Endorphins: the basis of pleasure?

The effect of saffron and corrective exercises on depression and quality of life in women with multiple sclerosis: A randomized controlled clinical trial

Multiple Sclerosis (MS) is a chronic inflammatory disease of the central nervous system which causes various complications such as reduced ability to do daily activities, depression and early death of patients. The present study aimed to compare the effect of saffron and corrective exercises on depression and quality of life in women with MS. This randomized controlled clinical trial was conducted on 80 MS women for 12 weeks. Participants were selected through convenience sampling and allocated into four study groups (three intervention groups and one control group) using the stratified block randomization. The Expanded Disability Status Scale, Beck Depression Inventory and The Multiple Sclerosis Impact Scale were used to collect data at the start of the study and also at the end of the sixth and the twelfth weeks. At the end of the twelfth week, the depression mean scores in all experimental groups (saffron group, corrective exercises group, corrective exercises + saffron group) were significantly different compared to the control group (P < 0.05), and this difference in corrective exercises + saffron group was more than the others. Also, at the end of the twelfth week, the mean scores of the quality of life (both physical and mental dimensions) in all experimental groups were significantly different from the control group (P < 0.05). The saffron group in physical dimension and the corrective exercises + saffron group in psychological dimension showed a significant difference with other groups. Although each of the corrective exercises program and saffron consumption alone were effective in reducing depression and enhancing the quality of life in MS patients, the consequences will be more beneficial in case these two interventions are used together. Therefore, it is necessary to encourage MS patients to consume saffron supplement along with doing physical activities in caring and rehabilitation programs.

The Endocannabinoid System and Physical Exercise

The endocannabinoid system (ECS) is involved in various processes, including brain plasticity, learning and memory, neuronal development, nociception, inflammation, appetite regulation, digestion, metabolism, energy balance, motility, and regulation of stress and emotions. Physical exercise (PE) is considered a valuable non-pharmacological therapy that is an immediately available and cost-effective method with a lot of health benefits, one of them being the activation of the endogenous cannabinoids. Endocannabinoids (eCBs) are generated as a response to high-intensity activities and can act as short-term circuit breakers, generating antinociceptive responses for a short and variable period of time. A runner's high is an ephemeral feeling some sport practitioners experience during endurance activities, such as running. The release of eCBs during sustained physical exercise appears to be involved in triggering this phenomenon. The last decades have been characterized by an increased interest in this emotional state induced by exercise, as it is believed to alleviate pain, induce mild sedation, increase euphoric levels, and have anxiolytic effects. This review provides information about the current state of knowledge about endocannabinoids and physical effort and also an overview of the studies published in the specialized literature about this subject.

Psychological resilience buffers the association between cell phone addiction and sleep quality among college students in Jiangsu Province, China

BACKGROUND AND AIMS

Excessive use of cell phones can take up college students' time and energy, and the sleep quality will inevitably be affected. A high level of psychological resilience can help them to maintain a positive attitude and cope with stressful events. However, few studies were conducted to investigate the effects of psychological resilience buffering cell phone addiction on sleep quality. In our hypothesis, psychological toughness would mitigate the worsening impact of cell phone addiction on sleep quality.

METHODS

The sample consisted of 7,234 Chinese college students who completed an electronic questionnaire that included demographic characteristics, such as the Mobile Phone Addiction Index (MPAI), the Psychological Resilience Index (CD-RISC), and the Pittsburgh Sleep Quality Index (PSQI). SPSS 26.0 was used for data analysis, the measurement data were described by x ¯ ± s for those conforming to normal distribution, and the comparison of means between groups was analyzed by group t-test or one-way ANOVA. Those that was not conforming to normal distribution were described by median M (P ₂₅, P ₇₅), and the comparison of M between groups was analyzed by Mann-Whitney U test and Kruskal-Wallis H test. Using Spearman correlation analysis, the associations between mobile phone addiction, psychological resilience, and sleep quality were evaluated. Using SPSS Process, the mediating role of psychological resilience was examined.

RESULTS

The mean scores of cell phone addiction and psychological resilience were 45.00 (SD = 13.59) and 60.58 (SD = 18.30), respectively; the sleep quality score M (P ₂₅, P ₇₅) was 5.0 (3.0, 7.0). Cell phone addiction among college students had a direct predictive effect on sleep quality (β = 0.260, P < 0.01), and psychological resilience had a negative correlation with both cell phone addiction and sleep quality (β = -0.073, P < 0.01, and β = -0.210, P < 0.01). Psychological resilience was responsible for a mediating effect value of 5.556% between cell phone addiction and sleep quality.

CONCLUSION

Cell phone addiction has an impact on sleep quality both directly and indirectly through the mediating effect of psychological resilience. Increased psychological resilience has the potential effect to buffer the exacerbating of cell phone addiction on sleep quality. These findings provide an evidence for cell phone addiction prevention, psychological management, and sleep improvement in China.

Effects of Exercise Training on the Autonomic Nervous System with a Focus on Anti-Inflammatory and Antioxidants Effects

Studies show that the autonomic nervous system (ANS) has an important impact on health in general. In response to environmental demands, homeostatic processes are often compromised, therefore determining an increase in the sympathetic nervous system (SNS)’s functions and a decrease in the parasympathetic nervous system (PNS)’s functions. In modern societies, chronic stress associated with an unhealthy lifestyle contributes to ANS dysfunction. In this review, we provide a brief introduction to the ANS network, its connections to the HPA axis and its stress responses and give an overview of the critical implications of ANS in health and disease—focused specifically on the immune system, cardiovascular, oxidative stress and metabolic dysregulation. The hypothalamic–pituitary–adrenal axis (HPA), the SNS and more recently the PNS have been identified as regulating the immune system. The HPA axis and PNS have anti-inflammatory effects and the SNS has been shown to have both pro- and anti-inflammatory effects. The positive impact of physical exercise (PE) is well known and has been studied by many researchers, but its negative impact has been less studied. Depending on the type, duration and individual characteristics of the person doing the exercise (age, gender, disease status, etc.), PE can be considered a physiological stressor. The negative impact of PE seems to be connected with the oxidative stress induced by effort.

Cortisol is not enough: A complex stress reaction in tethered goats

The purpose of this study was to assess the diversity of physiological stress responses elicited by tethering versus loose holding in the Swedish domestic goat (Capra hircus). Eight goats were randomly divided into two groups and the experiment was performed in a crossover design. Six goats had implanted transmitters that registered heart rate and arterial blood pressure telemetrically and blood samples were taken on separate days. Heart rate increased around feeding both when the goats were held loose in pairs, and when they were tied up. When the goats were tethered, the heart rates and blood pressures were higher, and the concentrations of β-endorphin and oxytocin lower, compared to when held loose in pairs. In conclusion, housing and the company of another animal affect arterial blood pressure, heart rate, and the concentrations of β-endorphin and oxytocin in goats, but the cortisol and vasopressin concentrations did not differ between the treatments. The higher arterial blood pressure and heart rate, and lower concentrations of β-endorphin and oxytocin in tethered goats indicate that being tied up may be more stressful for the goats compared to being held loose. The use of single measures, eg cortisol concentrations, was not sufficient to give an accurate picture of the animals' response to the management system. This study demonstrates the importance of using a wide variety of physiological measures when evaluating stress in animal welfare research.

The Relationship Between 5-Hydroxytryptamine and Its Metabolite Changes With Post-stroke Depression

Post-stroke depression (PSD) is the most common and serious sequelae of stroke. Approximately 33% of stroke survivors were affected by PSD. However, many issues (e.g., incidence, diagnostic marker, and risk factor) related to PSD remained unclear. The "monoamine hypothesis" is a significant hypothesis for depression, which suggests that three monoamines play a key role in depression. Therefore, most current antidepressants are developed to modulate the monoamines on PSD treatment, and these antidepressants have good effects on patients with PSD. However, the potential mechanisms of three monoamines in PSD are still unclear. Previously, we proposed "three primary emotions," which suggested a new model of basic emotions based on the three monoamines. It may provide a new way for PSD treatment. In addition, recent studies have found that monoamine-related emotional intervention also showed potential effects in the treatment and prevention of PSD. This study discusses these issues and attempts to provide a prospect for future research on PSD.

A role for endogenous opiates in incubation behavior in ring neck doves (Streptopelia risoria)

Incubation of eggs is a critical component of parental care in avian species. However, we do not fully understand the neuroendocrine mechanisms underlying this vital behavior. While prolactin is clearly involved, it alone cannot explain the fine-tuning of incubation behavior. The present experiments explored the possibility that incubation is reinforced through a hedonic system in which contact with eggs elicited an opiate-mediated reinforcing state. Blockade of opiate receptors with naloxone reduced time ring neck doves (Streptopelia risoria) spent on the nest, possibly by uncoupling the opiate-receptor mediated hedonic experience of contact with eggs from nest-sitting behavior. Likewise, activation of opiate receptors with morphine also reduced time spent on the nest, possibly by activating an opiate-receptor mediated hedonic experience, hence rendering the eliciting behavior (contact with eggs) unnecessary. Taken together, the results suggest that the opiate system may play a previously unrecognized role in facilitating incubation through reinforcement.

Activation of Astrocytic μ-Opioid Receptor Causes Conditioned Place Preference

The underlying mechanisms of how positive emotional valence (e.g., pleasure) causes preference of an associated context is poorly understood. Here, we show that activation of astrocytic μ-opioid receptor (MOR) drives conditioned place preference (CPP) by means of specific modulation of astrocytic MOR, an exemplar endogenous Gi protein-coupled receptor (Gi-GPCR), in the CA1 hippocampus. Long-term potentiation (LTP) induced by a subthreshold stimulation with the activation of astrocytic MOR at the Schaffer collateral pathway accounts for the memory acquisition to induce CPP. This astrocytic MOR-mediated LTP induction is dependent on astrocytic glutamate released upon activation of the astrocytic MOR and the consequent activation of the presynaptic mGluR1. The astrocytic MOR-dependent LTP and CPP were recapitulated by a chemogenetic activation of astrocyte-specifically expressed Gi-DREADD hM4Di. Our study reveals that the transduction of inhibitory Gi-signaling into augmented excitatory synaptic transmission through astrocytic glutamate is critical for the acquisition of contextual memory for CPP.

A new model for the HPA axis explains dysregulation of stress hormones on the timescale of weeks

Stress activates a complex network of hormones known as the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis is dysregulated in chronic stress and psychiatric disorders, but the origin of this dysregulation is unclear and cannot be explained by current HPA models. To address this, we developed a mathematical model for the HPA axis that incorporates changes in the total functional mass of the HPA hormone-secreting glands. The mass changes are caused by HPA hormones which act as growth factors for the glands in the axis. We find that the HPA axis shows the property of dynamical compensation, where gland masses adjust over weeks to buffer variation in physiological parameters. These mass changes explain the experimental findings on dysregulation of cortisol and ACTH dynamics in alcoholism, anorexia, and postpartum. Dysregulation occurs for a wide range of parameters and is exacerbated by impaired glucocorticoid receptor (GR) feedback, providing an explanation for the implication of GR in mood disorders. These findings suggest that gland-mass dynamics may play an important role in the pathophysiology of stress-related disorders.

Do vampire bats groom others based on need?

Allogrooming provides a window into the social lives of many group-living mammals and birds. The fitness benefits of allogrooming are encouraged by proximate mechanisms that make it physiologically rewarding for both actors and receivers. However, receivers might not always benefit from allogrooming. Some allogrooming decisions might be the actor’s response to cues of the recipient’s need. Other decisions might only be caused by the actor’s motivational state. To test these ideas, we studied what triggers allogrooming in common vampire bats. In test 1, subjects that had experimentally disturbed and wetted fur were more likely to be allogroomed, even when controlling for increased self-grooming. In test 2, allogrooming rates were elevated not only by receiver self-grooming (a cue for receiver need) but also by the actor’s previous self-grooming. Both effects were significantly greater than the effect of self-grooming by third parties. Interestingly, we detected a negative interaction: the positive effect of receiver need on allogrooming was smaller when the actor was previously self-grooming. This is consistent with the hypothesis that there are “receiver-driven” allogrooming decisions, which are responses to recipient need, and “actor-driven” decisions, which are not. We predict that receiver-driven allogrooming will bestow greater benefits to recipients compared with actor-driven allogrooming.

The healing power of well-being

Neuroendocrine system plays an important role in modulating our body functions and emotions. At the same time, emotions implicate a pivotal role in the regulation of brain function and neuroendocrine system. Negative affective states such as depression and stress are associated with premature mortality and increase the risk of various fatal diseases. It has been suggested that positive affective states are protective and improve our health and productiveness. Several potential mechanisms have been posited to account for these associations including improved health behaviour, direct physiological benefits, enhanced resistance and recovery from stress among individuals with high versus low positive emotional resources. This review summarises information concerning the neuronal and hormonal systems in mood, impact of negative and positive affective states on the level of cortisol, epinephrine, serotonin, dopamine and endorphins. The functional correlation of neuronal and hormonal systems in the development of diseases and their ability to enhance health-relevant biological processes are also evaluated.

Acute and chronic exercise modulates the expression of MOR opioid receptors in the hippocampal formation of rats

Exercise stimulates the release of beta-endorphin and other endogenous opioid peptides that are believed to be responsible for changes in mood, perception of pain and also performance. Although the vast majority of literature data support the role of physical exercise in increasing beta-endorphin levels, indirect measures such as increased endorphin levels in peripheral blood do not reflect opioid levels in the central nervous system. The purpose of the present study was to verify whether acute and chronic exercise using both voluntary and forced exercise procedures could modify the expression of μ-opioid receptors (MOR) in rat hippocampal formation. Immunoblotting analysis showed significantly enhanced MOR expression in the hippocampal formation in the acute (forced and voluntary) exercise groups when compared to the control group. Conversely, a significant reduction of MOR expression was noted in the chronic forced and chronic voluntary exercise groups compared to the acute forced and voluntary groups respectively. MOR expression was not significantly different in rats trained using both acute or chronic exercise. Immunohistochemistry analysis showed a higher number of MOR-positive cells for acute forced and voluntary exercise groups in the CA1, CA3, hilus and dentate gyrus regions compared to the control group. Our findings indicate that acute and chronic exercise modulates MOR expression in the hippocampal formation of rats.

Can non-invasive glucocorticoid measures be used as reliable indicators of stress in animals?

Refinement techniques are being increasingly employed in all fields of animal research to try to ensure that the highest standards of welfare are upheld. This review concerns one of the main emerging techniques for the assessment of welfare itself, namely the non-invasive measurement of glucocorticoids (GCs) as indicators of stress. The paper is divided into three sections. The first discusses the relationship between GCs and stress. The second section considers whether factors other than stress are linked to rises in GCs, eg exercise, oestrus cycle and diet. The final part examines the reliability of the non-invasive techniques that measure GCs from samples of saliva and faeces. Although it is important to take into account some caveats associated with the methodologies employed, it is concluded, nevertheless, that these techniques can give accurate and reliable information regarding the welfare status of an individual or group of animals without the procedures themselves causing any kind of distress to the subjects.

The functions of deliberate self-injury: a review of the evidence

Deliberate self-injury is defined as the intentional, direct injuring of body tissue without suicidal intent. The present article reviews the empirical research on the functions of self-injury. This literature includes self-reports of reasons for self-injuring, descriptions of the phenomenology of self-injury, and laboratory studies examining the effects of self-injury proxies on affect and physiological arousal. Results from 18 studies provide converging evidence for an affect-regulation function. Research indicates that: (a) acute negative affect precedes self-injury, (b) decreased negative affect and relief are present after self-injury, (c) self-injury is most often performed with intent to alleviate negative affect, and (d) negative affect and arousal are reduced by the performance of self-injury proxies in laboratory settings. Studies also provide strong support for a self-punishment function, and modest evidence for anti-dissociation, interpersonal-influence, anti-suicide, sensation-seeking, and interpersonal boundaries functions. The conceptual and empirical relationships among the different functions remain unclear. Future research should address the measurement, co-variation, clinical correlates, and treatment implications of different functions.

Emotion-processing deficits in eating disorders

OBJECTIVE

First, we measured both emotional awareness and alexithymia to understand better emotion-processing deficits in eating disorder patients (EDs). Second, we increased the reliability of the measures by limiting the influence of confounding factors (negative affects).

METHOD

Seventy females with eating disorders were compared with 70 female controls. Participants completed the Beck Depression Inventory (BDI; depression), the Hospital and Anxiety Depression Scale (HADS; anxiety), the Toronto Alexithymia Scale (TAS; alexithymia), and the Level of Emotional Awareness Scale (LEAS).

RESULTS

EDs exhibited higher alexithymia scores and lower LEAS scores, with an inability to identify and describe their own emotions, as well as an impairment in mentalizing others' emotional experience. Whereas alexithymia scores were related to depression scores, LEAS scores were not. After controlling for depression, alexithymia scores were similar in EDs and controls.

DISCUSSION

The marked impairment in emotion processing found in EDs is independent of affective disorders. Thus, the joint use of TAS and LEAS suggests a global emotion-processing deficit in EDs.

Neurologically plausible distinctions in cognition relevant to drug use etiology and prevention

This article outlines several distinctions in cognition and related topics in emotion that receive support from work in cognitive neuroscience and have important implications for prevention: implicit cognition, working memory, nonverbal memory, and neurobiological systems of habit. These distinctions have not been widely acknowledged or applied in drug use prevention research, despite their neural plausibility and the availability of methods to make this link. The authors briefly review the basis for the distinctions and indicate general implications and assessment possibilities for prevention researchers conducting large-scale field trials. Subse-quently, the article outlines a connectionist framework for specific applications in prevention interventions. These possibilities begin the attempt to derive useful fusions of normally distinct areas of prevention and cognitive neuroscience, in the spirit of a transdisciplinary approach.

Effect of acute alcohol intoxication on the opioid system in humans

We investigated the possible relations between the endogenous opioid system and acute alcoholic intoxication in 21 subjects, of whom 13 were drinkers who came to the emergency service with evident symptoms of drunkenness, and 8 were nondrinkers who consumed 1 g alcohol per kg body weight over a short period. Different patterns of changes were found in the two groups for plasma concentrations of beta-endorphin and adrenocorticotropic hormone. In drinkers, plasma levels of both substances increased, whereas in nondrinkers both concentrations decreased, the declines being especially notable 15, 30, and 45 min after ingestion. We found no differences between the two groups in plasma cortisol concentrations. The different levels of these substances may reflect differences in drinking behavior between the two groups.

Anhedonia: a neglected symptom of psychopathology

In the last century psychopathologists attached importance to the concept of anhedonia, the loss of ability to experience pleasure. Its role in the diagnosis of melancholia was considered to be crucial. In the present century attention to anhedonia has faded, possibly because of the focus upon depressed mood as the pathognomonic feature of depressive disorders. Research on the symptomatology of endogenous depression did not include the concept; anhedonia was also lacking from the major instruments of psychiatric research, the depression rating scales, Attention was drawn to anhedonia by two authors: by Meehl in the 1960s and by Klein in the 1970s. Meehl considered anhedonia from the point of view of a personality defect predisposing to mental illness; and Klein regarded anhedonia to be a symptom of depressive illness and probably the best clinical marker predicting response to antidepressant drugs. In 1980 the revised DSM presented the concept of 'loss of interest or pleasure' as one of the two cardinal symptoms of major depression. Since then there has been a gradual recovery of emphasis although many systems confuse the two concepts of 'loss of interest' and anhedonia. It is possible that anhedonia may provide the key to a more exact delineation of depressive disorders in biological research and in clinical practice. Further research will depend upon a more precise, cross-nationally agreed definition of the concept and the means of its assessment.