Long-term compulsive exercise reduces the rewarding efficacy of 3,4-methylenedioxymethamphetamine

Dopamine in Sports: A Narrative Review on the Genetic and Epigenetic Factors Shaping Personality and Athletic Performance

This narrative review examines the relationship between dopamine-related genetic polymorphisms, personality traits, and athletic success. Advances in sports genetics have identified specific single nucleotide polymorphisms (SNPs) in dopamine-related genes linked to personality traits crucial for athletic performance, such as motivation, cognitive function, and emotional resilience. This review clarifies how genetic variations can influence athletic predisposition through dopaminergic pathways and environmental interactions. Key findings reveal associations between specific SNPs and enhanced performance in various sports. For example, polymorphisms such as COMT Val158Met rs4680 and BDNF Val66Met rs6265 are associated with traits that could benefit performance, such as increased focus, stress resilience and conscientiousness, especially in martial arts. DRD3 rs167771 is associated with higher agreeableness, benefiting teamwork in sports like football. This synthesis underscores the multidimensional role of genetics in shaping athletic ability and advocates for integrating genetic profiling into personalized training to optimize performance and well-being. However, research gaps remain, including the need for standardized training protocols and exploring gene-environment interactions in diverse populations. Future studies should focus on how genetic and epigenetic factors can inform tailored interventions to enhance both physical and psychological aspects of athletic performance. By bridging genetics, personality psychology, and exercise science, this review paves the way for innovative training and performance optimization strategies.

Impact of Calorie-Restricted Cafeteria Diet and Treadmill Exercise on Sweet Taste in Diet-Induced Obese Female and Male Rats

The goal of the present study was to evaluate the sweet taste function in obese rats fed with a 30% calorie-restricted cafeteria diet (CAFR) and/or subjected to moderate treadmill exercise (12-17 m/min, 35 min, 5 days per week) for 9 weeks. A two-bottle preference test, a taste reactivity test, and a brief-access licking test were carried out when animals were aged 21 weeks; biometric and metabolic parameters were also measured along the interventions. Two separate experiments for females and males were performed. Behaviorally, CAF diet decreased sucrose intake and preference, as well as perceived palatability, in both sexes and decreased hedonic responses in males. Compared to the CAF diet, CAFR exerted a corrective effect on sweet taste variables in females by increasing sucrose intake in the preference test and licking responses, while exercise decreased sucrose intake in both sexes and licking responses in females. As expected, CAF diet increased body weight and Lee index and worsened the metabolic profile in both sexes, whereas CAFR diet ameliorated these effects mainly in females. Exercise had no noticeable effects on these parameters. We conclude that CAF diet might diminish appetitive behavior toward sucrose in both sexes, and that this effect could be partially reverted by CAFR diet in females only, while exercise might exert protective effects against overconsumption of sucrose in both sexes.

Impact of high-access exercise prior to and during early adolescence on later vulnerability to opioid use and relapse in male rats

Middle- and high-school athletes participating in certain team sports are at greater risk of opioid misuse and addiction than those who do not. While this risk is thought to be due to increased access to opioids, in this study we explored the possibility that the sensitizing effects of discontinued high-intensity exercise may also contribute. Specifically, using male rat models with fentanyl, we tested the hypothesis that high-access exercise (24 h/day access to a running wheel) during pre/early adolescence (two weeks, postnatal-day 24-37) would enhance vulnerability to opioid use and relapse during late adolescence/adulthood. Rats with a history of high-access exercise showed stronger fentanyl-associated lever discrimination during acquisition, greater motivation to obtain infusions of fentanyl following acquisition, and had an enhanced sensitivity to the reinstating effects of fentanyl-associated cues following extended (24 h/day), intermittent-access self-administration and protracted abstinence (14 days) compared to sedentary controls. In contrast, sedentary rats had greater overall responding (active- and inactive-lever) during acquisition and greater non-specific (inactive-lever) responding during extended-access self-administration. Molecular markers associated with opioid seeking/relapse were also differentially expressed in the nucleus accumbens core of rats with versus without a history of high-access exercise following relapse testing (e.g., Bdnf-IV and Drd2 expression). Together, these findings demonstrate that high-access exercise prior to and throughout early-adolescence enhances vulnerability to the reinforcing and cue-induced reinstating effects of opioids during later adolescence/adulthood. Thus, it is possible that the discontinuation of high intensity exercise contributes to the enhanced vulnerability observed in middle- and high-school athletes.

Craving among individuals with stimulant use disorder in residential social model-based treatment - Can exercise help?

BACKGROUND

In a randomized controlled 8-week trial, we examined the efficacy of aerobic and resistance exercise in reducing craving for methamphetamine (MA) among individuals with MA-use disorder during residential treatment.

METHODS

Individuals with MA use disorder (138) who were newly enrolled in residential treatment volunteered for random assignment to either an 8-week exercise intervention (EX) or health education control (HE), with both conditions meeting 3 times weekly; 3 dropped out of the trial, bringing the analysis sample to 135. The majority of participants were male (80%), and 48% were Latino/Hispanic. The mean age of the sample was 31.7 (SD = 6.9) years. Using multivariate mixed models, differences between conditions were examined in: (1) craving for MA, measured by self-reported ratings on a Visual Analog Scale over the 8-week trial and, (2) MA use, measured by self-report and urine drug screens at baseline and 30 and 60 days after discharge from the 8-week study.

RESULTS

Results revealed significantly lower craving scores among the participants in the EX group than those in the HE group over the 8-week trial (median daily craving score for EX = 13.5, for HE = 21.8; p = .009). In addition, participants with less craving during treatment had significantly lower rates of MA use after discharge than participants with high craving measured at 30-days (p = .004) and 60-days post-discharge (p < .001).

CONCLUSIONS

Results support the utility of incorporating a structured exercise program for individuals with MA-use disorder to reduce craving and improve MA-use outcomes.

The therapeutic potential of exercise for neuropsychiatric diseases: A review

Exercise is known to have a myriad of health benefits. There is much to be learned from the effects of exercise and its potential for prevention, attenuation and treatment of multiple neuropsychiatric diseases and behavioral disorders. Furthermore, recent data and research on exercise benefits with respect to major health crises, such as, that of opioid and general substance use disorders, make it very important to better understand and review the mechanisms of exercise and how it could be utilized for effective treatments or adjunct treatments for these diseases. In addition, mechanisms, epigenetics and sex differences are examined and discussed in terms of future research implications.

Exercise effects on brain and behavior in healthy mice, Alzheimer's disease and Parkinson's disease model-A systematic review and meta-analysis

This systematic review and meta-analysis examines how exercise modifies brain and behavior in healthy mice, dementia (D) and Parkinson disease (PD) models. A search was performed on the Medline and Scopus electronic databases (2008-2019). Search terms were "mice", "brain", "treadmill", "exercise", "physical exercise". In the total, 430 were found but only 103 were included. Animals n = 1,172; exercised 4-8 weeks (Range 24 h to 32 weeks), 60 min/day (Range 8-120 min per day), and 10/12 m/min (Range 0.2 m/min to 36 m/min). Hippocampus, cerebral cortex, striatum and whole brain were more frequently investigated. Exercise improved learning and memory. Meta-analysis showed that exercise increased: cerebral BDNF in health (n = 150; z = 5.8, CI 3.43-12.05; p < 0.001 I2 = 94.3 %), D (n = 124; z = 4.18, CI = 2.22-9.12; p < 0.001; I2 = 93.7 %) and PD (n = 16 z = 4.26, CI 5.03-48.73 p < 0.001 I2 = 94.8 %). TrkB improved in health (n = 84 z = 5.49, CI 3.8-17.73 p < 0.001, I2 = 0.000) and PD (n = 22; z = 3.1, CI = 2.58-67.3, p < 0.002 I2 = 93.8 %). Neurogenesis increased in health (n = 68; z = 7.08, CI 5.65-21.25 p < 0.001; I2 17.58) and D model (n = 116; z = 4.18, CI 2.22-9.12 p < 0.001 I2 93.7 %). Exercise augmented amyloid clearance (n = 166; z = 7.51 CI = 4.86-14.85, p < 0.001 I2 = 58.72) and reduced amyloid plaques in D models (n = 49; z = 4.65, CI = 3.94-15.3 p < 0.001 I2 = 0.000). In conclusion, exercise improved brain and behavior, neurogenesis in healthy and dementia models, reduced toxicity and cerebral amyloid. Evidence regarding inflammation, oxidative stress and energy metabolism were scarce. Studies examining acute vs chronic exercise, extreme training and the durability of exercise benefit were rare. Vascular or glucose metabolism changes were seldom reported.

Of mice and men on MDMA: A translational comparison of the neuropsychobiological effects of 3,4-methylenedioxymethamphetamine ('Ecstasy')

MDMA (3,4-methylendioxymethamphetamine), also known as Ecstasy, is a stimulant drug recreationally used by young adults usually in dance clubs and raves. Acute MDMA administration increases serotonin, dopamine and noradrenaline by reversing the action of the monoamine transporters. In this work, we review the studies carried out over the last 30 years on the neuropsychobiological effects of MDMA in humans and mice and summarise the current knowledge. The two species differ with respect to the neurochemical consequences of chronic MDMA, since it preferentially induces serotonergic dysfunction in humans and dopaminergic neurotoxicity in mice. However, MDMA alters brain structure and function and induces hormonal, psychomotor, neurocognitive, psychosocial and psychiatric outcomes in both species, as well as physically damaging and teratogen effects. Pharmacological and genetic studies in mice have increased our knowledge of the neurochemical substrate of the multiple effects of MDMA. Future work in this area may contribute to developing pharmacological treatments for MDMA-related disorders.

Exercise and substance abuse

Exercise intervention has long been used as one adjunctive treatment for drug abuse. Both animal studies and human trials suggest that exercise training effectively prevents addiction formation, suppresses drug-seeking behaviors, and ceases addictions. Moreover, exercise improves both mental and cognitive deficits that commonly occur during drug withdrawal. Those observations are supported by neurobiological studies in which exercise training modulates several neural networks including the dopaminergic reward system, and regulates neurogenesis and spinogenesis that affect cognitive behaviors and mental health. In sum, exercise training is a safe and effective way to relieve substance abuse, although both intervention guideline and biomarkers warrants further investigation.

Exercise as a Prevention for Substance Use Disorder: A Review of Sex Differences and Neurobiological Mechanisms

PURPOSE OF REVIEW

This report provides an update on clinical and preclinical findings for the efficacy of exercise to prevent substance use disorder with a focus on recent evidence for sex differences and neurobiological mechanisms.

RECENT FINDINGS

Exercise/physical activity is associated with decreased drug use in humans. Preclinical results further indicate that exercise decreases vulnerability to drug use and the development of features of substance use disorder, and suggest that females have an enhanced sensitivity to its reward-substitution effects. However, certain exercise conditions may sensitize the reward pathway and enhance vulnerability suggesting that parallel observations in humans (e.g., increased prescription opioid misuse and heroin use in high-school athletes) may be biologically-based.

SUMMARY

Exercise is a promising prevention strategy for substance use disorder. Further work is needed to establish its efficacy as a sex-specific strategy using larger samples, and to understand the exercise conditions that induce beneficial versus risk-enhancing effects.

Protective effects of physical exercise on MDMA-induced cognitive and mitochondrial impairment

Debate continues about the effect of 3, 4-methylenedioxymethamphetamine (MDMA) on cognitive and mitochondrial function through the CNS. It has been shown that physical exercise has an important protective effect on cellular damage and death. Therefore, we investigated the effect of physical exercise on MDMA-induced impairments of spatial learning and memory as well as MDMA effects on brain mitochondrial function in rats. Male wistar rats underwent short-term (2 weeks) or long-term (4 weeks) treadmill exercise. After completion of exercise duration, acquisition and retention of spatial memory were evaluated by Morris water maze (MWM) test. Rats were intraperitoneally (I.P) injected with MDMA (5, 10, and 15mg/kg) 30min before the first training trial in 4 training days of MWM. Different parameters of brain mitochondrial function were measured including the level of ROS production, mitochondrial membrane potential (MMP), mitochondrial swelling, mitochondrial outermembrane damage, the amount of cytochrome c release from the mitochondria, and ADP/ATP ratio. MDMA damaged the spatial learning and memory in a dose-dependent manner. Brain mitochondria isolated from the rats treated with MDMA showed significant increase in ROS formation, collapse of MMP, mitochondrial swelling, and outer membrane damage, cytochrome c release from the mitochondria, and finally increased ADP/ATP ratio. This study also found that physical exercise significantly decreased the MDMA-induced impairments of spatial learning and memory and also mitochondrial dysfunction. The results indicated that MDMA-induced neurotoxicity leads to brain mitochondrial dysfunction and subsequent oxidative stress is followed by cognitive impairments. However, physical exercise could reduce these deleterious effects of MDMA through protective effects on brain mitochondrial function.

Effects of swimming exercise on morphine-induced reward and behavioral sensitization in maternally-separated rat pups in the conditioned place preference procedure

This study was designed to examine the effects of swimming exercise during adolescence on morphine-induced conditioned place preference (CPP) and behavioral sensitization in maternally separated male and female rat pups. Male Wistar rats were allowed to mate with female virgin Wistar rats. Pups were separated from the dam daily for 180min during postnatal days 2-14. All pups were weaned on day 21.The exercising pups were allowed to swim (60min/d, five days per a week, for 30days) during adolescence. Then, rat pups were tested for behavioral sensitization and the CPP induced by morphine. Maternal separation produced a significant increase in morphine-induced CPP in both sexes, behavioral sensitization in male pups and tolerance to morphine-induced motor activity in female pups. Swimmer pups separated from the dam exhibited a decrease in morphine-induced CPP in both sexes and behavioral sensitization in male pups than those of their control pups. The present results have shown that swimming exercise during adolescence may exert a protective effect against morphine-induced reward and behavioral sensitization in adult male and female rats following maternal separation.

Sex differences in drug addiction and response to exercise intervention: From human to animal studies

Accumulated research supports the idea that exercise could be an option of potential prevention and treatment for drug addiction. During the past few years, there has been increased interest in investigating of sex differences in exercise and drug addiction. This demonstrates that sex-specific exercise intervention strategies may be important for preventing and treating drug addiction in men and women. However, little is known about how and why sex differences are found when doing exercise-induced interventions for drug addiction. In this review, we included both animal and human that pulled subjects from a varied age demographic, as well as neurobiological mechanisms that may highlight the sex-related differences in these potential to assess the impact of sex-specific roles in drug addiction and exercise therapies.

Evaluating Exercise as a Therapeutic Intervention for Methamphetamine Addiction-Like Behavior

The need for effective treatments for addiction and dependence to the illicit stimulant methamphetamine in primary care settings is increasing, yet no effective medications have been FDA approved to reduce dependence [1]. This is partially attributed to the complex and dynamic neurobiology underlying the various stages of addiction [2]. Therapeutic strategies to treat methamphetamine addiction, particularly the relapse stage of addiction, could revolutionize methamphetamine addiction treatment. In this context, preclinical studies demonstrate that voluntary exercise (sustained physical activity) could be used as an intervention to reduce methamphetamine addiction. Therefore, it appears that methamphetamine disrupts normal functioning in the brain and this disruption is prevented or reduced by engaging in exercise. This review discusses animal models of methamphetamine addiction and sustained physical activity and the interactions between exercise and methamphetamine behaviors. The review highlights how methamphetamine and exercise affect neuronal plasticity and neurotoxicity in the adult mammalian striatum, hippocampus, and prefrontal cortex, and presents the emerging mechanisms of exercise in attenuating intake and in preventing relapse to methamphetamine seeking in preclinical models of methamphetamine addiction.

Does physical activity protect against drug abuse vulnerability?

BACKGROUND

The current review examined recent literature to determine our state of knowledge about the potential ability of physical activity serve as a protectant against drug abuse vulnerability.

METHODS

Both preclinical and clinical studies were examined using either associational or random assignment study designs. In addition to examining drug use as an outcome variable, the potential neural mediators linking physical activity and drug abuse vulnerability were examined.

CONCLUSIONS

Several important conclusions may be drawn. First, the preclinical evidence is solid in showing that physical activity in various forms is able to serve as both a preventive and treatment intervention that reduces drug use, although voluntary alcohol drinking appears to be an exception to this conclusion. Second, the clinical evidence provides some evidence, albeit mixed, to suggest a beneficial effect of physical activity on tobacco dependent individuals. In contrast, there exists only circumstantial evidence that physical activity may reduce use of drugs other than nicotine, and there is essentially no solid information from random control studies to know if physical activity may prevent initiation of problem use. Finally, both preclinical and clinical evidence shows that various brain systems are altered by physical activity, with the medial prefrontal cortex (mPFC) serving as one potential node that may mediate the putative link between physical activity and drug abuse vulnerability. It is concluded that novel neurobehavioral approaches taking advantage of novel techniques for assessing the physiological impact of physical activity are needed and can be used to inform the longitudinal random control studies that will answer definitively the question posed.

Exercise as a novel treatment for drug addiction: a neurobiological and stage-dependent hypothesis

Physical activity, and specifically exercise, has been suggested as a potential treatment for drug addiction. In this review, we discuss clinical and preclinical evidence for the efficacy of exercise at different phases of the addiction process. Potential neurobiological mechanisms are also discussed focusing on interactions with dopaminergic and glutamatergic signaling and chromatin remodeling in the reward pathway. While exercise generally produces an efficacious response, certain exercise conditions may be either ineffective or lead to detrimental effects depending on the level/type/timing of exercise exposure, the stage of addiction, the drug involved, and the subject population. During drug use initiation and withdrawal, its efficacy may be related to its ability to facilitate dopaminergic transmission, and once addiction develops, its efficacy may be related to its ability to normalize glutamatergic and dopaminergic signaling and reverse drug-induced changes in chromatin via epigenetic interactions with brain-derived neurotrophic factor (BDNF) in the reward pathway. We conclude with future directions, including the development of exercise-based interventions alone or as an adjunct to other strategies for treating drug addiction.

The effects of exercise on cocaine self-administration, food-maintained responding, and locomotor activity in female rats: importance of the temporal relationship between physical activity and initial drug exposure

Previous studies have reported that exercise decreases cocaine self-administration in rats with long-term access (8+ weeks) to activity wheels in the home cage. The purpose of this study was to (a) examine the importance of the temporal relationship between physical activity and initial drug exposure, (b) determine the effects of exercise on responding maintained by a nondrug reinforcer (i.e., food), and (c) investigate the effects of exercise on cocaine-induced increases in locomotor activity. To this end, female rats were obtained at weaning and divided into 4 groups: (a) EXE-SED rats were housed in exercise cages for 6 weeks and then transferred to sedentary cages after the first day of behavioral testing; (b) SED-EXE rats were housed in sedentary cages for 6 weeks and then transferred to exercise cages after the first day of behavioral testing; (c) SED-SED rats remained in sedentary cages for the duration of the study; and (d) EXE-EXE rats remained in exercise cages for the duration of the study. Relative to the sedentary group (SED-SED), exercise reduced cocaine self-administration in both groups with access to activity wheels after initial drug exposure (EXE-EXE, SED-EXE) but did not reduce cocaine self-administration in the group with access to activity wheels only before drug exposure (EXE-SED). Exercise also decreased the effects of cocaine on locomotor activity but did not reduce responding maintained by food. These data suggest that exercise may reduce cocaine use in drug-experienced individuals with no prior history of aerobic activity without decreasing other types of positively reinforced behaviors.

Natural rewards, neuroplasticity, and non-drug addictions

There is a high degree of overlap between brain regions involved in processing natural rewards and drugs of abuse. "Non-drug" or "behavioral" addictions have become increasingly documented in the clinic, and pathologies include compulsive activities such as shopping, eating, exercising, sexual behavior, and gambling. Like drug addiction, non-drug addictions manifest in symptoms including craving, impaired control over the behavior, tolerance, withdrawal, and high rates of relapse. These alterations in behavior suggest that plasticity may be occurring in brain regions associated with drug addiction. In this review, I summarize data demonstrating that exposure to non-drug rewards can alter neural plasticity in regions of the brain that are affected by drugs of abuse. Research suggests that there are several similarities between neuroplasticity induced by natural and drug rewards and that, depending on the reward, repeated exposure to natural rewards might induce neuroplasticity that either promotes or counteracts addictive behavior.

Reduction of extinction and reinstatement of cocaine seeking by wheel running in female rats

RATIONALE AND OBJECTIVES

Previous work has shown that wheel running reduced the maintenance of cocaine self-administration in rats. In the present study, the effect of wheel running on extinction and reinstatement of cocaine seeking was examined. Female rats were trained to run in a wheel during 6-h sessions, and they were then catheterized and placed in an operant conditioning chamber where they did not have access to the wheel but were allowed to self-administer iv cocaine. Subsequently, rats were divided into four groups and were tested on the extinction and reinstatement of cocaine seeking while they had varying access to a wheel in an adjoining compartment. The four groups were assigned to the following wheel access conditions: (1) wheel running during extinction and reinstatement (WER), (2) wheel running during extinction and a locked wheel during reinstatement (WE), (3) locked wheel during extinction and wheel running during reinstatement (WR), and (4) locked wheel during extinction and reinstatement (WL). WE and WR were retested later to examine the effect of one session of wheel access on cocaine-primed reinstatement.

RESULTS

There were no group differences in wheel revolutions, in rate of acquisition of cocaine self-administration, or in responding during maintenance when there was no wheel access. However, during extinction, WE and WER responded less than WR and WL. WR and WER had lower cocaine-primed reinstatement than WE and WL. One session of wheel exposure in WE also suppressed cocaine-primed reinstatement.

CONCLUSIONS

Wheel running immediately and effectively reduced cocaine-seeking behavior, but concurrent access to running was necessary. Thus, exercise is a useful and self-sustaining intervention to reduce cocaine-seeking behavior.

Acquisition and reinstatement of MDMA-induced conditioned place preference in mice pre-treated with MDMA or cocaine during adolescence

Those who take ecstasy are more likely to consume other drugs than non-users with cocaine abuse being reported by 75.5% of high school student MDMA (+/- 3,4-methylenedioxymetamphetamine hydrochloride) users. The aim of this work was to evaluate the effects of exposure during adolescence to MDMA, cocaine or to both drugs on the MDMA-induced conditioned place preference (CPP) in adult mice. Animals received two daily administrations of saline, 10 mg/kg of MDMA, 25 mg/kg of cocaine or 10 mg/kg of MDMA plus 25 mg/kg of cocaine over 3 days (from PD28 to 30). Three weeks after pre-treatment, the MDMA-induced CPP procedure was initiated (PD52). Acquisition of CPP was induced with a sub-threshold dose of MDMA (1.25 mg/kg) only in animals treated during adolescence with MDMA alone. Preference was established in all the groups after conditioning with 10 mg/kg of MDMA, while the time required to achieve extinction was longer in those pre-treated with cocaine or MDMA alone (46 and 28 sessions, respectively). Moreover, preference was reinstated with progressively lower priming doses of MDMA in mice pre-treated with MDMA or cocaine alone. These results demonstrate that early exposure to MDMA or cocaine induces long-lasting changes that last until adulthood and modify the response of animals to MDMA.

Treadmill exercise reduces self-administration of morphine in male rats

Exercise can activate the same pathways as morphine. The aim of the present study was to clarify the effect of short-term and mid-term exercises on the self-administration of morphine in rats. Male Wistar rats were initially trained to receive small pellets of food by pressing the active lever in self-administration apparatus. Rats were divided into 4 groups: Saline, Morphine, Exercise 1 (11 days) and Exercise 2 (30 days). Their jugular vein was cannulated. The animals were placed in self-administration apparatus and allowed to self-administer morphine (0.5mg per infusion all test groups) or saline (Saline group) during consecutive days, for 2h/sessions. In the group 1 the rats were running before each session of self-administration and of group Exercise 2, 30 days before surgery as well as before each session. The pressing numbers of active and passive levers in each group and among different groups were compared. The number of active lever pressing of Morphine group was significantly higher than Saline group (p<0.001). In Exercise 1 and Exercise 2 groups, the number of active lever pressing was significantly lower than Morphine group (p<0.001). As exercise can activate many neurotransmitter systems involved in the addiction process and increase the release of endorphins, it is likely that could decrease the morphine self-administration in this experimental setup.