Plasma Β-endorphin Research Articles

Effect of Nei-Yi Recipe (内异方) on plasma β-endorphin level during menstrual cycle in women with endometriosis

In order to investigate the mechanism of Nei-Yi Recipe (NYR) in treatment of endometriosis, we observe the changes of plasma beta-endorphin concentrations in women with endometriosis treated by NYR. It was found that in luteal phase beta-endorphin concentrations in plasma were significantly reduced in moderate and severe dysmenorrhea groups compared with mild and control groups. Moreover, beta-endorphin level in severe dysmenorrhea group was lower in the luteal phase than that in the follicular phase, and it was lower in patients with pelvic pain than that without pelvic pain. In normal women, the contents of beta-endorphin in plasma were not changed during menstrual cycle. It was also found that plasma beta-endorphin levels were significantly increased in luteal phase and follicular phase after treatment by NYR. The therapeutical mechanism of NYR on dysmenorrhea and pelvic pain and enhancement of immune function might be mediated by increase of plasma beta-endorphin levels.

Decrease of anesthetics activity by electroacupuncture on Jen-Chung point in rabbits

The effect of acupuncture at life-saving point on the central nervous depressive action of anesthetics was investigated in rabbits. Stimulation with electroacupuncture (EA) inserted in Jen-Chung point, which is located at the mid-point on the upper lip, decreased the sleeping time induced by pentobarbital or propofol. However, this action of acupuncture was not modified by naloxone at the doses sufficient to block opiate receptors. Plasma β-endorphin detected by radioimmunoassay was also not markedly changed in rabbits which received similar electrostimulation. Moreover, pretreatment with para-chlorophenylalanine at a dose sufficient to deplete endogenous 5-hydroxytryptamine (5-HT) failed to influence the action of EA. Mediation of endogenous opioids and/or 5-HT in this action of EA was then ruled out. Prazosin reversed the sleeping time decreasing action of acupuncture in a dose-dependent manner. Also, the action of acupuncture was eliminated in rabbits which received intracerebroventricular injection of guanethidine at a dose which could block noradrenergic nerve terminals. It is suggested that stimulation of Jen-Chung point through EA can activate noradrenergic neurotransmission in the brain, which in turn reduces the central nervous depressive activity of anesthetics.

Low carbohydrate diet induces changes in central and peripheral beta-endorphins

Sprague-Dawley male rats (n=21) weighing 175 ± 10 g, after one week of control diet feeding, were assigned to one of two treatments for another week: a) control diet group (CD) which was fed a diet consisting of 65% carbohydrate (n=10), and b) low carbohydrate diet group (LCD) which was fed an isocaloric diet consisting of 5% carbohydrate (n=11). Rats were killed by decapitation under pentobarbital anesthesia after a 12 hour fast. Brain tissue and mixed arteriovenous blood were collected. Body weight, weight gain and food intake were unaffected by diet (159.2 ± 9.8 g vs 158.5 ± 7.5 g, 52.5 g vs 51.0 g, and 14.3 ± 1.7 g vs 14.5 ± 1.8 g for CD and LCD, respectively. Hypothalamic and plasma B-Endorphin (B-EP) were significantly elevated in the LCD compared to the CD (376.7 ± 17.5 pmol/g vs 153.0 ± 14.7 pmol/g, and 8.7 ± 1.2 pg/ml vs 4.7± 1.4 pg/ml, p< 0.05). Plasma glucose decreased in the LCD group almost to hypoglycemic levels compared to the CD group (63.5 ± 3.6 mg/dl vs 81.9 ± 3.4 mg/dl, p < 0.05). Significant negative correlations were obtained between plasma glucose concentration and hypothalamic (r = −0.77, p< 0.05) and plasma B-EP (r = −0.60 p < 0.05). Plasma insulin declined in the LCD compared to the CD (16.5 ± 2.4 uIU/ml vs 32.8 ± 2.8 uIU/ml, p < 0.05). Plasma glucagon was elevated in the LCD group compared to the CD group (309.4 ± 19.8 pg/ml vs 145.0 ± 13.3 pg/ml, p < 0.05). The data suggest that dietary carbohydrate restriction can result in low plasma glucose and may be a stimulus for a significant rise of both central and peripheral B-EP. These results support the notion that glucose homeostasis could be regulated, at least in part, by B-EP mechanisms which appear to occur independent of insulin stimulation.

Plasma concentrations of β-endorphin, adrenocorticotropic hormone, and cortisol in drinking and abstinent chronic alcoholics

Previous studies of the relationship between the endogenous opioid system and alcohol consumption have reported contradictory results. To shed light on this connection, we compared plasma concentrations of β-endorphin, adrenocorticotropic hormone, and cortisol in 70 alcoholic persons after different periods of abstinence and a group of 80 control subjects. Plasma β-endorphin was decreased in alcoholics (18.61 ± 1.38 vs. 39.31 ± 3.44 pg/ml), even after more than 10 years' abstinence. This effect may be mediated by the tetrahydroisoquinoline system, and may thus result from chronic alcohol consumption. On the other hand, lowered circulating concentrations of β-endorphin may be a cause, rather than an effect, of alcoholism. Plasma levels of adrenocorticotropic hormone and cortisol did not differ in alcoholics and controls (19.29 ± 1.66 vs. 13.27 ± 1.85 pg/ml for ACTH, 20.37 ± 0.78 vs. 17.22 ± 0.64 ng/ml for cortisol), and thus appear to have no relation with chronic alcohol consumption.

Classification of alcoholics on the basis of plasma β-endorphin concentration

Recent findings suggest that a genetic deficit in opioids may be a biological marker of alcoholism. In other words, decreased plasma concentrations of opioids may be a predisposing factor, rather than a consequence, of alcohol consumption. We attempted to classify 88 randomly chosen individuals as alcoholics or nonalcoholics on the basis of plasma concentration of β-endorphins. This criterion had a sensitivity of 73.30% and a specificity of 79.45%. Its positive predictive value was 42.30%, and its negative predictive value was 93.55%.

Heart rate responses and plasma cortisol and (β-endorphin concentrations in ewes subjected to laparoscopy and its associated handling procedures

AbstractTwo experiments were performed to monitor the stress responses of sheep to intra-uterine insemination by laparoscopy and its associated handling procedures. The results of experiment 1 indicated that both restraint alone and full laparoscopic intra-uterine insemination in animals which had been sedated with 0·2 mg/kg diazepam promoted similar, significant (P &lt; 0·001) short-lived increase in heart rate and plasma cortisol concentrations, but there was no effect of treatment on plasma β-endorphin concentrations. Experiment 2 compared restraint and full laparoscopy, with and without sedation in a 2 × 2 factorial design. The heart rate and cortisol responses following restraint and full laparoscopy were not significantly different, although laparoscopy tended (P = 0·06) to increase the duration of the heart rate response. Sedation with diazepam significantly (P&lt;0·05) increased the duration of the heart rate response but attenuated (P &lt; 0·05) the amplitude of the cortisol response. These results indicate that laparoscopic intra-uterine insemination does cause sheep to mount a typical stress response, but that most of this is attributable to the restraint required to effect insemination. However, the magnitude of the stress responses recorded were much lower than those reported to follow many other husbandry procedures.

Cortisol, progesterone and β-endorphin response to stress in calves

In evaluating stress in farm animals, it would be useful to know whether there were consistent endocrine responses that could be followed. Adrenal cortisol secretion is quite variable, but β-endorphin secretion and adrenal progesterone production may be useful indicators of stress. Changes in plasma concentrations of cortisol, β-endorphin and progesterone were studied in spring-born, castrated male calves (steers) (6 mo of age ± 18 d, 516 ± 26 kg, n = 12) subjected to the stress of routine dehorning. Steers were isolated from their dams for 2 h before headgate restraint (control) or restraint and dehorning. They were bled 60 and 10 min prior to headgate restraint or restraint and dehorning. Blood samples were also collected immediately after headgate restraint or restraint and dehorning (time 0) and 5, 10, 30 and 60 min later. All blood samples were taken from a jugular catheter, and the blood sampling that was done out of the headgate involved minimal manual restraint. Plasma β-endorphin concentrations were similar in control steers and dehorned steers (P &gt; 0.05) and decreased significantly following restraint or restraint and dehorning (P &lt; 0.05). Plasma cortisol concentrations rose significantly 5 min after dehorning and were elevated for 60 min; but with restraint only, plasma cortisol concentrations rose to a peak 5 min after release from chute restraint and then declined (P &lt; 0.05). Plasma cortisol concentrations were greater in dehorned steers than in control steers in the period from 10 min after dehorning or headgate restraint to 60 min after headgate restraint (P &lt; 0.0043). Plasma progesterone concentrations rose to a peak 10 min after dehorning and then declined, but in control steers, a peak was seen at 5 min after release from restraint (P &lt; 0.05). Plasma progesterone concentrations were greater in dehorned steers between 5 and 60 min after dehorning than in control steers (P &lt; 0.05). From these data, we concluded that in prepubertal, castrated male calves, β-endorphin was not released in any significant quantities in response to the stress of dehorning. In steers, adrenal cortisol and progesterone were secreted in response to acute stress, and a ratio of the two may provide a useful assessment of stress; this requires further study. Key words: Cortisol, progesterone, β-endorphin, stress, calves

EFFECTS OF VOLUNTARY ETHANOL INGESTION ON THE POMC GENE EXPRESSION IN THE RAT PITUITARY AND ON THE PLASMA β-ENDORPHIN CONTENT

Studies investigating the influence of chronic ethanol treatment on the beta-endorphin content and the proopiomelanocortin (POMC) gene expression in the rat pituitary revealed contradictory results. Because of this we decided to start a more complex study to investigate the effects of isolation stress, chronic ethanol treatment and voluntary ethanol consumption on the POMC mRNA level in the rat pituitary. The immediately prepared total RNA from rat pituitaries was used in hybridization experiments (Northern- and Dot-blots). The results suggest a correlation between the POMC gene expression and the different fashions of 'living conditions' tested. So the POMC gene expression in long-term alcohol-treated animals was decreased supporting the theory of beta-endorphin deficiency in alcoholism. More interestingly, data obtained from the group of voluntary ethanol consumption suggest an inverse correlation between total ethanol ingestion and POMC gene expression. This indicates the importance of the method of ethanol administration. Consistent with a decreased POMC gene expression in the pituitary during chronic ethanol treatment are previous studies showing a decrease in the plasma beta-endorphin content in such situations. Surprisingly, in the present study the plasma beta-endorphin levels measured by radioimmunoassay were only slightly decreased in chronically ethanol-treated rats. This may be due to dysregulatory effects of ethanol on post-translational processing, degradation and/or release of beta-endorphin.

Heart rate responses and plasma cortisol and β-endorphin concentrations in ewes subjected to laparoscopy and its associated handling procedures

The laparoscopic technique used for intra-uterine insemination of sheep within sire-referencing schemes involves a small degree of surgical intervention. Although current codes of practice require the use of sedation and local anaesthesia, the concept of laparoscopic procedures still raises welfare questions in the minds of some. In spite of its sensitivity, little work has yet been undertaken to objectively measure the stress responses of sheep to laparoscopic procedures, and the present studies were therefore designed to rectify this deficiency.

Heart rate responses and plasma cortisol and β-endorphin concentrations in ewes subjected to laparoscopy and its associated handling procedures

The laparoscopic technique used for intra-uterine insemination of sheep within sire-referencing schemes involves a small degree of surgical intervention. Although current codes of practice require the use of sedation and local anaesthesia, the concept of laparoscopic procedures still raises welfare questions in the minds of some. In spite of its sensitivity, little work has yet been undertaken to objectively measure the stress responses of sheep to laparoscopic procedures, and the present studies were therefore designed to rectify this deficiency.

Association between birth order, blood pc02 and β-endorphin concentration in newborn piglets

Parturition and delivery are stressful situations for the mother as well as the neonate. In newborn human babies and lambs, high plasma β-endorphin (β-EP) concentrations have been found, especially in conjunction with foetal distress. Foetal anoxia during parturition causes decreased blood pH, increased pC02, decreased piglet viability and stillbirth. Since high opioid levels can cause respiratory and circulatory difficulties. Piglets born later in the litter during prolonged parturition are more likely to suffer from these problems. It was, therefore, of interest to us to investigate whether late birth order and anoxia were associated with elevated plasma β-EP concentrations in newborn piglets.

Association between birth order, blood pc02 and β-endorphin concentration in newborn piglets

Parturition and delivery are stressful situations for the mother as well as the neonate. In newborn human babies and lambs, high plasma β-endorphin (β-EP) concentrations have been found, especially in conjunction with foetal distress. Foetal anoxia during parturition causes decreased blood pH, increased pC02, decreased piglet viability and stillbirth. Since high opioid levels can cause respiratory and circulatory difficulties. Piglets born later in the litter during prolonged parturition are more likely to suffer from these problems. It was, therefore, of interest to us to investigate whether late birth order and anoxia were associated with elevated plasma β-EP concentrations in newborn piglets.

1028-121 Stressful Public Speaking Elevates Plasma β-Endorphins

Public speaking psychological stress has previously been shown to be associated with silent ischemia. To test the hypothesis that psychological stress elevates plasma β-endorphin and that this changes pain threshold, we studied 20 patients with documented CAD and exercise induced ischemia, Following instrumentation and a 30 minute rest period, venous blood samples for β-endorphin were obtained prior to and immediately post psychological stress, Pain threshold was then assessed using a thermal probe technique at baseline and immediately post psychological stress. Patients gave 3 brief speeches lasting a total of 15 minutes about real life hassle situations.Empty CellBaselinePeak StressEmpty CellSBP (mmHg)138 ± 4180 ± 4HR (Beats/min)65 ± 378 ± 4Double Product9,047 ± 50814,240 ± 844Plasma β-endorphin (pMoI/L)4.3 ± 0.98.3 ± 2p &lt; 0.05Pain Threshold (C°)45.0 ± 0.545.4 ± 0.5P = 0.18 There was a significant positive correlation between pain threshold post stress and β-endorphin post stress (r = 0,58, p = 0.008) In patients with CAD and exercise induced ischemia 1) public speaking produces psychological stress manifested by increased cardiovascular reactivity 2) public speaking causes an increase in plasma β-endorphin which is significantly correlated with pain thresholds 3) this may explain the predominance of silent ischemia during psychological stress in patients with CAD.

Plasma endorphin species during dynamic exercise in humans

beta-Endorphin is metabolized to gamma- and alpha-endorphin. In order to evaluate endorphin metabolism during exercise, radioimmunoassay blood levels of alpha-, beta- and gamma-endorphins were recorded during exercise for 2 h on a cycling ergometer in 12 endurance-trained and 11 untrained male subjects. In untrained subjects, mild exercise (49 +/- 4% VO2max, mean +/- SD) did not show an increase in plasma beta-endorphin, while the levels of its metabolites rose. No changes were noted in the endurance-trained subjects. More intensive exercise (66 +/- 6% VO2max in untrained and 57 +/- 7% VO2max in trained subjects) resulted in an increase in beta-endorphin concentration in association with elevation of the alpha-endorphin level. While before and during exercise the beta-endorphin levels did not differ significantly between athletes and untrained subjects, the levels of gamma- and alpha-endorphins, as well as the molar ratios alpha/beta and gamma/beta, were significantly higher in untrained subjects. In conclusion, blood levels of beta-endorphin metabolites in the resting state and during exercise are dependent on previous training. In untrained subjects, mild exercise may result in accumulation of gamma- and alpha-endorphins in blood without a concomitant change in beta-endorphin level.

Change in circulating β-endorphin and cortisol in preterm infants: Lack of association with intrauterine-like sound stimulation

Abstract Exposure to intrauterine-like sound has been reported to be beneficial to newborn babies. As part of a larger study to develop methods to reduce arousal and stress experienced by sick, newborn babies, we evaluated the hormonal responses to intrauterine-like sound in a group of babies receiving intensive care. Plasma β-endorphin and cortisol concentrations were measured in nine preterm babies (median gestational age 27 weeks) (i) before, (ii) at the end of, and (iii) 1 hour after the end of a 30-minute period of intrauterine-like sound stimulation. There was a very wide range of basal plasma cortisol concentrations (15-1270 nmol l-1) and β-endorphin concentrations (80-550 pg ml-1). The highest concentrations were seen in the most severely ill baby. There was no significant change in either cortisol or β-endorphin in response to sound stimulation. A highly significant correlation existed between cortisol and β-endorphin concentrations at both the basal and after-stimulation states (r= 0.92 and 0.87...

Electroacupuncture Treatment of Post-Operative Pain in Oral Surgery

Electroacupuncture was used to relieve pain after oral surgery in 200 patients. They were divided in two groups. One hundred were needled only at the Hegu point, while the remainder were additionally stimulated at tooth specific points related to the area of surgery. Visual analogue pain scores demonstrated a significant relief of pain in both groups, with greater benefit from tooth specific points. Plasma β-endorphin estimations were carried out on pre-operative and post-electroacupuncture samples. A significant rise in β-endorphin levels was noted.

The effect of diet on cribbing behavior and plasma β-endorphin in horses

Five cribbing horses and six control horses were used in a latin square design dietary study to investigate the effects of different diets on the frequency of cribbing behavior and plasma levels of beta-endorphin in the horse. Feeding grain or sweetened grain rations was found to cause a significant increase in the cribbing frequency whereas alfalfa pelleted hay was without significant effect on the frequency of the behavior. Baseline beta-endorphin levels in cribbing horses were half those of the non-cribbing controls and remained significantly lower during the feeding trials. These results are discussed as they apply to treatment of cribbing horses and in terms of the underlying mechanism of cribbing.

Corticotrophin-releasing hormone and β-endorphin in labour

The objectives of this study were to determine whether the maternal plasma corticotrophin-releasing hormone (CRH) concentration influences the amount of uterine contractility induced by infused oxytocin during induction of labour, and secondly to assess changes in CRH and beta-endorphin in response to stress during labour. Serial plasma CRH and beta-endorphin measurements were made in 40 women undergoing induction of labour and correlated with uterine contractility, cervical dilatation, length of labour, analgesic usage and fetal distress. The plasma CRH concentration did not change throughout labour. In subjects receiving infused oxytocin there was a significant positive correlation between plasma CRH and the amount of uterine activity, and a high plasma CRH level was associated with shorter labour. The plasma beta-endorphin level rose with progressive cervical dilatation and fell after epidural anaesthesia. The plasma CRH level did not correlate with the plasma beta-endorphin level or rise with fetal distress. We conclude that high levels of maternal plasma CRH are associated with an increase in the uterine contractile response to infused oxytocin. The maternal plasma CRH level does not vary in response to maternal or fetal stress, but beta-endorphin secretion does rise in response to the stress of labour and is influenced by pain perception.

Plasma beta-endorphin concentrations and analgesia-muscle relaxation in the newborn infant supported by mechanical ventilation

We evaluated the effects of pancuronium and opiates on plasma β-endorphin concentrations in 25 infants supported by mechanical ventilation. Infants receiving opiate were randomly assigned to receive either fentanyl or morphine. There was no change in β-endorphin concentrations after administration of pancuronium, whereas both fentanyl and morphine reduced β-endorphin concentrations by approximately 60%. (J P EDIATR 1994;125:113-6)

Effects of the Opiate Antagonist, Naltrexone, on Binging Antecedents and Plasma β-Endorphin Concentrations

The effects of the opiate receptor antagonist, naltrexone, were examined on antecedent thoughts of binging and plasma beta-endorphin concentrations in an adolescent girl who was hospitalized with bulimia nervosa. Significant decreases in urge to binge were obtained during naltrexone administration compared with control sessions. Baseline plasma beta-endorphin concentrations for the bulimic adolescent were not different from those of nonbulimic controls, but plasma beta-endorphins increased significantly during naltrexone administration. After discharge from the hospital, the adolescent refused to take naltrexone because she felt she could not deal with her life without the "pleasure of binging." The case points to the interplay of biological and psychological factors in bulimia nervosa.