[Sensitivity of T-Lymphocytes to Hormones of the Anterior Pituitary Gland]

The review provides information about the features of the sensitivity of thymocytes, lymphoid organs' cells and T-lymphocytes of peripheral blood to the hormones secreted by anterior pituitary gland's cells: growth hormone, thyrotropin, adrenocorticotropic hormone, prolactin and β-endorphin. Some aspects of the T-lymphocytes's response to humoral signals from the hypophysis are shown in the article. Also the pituitary hormones' role in the regulation of proliferation, differentiation, and cytokine production of T-lymphocytes in normal and pathological conditions of the organism being discussed.

[Anti-inflammatory and synovial-opioid system effects of electroacupuncture intervention on chronic pain in arthritic rats]

OBJECTIVE

To observe the analgesic effect of electroacupuncture (EA) on collagen-induced arthritis (CIA) rats and its regulating effect on inflammation reaction and the endogenous opioid system of synovial tissues. Methods A total of 30 healthy male Wistar rats were randomly divided into a control group, a model group and an EA group, 10 rats in each one. The chronic pain model of CIA rats was made by cattle type-II collagen in the model group and EA group. Rats in the EA group were treated with EA at "Zusanli" (ST 36) and "Kunlun" (BL 60) for 30 min from 16th day after model establishment, once a day for consecutive 10 days. Rats in the control group did not receive any treatment. Rats in the model group were treated with fixation as the EA group. Threshold of pain, arthritis index, paw swelling were measured before model establishment and 16 d, 20 d, 23 d and 25 d after model establishment. The levels of beta-endorphin (β-END), met-enkephalin (met-ENK), dynorphin A (Dyn A) were measured by radioimmunoassay; the mRNA expressions of mu opioid receptor (MOR), kappa opioid receptor (KOR) and delta opioid receptor (DOR) in synovial tissues of CIA rats were detected by I quantitative polymerase chain reaction (qPCR).

RESULTS

Compared with the control group, threshold of pain was reduced (all P<0. 01), arthritis index was increased (all P<0. 01) and paw swelling was increased (all P<0. 01) in the model group on the 16th day, 20th day, 23rd day, 25th day after model establishment. Compared with the model group, the threshold of pain was increased in the EA group (all P<0. 01), arthritis index and paw swelling were reduced (all P<0. 01) on the 23rd day and 25th day after model establishment. Compared with the control group, the level of Dyn A in synovial tissues of CIA rats was increased in the model group (P<0. 01); the mRNA expressions of MOR, KOR and DOR were down-regulated lower than 0. 5 fold of normal level. Compared with the model group, the level of β-END in synovial tissues of the knee joint was increased in the EA group (P<0. 05), and the mRNA expressions of MOR, KOR and DOR in synovial tissues of CIA rats were up-regulated more than 2 folds of normal level.

CONCLUSION

The intervention of EA on chronic pain of CIA rats is superior, which is likely to be related with effects of EA on anti-inflammation and up-regulation of synovial tissue β-END and MOR, KOR, DOR.

[Dynamics of pain tolerance thresholds and humoral immunity factors at dorsalgy]

OBJECTIVE

Our aim was to study the possible markers of pain syndrome--indicators of pain sensitivity--pain pressure tolerance thresholds (PPTT), and immuno-indicators--natural antibodies against pain processing mediators (eAb) for evaluation the possibility of its using for a objective pain assessment at chronic low back pain.

METHODS

Pain sensitivity was assessed daily and nightly, by measuring the PPTT The natural antibody levels (eAb), were determined in serum by ELISA. Measurement of all parameters were performed at 1st, 10th and 21 days.

RESULTS

173 patients (93 women and 80 men) with chronic low back pain were included in the study. At 1st day most patients had lowered PPTT: 55% of men and 74% during the day, 72% of men and 89% of women at night. Dynamic study has shown a tendency of PPTT normalization in men. The study of diurnal PPTT variations have shown that night PPTT lower than day PPTT on 15-17%. We found gender PPTT differences: PPTT values in women 17-26% lower than in men. Analysis of individual eAb profiles has showed that elevated and high levels of eAb to β-endorphin, orphanin and histamine have 84%, 78%, 84% women and 82%, 85 and 95% men, respectively. These indicators higher than those for serotonin, dopamine and angiotensin (55%, 65%, 70% in women and 65%, 66%, 66% in men, respectively; p < 0.05). Dynamic study of eAb levels have shown a significant anti-histamine eAbs decrease (23%; p = 0.015) only.

CONCLUSION

The pathological changes in pain sensitivity and levels of eAbs to pain-processing mediatos are evidenced. Further investigations are necessary to clarify to role of these variations in pain processing and for use these indicators for objective pain assessment.

[Antibodies to endogenous bioregulators and their association with age and sex in chronic pain syndrome]

Authors studied changes in the levels of antibodies to endogenous bioregulators (Ab) to Β-endorphin, orphanin, serotonin, dopamine and angiotensin in 36 healthy people and 109 patients with dorsopathy with chronic pain syndrome. The association of these immunological indicators with age and sex was found. It has been concluded that the levels of Ab to endogenous bioregulators may be considered as a marker of algic system pathology that does not depend on age and is sex-related.

Immune modulation in response to stress and relaxation

Traditional medical science has kept the mind separate from the body. Recently people realize the effect of mind on health and psychoneuroimmunology is the new evolved science that describes the interactions between psyche and soma. In this review through a typical psycho-neuro-endocrino-immune network the effects of psychological stress (acute, brief naturalistic and chronic) and relaxation on immune modulation has been shown. From this network Corticotrophin Releasing Factor (CRF), Adrenocorticotrophic Hormone (ACTH), Glucocorticoids (GC), alpha-endorphin and Met-enkephalin are found as important endocrine components and T cells, B cells, monocytes/macrophages, Natural Killer (NK) cells and their cytokines that is Tumor Necrosis Factor-alpha (TNF-alpha), Interferon Gamma (IFN-alpha) and interleukins such as IL-1, IL-2, IL-4, IL-6, IL-10, IL-12 etc. are found as important immune components. Finally, it has been shown that, acute, brief naturalistic and chronic stress have different immune modulatory activities which are harmful to one's homeostasis and relaxation can help to maintain that homeostasis.

[Beta-endorphin as the endogenous regulator of immune processes]

Endogenous opioid peptides represent the group of bioregulatory factors possessing a wide range of biologically active effects. One of most essential functions of endogenous opioids appears to be the realization of cellular interaction between nervous and immune systems. Beta-endorphin is a peptide hormone that is the most active and multi-functional representative of the opioid peptide family. This review summarizes current observations on the nature ofbeta-endorphin, its production by the immune system cells, opiate receptor structure and expression, as well as the peptide effect on the processes of cellular activation, proliferation, and differentiation in innate and adaptive immunity.

Influence of pain treatment by epidural fentanyl and bupivacaine on homing of opioid-containing leukocytes to surgical wounds

Endogenous opioids released from leukocytes extravasating into injured tissue can interact with peripheral opioid receptors to inhibit nociception. Animal studies have shown that the homing of opioid-producing leukocytes to the injured site is modulated by spinal blockade of noxious input. This study investigated whether epidural analgesia (EDA) influences the migration of beta-endorphin (END) and/or met-enkephalin (ENK)-containing leukocytes into the subcutaneous wound tissue of patients undergoing abdominal surgery. In part I patients received general anesthesia combined either with intra- and postoperative EDA (with bupivacaine and fentanyl) or with postoperative patient controlled intravenous analgesia (PCIA; with the opioid piritramide). In part II patients received general anesthesia combined with either epidural fentanyl or bupivacaine which was continued postoperatively. Samples of cutanous and subcutanous tissue were taken from the wound site at the beginning, at the end and at various times after surgery, and were examined by immunohistochemistry for the presence of END and ENK. We found that (i) epidural bupivacaine, fentanyl and PCIA provided similar and clinically acceptable postoperative pain relief; (ii) compared to PCIA, epidural bupivacaine or fentanyl did not change the gross inflammatory reaction within the surgical wound; (iii) opioid-containing leukocytes were almost absent in normal subcutaneous tissue but migrated to the inflamed wound tissue in ascending numbers within a few hours, reaching a peak at about 24 h after surgery; (iv) compared to PCIA, EDA resulted in significantly decreased homing of END-containing leukocytes to the injured site at 24 h after surgery; and (v) the magnitude of this decrease was similar regardless of the epidural medication. These findings suggest that nociceptive but not sympathetic neurons are primarily involved in the attraction of opioid-containing leukocytes during early stages of inflammation.

Minimal immunoreactive plasma beta-endorphin and decrease of cortisol at standard analgesia or different acupuncture techniques

BACKGROUND AND OBJECTIVE

Acupuncture has been claimed to be associated with activation of the endogenous antinociceptive system. The analgesic effects of acupuncture have been ascribed to beta-endorphin interacting with opioid receptors. However, firstly, the release of beta-endorphin into the blood has been proven to be induced by stress, i.e. under dysphoric conditions, and, secondly, if released under stress, beta-endorphin has been shown not to be analgesic. Our aim was to test whether beta-endorphin immunoreactive material is released into the cardiovascular compartment during acupuncture comparing the most frequently used types of acupuncture with standard pain treatment under apparently low stress conditions.

METHODS

This prospective study included 15 male patients suffering from chronic low back pain. beta-Endorphin immunoreactive material and cortisol were measured in the plasma of patients who underwent, in random order, therapy according to a standard pain treatment, traditional Chinese acupuncture, sham acupuncture, electro acupuncture and electro acupuncture at non-acupuncture points before, at and after the treatment. Statistical analysis was performed using two-way ANOVA with repeated measures.

RESULTS

A decrease in plasma cortisol concentration measured over the five treatment protocols was highly significant (P < 0.001). The beta-endorphin immunoreactive material concentrations in plasma were minimal at all times and in all treatment conditions. The influence of treatments by various acupuncture procedures on cortisol and beta-endorphin immunoreactive material plasma concentrations over the three time points was not significantly different.

CONCLUSIONS

beta-endorphin immunoreactive material in blood is not released by any type of acupuncture as tested under low stress conditions.

Methodological aspects of rat β-endorphin analysis—influence of diurnal variation

Beta-endorphin radioimmunoassays (RIAs) are widely performed following physical, emotional and environmental challenges in the rat. In the literature, a wide range of techniques have been described, but in the present study, we have focused on methodological aspects of beta-endorphin RIAs, investigating various characteristics of human and rat specific antibodies. Initial studies verified that the RIA outcome was not appropriate when using non-species compatible components. Novel rat beta-endorphin antibodies, r 4114 and r 4268, were raised in rabbits and characterised in terms of specificity, avidity and titer. Both of the new antisera showed 68.1% cross-reactivity with human beta-endorphin. The ED50 was 50+/-8 pmol/l, and the mean ED80 was 17 pmol/l for r 4268 but three-fold higher for r 4114. The intra-assay coefficient of variation (CV) was 7% at 100 pmol/l and the inter-assay CV was 10% at the same level for r 4268 and similar for r 4114. Using this novel rat beta-endorphin RIA for analyses of diurnal influence and removal from the Animal House cage, no significant changes were observed in either the hypothalamus or peri-aqueductal grey regions. These results suggest that rat beta-endorphin concentrations in these brain areas are not affected by order of removal or diurnal variation.

Beta-endorphin prevents collagen induced arthritis by neuroimmuno-regulation pathway

OBJECTIVE

To observe the effects and mechanisms of beta-endorphin (beta-END) preventing collagen induced arthritis (CIA) by neuroimmuno-regulating pathway.

METHODS

Female wistar (Ws) rats were used in this study. CIA was induced by Native bovine type II collagen emulsified with complete Freund's adjuvant (CFA). Beta-END was administered i.p. to CIA rats every other day from the 14th day (secondary immunization) to the 35th day after primary immunization. Clinical assessments were performed by two independent, blinded examiners every other day. Pathological and radiological observations were taken on the 35th day after the primary immunization. Tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), interleukin-6 (IL-6), regulated upon activation, normal T-cell expressed and secreted (RANTES), inducible NO syntheses (iNOS), matrix metalloproteinase-2 (MMP-2) and MMP-9 mRNA expression of synovium tissues of CIA rats was estimated by quantitative RT-PCR. The frequency of spleen Th1 and Th2 cells were assessed by fluorescence activated cell sorter (FACS) assay.

RESULTS

Clinical manifestation of rats with CIA were significantly abrogated or ameliorated by treatment with beta-END. Beta-END treatment in vivo could down-regulate mRNA expression of several pro-inflammatory cytokines, chemokines and MMPs in CIA synovial, and polarize Th1/Th2 balance to Th2.

CONCLUSION

Beta-END alleviates CIA through both depressing Th1 responses and down-regulating proinflammatory and other rheumatic factors, suggesting beta-END is a promising anti-inflammatory and anti-rheumatic agent in treating CIA.

Nonopioidergic mechanism mediating morphine-induced antianalgesia in the mouse spinal cord

Intrathecal (i.t.) pretreatment with a low dose (0.3 nmol) of morphine causes an attenuation of i.t. morphine-produced analgesia; the phenomenon has been defined as morphine-induced antianalgesia. The opioid-produced analgesia was measured with the tail-flick (TF) test in male CD-1 mice. Intrathecal pretreatment with low dose (0.3 nmol) of morphine time dependently attenuated i.t. morphine-produced (3.0 nmol) TF inhibition and reached a maximal effect at 45 min. Intrathecal pretreatment with morphine (0.009-0.3 nmol) for 45 min also dose dependently attenuated morphine-produced TF inhibition. The i.t. morphine-induced antianalgesia was dose dependently blocked by the nonselective mu-opioid receptor antagonist (-)-naloxone and by its nonopioid enantiomer (+)-naloxone, but not by endomorphin-2-sensitive mu-opioid receptor antagonist 3-methoxynaltrexone. Blockade of delta-opioid receptors, kappa-opioid receptors, and N-methyl-D-aspartate (NMDA) receptors by i.t. pretreatment with naltrindole, nor-binaltorphimine, and (-)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801), respectively, did not affect the i.t. morphine-induced antianalgesia. Intrathecal pretreatment with antiserum against dynorphin A(1-17), [Leu]-enkephalin, [Met]-enkephalin, beta-endorphin, cholecystokinin, or substance P also did not affect the i.t. morphine-induced antianalgesia. The i.t. morphine pretreatment also attenuated the TF inhibition produced by opioid muagonist [D-Ala2, N-Me-Phe4,Gly-ol5]-enkephalin, delta-agonist deltorphin II, and kappa-agonist U50,488H. It is concluded that low doses (0.009-0.3 nmol) of morphine given i.t. activate an antianalgesic system to attenuate opioid mu-, delta-, and kappa-agonist-produced analgesia. The morphine-induced antianalgesia is not mediated by the stimulation of opioid mu-, delta-, or kappa-receptors or NMDA receptors. Neuropeptides such as dynorphin A(1-17), [Leu]-enkephalin, [Met]-enkephalin, beta-endorphin, cholecystokinin, and substance P are not involved in this low-dose morphine-induced antianalgesia.

Long-term immune-endocrine effects of bereavement: relationships with anxiety levels and mood

Psychological, endocrine and immune parameters were measured over a 6-month period in 14 healthy subjects who underwent an unpredictable acute emotional stress (e.g. sudden death of a loved one) compared with 14 controls who did not. Probands were profoundly stressed as assessed 10 days after bereavement by their scores on the Hamilton Rating Scales of Anxiety and Depression, adrenocorticotropin and cortisol plasma concentrations, and non-suppression in response to dexamethasone. Functional alterations of immune parameters, such as responsiveness of peripheral blood lymphocytes to mitogens, were found 40 days after bereavement. Despite a normal number of circulating lymphocyte subsets, the functional activity of natural killer (NK) cells was markedly reduced at day 40. Changes in the intracellular concentration of beta-endorphin in peripheral blood mononuclear cells correlated with anxiety and depression scores. Controls showed no changes in psychometric, endocrine and immune measures during the 6-month study. Cluster analysis revealed two groups of bereaved subjects with different patterns of immune and endocrine changes: (1) Five subjects, characterized by harm-avoidant temperament and long-lasting dysphoric mood, showed reduced responsiveness of peripheral blood lymphocytes to mitogens, decreased NK cell activity and non-suppression in response to dexamethasone that persisted for 6 months. (2) Nine subjects showed significant changes only during the early phase after bereavement. Our data suggest that the immunological consequences of stress do not simply overlap with psychological and endocrine alterations, and are particularly severe and long-lasting in a subgroup of subjects, indicating the importance of individual variability in the capacity to cope with stress.

Effects of endogenous and synthetic opioid peptides on neutrophil function in vitro

BACKGROUND

Opioid peptides released from immunocytes during inflammation and stress in critically ill patients are associated with an altered immune response. Moreover, concentrations of opioid peptides are increased in peripheral blood and at the sites of inflammatory reactions.

METHODS

Using flow cytometric assay of whole human blood, we investigated direct effects of endogenous and synthetic opioid peptides on surface expression of complement receptors CD35 and CD11b/CD18 and Fcã receptor III CD16, and superoxide anion generation of neutrophils.

RESULTS

The endogenous opioid peptides beta-endorphin(1-31) and met-enkephalin, representing the N-terminal fragment of beta-endorphin(1-31), and the synthetic delta opioid receptor agonists D-Ala(2)-D-Leu(5)-enkephalin and D-Pen(2)-enkephalin produced concentration-dependent stimulation of neutrophil activity. Incubation with met-enkephalin 10(-7) M or beta-endorphin(1-31) 10(-7) M led to an increase in receptor expression of up to 10% (met-enkephalin) and 15% (beta-endorphin(1-31)). After incubation with D-Ala(2)-D-Leu(5)-enkephalin or D-Pen(2/5)-enkephalin, receptor expression was increased by up to 30%. This correlated with concentration-dependent stimulation of the production of reactive oxygen intermediates, as shown by an increase of up to 40% in oxidative burst activity. All effects were abolished after preincubation with naloxone or with the selective delta opioid antagonist naltrindole, whereas the selective micro receptor antagonist d-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH(2) showed only partial inhibitory effects.

CONCLUSIONS

Our data suggest a delta opioid receptor-mediated stimulatory effect on neutrophil function. beta-Endorphin(27-31), the C-terminal fragment of beta-endorphin(1-31), did not alter neutrophil function, indicating that beta-endorphin(1-31) mediates its effect on neutrophils via the N-terminal fragment. This study may contribute to a better understanding of neuroimmune interaction.

[Humoral factors (beta-endorphin and adrenocorticotropin) in irritable bowel syndrome and their relations with psychological disorders and characteristics of disorders in the large intestine motility]

The object of this study was to discover mental functions, humoral regulation and large intestinal motor dysfunction in patients with the irritable bowels syndrome (IBS) in order to develop principles of their differential correction. A group of 106 patients (26 men and 80 women) with the irritable bowels syndrome was examined. The IBS diagnosis was made in accordance with the Rome criteria (1999). The control group included 21 somatically healthy volunteers (16 women and 5 men). Patients from both of the groups underwent clinical and psychological as well as plasma beta-endorphin concentration studies; colonic motor activity was also studied in patients with the IBS by the method of electric colonoscopy. Mental changes and certain particular features of the large intestine humoral regulation and motor activity determining the differential treatment for this category of patients were discovered.

Peripheral blood mononuclear cell beta-endorphin concentration is decreased in chronic fatigue syndrome and fibromyalgia but not in depression: preliminary report

OBJECTIVE

The aim of this study was to examine the possible role of the immune system in the pathophysiology of chronic fatigue syndrome and fibromyalgia syndrome and in the differential diagnosis of depression by investigating changes in peripheral blood mononuclear cell levels of beta-endorphin, an endogenous opioid known to be involved in regulation of the immune system function.

DESIGN

Beta-endorphin concentrations were measured by radioimmunoassay in peripheral blood mononuclear cells from healthy controls (n = 8) and patients with chronic fatigue syndrome (n = 17), fibromyalgia syndrome (n = 5), or depression (n = 10).

RESULTS

Beta-endorphin concentrations were significantly lower in patients with chronic fatigue syndrome or fibromyalgia syndrome than in normal subjects and depressed patients (p <0.001 and p <0.01, respectively). They were significantly higher in depressed patients than in controls (p <0.01).

CONCLUSIONS

Evaluation of peripheral blood mononuclear cell beta-endorphin concentrations could represent a diagnostic tool for chronic fatigue syndrome and fibromyalgia and help with differential diagnosis of these syndromes versus depression. The results obtained are also consistent with the hypothesis that the immune system is activated in both chronic fatigue syndrome and fibromyalgia syndrome.

[Long-term correction of brain function. Prospects of immunologic approaches]

Among various approaches to long-term correction of the highest functions of the brain there are two methods that are particularly promising. These included: 1) induction of autoantibodies against the enzymes involved in the metabolism of neuroregulators by means of immunization of respective heterologous enzymes; 2) immunization by covalent conjugates of monomolecular neurotropic compounds and neuropeptides with antigen carriers. The investigations of both methods are reviewed and illustrated in experiments on albino rats during alcoholization and some other processes of pathological behavior formation. Evidence is provided for that behavior can be corrected for several months or longer.

Are POMC neurons targets for sex steroids in the arcuate nucleus of the rat?

Testosterone alters the expression of proopiomelanocortin (POMC) mRNA in the neurons of the arcuate nucleus. While observations suggest that both estrogen and androgen receptors (AR) can mediate this action, only a negligible number of POMC neurons has previously been shown to contain estrogen receptor (ER)-alpha. To determine whether the putative action of testosterone is mediated via ER-beta or AR we double immuno- labeled hypothalamic sections from colchicine-pretreated male rats. Only few cells were immunostained for ER-beta and they were never found to co-localize POMC. In spite of the overlap in the anatomical distribution, only 3% of POMC cells appeared to contain AR. These results suggest that sex steroids have an indirect effect on most POMC neurons.

Total body exposure to ultraviolet radiation does not influence plasma levels of immunoreactive beta-endorphin in man

BACKGROUND/AIMS

A growing number of reports support evidence of proopiomelanocortin (POMC)-derived peptides in human skin cells, although not consistently. Also the effect of ultraviolet radiation (UVR) on cutaneous and plasma levels of these POMC peptides has not been established unequivocally. We hypothesized that production of beta-endorphin (betaE) may explain the sense of well-being many people experience when sun-bathing. The aim of the present study was to investigate whether exposure of the skin to UVR elevates plasma betaE.

METHOD

Healthy volunteers (n=26) received a single, weighted dose of 15 J/cm2 of UVA. Several times during the hour following irradiation, plasma betaE- immunoreactivity (betaE-IR) was determined by radioimmunoassay. The effect of repeated exposure was assessed in 35 patients treated with UVB, UVA, or UVA-1. Plasma ACTH-IR was monitored in parallel.

RESULTS

Overall, plasma levels of betaE-IR and ACTH-IR showed no significant changes during the experiment, indicating that these peptides are not influenced by single or repeated exposures to UVR of different wavelengths.

CONCLUSION

On the basis of these results, the skin does not appear to contribute significantly to the levels of circulating betaE or ACTH. These data offer no support for the hypothesis that exposure to UVR leads to an increased concentration of circulating betaE, which could contribute to the feeling of well-being that often accompanies sun-bathing.

Chronic ethanol inhibits NK cell cytolytic activity: role of opioid peptide beta-endorphin

The role of beta-endorphin (beta-EP) in ethanol-altered NK cell cytolytic activity is studied using male Fischer-344 rats as an animal model. Ethanol was administered for 1, 2, 3, or 4 wk in a liquid diet containing 8.7% ethanol (v/v), which means that 37% of the total calories were derived from ethanol. Rats treated with ethanol for 1 wk showed an increase in hypothalamic and plasma levels of immunoreactive (IR)-beta-EP, but displayed no significant effect on NK cell activity determined by (51)Cr release assay, as compared with those in pair-fed and ad libitum-fed animals. However, animals treated with ethanol for 2, 3, or 4 wk showed decreased hypothalamic and plasma levels of IR-beta-EP and decreased splenic NK cell activity. No significant decrease in the number of splenocytes and NK cells or in the percentage of NK cells was seen until after 3 and 4 wk of ethanol treatment. Exposure in vitro of splenic lymphocytes obtained from control animals to various concentrations of beta-EP increased NK cell activity. The opiate antagonist naltrexone blocked the beta-EP-stimulated effect. The in vitro NK cell response to beta-EP was reduced in the splenocytes obtained from animals treated with ethanol for 2 wk, but not in those obtained from animals treated with ethanol for 1 wk as compared with those in control animals. Additionally, beta-EP administration into the paraventricular nucleus of the hypothalamus stimulated NK cell cytolytic activity, whereas the opiate blocker administration reduced NK cell activity. The NK cell responses to paraventricular nucleus beta-EP were reduced in the animals treated with ethanol for 2 wk. These data provide evidence for the first time that ethanol inhibits NK cell cytolytic activity, possibly by reducing beta-EP-regulated splenic NK cell function.

Beta-endorphin immunoreactivity during high-intensity exercise with and without opiate blockade

Nine highly fit men [mean (SE) maximum oxygen uptake, VO2max: 63.9 (1.7) ml x kg(-1) x min(-1); age 27.6 (1.6) years] were studied during two treadmill exercise trials to determine plasma beta-endorphin immunoreactivity during intense exercise (80% VO2max). A double-blind experimental design was used, and subjects performed the two exercise trials in counterbalanced order. Exercise trials were 30 min in duration and were conducted 7 days apart. One exercise trial was undertaken following administration of naloxone (1.2 3 cm3) and the other after receiving a placebo (0.9% NaCl saline; 3 cm3). Prior to each experimental trial, a flexible catheter was placed into an antecubital vein and baseline blood samples were collected. Thereafter, each subject received either a naloxone or placebo bolus injection. Blood samples were also collected after 10, 20 and 30 min of continuous exercise. beta-Endorphin was higher (P < 0.05) during exercise when compared to pre-exercise in both trials. However, no statistically significant difference was found (P> 0.05) between exercise time points within either experimental trial. beta-endorphin immunoreactivity was greater (P < 0.05) in the naloxone than in the placebo trial during each exercise sampling time point [10 min: 63.7 (3.9) pg x ml(-1) vs 78.7 (3.8) pg x ml(-1); 20 min: 68.7 (4.1) pg x ml(-1) vs (4.3) pg x ml(-1); 30 min: 71.0 (4.3) pg x ml(-1) vs 82.5(3.2) pg x ml(-1)]. These data suggest that intense exer induces significant increases in beta-endorphin that are maintained over time during steady-rate exercise. Exercise and naloxone had an interactive effect on beta-endorphin release that warrants further investigation.

Melatonin and beta-endorphin changes in children sensitized to olive and grass pollen after treatment with specific immunotherapy

BACKGROUND

Specific immunotherapy for respiratory allergy, a seasonal disease, significantly reduces the inflammatory process, attenuating the clinical symptoms. The mechanism for the clinical beneficial effect of immunotherapy has not yet been clarified. Melatonin shows a circadian and seasonal variation and together with the endogenous opioid system plays an immunomodulatory role acting on both specific and nonspecific immunity responses. Thus, the possibility that immunotherapy involved changes in the melatonin-opioid system was investigated.

METHODS

Thirty-five children aged 3-15 years with rhinitis and asthma due to olive + grass pollen sensitization were studied. The patients were treated with depot extracts containing the identified allergens with increasing doses from 1 to 1,000 IU/ml during 3 months. Melatonin, beta-endorphin, total and specific IgE and IgG4 were determined before and after treatment.

RESULTS

All children showed a significant improvement of their symptoms at the end of the treatment, coinciding with a significant drop of both melatonin and beta-endorphin levels. Total IgE decreased in most of the cases although the mean values did not show significant changes. Specific IgE and IgG4 were also unchanged. A significant correlation between melatonin and beta-endorphin and between beta-endorphin and IgG4 was found before immunotherapy, and these correlations disappeared when the treatment was finished.

CONCLUSIONS

The decrease in the levels of melatonin and beta-endorphin suggests the disappearance of their stimulating influence on the immune system. Thus, hyposensitization after immunotherapy may involve, at least in part, the inhibition of the immunoenhancing properties of the melatonin-opioid system.

Antisera against endogenous opioids increase the nocifensive response to formalin: demonstration of inhibitory beta-endorphinergic control

The roles of endogenous opioid peptides in the brain in the modulation of nocifensive responses to formalin in ICR mice were studied. Mice were pretreated intracerebroventricularly (i.c.v.) with rabbit antiserum against beta-endorphin, [Leu5]enkephalin, [Met5]enkephalin or dynorphin A-(1-17) 1 h prior to intraplantar injection of formalin (0.5%, 25 microl) and the nocifensive licking responses were then observed. Pretreatment of mice with antiserum against beta-endorphin enhanced the second phase, but not the first phase of the nocifensive responses to formalin. Pretreatment with antiserum against [Leu5]enkephalin also caused a small but statistically significant enhancement of the second phase, but not the first phase of nocifensive responses to formalin. On the other hand, pretreatment with antiserum against [Met5]enkephalin or dynorphin A-(1-17) did not affect the nocifensive response to formalin. Our results indicate that beta-endorphinergic, and to a lesser extent, [Leu5]enkephalinergic systems are activated at the supraspinal sites to attenuate the nocifensive responses to formalin stimulation.

Involvement of central, but not placental corticotropin releasing hormone (CRH) in heat stress induced immunosuppression during pregnancy

To clarify whether corticotropin releasing hormone (CRH) and beta-endorphin (betaEP) system mediate maternal immunosuppression in pregnant rats exposed to heat through central or placental pathway, we examined the effects of intravenous (iv) (100 or 500 microg) or intracerebroventricular (icv) (5 microg) administration of CRH receptor antagonist alpha-helical CRH (9-41) on splenic natural killer cell activity (NKCA) as well as betaEP in blood, pituitary lobes, and placenta in pregnant rats at 15 to 16 days gestation. Two-way ANOVA revealed that heat reduced NKCA and elevated blood and pituitary betaEP but did not change placental betaEP. Iv administered 500 microg and icv administered alpha-helical CRH reversed the reduced NKCA and the elevated pituitary betaEP, while iv administration of 100 microg alpha-helical CRH did not. The increased blood betaEP was reversed by iv 100 and 500 microg alpha-helical CRH and icv administration. Both iv and icv administrations reduced placental betaEP independent of heat exposure. Thus, the response of placental betaEP to iv administration of alpha-helical CRH seemed to be stronger than that of pituitary betaEP. These results indicate that alpha-helical CRH which acts on pituitary betaEP antagonizes heat-induced immunosuppression during pregnancy, suggesting that immunosuppression produced by heat stress during pregnancy is mediated by the central CRH system. The placental CRH-betaEP system seems unlikely to be involved in the immunosuppression. Physiologic roles of placental CRH and opioid system should be clarified by future in vitro experiments using placenta specimen including placental immunocyte.

beta-Endorphin immunoreactive material and authentic beta-endorphin in the plasma of males undergoing anaerobic exercise on a rowing ergometer

Adrenocorticotropic hormone (ACTH), beta-endorphin immunoreactive material (beta-endorphin IRM), and authentic beta-endorphin (1 -31) have been determined in the plasma of 23 volunteers undergoing anaerobic exercise on a rowing ergometer. The volunteers had different histories of training from occasional physical activities up to intensive preparation for international rowing competitions. ACTH and beta-endorphin-IRM were determined using commercially available immunometric assays; for determination of beta-endorphin (1-31) a highly specific two-site fluid phase immunoprecipitation radioimmunoassay was developed, which did not cross-react with any beta-endorphin derivative or any other opioid peptide tested. In agreement with reports from the literature ACTH and beta-endorphin-IRM concentrations in the plasma rose upon anaerobic exercise in all 23 subjects; this increase in the ACTH and beta-endorphin IRM levels was significantly correlated with the increase of lactate levels observed upon anaerobic exercise. Authentic beta-endorphin (1-31) was only found in two plasma samples containing minor concentrations of the peptide. We conclude that the beta-endorphin immunoreactive material released into blood under anaerobic exercise is identical with authentic beta-endorphin (1-31) only to a minor extent and thus should not be called "beta-endorphin". The major part of the material in fact released into the blood upon anaerobic exercise is probably identical with beta-lipotropin and further components so far unknown.

Involvement of dynorphin in immobilization stress-induced antinociception in the mouse

The effect of antiserum against [Met(5)]-enkephalin, [Leu(5)]-enkephalin, beta-endorphin, or dynorphin A-(1-13) administered intracerebroventricularly (i.c.v.) or intrathecally (i. t.) on immobilization-induced antinociception was studied in ICR mice. Antinociception was assessed by the tail-flick assay. Immobilization of the mouse increased inhibition of the tail-flick response at least 1 h. The i.c.v. or i.t. injection with antiserum against dynorphin A-(1-13) at the dose of 200 microg significantly attenuated immobilization-induced inhibition of the tail-flick response. However, antiserum against [Met(5)]-enkephalin, [Leu(5)]-enkephalin, or beta-endorphin did not affect the immobilization stress-induced antinociception. Furthermore, i.c.v. or i.t. injection with nor-binaltorphimine (Nor-BNI; from 1 to 20 microg) effectively inhibited immobilization stress-induced inhibition of the tail-flick response in a dose-dependent manner. However, beta-FNA (from 0.5 to 2 microg) or naltrindole (from 1 to 20 microg) administered i.c.v. or i.t. did not affect immobilization stress-induced antinociception. Our results suggest that supraspinally and spinally located dynorphin appears to be involved in the production of immobilization stress-induced antinociception via stimulating kappa-opioid receptors.

Antagonism of nitrous oxide antinociception in mice by intrathecally administered antisera to endogenous opioid peptides

Previously it was demonstrated that nitrous oxide antinociception in the mouse abdominal constriction test is mediated by kappa-opioid receptors. Since nitrous oxide is thought to cause the neuronal release of endogenous opioid peptide to stimulate opioid receptors, this study was designed to identify the opioid peptides involved, especially in the spinal cord, by determining whether nitrous oxide antinociception can be differentially inhibited by intrathecally (i. t.) administered antisera to different opioid peptides. Male NIH Swiss mice were pretreated i.t. with rabbit antisera to opioid peptides then exposed 24 h later to one of three different concentrations of nitrous oxide in oxygen. Dose-response curves constructed from the data indicated that the antinociceptive effect of nitrous oxide was significantly antagonized by antisera to various dynorphins (DYNs) and methionine-enkephalin (ME), but not by antiserum to beta-endorphin (beta-EP). The AD(50) values for nitrous oxide antinociception were significantly elevated by antisera to DYNs and ME but not beta-EP. These findings of this study support the hypothesis that nitrous oxide antinociception in the mouse abdominal constriction test involves the neuronal release of DYN and ME in the spinal cord.

Melatonin attenuates the intensity of beta-endorphin immunoreactivity in the arcuate nucleus of rat hypothalamus

The present study was undertaken to observe the effect of exogenously administered melatonin on the intensity of beta-endorphin (beta-Ep) immunoreactivity of the neuron in the arcuate nucleus of rat hypothalamus with an aim to explore the possible mechanisms of the analgesic effect of melatonin. The experimental rats were divided into two groups, one injected intraperitoneally with melatonin (110 mg/kg) and the other with only a vehicle. One hour after injection, the brain was processed for coronal sections, which were stained with immunohistochemical ABC technique. The integral optical density (IOD) and mean optical density (OD) of the stained sections were measured with a computer-assisted image-processing and analytical system. beta-Ep immunoreactivity was much decreased in the sections treated with melatonin and the IOD and OD were also decreased significantly (P<0.01; P<0.05). The above results suggest that melatonin may result in a decrease of beta-Ep content in the arcuate nucleus, as a result of increased beta-Ep release induced by administration of melatonin. It is likely that the analgesic effect of melatonin may be in part mediated by the release of beta-endorphin from the arcuate nucleus.

[Distinct structural bases of the immunoregulatory and central analgesic effects of IFNalpha]

Interferon-alpha (IFNalpha), a cytokine, is also an analgesic molecule. There is significant cross reactivity between IFNalpha and anti-opioid sera, suggesting a strong antigenic relatedness between human IFNalpha molecules and opioid peptides. Different structural basis of the immunoactivity and analgesic effect of IFNalpha can be demonstrated by different reactivities of the two reactions towards different mutants of IFNalpha obtained by using the site-directed mutagenesis. When the 129th Tyr residue of human IFNalpha was mutated to Ser, the immunoactivity of the mutant almost disappeared, while the strong analgesic activity still persisted, which could be blocked by naloxone. These results indicate that there exist distinct domains in the IFNalpha molecule, which mediate immune and analgesic effects differentially, and that the receptor mechanism underlying immune and analgesic effects of IFNalpha may be different.

Interleukin-2: structural and biological relatedness to opioid peptides

Interleukin (IL)-2 is not only an immunoregulatory factor, but also an analgesic molecule. There are distinct domains of immune and analgesic functions in the IL-2 molecule. The analgesic domain is located around the 45th Tyr residue of human IL-2 in tertiary structure. Antiopioid (beta-endorphin, Leu-enkephalin, Met-enkephalin and dynorphin A1-13) sera partially neutralized the analgesic activity of IL-2. Monoclonal antibody against the IL-2 receptor alpha subunit (Tac) could not block the analgesic activity of IL-2. There existed cross-reactivity between IL-2 and antiopioid sera by indirect ELISA. These studies show strong structural and biological similarities between IL-2 and opioid peptides. The tertiary structure around the 45th residue of IL-2 composes the analgesic domain that is similar to that of endogenous opioids. These results are consistent with the hypothesis that multiple domains of cytokines serve as the structural bases for the immunoregulatory and neuroregulatory effects of cytokines.

Kidney leucocytes of rainbow trout, Oncorhynchus mykiss, are activated by intraperitoneal injection of beta-endorphin

The immunomodulatory effects of beta-endorphin were studied by measurements of the production of superoxide anion, phagocytosis and chemotaxis of kidney phagocytic cells in rainbow trout, Oncorhynchus mykiss. The production of superoxide anion in phagocytic cells increased significantly in rainbow trout injected with chum salmon beta-endorphin. The responses were dose-dependent. The phagocytosis and chemotaxis also significantly increased in kidney phagocytic cells of rainbow trout injected with alpha-endorphin. These results show that beta-endorphin in rainbow trout activates the function of phagocytic cells in vivo.

Hypothalamic beta-endorphin concentrations are decreased in animals models of autoimmune disease

Complex interactions between the neuroendocrine and the immune systems are present in autoimmune diseases. The central opioid peptide beta-endorphin (BE) has been shown to modulate peripheral immune responses in normal animals. In the present study we analyze the hypothalamic concentrations of this peptide in two models of spontaneous autoimmune disease, the MRL [corrected] lpr/lpr mouse, that develops a lupus-like autoimmune disease, and the obese strain (OS) chickens afflicted with spontaneous autoimmune thyroiditis. In both instances, hypothalamic concentrations of BE are significantly lower than normal controls. In MRL [corrected] lpr/lpr mice, BE is already lower at 1 month of age, when no clinical sign of the disease is yet present. Similarly, low levels of BE are observed in OS chickens before the onset of thyroiditis, i.e., already at the embryonic stage. Moreover, a further decrease of BE is observed in OS chickens in correspondence with the first signs of thyroid mononuclear infiltration. Considering the immunosuppressive effects exerted by central BE, these results are suggestive of the fact that in autoimmune disease prone animals the low hypothalamic concentrations may be one of several factors predisposing for the development of autoimmune disease.

[Effect of anti-opioid peptide sera on the enhancement of electroacupuncture analgesia induced by neurotensin in PAG of rats]

With the use of potassium iontophoresis induced tail-flick for measuring the pain threshold, the effects of injecting neurotensin (NT), naloxone (NX), anti-metenkephalin serum (AMEKS), anti-beta-endorphin serum (AEPS) and anti-dynorphin A1-13 serum (ADYNS) into periaqueductal gray (PAG) on electroacupuncture (EA) analgesia in rats were investigated. NT administration enhanced EA analgesia remarkably. Pre-injection of NX, AMEKS and AEPS into PAG could significantly attenuate the enhancement of EA analgesia induced by NT, but not by administration of ADYNS. The results indicate that NT in PAG is responsible for the enhancement of EA analgesia. The effect of NT may be partly mediated by met-enkephalin and beta-endorphin.

CNS pattern of metabolic activity during tonic pain: evidence for modulation by beta-endorphin

CNS correlates of acute prolonged pain, and the effects of partial blockade of the central beta-endorphin system, were investigated by the quantitative 2-deoxyglucose technique in unanaesthetized, freely moving rats. Experiments were performed during the second, tonic phase of the behavioural response to a prolonged chemical noxious stimulus (s.c. injection of dilute formalin into a forepaw), or after minor tissue injury (s.c. saline injection). During formalin-induced pain, local glucose utilization rates in the CNS were bilaterally increased in the grey matter of the cervical spinal cord, in spinal white matter tracts and in several supraspinal structures, including portions of the medullary reticular formation, locus coeruleus, lateral parabrachial region, anterior pretectal nucleus, the medial, lateral and posterior thalamic regions, basal ganglia, and the parietal, cingulate, frontal, insular and orbital cortical areas. Pretreatment with anti-beta-endorphin antibodies, injected i.c.v., led to increased metabolism in the tegmental nuclei, locus coeruleus, hypothalamic and thalamic structures, putamen, nucleus accumbens, diagonal band nuclei and dentate gyrus, and in portions of the parietal, cingulate, insular, frontal and orbital cortex. In formalin-injected rats, pretreated with anti-beta-endorphin, behavioural changes indicative of hyperalgesia (increased licking response) were found, which were paralleled by a significant enhancement of functional activity in the anterior pretectal nucleus and in thalamo-cortical systems. A positive correlation was found between the duration of the licking response and metabolic activity of several forebrain regions. These results provide a map of the CNS pattern of metabolic activity during tonic somatic pain, and demonstrate a modulatory role for beta-endorphin in central networks that process somatosensory inputs.

Beta-endorphin-like immunoreactivity in the forebrain and pituitary of the teleost Clarias batrachus (Linn.)

The organization of beta-endorphin-like immunoreactivity in the olfactory system, forebrain, and pituitary of the teleost Clarias batrachus was investigated. Immunoreactivity was prominently seen in the sensory neurons and basal cells in the olfactory epithelium and in some cells in the periphery and center (granule cells) of the olfactory bulb. Immunoreactive fibers in the olfactory nerve enter the olfactory nerve layer of the olfactory bulb and branch profusely to form tufts organized as spherical neuropils in the glomerular layer. While fascicles of immunoreactive fibers were seen in the medial olfactory tracts, the lateral olfactory tracts showed individual immunoreactive fibers. Immunoreactive fibers in the medial olfactory tract extend into the telencephalon and form terminal fields in discrete telencephalic and preoptic areas; some immunoreactive fibers decussate in the anterior commissure, while others pass into the thalamus. While neurons of the nucleus lateralis tuberis revealed weak immunoreactivity, densely staining somata were seen at discrete sites along the wall of the third ventricle. Although a large population of immunoreactive cells was seen in the pars intermedia of the pituitary gland, few were seen in the rostral pars distalis and proximal pars distalis; immunoreactive fibers were seen throughout the pituitary gland.

Decreased immunoreactive beta-endorphin in mononuclear leucocytes from patients with chronic fatigue syndrome

OBJECTIVE

To investigate beta-endorphin concentrations in the peripheral blood mononuclear cells (PBMC) of patients with chronic fatigue syndrome (CFS).

METHODS

Sixteen patients with CFS were enrolled in this study. Ten healthy subjects were studied as controls. Beta-endorphin concentrations were measured in PBMC by radioimmunoassay performed with antibodies specific for the C-terminal portion of human beta-endorphin.

RESULTS

Beta-endorphin concentrations in the PBMC of chronic fatigue patients were significantly lower (p < 0.001) than in healthy subjects (mean +/- SD: 8.5 +/- 7.0 vs. 42.6 +/- 22.6).

CONCLUSION

Patients with CFS were found to have low levels of PBMC beta-endorphin. This finding may reflect the condition of chronic immune activation in CFS that has been reported in previous investigations. Beta-endorphin concentrations in PBMC seem to mirror the central nervous system homeostasis of the opioid. Therefore, we would postulate that the fatigue and weakness typical of CFS could be related to low beta-endorphin concentrations at the central nervous system level.

An immunological model connecting the pathogenesis of stress, depression and carcinoma

Recently there has been considerable conjecture in the literature concerning a possible relationship between stress, depression and bereavement, and carcinoma. We shall propose a causal model in which the relationship between stress, depression and carcinoma is clarified. This relationship is grounded on dysregulation of the inflammatory cytokines in stress and depression. Stress is associated with increased expression of interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha), and reduced expression of IL-2, interferon-gamma (IFN-gamma), major histocompatability complex (MHC) class II molecules and natural killer cell activity (NKA). Depression is associated with elevated IFN-gamma and IL-1 beta, downregulated IL-2, and reduced NKA. Most organ-related carcinomas are associated with elevated TNF-alpha, which inhibits the activity of protein tyrosine phosphatase (PTPase), the enzyme that initiates activation of the MHC class I pathway. Sustained elevation of TNF-alpha inhibits the activity of PTPase which results in diminished expression of the MHC class I antigen on the cell surface and thus, malignant cells escape immune surveillance. Therefore, stress and depression can foster tumor progression by means of inhibiting the expression of MHC class I and II molecules and through the reduction of NKA.

Decreased levels of beta-endorphin in circulating mononuclear leukocytes from patients with acute myocardial infarction

Lymphocytes can be activated to produce and release opioid peptides. We investigated the levels of immunoreactive beta-endorphin in peripheral blood mononuclear cells from 11 patients with acute myocardial infarction. The concentrations of beta-endorphin in mononuclear leukocytes of 30.2 +/- 6.9 pg/10(6) cells on admission were in the normal range of 20-40 pg/10(6) cells and decreased significantly to 6.9 +/- 1.9 pg/10(6) cells after 48 h (p < 0.05). Decreased levels of mononuclear leukocyte-associated beta-endorphin in acute myocardial infarction may be due to the release of endogenous opioid after stimulation by stress and acute-phase reactants and play a role in inflammation and pain.

Metabolic and endocrine responses to cold air in women differing in aerobic capacity

PURPOSE

The purpose of this study was to measure resting metabolic rate, plasma norepinephrine, and plasma immunoreactive beta endorphin during exposures to cold air during two consecutive 5-d periods, separated by 2 weekend days, in two groups of women differing in aerobic fitness.

METHODS

Plasma norepinephrine (NE), plasma immunoreactive beta-endorphin (IBE), and resting metabolic response (RMR) were measured during repeated exposures to 3.5 degrees C air in two groups of women differing in aerobic fitness. Ten women, separated into highly fit (HFW) and less fit (LFW) groups, sat in 22 degrees C air for 45 min followed by 45 min in 3.5 degrees C air each day during two consecutive 5-d periods separated by two weekend days.

RESULTS

Norepinephrine was not different between groups during warm air exposure; however, following 45 min of cold air, NE was two times higher in HFW compared with that in LFW (P < 0.001). Plasma IBE was elevated (P < 0.02) in HFW compared with that in LFW but was not affected by exposure to cold on any test day. Warm RMR was not different between groups and remained unchanged during the study period. Cold RMR was significantly higher in LFW compared with that in HFW (P < 0.01). Resting metabolic rate peaked at 30% of VO2peak in LFW by the 5th minute of cold exposure on day 1 before declining to 21% and remaining steady. In contrast, RMR in HFW peaked at about 13% and then fell to 9.4% before slowly increasing to 14% by the end of 45 min. On other test days HFW RMR increased to 14% of VO2peak and rose slowly through 45 min of cold exposure while LFW RMR peaked at 24% of VO2peak before declining to 20% and remaining steady.

CONCLUSIONS

Our findings suggest that, in women, aerobic fitness alters the endocrine and metabolic responses to acute cold air exposure. The norepinephrine response is exaggerated in highly fit women exposed to cold but not the metabolic response. Immunoreactive beta endorphin was not affected by exposure to cold but was elevated in highly fit women. We further conclude that the temperature threshold for acclimation to cold air by women may be higher than the air temperature used in this study.

Fine-tuning control of testicular functions

The effect of testicular administration of peptides synthesized in the testis (somatostatin, oxytocin) or peptide antagonists (opioid receptor antagonists naloxone, nalmefene, anti-corticotrop hormone-releasing hormone antiserum, beta-endorphin antiserum), partial denervation of the testis, and combination of local treatment with peptides/peptide antagonists and denervation was studied on testicular steroidogenesis in immature hemicastrated rats. The observations indicate that beta-endorphin, corticotrop hormone-releasing hormone, oxytocin, and somatostatin exert a stimulatory, whereas enkephalin has an inhibitory action on steroidogenesis. Surgical (vasectomy) or pharmacological (local injection of 6-hydroxydoparnine) denervation suppresses testosterone secretion. Following partial denervation of the testis the effect of naloxone or oxytocin on steroidogenesis observed in fully innervated gonad is not present or the effect is paradoxical. These results indicate that steroidogenesis is fine-tuned by local peptide actions, and neural inputs. Data further suggest an interaction between local peptide action and neural control.

Studies on the effect of intratesticular administration of opioid peptides, naloxone or N-acetyl beta-endorphin antiserum on some testicular parameters in rats

Opioid peptides have been localized in a variety of peripheral tissues like placenta, thyroid, pancreas, gastrointestinal tract, in the reproductive tract of male and female and in the testes of rats. Immunoassayable material was detected in extracts of gonads, reproductive tract and accessory reproductive organs. Studies with naloxone have suggested that beta-endorphin may have an important role in steroidogenesis and may have a role in regulating transport of luminal material. In our studies met-enkephalin, beta-endorphin, naloxone or N-acetyl beta-endorphin antiserum were microinjected intra testicularly once on alternate days for one week and autopsied 24 h after the last injection. Intratesticular administration of 25, 50 and 100 micrograms doses of naloxone induced significant decrease in in vitro secretion of testosterone per se, which was significantly greater with 50 micrograms dose than with those of the other two doses. A 25 micrograms dose had no effect on hyaluronidase or acid phosphatase activity while 50 micrograms dose significantly decreased the enzyme activity. One hundred micrograms dose also significantly decreased hyaluronidase activity. Intratesticular injection of 10 micrograms met-enkephalin or 1 microgram beta-endorphin significantly decreased hyaluronidase activity whereas 20 microliters N-acetyl beta-endorphin antiserum increased the specific activity of hyaluronidase. There was no change in the weight of the testes on treatment with the above agents.

Brain beta-endorphin and other opioids are involved in restraint stress-induced stimulation of the hypothalamic-pituitary-adrenal axis, the sympathetic nervous system, and the adrenal medulla in the rat

Opiates and opioids have complex effects on the hypothalamic-pituitary-adrenal axis, and they stimulate the sympathetic nervous system. This study was designed to clarify the role of brain beta-endorphin in the mechanism by which stress increases plasma concentrations of adrenocorticotropin (ACTH), epinephrine (E), and norepinephrine (NE). Intracerebroventricular (i.c.v.) administration of beta-endorphin to rats significantly increased plasma ACTH levels at doses of 0.09, 0.3, and 1.5 nmol, and plasma E and NE levels at doses of 0.3 and 1.5 nmol. The rise of plasma ACTH, E, and NE levels by 0.3 nmol beta-endorphin was inhibited by intravenous (i.v.) administration of 2 mg/kg b.wt. naloxone. I.v. administration of anti-rat corticotropin-releasing hormone (CRH) rabbit serum completely blocked the beta-endorphin-induced ACTH secretion without affecting the secretion of E and NE. I.c.v. administration of anti-beta-endorphin rabbit gamma-globulin attenuated a 30-min restraint stress-induced rise of plasma ACTH levels without significant influence on the rise of E and NE levels, whereas i.v. administration of naloxone attenuated the restraint stress-induced rise of plasma ACTH, E and NE levels. These results suggest that i.c.v. administration of beta-endorphin stimulates the secretion of ACTH, E, and NE through opiate receptor, and that brain CRH mediates the beta-endorphin-induced secretion of ACTH. The results also suggest that brain beta-endorphin is, at least in part, involved in the restraint stress-induced stimulation of the hypothalamic-pituitary-adrenal axis, and that some opioids other than beta-endorphin are involved in the stimulatory mechanism of the autonomic nervous system and the adrenal medulla in the rat.

Identification and measurement of beta-endorphin levels in the skin during induced hair growth in mice

We describe new and effective techniques for extracting proopiomelanocortin (POMC)-derived peptides from mammaliar skin. Using this methodology (hot-acid extraction) and two independent HPLC-controlled RIA systems, we identify beta-endorphin peptide in mammalian skin and demonstrate significant hair cycle-dependent fluctuations in both the skin concentration and the in situ expression pattern of beta-endorphin (sebaceous glands) during the entire murine hair cycle. The observed anagen (growth phase) associated increase in beta-endorphin concentration and its decline during the follicle involution (catagen) or resting (telogen) phase raise the possibility of a regulatory function of this neuropeptide in cyclic changes of skin physiology.

Microscale epitope mapping by affinity capillary electrophoresis-mass spectrometry

Using beta-endorphin as a model system, a new microscale solution-based approach for linear epitope mapping based on affinity capillary electrophoresis-mass spectrometry (ACE-MS) is demonstrated. Tryptic peptides are separated in a neutral coated capillary and monitored by ultraviolet absorbance and electrospray mass spectrometry. Then, following injection of the peptide digest mixture, anti-beta-endorphin antibody is injected. The peptide, which binds to the antibody, is captured and disappears from its migration time. Following this subtraction-screening procedure, the binding of the individually synthesized or isolated immunoreactive peptide is examined by the ACE-MS procedure to confirm that the epitope resides on the peptide. A series of truncated peptides can then be made and the precise epitope determined by ACE-MS. The method utilizes low femtomole amounts of antibody and peptide digest per run and is rapid and easily automatable.

[Met5]enkephalin and delta2-opioid receptors in the spinal cord are involved in the cold water swimming-induced antinociception in the mouse

Mice made cold water swimming (CWS: 4 degrees C, 3 min) produced an opioid-mediated antinociception. Experiments were designed to determine what types of opioid receptors and endogenous opioid peptides in the spinal cord are involved in the CWS-induced antinociception in male ICR mice. Antinociception was measured by the tail-flick test. CWS-induced antinociception was blocked by intrathecal (i.t.) pretreatment with antiserum to [Met5]enkephalin (100 microg, 1 hr), but not by antiserum (100 microg, 1 hr) to [Leu5]enkephalin, beta-endorphin or dynorphin A (1-17). Moreover, i.t. pretreatment with delta2-opioid receptor antagonist naltriben (NTB: 10 microg, 10 min) blocked the antinociception induced by CWS or i.t.-administered [Met5]enkephalin (10 microg). However, the antinociception induced by CWS or i.t.-administered [Met5]enkephalin was not blocked by i.t. pretreatment with delta1-opioid receptor antagonist 7-benzylidene naltrexone (BNTX: 1 microg, 10 min), mu-opioid receptor antagonist D-Phe-Cys-Try-D-Try-Om-Thr-Phe-Thr-NH2 (CTOP: 50 ng, 10 min), or kappa-opioid receptor antagonist norbinaltorphimine (norBNI: 5 microg, 24 hr). These data indicate that [Met5]enkephalin and delta2-opioid receptor in the spinal cord are involved in antinociception induced by CWS.

Adrenocorticotropic hormone immunoreactivity in the hippocampal formation of temporal lobe epilepsy patients

PURPOSE

We wished to identify immunocytochemically the distribution of proopiomelanocortin-related peptides in the hippocampal formation of patients with epilepsy.

METHODS

Surgical hippocampal specimens from temporal lobe epilepsy (TLE) patients and autopsy control tissue were examined immunocytochemically for ACTH, alpha-melanocyte-stimulating hormone (alpha-MSH) and beta-endorphin.

RESULTS

There was a dense distribution of ACTH-immunoreactive neurons in the hippocampal formation of patients with mesial TLE syndrome (MTLE). These hippocampal specimens showed significant cell loss. ACTH-positive neurons were most prominent in the subiculum, with scattered ACTH-immunoreactive neuronal elements distributed in the cornu ammonis fields and hilus. Light ACTH immunoreactivity was detected in the tumor-related epileptic hippocampal specimens, which showed minimal cell loss. Although autopsy control tissue from the hypothalamus showed intense ACTH staining patterns in cells and fibers, there was little or no ACTH immunoreactivity in the autopsy hippocampal tissue. The expression of ACTH immunoreactive elements was correlated with patterns of cell loss. No alpha-MSH- or beta-endorphin-immunoreactive neurons were detected in any of the hippocampal specimens.

CONCLUSIONS

ACTH has anticonvulsant properties, and its novel expression in the glutamatergic subicular neurons, which provide the main outflow of the hippocampal formation, may represent an attempt by the damaged hippocampal circuit to restore the balance of excitatory/inhibitory neurotransmission in TLE.