Beta-endorphin and the immune system--possible role in autoimmune diseases

Pain, Fear, Anxiety, and Stress: Relations to the Endogenous Opioid System

Pain, fear, stress, and anxiety are separate yet interrelated phenomena. Each of these concepts has an extensive individual body of research, with some more recent work focusing on points of conceptual overlap. The role of the endogenous opioid system in each of these phenomena is only beginning to be examined and understood. Research examining the ways in which endogenous opioids (e.g., beta-endorphin; βE) may mediate the relations among pain, fear, stress, and anxiety is even more nascent. This chapter explores the extant evidence for endogenous opioid activity as an underpinning mechanism of these related constructs, with an emphasis on research examining βE.

Immunosuppression by opioids: Mechanisms of action on innate and adaptive immunity

Opioids are excellent analgesics for the clinical treatment of various types of acute and chronic pain, particularly cancer-related pain. Nevertheless, it is well known that opioids have some nasty side effects, including immunosuppression, which is commonly overlooked. As a result, the incidence of opportunistic bacterial and viral infections increases in patients with long-term opioid use. Nowadays, there are no effective medications to alleviate opioid-induced immunosuppression. Understanding the underlying molecular mechanism of opioids in immunosuppression can enable researchers to devise effective therapeutic interventions. This review comprehensively summarized the exogenous opioids-induced immunosuppressive effects and their underlying mechanisms, the regulatory roles of endogenous opioids on the immune system, the potential link between opioid immunosuppressive effect and the function of the central nervous system (CNS), and the future perspectives in this field.

Role of neurotransmitters in immune-mediated inflammatory disorders: a crosstalk between the nervous and immune systems

Immune-mediated inflammatory diseases (IMIDs) are a group of common heterogeneous disorders, characterized by an alteration of cellular homeostasis. Primarily, it has been shown that the release and diffusion of neurotransmitters from nervous tissue could result in signaling through lymphocyte cell-surface receptors and the modulation of immune function. This finding led to the idea that the neurotransmitters could serve as immunomodulators. It is now manifested that neurotransmitters can also be released from leukocytes and act as autocrine or paracrine modulators. Increasing data indicate that there is a crosstalk between inflammation and alterations in neurotransmission. The primary goal of this review is to demonstrate how these two pathways may converge at the level of the neuron and glia to involve in IMID. We review the role of neurotransmitters in IMID. The different effects that these compounds exert on a variety of immune cells are also reviewed. Current and future developments in understanding the cross-talk between the immune and nervous systems will undoubtedly identify new ways for treating immune-mediated diseases utilizing agonists or antagonists of neurotransmitter receptors.

Critical neurological features of COVID-19: Role of imaging methods and biosensors for effective diagnosis

COVID-19 is a respiratory infection that has been declared as a global health crisis by the WHO. It mainly affects the respiratory system. Apart from respiratory system, it also affects other organs as well including the brain. Numerous emerging reports have demonstrated that the COVID-19 has detrimental effects on neurological functions, and can lead to severe impairment of the central nervous system (CNS). The neurological manifestations linked with COVID-19 include headache, anosmia, encephalitis, epileptic seizures, Guillain-Barre syndrome, stroke and intracerebral hemorrhage alongwith multiple others complications. The CNS related complications may be severe and are linked with poor diagnosis which may worsen the condition. Therefore, there is a need to precisely understand the neurological sequelae along with upcoming clinical outcomes. Here, we present a brief review of the neurological complications and symptoms associated with COVID-19 along with brain imaging findings. Further, we have discussed about the emerging biosensing approaches which may aid in rapid, precise and mass diagnosis of COVID-19.

Interaction of neurotransmitters and neurochemicals with lymphocytes

Neurotransmitters and neurochemicals can act on lymphocytes by binding to receptors expressed by lymphocytes. This review describes lymphocyte expression of receptors for a selection of neurotransmitters and neurochemicals, the anatomical locations where lymphocytes can interact with neurotransmitters, and the effects of the neurotransmitters on lymphocyte function. Implications for health and disease are also discussed.

Effects and mechanism of action of transcutaneous electrical acupuncture point stimulation in patients with abnormal semen parameters

Objective:

To evaluate the effect of transcutaneous electrical acupuncture point stimulation (TEAS) on sperm parameters and the underlying molecular mechanisms.

Methods:

A total of 121 patients diagnosed with oligozoospermia, asthenozoospermia or oligoasthenozoospermia were randomised into four groups (three treatment groups, one control): the TEAS groups were treated with 2 Hz (n=31), 100 Hz (n=31), or mock stimulation (n=29) at acupuncture points BL23, ST36, CV1 and CV4 for 2 months. The control group (n=30) was provided with lifestyle advice only.

Results

The changes in total sperm count and motility in the 2 Hz TEAS group were significantly greater than those in the mock group and the control group. The change in neutral α-glucosidase (NAG) and zinc levels in the 2 Hz group were significantly greater than those in the mock group and control group, and the changes in fructose levels of the 2 Hz group were significantly greater than those in the control group. Significant increases in calcium and integrin-binding protein 1 (CIB1) and reduction of cyclin-dependent kinase 1 b (CDK1) were also found after 2 Hz TEAS treatment.

Conclusions

The present findings suggest that 2 Hz TEAS can improve sperm count and motility in patients with abnormal semen parameters, and is associated with increases in seminal plasma zinc, NAG and fructose. The upregulation of CIB1 and downregulation of CDK1 by TEAS may be associated with its positive effects on sperm motility and count.

Trial registration:

http://www.chictr.org ; registration no. ChiCTR-TRC-11001775.

The HIV-1 transgenic rat model of neuroHIV

Despite the ability of current combination anti-retroviral therapy (cART) to limit the progression of HIV-1 to AIDS, HIV-positive individuals continue to experience neuroHIV in the form of HIV-associated neurological disorders (HAND), which can range from subtle to substantial neurocognitive impairment. NeuroHIV may also influence substance use, abuse, and dependence in HIV-positive individuals. Because of the nature of the virus, variables such as mental health co-morbidities make it difficult to study the interaction between HIV and substance abuse in human populations. Several rodent models have been developed in an attempt to study the transmission and pathogenesis of the HIV-1 virus. The HIV-1 transgenic (HIV-1Tg) rat is a reliable model of neuroHIV because it mimics the condition of HIV-infected patients on cART. Research using this model supports the hypothesis that the presence of HIV-1 viral proteins in the central nervous system increases the sensitivity and susceptibility of HIV-positive individuals to substance abuse.

Detection of the Levels of Neuropeptides, ACTH and Cortisol in the Blood of Patients with Polymyositis/Dermatomyositis and Their Significance

Recent research has shown that the neuroendocrine system can regulate the function of the immune system and that ACTH and cortisol play important roles in maintaining the immune homeostasis. Polymyositis and dermatomyositis (PM/DM) are autoimmune diseases with unclear pathogeneses closely related with immune disorders, so we detected the levels of neuropeptide Y (NPY), beta-endorphin (beta-EP), calcitonin gene-related peptide (CGRP), adrenocoricotropic hormone (ACTH), and cortisol in blood of patients with PM/DM to investigate the relationship between these indices and the pathogenesis of PM/DM. The detection of NPY, beta-EP, CGRP, and ACTH concentrations in plasma and cortisol in serum of 28 cases of PM/DM was carried out using radioimmunoassay methods, and the results were compared with those of 20 normal controls. The levels of NPY in the plasma of PM/DM was significantly higher than those of the controls, while beta-EP, CGRP and ACTH were significantly lower than those of the controls, and cortisol was not significantly different before treatment. Linear correlation analysis indicated that NPY was significantly positively correlated with CPK, and beta-EP and CGRP were significantly negatively correlated with CPK. There were no significant correlations among cortisol ACTH, and CPK and no significant correlations between NPY, beta-EP, CGRP, ACTH, cortisol and age or duration of disease before treatment. After treatment for three months, NPY, beta-EP and CGRP tended to become normal and no longer significantly different from the control values. However, ACTH fell further and was significantly lower than the level before treatment. Therefore the increase in NPY and the decreases in beta-EP, CGRP, and ACTH in the plasma of PM/DM patients may be related to the pathogenesis of PM/DM.

NeuroHIV and use of addictive substances

In the past three decades, substance abuse has been identified as a key comorbidity of human immunodeficiency virus-1 (HIV-1) infection. Many studies have found that the use and abuse of addictive substances hastens the progression of HIV-1 infection and HIV-associated neurocognitive disorders. Advances in highly active antiretroviral therapy (HAART) in the mid-1990s have been successful in limiting the HIV-1 viral load and maintaining a relatively healthy immune response, allowing the life expectancy of patients infected with HIV to approach that of the general population. However, even with HAART, HIV-1 viral proteins are still expressed and eradication of the virus, particularly in the brain, the key reservoir organ, does not occur. In the post-HAART era, the clinical challenge in the treatment of HIV infection is inflammation of the central nervous system (CNS) and its subsequent neurological disorders. To date, various explicit and implicit connections have been identified between the neuronal circuitry involved in immune responses and brain regions affected by and implicated in substance abuse. This chapter discusses past and current medical uses of prototypical substances of abuse, including morphine, alcohol, cocaine, methamphetamine, marijuana, and nicotine, and the evidence that systemic infections, particularly HIV-1 infection, cause neurological dysfunction as a result of inflammation in the CNS, which can increase the risk of substance abuse.

The mechanism of effective electroacupuncture on T cell response in rats with experimental autoimmune encephalomyelitis

Previously, we demonstrated that electroacupuncture (EA) decreased lymphocyte infiltration into the spinal cords of rats presenting with experimental autoimmune encephalomyelitis (EAE), a disease model used in the study of multiple sclerosis (MS). The aim of this study was to characterize the effects of EA on the EAE. Female Lewis rats were divided into either CFA, EAE, EA, or injection with naloxone after electroacupuncture (NAL) groups. Electroacupuncture was administered every day for 21 days. To evaluate proliferation and apoptosis, lymphocytes from rats presenting with EAE were collected and cultured with β-endorphin. Immunohistochemisty, flow cytometry and radio-immunity methods were applied to detect the expression of β-endorphin. Results presented in this report demonstrate that the beneficial anti-inflammatory effects of EA on EAE were related to β-endorphin production that balances the Thl/Th2 and Th17/Treg responses. These results suggest that β-endorphin could be an important component in the development of EA-based therapies used for the treatment of EAE.

The role of the endogenous opioid system in polycystic ovary syndrome

OBJECTIVE

To review the complex role of the opioid system in reproduction and carbohydrate metabolism, abnormalities in the opioid system in women with polycystic ovary syndrome (PCOS), and the role of opioid antagonists in the management of PCOS-related infertility.

DESIGN

Pertinent articles were identified through a computer PubMed search. References of selected articles were hand searched for additional citations.

CONCLUSION(S)

Endogenous opioids are generally considered inhibitory central neurotransmitters. Peripherally, opioids are involved in the regulation of pancreatic islet function, hepatic insulin clearance, and glucose metabolism, potentially contributing to the pathogenesis of hyperinsulinemia and insulin resistance in PCOS. The presence of sex steroids is required for normal function of the opioid system in both GnRH secretion and carbohydrate metabolism. In women with PCOS, growing evidence suggests dysregulation of the opioid system both centrally and peripherally, with complex interactions. The opioid system effects on carbohydrate metabolism appear to be modulated by obesity. Finally, naltrexone has been demonstrated to successfully augment traditional ovulation induction regimens, but has limited support as a single ovulation induction agent for PCOS.

Effect of restraint stress duration on humoral immune response in albino rats: modulation by chlordiazepoxide

We evaluated the effect of restraint stress (1 hr/day) for 6, 10, 14 and 21 days on antibody response against sheep RBC (SRBC) and modulation by chlordiazepoxide (CDP) pretreatment (10 mg/kg/day) in albino rats. Anti-SRBC titer was significantly decreased with increase in number of days of restraint stress exposure. CDP pretreatment significantly reversed the effects of 6, 10 and 14 (but not of 21) days of restraint stress. CDP treatment for 21 days per se suppressed immune response, but no additive effect was observed. CDP was not effective in chronic stress (i.e., 21 days of stress). Hence, the rationale behind benzodiazepines therapy in chronic stress needs to be evaluated.

Influência dos exercícios físicos de baixa e alta intensidade sobre o limiar de hipernocicepção e outros parâmetros em ratos

A prática de exercícios físicos é um hábito importante para manutenção do bem-estar físico e emocional de quem a adota com regularidade, podendo trazer grandes benefícios à saúde. Todavia, dependendo do seu tipo, intensidade, freqüência e duração, os exercícios também podem causar certos prejuízos para o organismo. Como benefício, é descrito o seu papel na função imune específica e não-específica e, nesta última, destaca-se o processo inflamatório. Assim, este trabalho teve como objetivo estudar os efeitos dos exercícios físicos de baixa e alta intensidade sobre a hipernocicepção, além de avaliar a massa corporal e o peso relativo de alguns órgãos de ratos. Para isso, foram utilizados ratos machos, adultos, da linhagem Wistar, os quais foram submetidos (grupo treinado) ou não (grupo não treinado) a exercícios em esteira ergométrica. A inflamação aguda foi induzida pela injeção de carragenina-0,5% no coxim da pata posterior esquerda dos ratos e a nocicepção foi mensurada por meio do teste plantar antes e após 1, 2, 3, 4, 6, 8 e 24 horas. Ao final das avaliações os ratos foram submetidos a anestesia profunda, até a eutanásia, para coleta e pesagem das glândulas adrenais, coração, baço e rins e posterior estudo anatomopatológico destes tecidos. A análise estatística dos resultados mostrou aumento significante (P < 0,05) no limiar de hipernocicepção nos momentos H2, H3, H4 e H6 nos animais treinados em alta intensidade. Houve também redução (P < 0,05) na massa corporal, bem como hipertrofia das glândulas adrenais e coração e aumento dos rins nos ratos treinados em alta intensidade, além de hipertrofia das adrenais naqueles treinados em baixa intensidade. Não ocorreram alterações estatisticamente significantes nos demais parâmetros. Concluiu-se que os exercícios físicos em esteira ergométrica alteraram a nocicepção, a massa corporal e o peso relativo de alguns órgãos, porém, de modo dependente do protocolo de exercícios aplicado aos animais.

beta-Endorphin as a regulator of human hair follicle melanocyte biology

The pro-opiomelanocortin (POMC)-derived peptides, alpha-melanocyte-stimulating hormone, and adrenocorticotropic hormone, are important mediators of human skin pigmentation via action at the melanocortin-1 receptor. Recent data suggests that such a regulatory role also exists for the endogenous opiate, beta-endorphin (beta-END). A role for this beta-END in the regulation of follicular pigmentation, however, has not been determined. This study was designed to examine the involvement of the beta-END/mu-opiate receptor system in human follicular melanocyte biology. We employed RT-PCR, and immunohisto/cytochemistry and immunoelectron microscopy using beta-END and mu-opiate receptor specific antibodies and a functional role for beta-END was assessed by direct stimulation with the peptide. This study has demonstrated that human hair follicle melanocytes (HFM) express mRNA for the mu-opiate receptor and POMC. Furthermore, beta-END and its high affinity mu-opiate receptor are expressed at the protein level in glycoprotein100-positive follicular melanocytes and as a function of their anatomic location and differentiation status during the hair growth cycle. Functional studies revealed that beta-END is a modifier of HFM phenotype via its ability to upregulate melanogenesis, dendricity, and proliferation. These findings suggest a new regulatory role for beta-END in human HFM biology, providing a new research direction into the fundamental regulation of human hair pigmentation.

Immunity and β-Endorphin Concentrations in Hypothalamus and Plasma in Rats with Steroid-Induced Polycystic Ovaries: Effect of Low-Frequency Electroacupuncture1

The human endocrinological disorder polycystic ovary syndrome (PCOS) is a common cause of reproductive failure. Even though the cause of PCOS is unknown, hormone and immune disturbances as well as hyperactivity in the sympathetic nervous system are likely to be involved in the pathogenesis of the disease. The present study was undertaken to elucidate if rats with estradiol valerate (EV)-induced polycystic ovaries (PCO) have altered beta-endorphin concentrations in the hypothalamus and in plasma and if they have alterations in circulating immune cell populations and the activity. Repeated low-frequency (2 Hz) electroacupuncture (EA) treatments are known to modulate the release of beta-endorphin, immune responses, and the activity in the autonomic nervous system. We therefore also investigated the effect of EA treatments on the beta-endorphin and the immune systems. Low-frequency EA was given 12 times, 25 min each, over 30 days starting 2-3 days after i.m. injection of EV. The beta-endorphin concentrations in the hypothalamus and in plasma as well as the frequencies of CD4+ T cells and CD8+ T cells were significantly lower in EV-injected control rats as compared to oil-injected control rats. Repeated EA treatments in EV-injected rats significantly increased beta-endorphin concentrations in the hypothalamus. In conclusion, these findings show that both the beta-endorphinergic and the immune system are significantly impaired in rats with steroid-induced PCO and that repeated EA treatments can restore some of these disturbances.

Regulation of human epidermal melanocyte biology by beta-endorphin

beta-Endorphin is an opioid peptide cleaved from the precursor pro-hormone pro-opiomelanocortin, from which other peptides such as adrenocorticotropic hormone, beta-lipotropic hormone, and alpha-melanocyte-stimulating hormone are also derived. alpha-Melanocyte-stimulating hormone and adrenocorticotropic hormone are well documented to regulate human skin pigmentation via action at the melanocortin-1 receptor. Whereas plasma beta-endorphin is reported to increase after exposure to ultraviolet radiation, to date a functional role for beta-endorphin in the regulation of human epidermal melanocyte biology has not been demonstrated. This study was designed to examine the involvement of the beta-endorphin/mu-opiate receptor system in human epidermal melanocytes. To address this question we employed reverse transcription-polymerase chain reaction, and immunohistochemistry/cytochemistry and immunoelectron microscopy using beta-endorphin and mu-opiate receptor specific antibodies. A functional role for beta-endorphin was assessed in epidermal melanocyte cultures by direct stimulation with the peptide. This study demonstrated the expression of mu-opiate receptor mRNA in cultured epidermal melanocytes, as well as mRNA for pro-opiomelanocortin. In addition, we have shown that beta-endorphin and mu-opiate receptor are expressed at the protein level in situ in glycoprotein100-positive melanocytes. The expression of both beta-endorphin and mu-opiate receptor correlated positively with their differentiation status in vitro. Furthermore, immunoelectron microscopy studies revealed an association of beta-endorphin with melanosomes. Functional studies showed that beta-endorphin has potent melanogenic, mitogenic, and dendritogenic effects in cultured epidermal melanocytes deprived of any exogenous supply of pro-opiomelanocortin peptides. Thus, we report that human epidermal melanocytes express a fully functioning beta-endorphin/mu-opiate receptor system. In the absence of any data showing cross-talk between the mu-opiate receptor and the melanocortin-1 receptor, we conclude that the beta-endorphin/mu-opiate receptor system participates in the regulation of skin pigmentation.

Increased splenocyte proliferative response and cytokine production in beta-endorphin-deficient mice

We used beta-endorphin-deficient mice as a novel approach to confirm the physiological role that opioid peptides play in the development or regulation of the immune system. We found that mice lacking beta-endorphin possessed an enhanced immune response, measured in terms of splenocyte proliferation and interleukin (IL)-2 mRNA levels, in vitro production of the splenic macrophage inflammatory cytokines IL-6 and Tumor Necrosis Factor (TNF)-alpha and plasma IL-6 following lipopolysaccharide (LPS) administration. beta-Endorphin-deficient mice had attenuated increases of plasma ACTH and corticosterone levels in response to LPS. These results are consistent with a postulated inhibitory role of endogenous beta-endorphin on the immune system at multiple levels.

Levels of beta-endorphin in the plasma and skin tissue fluids of patients with vitiligo

In order to study the possible role of beta-endorphin in the pathogenesis of vitiligo, the authors measured the levels of beta-endorphin in the plasma from 40 patients and the tissue fluids of skin lesions and uninvolved skin from 33 patients with vitiligo, using a 125I RIA kit. The results showed that the levels of plasma beta-endorphin in the patients with vitiligo of all of the generalized, focal and segmental types and in either progressive and stable stages were significantly higher then the normal controls. The levels of beta-endorphin in the tissue fluids from skin lesions were significantly higher than those from uninvolved skin in both the local type and segmental type. In the generalized type, the levels of beta-endorphin were obviously increased in both the tissue fluids from skin lesions and those from uninvolved skin. It seems that beta-endorphin plays a role in the pathogenesis of vitiligo.

Special feature for the Olympics: effects of exercise on the immune system: neuropeptides and their interaction with exercise and immune function

It is known today that the immune system is influenced by various types of psychological and physiological stressors, including physical activity. It is well known that physical activity can influence neuropeptide levels both in the central nervous system as well as in peripheral blood. The reported changes of immune function in response to exercise have been suggested to be partly regulated by the activation of different neuropeptides and the identification of receptors for neuropeptides and steroid hormones on cells of the immune system has created a new dimension in this endocrine-immune interaction. It has also been shown that immune cells are capable of producing neuropeptides, creating a bidirectional link between the nervous and immune systems. The most common neuropeptides mentioned in this context are the endogenous opioids. The activation of endogenous opioid peptides in response to physical exercise is well known in the literature, as well as the immunomodulation mediated by opioid peptides. The role of endogenous opioids in the exercise-induced modulation of immune function is less clear. The present paper will also discuss the role of other neuroendocrine factors, such as substance P, neuropeptide Y and vasoactive intestinal peptide, and pituitary hormones, including growth hormone, prolactin and adrenocorticotrophin, in exercise and their possible effects on immune function.

High levels of endorphin and related pathologies of veterinary concern. A review

The authors report information about endogenous opioid peptides (EOP), receptors, antagonists and their interference with pain, stress, endocrine and immune system. A relationship between EOP and calcium homeostasis, both at extracellular and intracellular level, has been observed. In vitro, beta-endorphin exerts different actions through calcium channel functionality in epithelial cells. In rat aorta and cerebral cortex: beta-endorphin or Naloxone alternatively influence oocyte maturation through the mu-receptor gene expression and intracellular calcium concentration in granulosa and cumulus cells. Calcium channel block is removed by administrating Naloxone and calcium. In vivo, Naloxone and calcium removes EOP induced apoptosis in granulosa cells; is the most safe therapy in cow's milk fever; allow to remove ovarian follicular cysts. A negative influence of opioids on immune response after vaccination was established; EOP-related metabolic problems in post-partum cows. Abnormal intestinal motility, in which a Ca++ influence is well known, can be removed by Naloxone and calcium administration. Calcium-related function and neuromodulation must be re-evaluated since high level of EOP are involved in many pathologies through their influence on calcium activity. The use of calcium salts and Naloxone offers a safe and supplementary therapeutical possibility, active in any condition of altered endogenous opioids.

Special feature for the Olympics: effects of exercise on the immune system: neuropeptides and their interaction with exercise and immune function

It is known today that the immune system is influenced by various types of psychological and physiological stressors, including physical activity. It is well known that physical activity can influence neuropeptide levels both in the central nervous system as well as in peripheral blood. The reported changes of immune function in response to exercise have been suggested to be partly regulated by the activation of different neuropeptides and the identification of receptors for neuropeptides and steroid hormones on cells of the immune system has created a new dimension in this endocrine-immune interaction. It has also been shown that immune cells are capable of producing neuropeptides, creating a bidirectional link between the nervous and immune systems. The most common neuropeptides mentioned in this context are the endogenous opioids. The activation of endogenous opioid peptides in response to physical exercise is well known in the literature, as well as the immunomodulation mediated by opioid peptides. The role of endogenous opioids in the exercise-induced modulation of immune function is less clear. The present paper will also discuss the role of other neuroendocrine factors, such as substance P, neuropeptide Y and vasoactive intestinal peptide, and pituitary hormones, including growth hormone, prolactin and adrenocorticotrophin, in exercise and their possible effects on immune function.

Exercise and the immune system: regulation, integration, and adaptation

Stress-induced immunological reactions to exercise have stimulated much research into stress immunology and neuroimmunology. It is suggested that exercise can be employed as a model of temporary immunosuppression that occurs after severe physical stress. The exercise-stress model can be easily manipulated experimentally and allows for the study of interactions between the nervous, the endocrine, and the immune systems. This review focuses on mechanisms underlying exercise-induced immune changes such as neuroendocrinological factors including catecholamines, growth hormone, cortisol, beta-endorphin, and sex steroids. The contribution of a metabolic link between skeletal muscles and the lymphoid system is also reviewed. The mechanisms of exercise-associated muscle damage and the initiation of the inflammatory cytokine cascade are discussed. Given that exercise modulates the immune system in healthy individuals, considerations of the clinical ramifications of exercise in the prevention of diseases for which the immune system has a role is of importance. Accordingly, drawing on the experimental, clinical, and epidemiological literature, we address the interactions between exercise and infectious diseases as well as exercise and neoplasia within the context of both aging and nutrition.

Physical Exercise, Acupuncture and Immune Function

Experimental evidence suggests that the immune system is influenced by various types of psychological and physiological stressors, including physical activity. Natural immunity, representing a first line of defence in viral infections and cytotoxicity to a variety of tumour cells, is strongly influenced by frequent exercise. This regulation includes interaction between the nervous, endocrine and immune systems and central mechanisms including the endogenous opioids are of great interest here. Chronic activation of endogenous opioid systems augments natural cytotoxicity, and the possible involvement of opioids in the exercise-induced enhancement of natural immunity is discussed. Few reports are available on acupuncture and its effect on immune function but, interestingly, the effects of acupuncture and physical exercise are somewhat similar. The physiological significance as well as the underlying mechanisms of the reported changes in natural cytotoxicity after exercise training and acupuncture is as yet unclear. However, moderate exercise training has been associated with elevated natural immune function and reduced upper respiratory tract infections and available epidemiological and experimental studies suggest that moderate physical exercise may protect against several forms of cancer.

Priming effect of met-enkephalin and beta-endorphin on chemiluminescence, chemotaxis and CD11b molecule expression on human neutrophils in vitro

The opioid peptides are widely distributed throughout the body, and they are generated during stress and inflammatory reaction. Opioids are involved in the communication between the immune and neuroendocrine systems. In the present study we have investigated the ability of both met-enkephalin and beta-endorphin to stimulate and prime the human neutrophils for enhanced chemiluminescence (CL) and chemotaxis induced with fMLP, OZ or PMA. We have also tested the effect of beta-endorphin and met-enkephalin on CD11a, CD11b, CD18 and CD16 molecule expression on PMN in vitro. PMN from ten healthy donors were incubated in vitro with different concentrations of beta-endorphin or met-enkephalin, and the CL response was evaluated with luminometer. To assess the effect of opioid peptides on CD11a, CD11b, CD18 and CD16 molecule expression the whole blood samples were incubated with different concentrations of the opioids, then the white cells were labelled with respective PE-conjugated MoAb and evaluated by flow cytometry. We have shown that: (1) met-enkephalin and beta-endorphin at physiological concentrations relevant to that of in vivo (10(-8) and 10(-6) M) enhanced fMLP, PMA or OZ stimulated chemiluminescence and induced chemotactic response, (2) High concentrations of beta-endorphin (10(-3) M) or met-enkephalin (10(-5) M) decreased the CL response of PMN in vitro, (3) The opioid peptides at lower concentrations resulted in CD11b and CD18 molecule up-regulation on neutrophils. We may conclude that opioid peptides in physiological concentration are involved in neutrophil priming whereas in higher concentration exert immunosuppressive potency. Opioid peptides like inflammatory cytokines may prime the neutrophils inflammatory response.

The response on glucoregulatory hormones of in vivo whole body hyperthermia

This study was designed to examine the effects of in vivo hyperthermia on the circulating concentrations of a number of glucoregulatory hormones potentially involved in immunomodulation. Eight healthy male volunteers were immersed for 2 h in a hot water bath (water temperature 39.5 degrees C) (WI) during which period their rectal temperature rose to 39.5 degrees C. In a control study the subjects were immersed in thermoneutral water (water temperature 34.5 degrees C). Blood samples were collected before, at body temperature 38 degrees C (42.5 (30-52), median and range), minutes of hot WI, 39 degrees C (72.5 (58-97) minutes of hot WI), and 39.5 degrees C (at the end of 2 h of hot WI), as well as 1 and 2 h after cessation of 2 h of hot WI. In the control experiment blood samples were collected at identical time points. The growth hormone concentrations were elevated already at 38 degrees C to 24.2 (3.9-55.0) mU/l and peaked at 39 degrees C to 48.4 (20.8-81.5) mU/l compared to 0.3 (0.3-9.0) mU/l at baseline; at 39.5 degrees C the concentration declined to 31.6 (13.0-48.0) mU/l and further to 7.4 (0.8-17.3) mU/l 1 h after ending hot WI. The beta-endorphin levels were augmented at 39 degrees C and 39.5 degrees, to 8.0 (3.4-27.8) pmol/l and 8.1 (3.1-44.6) pmol/l, respectively, from 2.2 (0.7-5.6) pmol/l baseline. Glucagon levels raised from 23.0 (12.0-32.0) pmol/l to 32.0 (24.0-52.0) pmol/l at 39 degrees C, and to 38.5 (26.0-57.0) pmol/l at 39.0 degrees C. Insulin levels remained unchanged. Plasma glucose increased from 4.75 (4.2-7.6) mmol/l to 5.20 (4.6-5.6) mmol/l alone after 90 min of WI (temperature 39-39.5 degrees C). It is concluded that in vivo whole body WI hyperthermia increases the circulating levels of several essential glucoregulatory hormones.

Endogenous opiates: 1995

This article is the eighteenth installment of our annual review of research concerning the opiate system. It includes articles published during 1995 reporting the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects. The specific topics covered this year include stress: tolerance and dependence; eating; drinking; gastrointestinal, renal, and hepatic function; mental illness and mood; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; sex, pregnancy, and development; immunological responses; and other behaviors.