent years, physical exercise interventions have been used as an adjunctive treatment for patients with opioid use disorders (OUDs). Indeed, exercise has positive effects on both the biological and psychosocial basis of addiction, modifying neural circuits such as the reward, inhibition, and stress systems, and thus causing behavioral changes. This review focuses on the possible mechanisms that contribute to the beneficial effects of exercise on the treatment of OUDs, with emphasis placed on the description of a sequential consolidation of these mechanisms. Exercise is thought to act initially as a factor of internal activation and self-regulation and eventually as a factor of commitment. This approach suggests a sequential (temporal) consolidation of the functions of exercise in favor of gradual disengagement from addiction. Particularly, the sequence in which the exercise-induced mechanisms are consolidated follows the pattern of internal activation-self-regulation-commitment, eventually resulting in stimulation of the endocannabinoid and endogenous opioid systems. Additionally, this is accompanied by modification of molecular and behavioral aspects of opioid addiction. Overall, the neurobiological actions of exercise in combination with certain psychological mechanisms appear to promote its beneficial effects. Given the positive effects of exercise on both physical and mental health, exercise prescription is recommended as a complement to conventional therapy for patients on opioid maintenance treatment.

Aerobic exercise as a promising nonpharmacological therapy for the treatment of substance use disorders

Despite the prevalence and public health impact of substance use disorders (SUDs), effective long-term treatments remain elusive. Aerobic exercise is a promising, nonpharmacological treatment currently under investigation as a strategy for preventing drug relapse. Aerobic exercise could be incorporated into the comprehensive treatment regimens for people with substance abuse disorders. Preclinical studies of SUD with animal models have shown that aerobic exercise diminishes drug-seeking behavior, which leads to relapse, in both male and female rats. Nevertheless, little is known regarding the effects of substance abuse-induced cellular and physiological adaptations believed to be responsible for drug-seeking behavior. Accordingly, the overall goal of this review is to provide a summary and an assessment of findings to date, highlighting evidence of the molecular and neurological effects of exercise on adaptations associated with SUD.

Effects of aerobic exercise on event-related potentials related to cognitive performance: a systematic review

Introduction

Aerobic exercise interventions may affect different cognitive domains such as attention, working memory, inhibition, etc. However, the neural mechanisms underlying this relationship, remains uncertain.

Objective

To perform a systematic review on exercise intervention studies that use event-related potentials (ERPs) as outcome for cognitive performance.

Methods

We identified studies through searches in four databases reporting the effects of either an acute bout or chronic exercise on any ERP associated with cognitive performance. Study population included participants >17 years of age with or without a diagnosis.

Results

A total of 5,797 records were initially identified through database searching of which 52 were eligible for inclusion. Most studies were of acute aerobic exercise with moderate intensity. Results were heterogenious across studies, but there was a trend that ERP amplitude increased and (to a lesser extent) latencies decreased post-exercise. The P3 ERP was the most often reported ERP.

Conclusion

Heterogeneity across studies regarding methodology limited the possibility to draw definitive conclusions but the most consistent findings were that acute aerobic exercise was associated with higher amplitudes, and to a lesser extent shorter latencies, of ERPs.

Does being overweight play a role in the reduced inhibitory control of patients receiving treatment for substance use disorder?

BACKGROUND

Impaired inhibitory control is present in individuals with substance use disorder (SUD) and in those with obesity. However, the question as to whether patients with SUD who are either overweight or obese have impaired inhibitory control, relative to patients with SUD and normal weight, remains unanswered.

METHODS

Sixty-two adult men (mean age: 31.17±8.79) under treatment for SUD performed a general and drug-specific inhibitory control test (GoNogo). Participants were divided in two groups based on their BMI. Patients with a BMI higher or equal than ≥25 kg/m² were in the overweight and obese group (OB), and patients with a BMI lower than 25 kg/m² were in the normal weight group (NW). Analyses of covariance (ANCOVA) were performed to explore differences in drug-specific and general commission errors, as well as reaction time for go trials during both drug-specific and general inhibition tasks. Models were adjusted for anxiety, depression, age, and duration of drug use.

RESULTS

No differences were found for commission errors in both tasks. With regards to reaction time, no differences were found for the general inhibitory control paradigm, whereas the OB group demonstrated slower reaction time during the drug specific paradigm, relative to the NW group (p=0.03, f² = 0.09; OB: 520.65±71.39 ms vs. NW: 486.07±51.75 ms).

CONCLUSION

Our findings suggest that those undergoing treatment for SUD and are either overweight or obese present impaired inhibitory control when facing drug cues. Future research should explore the effects of physical activity, nutritional counseling, and food monitoring on inhibitory control outcomes in SUD rehabilitation.