The fatty acid amide hydrolase in lymphocytes from sedentary and active subjects

Aerobic Exercise and Endocannabinoids: A Narrative Review of Stress Regulation and Brain Reward Systems

Aerobic exercise is a widely adopted practice, not solely for enhancing fitness and reducing the risk of various diseases but also for its ability to uplift mood and aid in addressing depression and anxiety disorders. Within the scope of this narrative review, we seek to consolidate current insights into the endocannabinoid-mediated regulation of stress and the brain's reward mechanism resulting from engaging in aerobic exercise. A comprehensive search was conducted across Medline, SPORTDiscus, Pubmed, and Scopus, encompassing data available until November 30, 2023. This review indicates that a bout of aerobic exercise, particularly of moderate intensity, markedly augments circulating levels of endocannabinoids - N-arachidonoyl-ethanolamine (AEA) and 2-acylglycerol (2-AG), that significantly contributes to mood elevation and reducing stress in healthy individuals.  The current understanding of how aerobic exercise impacts mental health and mood improvement is still unclear. Moderate and high-intensity aerobic exercise modulates stress through a negative feedback mechanism targeting both the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic nervous system, thereby facilitating stress regulation crucial role in endocannabinoid synthesis, ultimately culminating in the orchestration of negative feedback across multiple tiers of the HPA axis, coupled with its influence over cortical and subcortical brain structures. The endocannabinoid has been observed to govern the release of neurotransmitters from diverse neuronal populations, implying a universal mechanism that fine-tunes neuronal activity and consequently modulates both emotional and stress-related responses. Endocannabinoids further assume a pivotal function within brain reward mechanisms, primarily mediated by CB1 receptors distributed across diverse cerebral centers. Notably, these endocannabinoids partake in natural reward processes, as exemplified in aerobic exercise, by synergizing with the dopaminergic reward system. The genesis of this reward pathway can be traced to the ventral tegmental area, with dopamine neurons predominantly projecting to the nucleus accumbens, thereby inciting dopamine release in response to rewarding stimuli.

Endocannabinoid and psychological responses to acute resistance exercise in trained and untrained adults

INTRODUCTION

This study examined the effects of acute resistance exercise on circulating endocannabinoid (eCB) and mood responses in trained and untrained healthy adults.

METHODS

Thirty-two healthy adults (22.1 ± 2.9 years) were recruited from trained (reporting resistance exercise at least twice per week for ≥ previous three months) and untrained (performing no resistance exercise for ≥ previous three months) groups. Participants (13 male, 19 female) completed three sets of resistance exercise (16 repetitions at 50% 1-repetition max, 12 repetitions at 70% 1-repetition max, 8 repetitions at 80% 1-repetition max). Resistance machines targeted the legs, chest, back, and abdominal muscles. Mood states, affect, and circulating eCB concentrations were evaluated before and after resistance exercise.

RESULTS

There were significant decreases in AEA, PEA, and OEA levels following acute resistance exercise (p <0.05; ds = -0.39, -0.48, -0.65, respectively), with no significant group differences or group by time interactions. 2-AG did not change significantly. Positive affect increased significantly following resistance exercise (p = 0.009), while negative affect decreased (p <0.001). Depressive symptoms, anger, confusion, and total mood disturbance decreased significantly (p <0.05), while vigor increased significantly following resistance exercise (p = 0.005). There were no significant group differences or group by time interactions for any psychological outcomes.

CONCLUSION

These results indicate that acute resistance exercise may reduce eCB and related lipid concentrations, which is opposite to the increase in lipids typically observed with acute aerobic exercise. Furthermore, psychological improvements occur after resistance exercise regardless of decreases in eCBs, supporting the notion that psychological changes with exercise likely occur through a wide variety of biological and environmental mechanisms.

Physical Activity to Prevent the Age-Related Decline of Endogenous Pain Modulation

As humans age, the capacity of the central nervous system to endogenously modulate pain significantly deteriorates, thereby increasing the risk for the development of chronic pain. Older adults are the least physically active cohort of all age groups. We hypothesize that a sedentary lifestyle and decreased physical activity may contribute to the decline of endogenous pain modulation associated with aging.

Endocannabinoid hydrolases differentially distribute in platelets and red blood cells and are differentially released by thrombin

BACKGROUND

Plasma levels of the major endocannabinoids 2-arachidonoylgycerol (2AG) and anandamide (N-arachidonoylethanolamine, AEA) have been identified to vary independently with particular pathological conditions. The levels of these endocannabinoids are tightly regulated by two hydrolytic enzymes, monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), respectively.

OBJECTIVES

In this study, we have quantified these enzyme activities in the major blood fractions.

PATIENTS/METHODS

In blood fractions from human volunteers, radiometric assays were used to quantify monoacylglycerol lipase and fatty acid amide hydrolase. Tagging with fluorophosphonate-rhodamine allowed quantification of platelet serine hydrolase activities.

RESULTS

Fatty acid amide hydrolase activity was highest in platelets, while MAGL activity was most abundant in erythrocytes. Sampling the blood of donors on two further occasions 15 days apart showed no significant change in platelet FAAH or erythrocyte MAGL activities. Activities were not different when comparing female donors with males. Storage of these blood fractions at - 80 °C was associated with a rapid loss in enzyme activities, which could largely by avoided by storage in liquid nitrogen. Incubation of platelets and erythrocytes in the presence of thrombin lead to release of measurable FAAH, but not MAGL, activity. Tagging of serine hydrolase activities with fluorophosphonate-rhodamine allowed confirmation of MAGL activity in platelet preparations, as well as multiple other enzymes.

CONCLUSIONS

These investigations suggest a potential role for FAAH in regulation of coagulation, while the role of MAGL in blood requires further investigation.

Investigating the Long-Term Effect of an Interdisciplinary Multimodal Rehabilitation Program on Levels of Bioactive Lipids and Telomerase Activity in Blood from Patients with Chronic Pain

Mechanism-based diagnosis and therapies for chronic pain are lacking. However, bio-psycho-social interventions such as interdisciplinary multimodal rehabilitation programs (IPRPs) have shown to be relatively effective treatments. In this context we aim to investigate the effects of IPRP on the changes in levels of bioactive lipids and telomerase activity in plasma, and if these changes are associated with changes in pain intensity and psychological distress. This exploratory study involves 18 patients with complex chronic pain participating in an IPRP. Self-reports of pain, psychological distress, physical activity, and blood samples were collected before the IPRP and at a six-month follow-up. Levels of arachidonoylethanolamide (AEA) and 2-arachidonoylglycerol (2-AG), palmitoylethanolamide (PEA), oleoylethanolamide (OEA), stearoylethanolamide (SEA), and telomerase activity were measured. Pain intensity was decreased, and SEA levels were increased at the six-month follow up. A significant correlation existed between changes in SEA levels and pain intensity. AEA levels, were inversely correlated with physical activity. Furthermore, 2-AG and telomerase activity was significantly correlated at the six-month follow-up. This study confirms that IPRP is relatively effective for reduction in chronic pain. Changes in SEA were correlated with changes in pain intensity, which might indicate that SEA changes reflect the pain reduction effects of IPRP.

Do Endocannabinoids Cause the Runner’s High? Evidence and Open Questions

The runner’s high is an ephemeral feeling some humans experience during and after endurance exercise. Recent evidence in mice suggests that a runner’s high depends on the release of endocannabinoids (eCBs) during exercise. However, little is known under what circumstances eCBs are released during exercise in humans. This systematic review sampled all data from clinical trials in humans on eCB levels following exercise from the discovery of eCBs until April 20, 2021. PubMed/NCBI, Ovid MEDLINE, and Cochrane library were searched systematically and reviewed following the PRISMA guidelines. From 278 records, 21 met the inclusion criteria. After acute exercise, 14 of 17 studies detected an increase in eCBs. In contrast, after a period of long-term endurance exercise, four articles described a decrease in eCBs. Even though several studies demonstrated an association between eCB levels and features of the runner’s high, reliable proof of the involvement of eCBs in the runner’s high in humans has not yet been achieved due to methodological hurdles. In this review, we suggest how to advance the study of the influence of eCBs on the beneficial effects of exercise and provide recommendations on how endocannabinoid release is most likely to occur under laboratory conditions.

Cannabinoids: an Effective Treatment for Chemotherapy-Induced Peripheral Neurotoxicity?

Chemotherapy-induced peripheral neurotoxicity (CIPN) is one of the most frequent side effects of antineoplastic treatment, particularly of lung, breast, prostate, gastrointestinal, and germinal cancers, as well as of different forms of leukemia, lymphoma, and multiple myeloma. Currently, no effective therapies are available for CIPN prevention, and symptomatic treatment is frequently ineffective; thus, several clinical trials are addressing this unmet clinical need. Among possible pharmacological treatments of CIPN, modulation of the endocannabinoid system might be particularly promising, especially in those CIPN types where analgesia and neuroinflammation modulation might be beneficial. In fact, several clinical trials are ongoing with the specific aim to better investigate the changes in endocannabinoid levels induced by systemic chemotherapy and the possible role of endocannabinoid system modulation to provide relief from CIPN symptoms, a hypothesis supported by preclinical evidence but never consistently demonstrated in patients. Interestingly, endocannabinoid system modulation might be one of the mechanisms at the basis of the reported efficacy of exercise and physical therapy in CIPN patients. This possible virtuous interplay will be discussed in this review.

Role of the endocannabinoid system in the regulation of the skeletal muscle response to exercise

Exercise is a valuable tool in the prevention and treatment of cardiometabolic diseases like obesity and type 2 diabetes. Interestingly, endocannabinoids (eCBs), involved in a large range of physiological processes, are elevated with both obesity and acute exercise. In this review we outline this paradox overlap in the context of metabolic health and delineate the transcriptomic response of skeletal muscle to acute and chronic aerobic and resistance exercise in relation to the endocannabinoid system by utilizing a meta-analyses tool. We show that exercise modulates the expression of receptors and enzymes involved in the synthesis and breakdown of eCBs and discuss that eCBs possibly interfere with the anti-inflammatory effect of exercise. The endocannabinoid system (ECS), consisting of certain endogenous lipids (i.e. endocannabinoids), their receptors and associated metabolic enzymes, is involved in the modulation of a plethora of cognitive and physiological processes. Besides its role in the control of, for example, mood formation and immune responses, the ECS takes part in the regulation of appetite and energy metabolism [1,2]. In this current opinion review we will focus on the increased activity of the ECS that is associated with cardiometabolic diseases like obesity and type 2 diabetes (T2D), which paradoxically overlaps with the acute physiological response to exercise. After 1) outlining the role of the ECS in metabolic health, we will 2) discuss the link between endocannabinoid (eCB) action in skeletal muscle and cardiometabolic disease, 3) investigate how exercise modulates the gene expression of ECS components in skeletal muscle and 4) delineate the impact of the ECS on the immune response by skeletal muscle.

Lipid Hydrolase Enzymes: Pragmatic Prolongevity Targets for Improved Human Healthspan?

Compelling evidence suggests that lipid metabolism, which plays critical roles in fat storage, cell membrane maintenance, and cell signaling, is intricately linked to aging. Lipid hydrolases are important enzymes that catalyze the hydrolysis of more complex lipids into simpler lipids. Diverse interventions targeting lipid hydrolases can prolong or shorten life in model organisms. For example, the genetic removal of or RNAi knockdown against a phospholipase can reduce lifespan in Caenorhabditis elegans, Drosophila melanogaster, and Mus musculus. The removal of lysosomal acid lipase results in premature death in mice, while its overexpression in nematodes generates lean, long-lived individuals. The overexpression or inhibition of diacylglycerol lipase leads to enhanced or reduced longevity, respectively, in both worms and flies. Lifespan can also be extended by knocking down triacylglycerol lipases in yeast, overexpressing fatty acid amide hydrolase in worms, or removing hepatic lipase in a mouse model of coronary disease. Conversely, flies lacking the triacylglycerol lipase Brummer are obese and short lived. Linking sphingolipids and aging, removing the sphingomyelinase inositol phosphosphingolipid phospholipase shortens chronological lifespan in Saccharomyces cerevisiae, while inhibiting an acid sphingomyelinase in worms or inactivating alkaline ceramidase in flies extends lifespan. The clinical potential of manipulating these enzymes is highlighted by the FDA-approved obesity drug orlistat, which is an inhibitor of pancreatic and hepatic lipases that induces weight loss and improves insulin/glucose homeostasis. Additional research is warranted to better understand how these lipid hydrolases impact aging and to determine if clinical interventions targeting them are capable of improving human healthspan.

Lifestyle and Metabolic Syndrome: Contribution of the Endocannabinoidome

Lifestyle is a well-known environmental factor that plays a major role in facilitating the development of metabolic syndrome or eventually exacerbating its consequences. Various lifestyle factors, especially changes in dietary habits, extreme temperatures, unusual light-dark cycles, substance abuse, and other stressful factors, are also established modifiers of the endocannabinoid system and its extended version, the endocannabinoidome. The endocannabinoidome is a complex lipid signaling system composed of a plethora (>100) of fatty acid-derived mediators and their receptors and anabolic and catabolic enzymes (>50 proteins) which are deeply involved in the control of energy metabolism and its pathological deviations. A strong link between the endocannabinoidome and another major player in metabolism and dysmetabolism, the gut microbiome, is also emerging. Here, we review several examples of how lifestyle modifications (westernized diets, lack or presence of certain nutritional factors, physical exercise, and the use of cannabis) can modulate the propensity to develop metabolic syndrome by modifying the crosstalk between the endocannabinoidome and the gut microbiome and, hence, how lifestyle interventions can provide new therapies against cardiometabolic risk by ensuring correct functioning of both these systems.

Weight loss and improved mood after aerobic exercise training are linked to lower plasma anandamide in healthy people

Anandamide, a major endocannabinoid, participates in energy metabolism homeostasis and neurobehavioral processes. In a secondary analysis of an open-label, randomized controlled trial, we investigated the long-term effect of aerobic exercise on resting plasma anandamide, and explored its relationship with changes in body weight, cardiorespiratory fitness, and mood status in healthy, physically inactive individuals. Participants recruited between March 2013 to August 2015 at the UNIFESP's Neurology/Psychobiology Department were randomly allocated into a 12-weeks supervised moderate exercise program, or into waitlist, control condition. Thirty-four participants (age = 38 ± 11.5, BMI = 26.6 ± 3.6) were intention to treat-analysed (Exercise: n = 17; Control: n = 17). After intervention, there were significant decreases in plasma anandamide (p < .01), anger, anxiety, and body weight (all p < .05), whereas cardiorespiratory fitness increased (p < .05) in the exercise group. There were no significant changes in any variable for the control group. In the whole cohort, adjusted R² of multiple linear regressions showed that 12.2% of change body weight was explained by changes in anandamide (β = 0.391, p = .033), while 27% of change in mood disturbance (β = 0.546, p = .003), and 13.1% of change in anger (β = 0.404, p = .03) was explained by changes in anandamide. Our data suggest that the weight loss and mood improvement through regular moderate exercise may involve changes in anandamide metabolism/signaling. Trials registration: #NCT01972607.

Circulating Endocannabinoids: From Whence Do They Come and Where are They Going?

The goal of this review is to summarize studies in which concentrations of circulating endocannabinoids in humans have been examined in relationship to physiological measurements and pathological status. The roles of endocannabinoids in the regulation of energy intake and storage have been well studied and the data obtained consistently support the hypothesis that endocannabinoid signaling is associated with increased consumption and storage of energy. Physical exercise mobilizes endocannabinoids, which could contribute to refilling of energy stores and also to the analgesic and mood-elevating effects of exercise. Circulating concentrations of 2-arachidonoylglycerol are very significantly circadian and dysregulated when sleep is disrupted. Other conditions under which circulating endocannabinoids are altered include inflammation and pain. A second important role for endocannabinoid signaling is to restore homeostasis following stress. Circulating endocannabinoids are stress-responsive and there is evidence that their concentrations are altered in disorders associated with excessive stress, including post-traumatic stress disorder. Although determination of circulating endocannabinoids can provide important information about the state of endocannabinoid signaling and thus allow for hypotheses to be defined and tested, the large number of physiological factors that contribute to their circulating concentrations makes it difficult to use them in isolation as a biomarker for a specific disorder.

Exercise as an adjunctive treatment for cannabis use disorder

BACKGROUND

Despite cannabis being the most widely used illicit substance in the United States, individuals diagnosed with cannabis use disorder (CUD) have few well-researched, affordable treatment options available to them. Although found to be effective for improving treatment outcomes in other drug populations, exercise is an affordable and highly accessible treatment approach that has not been routinely investigated in cannabis users.

OBJECTIVES

The aim of this paper is to inform the topic regarding exercise's potential as an adjunctive treatment for individuals with CUD.

METHODS

We reviewed the evidence surrounding cannabis use and its current treatment in the United States, explored the rationale for including exercise in the treatment of substance use disorders (SUDs), and in particular, proposed a biological mechanism (i.e., endocannabinoids (eCBs)) that should be examined when utilizing exercise for the treatment of CUD.

RESULTS

Cannabis use is widespread and increasing in the United States. Chronic, heavy cannabis use may dysregulate the endogenous cannabinoid system, which has implications for several psychobiological processes that interact with the eCB system such as reward processing and the stress response. Given that exercise is a potent activator of the eCB system, it is mechanistically plausible that exercise could be an optimal method to supplement cessation efforts by reducing psychophysical withdrawal, managing stress, and attenuating drug cravings.

CONCLUSION

We suggest there is a strong behavioral and physiological rationale to design studies which specifically assess the efficacy of exercise, in combination with other therapies, in treating CUD. Moreover, it will be especially important to include the investigation of psychobiological mechanisms (e.g., eCBs, hippocampal volume), which have been associated with both exercise and SUDs, to examine the broader impact of exercise on behavioral and physiological responses to treatment.

The Endocannabinoid Signaling System in the CNS: A Primer

The purpose of this chapter is to provide an introduction to the mechanisms for the regulation of endocannabinoid signaling through CB1 cannabinoid receptors in the central nervous system. The processes involved in the synthesis and degradation of the two most well-studied endocannabinoids, 2-arachidonoylglycerol and N-arachidonylethanolamine are outlined along with information regarding the regulation of the proteins involved. Signaling mechanisms and pharmacology of the CB1 cannabinoid receptor are outlined, as is the paradigm of endocannabinoid/CB1 receptor regulation of neurotransmitter release. The reader is encouraged to appreciate the importance of the endocannabinoid/CB1 receptor signaling system in the regulation of synaptic activity in the brain.

2-Arachidonoylglycerol enhances platelet formation from human megakaryoblasts

Platelets modulate vascular system integrity, and their loss is critical in haematological pathologies and after chemotherapy. Therefore, identification of molecules enhancing platelet production would be useful to counteract thrombocytopenia. We have previously shown that 2-arachidonoylglycerol (2-AG) acts as a true agonist of platelets, as well as it commits erythroid precursors toward the megakaryocytic lineage. Against this background, we sought to further interrogate the role of 2-AG in megakaryocyte/platelet physiology by investigating terminal differentiation, and subsequent thrombopoiesis. To this end, we used MEG-01 cells, a human megakaryoblastic cell line able to produce in vitro platelet-like particles. 2-AG increased the number of cells showing ruffled surface and enhanced surface expression of specific megakaryocyte/platelet surface antigens, typical hallmarks of terminal megakaryocytic differentiation and platelet production. Changes in cytoskeleton modeling also occurred in differentiated megakaryocytes and blebbing platelets. 2-AG acted by binding to CB1 and CB2 receptors, because specific antagonists reverted its effect. Platelets were split off from megakaryocytes and were functional: they contained the platelet-specific surface markers CD61 and CD49, whose levels increased following stimulation with a natural agonist like collagen. Given the importance of 2-AG for driving megakaryopoiesis and thrombopoiesis, not surprisingly we found that its hydrolytic enzymes were tightly controlled by classical inducers of megakaryocyte differentiation. In conclusion 2-AG, by triggering megakaryocyte maturation and platelet release, may have clinical efficacy to counteract thrombocytopenia-related diseases.

Decreased circulating anandamide levels in preeclampsia

The endocannabinoid system has a key role in female reproduction, including implantation, decidualization and placentation. A growing number of studies indicate that placental and peripheral blood anandamide levels correlate closely with both spontaneous miscarriage and ectopic pregnancy. Anandamide has also been implicated in blood pressure regulation. In this study, we aimed to determine circulating anandamide levels in preeclampsia for the first time in the literature. Forty-three preeclamptic patients and 71 healthy pregnant women were involved in this case-control study. Serum anandamide concentrations were determined by high-performance liquid chromatography-mass spectrometry technique. Serum total soluble fms-like tyrosine kinase-1 (sFlt-1) and biologically active placental growth factor (PlGF) levels were measured by electrochemiluminescence immunoassay. For statistical analyses, nonparametric methods were applied. Serum levels of anandamide were significantly lower in preeclamptic patients than in healthy pregnant women (0.75 (0.44-1.03) ng ml(-1) vs. 1.30 (0.76-2.0) ng ml(-1), P<0.001). Preeclamptic patients had significantly higher sFlt-1 levels (12,121 (7963-18,316) pg ml(-1) vs. 2299 (1393-3179) pg ml(-1), P<0.001) and significantly lower PlGF concentrations (71.2 (39.2-86.4) pg ml(-1) vs. 256.8 (181.1-421.0) pg ml(-1), P<0.001) as compared with healthy pregnant women. Serum anandamide concentrations did not correlate with serum levels of sFlt-1 and PlGF in our healthy pregnant and preeclamptic groups. In conclusion, we demonstrated for the first time in the literature that serum anandamide concentrations are decreased in women with preeclampsia. However, the cause and consequence of this observation remain to be determined.

Effects of tadalafil administration on plasma markers of exercise-induced muscle damage, IL6 and antioxidant status capacity

INTRODUCTION

Physical exercise is associated with enhanced production of reactive oxygen species, which if uncontrolled can result in tissue injury. Phosphodiesterase type 5 inhibitors (PDE5i) exhibit protective effect against oxidative stress, both in animals and healthy/unhealthy humans. However, the effect of a chronic administration of PDE5i, particularly combined with physical exercise, has never been investigated.

PURPOSE

The present study was designed to evaluate the effect of the long-acting PDE5i tadalafil on oxidative status and muscle damage after exhaustive exercise in healthy males included in a double-blind crossover trial.

HYPOTHESIS

Tadalafil, having a putative antioxidant activity, may reduce oxidative damage after strenuous exercise.

METHODS

Each volunteer randomly received two tablets of placebo or tadalafil (20 mg/day) with 36 h of interval before performing exhaustive exercise. After 2 weeks of washout, the volunteers were crossed over. Blood samples were collected immediately before exercise, immediately after, and during recovery (15, 30, 60 min). Plasma total antioxidant status, glutathione homeostasis (GSH/GSSG), malondialdehyde (MDA), protein carbonyls, creatine kinase (CK), lactate dehydrogenase (LDH) and the inflammatory cytokine interleukin 6 were assessed.

RESULTS

Tadalafil administration per se affected redox homeostasis (GSH/GSSG -36%; p < 0.05), cellular (CK +75% and LDH +36%; p < 0.05) and oxidative damage (MDA +41% and protein carbonyls +50%; p < 0.05) markers. The exhaustive exercise increased all the above-reported biochemical parameters, with subjects from the tadalafil group showing significantly higher values with respect to the placebo group.

CONCLUSIONS

A prolonged exposure to tadalafil decreases antioxidant capacity at resting condition, therefore making subjects more susceptible to the oxidative stress induced by an exhaustive bout of exercise.

Moderate-vigorous physical activity across body mass index in females: moderating effect of endocannabinoids and temperament

BACKGROUND

Endocannabinoids and temperament traits have been linked to both physical activity and body mass index (BMI) however no study has explored how these factors interact in females. The aims of this cross-sectional study were to 1) examine differences among distinct BMI groups on daytime physical activity and time spent in moderate-vigorous physical activity (MVPA), temperament traits and plasma endocannabinoid concentrations; and 2) explore the association and interaction between MVPA, temperament, endocannabinoids and BMI.

METHODS

Physical activity was measured with the wrist-worn accelerometer Actiwatch AW7, in a sample of 189 female participants (43 morbid obese, 30 obese, and 116 healthy-weight controls). The Temperament and Character Inventory-Revised questionnaire was used to assess personality traits. BMI was calculated by bioelectrical impedance analysis via the TANITA digital scale. Blood analyses were conducted to measure levels of endocannabinoids and endocannabinoid-related compounds. Path-analysis was performed to examine the association between predictive variables and MVPA.

RESULTS

Obese groups showed lower MVPA and dysfunctional temperament traits compared to healthy-weight controls. Plasma concentrations of 2-arachidonoylglyceryl (2-AG) were greater in obese groups. Path-analysis identified a direct effect between greater MVPA and low BMI (b = -0.13, p = .039) and high MVPA levels were associated with elevated anandamide (AEA) levels (b = 0.16, p = .049) and N-oleylethanolamide (OEA) levels (b = 0.22, p = .004), as well as high Novelty seeking (b = 0.18, p<.001) and low Harm avoidance (b = -0.16, p<.001).

CONCLUSIONS

Obese individuals showed a distinct temperament profile and circulating endocannabinoids compared to controls. Temperament and endocannabinoids may act as moderators of the low MVPA in obesity.

Physical activity and the endocannabinoid system: an overview

Recognized as a "disease modifier", physical activity (PA) is increasingly viewed as a more holistic, cost-saving method for prevention, treatment and management of human disease conditions. The traditional view that PA engages the monoaminergic and endorphinergic systems has been challenged by the discovery of the endocannabinoid system (ECS), composed of endogenous lipids, their target receptors, and metabolic enzymes. Indeed, direct and indirect evidence suggests that the ECS might mediate some of the PA-triggered effects throughout the body. Moreover, it is now emerging that PA itself is able to modulate ECS in different ways. Against this background, in the present review we shall discuss evidence of the cross-talk between PA and the ECS, ranging from brain to peripheral districts and highlighting how ECS must be tightly regulated during PA, in order to maintain its beneficial effects on cognition, mood, and nociception, while avoiding impaired energy metabolism, oxidative stress, and inflammatory processes.