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Hormone and Metabolic Research =... Jun 1991The discovery of several endogenous substances with morphine-like activity (endorphins and enkephalins) which possess potent behavioral effects, interfering with food... (Review)
Review
The discovery of several endogenous substances with morphine-like activity (endorphins and enkephalins) which possess potent behavioral effects, interfering with food and water intake, has led to suggest their implications in the pathogenesis of human obesity. This suggestion is mainly based on: 1) the ability of opiate antagonists naloxone and naltrexone to reduce food intake in some particular situations associated with obesity: 2) the existence of raised plasma levels of beta-endorphin in obese children and adults not corrected by weight loss; and 3) the increased responsiveness to the metabolic and hormonal effects of opiate agonism and antagonism found in obese but not in normal weight subjects. Although the problem still awaits a definite answer, it seems not hazardous to hypothesize a role for beta-endorphin in some pathogenetic events associated with human obesity.
Topics: Humans; Obesity; beta-Endorphin
PubMed: 1916633
DOI: 10.1055/s-2007-1003667 -
Alcohol (Fayetteville, N.Y.) Jun 2016Animal models have long been used to study the mechanisms underlying the complex association between alcohol and stress. Female mice prevented from running on a...
Animal models have long been used to study the mechanisms underlying the complex association between alcohol and stress. Female mice prevented from running on a home-cage activity wheel increase voluntary ethanol consumption. β-endorphin is an endogenous opioid involved in negatively regulating the stress response and has also been implicated in the risk for excessive drinking. The present study investigates the role of β-endorphin in moderating free-choice consumption of ethanol in response to a blocked activity wheel. Female, transgenic mice with varying levels of the opioid peptide were given daily 2-h access to 20% ethanol with rotations on a running wheel blocked on alternate days. Subjects with low β-endorphin exhibited enhanced stress sensitivity by self-administering larger quantities of ethanol on days when wheel running was prevented. β-endorphin levels did not influence voluntary activity on the running wheel. There were genotypic differences in plasma corticosterone levels as well as corticotropin-releasing hormone mRNA content in multiple brain regions associated with the stress response in these free drinking and running subjects. Susceptibility to stress is enhanced in female mice with low levels of β-endorphin, and better understanding of the role for this opioid in mitigating the response to stressors may aid in the development of interventions and treatments for excessive use of alcohol in women.
Topics: Alcohol Drinking; Animals; Brain; Female; Mice; Mice, Inbred C57BL; Mice, Knockout; Motor Activity; Physical Conditioning, Animal; Self Administration; beta-Endorphin
PubMed: 27286936
DOI: 10.1016/j.alcohol.2016.04.003 -
Psychiatry Research Oct 2022Despite the well-recognized effects of endogenous opioids on mood and behavior, research on its role in bipolar disorder (BD) is still limited to small or anecdotal...
Despite the well-recognized effects of endogenous opioids on mood and behavior, research on its role in bipolar disorder (BD) is still limited to small or anecdotal reports. Considering that Beta-endorphins (β-END) and Mu-opioid receptors (MOR), in particular, have a crucial activity in affective modulation, we hypothesized their alteration in BD. A cross-sectional study was conducted. We compared: (1) BD type I (BD-I) patients (n = 50) vs healthy controls (n = 27), (2) two BD-I subject subgroups: manic (MAN; n = 25) vs depressed (DEP; n = 25) subjects. Plasma levels of β-END and MOR gene expression in peripheral blood mononuclear cells were analyzed using ELISA Immunoassay qRT-PCR. We found that subjects with BD exhibited a significant upregulation of MOR gene expression and a decrease of β-END (p<0.0001 for both). MAN display higher MOR levels than DEP (p<0.001) and HC (p<0.0001). Plasma levels of β-END were lower in DEP compared to MAN (p<0.05) and HC (p<0.0001). The main limitations are the cross-sectional design and the lack of a group of euthymic subjects. Although preliminary, our results suggest a dysregulation of the endogenous opioid systems in BD. In particular, both MAN and DEP showed a reduction of β-END levels, whereas MAN was associated with MOR gene overexpression.
Topics: Bipolar Disorder; Cross-Sectional Studies; Gene Expression; Humans; Leukocytes, Mononuclear; Receptors, Opioid, mu; beta-Endorphin
PubMed: 35988328
DOI: 10.1016/j.psychres.2022.114787 -
Neuropsychopharmacology : Official... Nov 2013Cue-induced cocaine craving intensifies, or 'incubates', during the first few weeks of abstinence and persists over extended periods of time. One important factor...
Cue-induced cocaine craving intensifies, or 'incubates', during the first few weeks of abstinence and persists over extended periods of time. One important factor implicated in cocaine addiction is the endogenous opioid β-endorphin. In the present study, we examined the possible involvement of β-endorphin in the incubation of cocaine craving. Rats were trained to self-administer cocaine (0.75 mg/kg, 10 days, 6 h/day), followed by either a 1-day or a 30-day period of forced abstinence. Subsequent testing for cue-induced cocaine-seeking behavior (without cocaine reinforcement) was performed. Rats exposed to the drug-associated cue on day 1 of forced abstinence demonstrated minimal cue-induced cocaine-seeking behavior concurrently with a significant increase in β-endorphin release in the nucleus accumbens (NAc). Conversely, exposure to the cue on day 30 increased cocaine seeking, while β-endorphin levels remained unchanged. Intra-NAc infusion of an anti-β-endorphin antibody (4 μg) on day 1 increased cue-induced cocaine seeking, whereas infusion of a synthetic β-endorphin peptide (100 ng) on day 30 significantly decreased cue response. Both intra-NAc infusions of the δ opioid receptor antagonist naltrindole (1 μg) on day 1 and naltrindole together with β-endorphin on day 30 increased cue-induced cocaine-seeking behavior. Intra-NAc infusion of the μ opioid receptor antagonist CTAP (30 ng and 3 μg) had no behavioral effect. Altogether, these results demonstrate a novel role for β-endorphin and the δ opioid receptor in the development of the incubation of cocaine craving.
Topics: Animals; Cocaine; Cocaine-Related Disorders; Cues; Drug-Seeking Behavior; Male; Nucleus Accumbens; Rats; Rats, Sprague-Dawley; Receptors, Opioid, delta; Self Administration; beta-Endorphin
PubMed: 23800967
DOI: 10.1038/npp.2013.155 -
Cell Jun 2014UV light is an established carcinogen, yet evidence suggests that UV-seeking behavior has addictive features. Following UV exposure, epidermal keratinocytes synthesize...
UV light is an established carcinogen, yet evidence suggests that UV-seeking behavior has addictive features. Following UV exposure, epidermal keratinocytes synthesize proopiomelanocortin (POMC) that is processed to melanocyte-stimulating hormone, inducing tanning. We show that, in rodents, another POMC-derived peptide, β-endorphin, is coordinately synthesized in skin, elevating plasma levels after low-dose UV. Increases in pain-related thresholds are observed and reversed by pharmacologic opioid antagonism. Opioid blockade also elicits withdrawal signs after chronic UV exposure. This effect was sufficient to guide operant behavioral choices to avoidance of opioid withdrawal (conditioned place aversion). These UV-induced nociceptive and behavioral effects were absent in β-endorphin knockout mice and in mice lacking p53-mediated POMC induction in epidermal keratinocytes. Although primordial UV addiction, mediated by the hedonic action of β-endorphin and anhedonic effects of withdrawal, may theoretically have enhanced evolutionary vitamin D biosynthesis, it now may contribute to the relentless rise in skin cancer incidence in humans.
Topics: Animals; Behavior, Addictive; Humans; Mice; Mice, Inbred C57BL; Models, Animal; Skin; Ultraviolet Rays; beta-Endorphin
PubMed: 24949966
DOI: 10.1016/j.cell.2014.04.032 -
Trends in Pharmacological Sciences Dec 2001Among the opioid receptors, which have been pharmacologically classified as mu, delta, kappa and epsilon, the existence of the epsilon receptor has been controversial,... (Review)
Review
Among the opioid receptors, which have been pharmacologically classified as mu, delta, kappa and epsilon, the existence of the epsilon receptor has been controversial, and this receptor is generally not recognized as a member of the opioid peptide receptor family because it has not been precisely characterized. However, results from pharmacological, physiological and opioid receptor binding studies clearly indicate the presence of epsilon-opioid receptors, which are distinct from mu-, delta- or kappa-opioid receptors. This putative epsilon-opioid receptor is stimulated supraspinally by the endogenous opioid peptide beta-endorphin, which induces the release of Met-enkephalin, which, in turn, acts on spinal delta2-opioid receptors to produce antinociception. In this article, this beta-endorphin-sensitive epsilon-opioid receptor-mediated descending pain control system, which is distinct from that activated by the mu-opioid receptor agonist morphine, is described and the physiological role of the beta-endorphin-mediated system in pain control activated by cold-water swimming and intraplantar injection of formalin is discussed.
Topics: Analgesics, Opioid; Animals; Humans; Injections, Spinal; Receptors, Opioid; beta-Endorphin
PubMed: 11730972
DOI: 10.1016/s0165-6147(00)01843-5 -
Journal of Neuroendocrinology Mar 2023Opioid peptides are well-known modulators of the central control of reproduction. Among them, dynorphin coexpressed in kisspeptin (KP) neurons of the arcuate nucleus...
Opioid peptides are well-known modulators of the central control of reproduction. Among them, dynorphin coexpressed in kisspeptin (KP) neurons of the arcuate nucleus (ARC) has been thoroughly studied for its autocrine effect on KP release through κ opioid receptors. Other studies have suggested a role for β-endorphin (BEND), a peptide cleaved from the pro-opiomelanocortin precursor, on food intake and central control of reproduction. Similar to KP, BEND content in the ARC of sheep is modulated by day length and BEND modulates food intake in a dose-dependent manner. Because KP levels in the ARC vary with photoperiodic and metabolic status, a photoperiod-driven influence of BEND neurons on neighboring KP neurons is plausible. The present study aimed to investigate a possible modulatory action of BEND on KP neurons located in the ovine ARC. Using confocal microscopy, numerous KP appositions on BEND neurons were found but there was no photoperiodic variation of the number of these interactions in ovariectomized, estradiol-replaced ewes. By contrast, BEND terminals on KP neurons were twice as numerous under short days, in ewes having an activated gonadotropic axis, compared to anestrus ewes under long days. Injection of 5 μg BEND into the third ventricle of short-day ewes induced a significant and specific increase of activated KP neurons (16% vs. 9% in controls), whereas the percentage of overall activated (c-Fos positive) neurons, was similar between both groups. These data suggest a photoperiod-dependent influence of BEND on KP neurons of the ARC, which may influence gonadotropin-releasing hormone pulsatile secretion and inform KP neurons about metabolic status.
Topics: Female; Animals; Sheep; Arcuate Nucleus of Hypothalamus; Kisspeptins; beta-Endorphin; Gonadotropin-Releasing Hormone; Neurons
PubMed: 36880357
DOI: 10.1111/jne.13242 -
Nihon Rinsho. Japanese Journal of... Jul 2010
Topics: Female; Humans; Infant, Newborn; Pregnancy; beta-Endorphin
PubMed: 20963872
DOI: No ID Found -
Biomedicine & Pharmacotherapy =... 1993
Topics: Humans; Narcotics; Substance Withdrawal Syndrome; beta-Endorphin
PubMed: 8061251
DOI: 10.1016/0753-3322(93)90077-x -
Psychopharmacology Bulletin 1989Patients with anorexia nervosa have neuroendocrine and behavioral alterations that starvation and weight loss are thought to cause, or contribute to, since they are... (Review)
Review
Patients with anorexia nervosa have neuroendocrine and behavioral alterations that starvation and weight loss are thought to cause, or contribute to, since they are reversed by weight restoration. We have found that anorexics have starvation-related disturbances of neuropeptide Y (NPY), corticotropin-releasing hormone (CRH), and beta-endorphin, as determined by their measurements in cerebrospinal fluid. The relationship between these neuropeptides and several symptoms in anorexia, together with findings in experimental animals, raise a possibility that changes in the activity of these neuropeptides contribute to neuroendocrine and behavioral alterations in anorexia. Specifically, a disturbance of central nervous system CRH activity is likely to be responsible for hypercortisolemia, while a disturbance of central nervous system NPY may contribute to amenorrhea. In addition, disturbances of these neuropeptides could contribute to other symptoms such as increased physical activity, hypotension, reduced sexual interest, depression, and pathological feeding behavior.
Topics: Adult; Anorexia Nervosa; Corticotropin-Releasing Hormone; Female; Humans; Neuropeptide Y; Neuropeptides; beta-Endorphin
PubMed: 2533990
DOI: No ID Found