Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The opioids beta-endorphin and the dynorphins belong to two separate families of endogenous opioid peptides (EOP). They are produced not only in the central nervous system but also in nonneural tissues where, as it appears, they act locally via paracrine mechanisms. These opioids have been shown to be produced at multiple sites along the mammalian reproductive tract including the intrauterine cavity. The aim of the present work was to find out if the well differentiated human endometrial cell line of Ishikawa, which has been shown to be a good in vitro model for the study of the effects of steroid hormones on human epithelial endometrium, expresses these two EOP. Northern blot hybridization of RNA from these cells showed the presence of a 1.2-kb POMC and a 2.4-kb PDYN transcript. Radioimmunoassay and gel filtration chromatography characterization of the immunoreactive (IR) opioid peptides present in the culture media showed the presence of IR-beta-endorphin and IR-dynorphins. The apparent molecular weight of IR-beta-endorphin was that of authentic beta-endorphin while the bulk of the IR-dynorphin had an apparent molecular weight of 8 kd. The secretion of both opioids could be increased by KCl-induced depolarization. Estrogen and glucocorticoids decreased, in a dose- and time-dependent manner, the secretion of beta-endorphin from the Ishikawa cells while progesterone and dihydrotestosterone did not have a statistically significant effect. The antiprogestin-antiglucocorticoid RU486 acted as an agonist, i.e., it diminished beta-endorphin secretion possibly via glucocorticoid receptors. On the other hand, the secretion of dynorphins was not affected by any of the steroids tested while LHRH, the inducer of gonadotropins and anterior pituitary dynorphins secretion, provoked a time- and dose-dependent increase of their secretion without affecting that of beta-endorphin. These data suggest that the regulation of endometrial opioids production is type-specific. Thus, it is possible that each type of endometrial opioid participates in different local homeostatic loops and exerts distinct paracrine effects.
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PMID:Interaction between steroid hormones and endometrial opioids. 797 24

The advance in our understanding of the biogenesis of various endogenous opioid peptides, their anatomical distribution, and the characteristics of the multiple receptors with which they interact open a new avenue for understanding the role of opioid peptide systems in chronic pain. The main groups of opioid peptides: enkephalins, dynorphins and beta-endorphin derive from proenkephalin, prodynorphin and proopiomelanocortin, respectively. Recently, a novel group of peptides has been discovered in the brain and named endomorphins, endomorphin-1 and -2. They are unique in comparison with other opioid peptides by atypical structure and high selectivity towards the mu-opioid receptor. Another group, which joined the endogenous opioid peptide family in the last few years is the pronociceptin system comprising the peptides derived from this prohormone, acting at ORL1 receptors. Three members of the opioid receptor family were cloned in the early 1990s, beginning with the mouse delta-opioid receptor (DOR1) and followed by cloning of mu-opioid receptor (MOR1) and kappa-opioid receptor (KOR1). These three receptors belong to the family of seven transmembrane G-protein coupled receptors, and share extensive structural homologies. These opioid receptor and peptide systems are significantly implicated in antinociceptive processes. They were found to be represented in the regions involved in nociception and pain. The effects of opioids in animal models of inflammatory pain have been studied in great detail. Inflammation in the periphery influences the central sites and changes the opioid action. Inflammation increased spinal potency of various opioid receptor agonists. In general, the antinociceptive potency of opioids is greater against various noxious stimuli in animals with peripheral inflammation than in control animals. Inflammation-induced enhancement of opioid antinociceptive potency is characteristic predominantly for mu opioid receptors, since morphine elicits a greater increase in spinal potency of mu- than of delta- and kappa-opioid receptor agonists. Enhancement of the potency of mu-opioid receptor agonists during inflammation could arise from the changes occurring in opioid receptors, predominantly in affinity or number of the mu-opioid receptors. Inflammation has been shown to alter the expression of several genes in the spinal cord dorsal horn. Several studies have demonstrated profound alterations in the spinal PDYN system when there is peripheral inflammation or chronic arthritis. Endogenous dynorphin biosynthesis also increases under various conditions associated with neuropathic pain following damage to the spinal cord and injury of peripheral nerves. Interestingly, morphine lacks potent analgesic efficacy in neuropathic pain. A vast body of clinical evidence suggests that neuropathic pain is not opioid-resistant but only that reduced sensitivity to systemic opioids is observed in this condition, and an increase in their dose is necessary in order to obtain adequate analgesia. Reduction of morphine antinociceptive potency was postulated to be due to the fact that nerve injury reduced the activity of spinal opioid receptors or opioid signal transduction. Our recent study with endogenous ligands of the mu-opioid receptor, endomorphins, further complicates the issue, since endomorphins appear to be effective in neuropathic pain. Identification of the involved differences may be of importance to the understanding of the molecular mechanism of opioid action in neuropathic pain, as well as to the development of better and more effective drugs for the treatment of neuropathic pain in humans.
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PMID:Opioids in chronic pain. 1169 29

We have shown that supplementation of proinflammatory agent with a high dose of morphine not only abolishes inflammation-related pain symptoms but also inhibits influx of leukocytes to the inflamed peritoneal cavity. Present investigations focused on effects of morphine on proopiomelanocortin and prodynorphin systems during zymosan-induced peritonitis. Males of SWISS mice were ip injected with zymosan (Z, 40 mg/kg) or zymosan with morphine (ZM, 20 mg/kg). At time 0 (controls) and 4 and 24h after stimulation, peritoneal leukocytes (PTLs) were counted, PTL levels of opioid peptides (beta-endorphin and dynorphin) measured by radioimmunoassays, while mRNAs coding their respective precursors (POMC and PDYN) and receptors (MOR and KOR) determined by QRT-PCR. Influx of inflammatory PTLs, mainly PMNs, was significantly delayed by morphine co-injection. Total levels of beta-endorphin and dynorphin corresponded with PTL numbers, while levels per cell were similar in all groups except of beta-endorphin, decreased in ZM at 4h. Levels of both peptides in peritoneal fluid were increased in Z and ZM groups at 4h, while at 24h only in case of beta-endorphin in Z group. POMC was increased only in ZM group at 4h of peritonitis, while PDYN in both Z and ZM groups at the same time. MOR mRNA was increased 24h after injection in Z and ZM groups, while KOR mRNA was similar in all groups except of decrease in Z at 24h. In conclusion, endogenous opioids and their receptors are involved in zymosan-induced peritonitis and affected in various ways by morphine co-injection.
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PMID:Morphine-induced changes in the activity of proopiomelanocortin and prodynorphin systems in zymosan-induced peritonitis in mice. 1597 27