methionine enkephalin


Summary: One of the endogenous pentapeptides with morphine-like activity. It differs from LEU-ENKEPHALIN by the amino acid METHIONINE in position 5. Its first four amino acid sequence is identical to the tetrapeptide sequence at the N-terminal of BETA-ENDORPHIN.

Top Publications

  1. Durand S, Liang W, Brauth S. Methionine enkephalin immunoreactivity in the brain of the budgerigar (Melopsittacus undulatus): similarities and differences with respect to oscine songbirds. J Comp Neurol. 1998;393:145-68 pubmed
    ..that acquires new vocalizations throughout life, was examined for immunoreactivity to the opioid peptide methionine enkephalin (mENK)...
  2. Cheng F, Zagon I, Verderame M, McLaughlin P. The opioid growth factor (OGF)-OGF receptor axis uses the p16 pathway to inhibit head and neck cancer. Cancer Res. 2007;67:10511-8 pubmed
    ..These data are the first to reveal that the target of cell proliferative inhibitory action of OGF in human HNSCC is a cyclin-dependent kinase inhibitory pathway, and this may be useful in the diagnosis and treatment of HNSCC. ..
  3. Rittner H, Labuz D, Richter J, Brack A, Schafer M, Stein C, et al. CXCR1/2 ligands induce p38 MAPK-dependent translocation and release of opioid peptides from primary granules in vitro and in vivo. Brain Behav Immun. 2007;21:1021-32 pubmed
    ..Taken together, these findings indicate that END and ENK are contained in primary granules of PMN, and that CXCR1/2 ligands induce p38-dependent translocation and release of these opioid peptides to inhibit inflammatory pain. ..
  4. Zagon I, Verderame M, McLaughlin P. The biology of the opioid growth factor receptor (OGFr). Brain Res Brain Res Rev. 2002;38:351-76 pubmed
    ..This report reviews the history of OGF-OGFr, examines emerging insights into the mechanisms of action of opioid peptide-receptor interfacing, and discusses the clinical significance of these observations. ..
  5. Heurich M, Mousa S, Lenzner M, Morciniec P, Kopf A, Welte M, et al. Influence of pain treatment by epidural fentanyl and bupivacaine on homing of opioid-containing leukocytes to surgical wounds. Brain Behav Immun. 2007;21:544-52 pubmed
    ..These findings suggest that nociceptive but not sympathetic neurons are primarily involved in the attraction of opioid-containing leukocytes during early stages of inflammation. ..
  6. Machelska H, Schopohl J, Mousa S, Labuz D, Schafer M, Stein C. Different mechanisms of intrinsic pain inhibition in early and late inflammation. J Neuroimmunol. 2003;141:30-9 pubmed
    ..Corticotropin-releasing hormone (CRH) is an endogenous trigger of these effects at both stages. These findings indicate that peripheral opioid mechanisms of pain inhibition gain functional relevance with the chronicity of inflammation. ..
  7. Rosen A, Lundeberg T, Bytner B, Nylander I. Central changes in nociceptin dynorphin B and Met-enkephalin-Arg-Phe in different models of nociception. Brain Res. 2000;857:212-8 pubmed
    ..The changes in the NOC-LI concentrations were not parallelled by changes in DYN B-LI and MEAP-LI, suggesting that NOC and opioid peptides elicit different reactions in the systems of nociception/antinociception. ..
  8. Zagon I, Ruth T, McLaughlin P. Nucleocytoplasmic distribution of opioid growth factor and its receptor in tongue epithelium. Anat Rec A Discov Mol Cell Evol Biol. 2005;282:24-37 pubmed
    ..Moreover, the unique finding that OGFr was found in the cytoplasm and nucleus in NTX-treated specimens may suggest that NTX-OGFr complexes have the same pathway as OGF-OGFr. ..
  9. McLaughlin P, Stack B, Braine K, Ruda J, Zagon I. Opioid growth factor inhibition of a human squamous cell carcinoma of the head and neck in nude mice: dependency on the route of administration. Int J Oncol. 2004;24:227-32 pubmed

More Information


  1. Zagon I, Jaglowski J, Verderame M, Smith J, Leure Dupree A, McLaughlin P. Combination chemotherapy with gemcitabine and biotherapy with opioid growth factor (OGF) enhances the growth inhibition of pancreatic adenocarcinoma. Cancer Chemother Pharmacol. 2005;56:510-20 pubmed
    ..This preclinical evidence shows that combined chemotherapy (e.g. gemcitabine) and biotherapy (OGF) provides an enhanced therapeutic benefit for pancreatic cancer. ..
  2. Spetea M, Rydelius G, Nylander I, Ahmed M, Bileviciute Ljungar I, Lundeberg T, et al. Alteration in endogenous opioid systems due to chronic inflammatory pain conditions. Eur J Pharmacol. 2002;435:245-52 pubmed
    ..Thus, dynamic modification and modulation of nociceptive information takes place during chronic inflammation. This supports the key role of the central nervous system in chronic inflammatory pain conditions. ..
  3. Zagon I, Ruth T, Leure Dupree A, Sassani J, McLaughlin P. Immunoelectron microscopic localization of the opioid growth factor receptor (OGFr) and OGF in the cornea. Brain Res. 2003;967:37-47 pubmed
  4. Chadzinska M, Scislowska Czarnecka A, Pierzchala Koziec K, Plytycz B. Inflammation-induced alternations in local and central Met-enkephalin in mice. Pol J Pharmacol. 2003;55:467-70 pubmed
  5. Brack A, Rittner H, Machelska H, Shaqura M, Mousa S, Labuz D, et al. Endogenous peripheral antinociception in early inflammation is not limited by the number of opioid-containing leukocytes but by opioid receptor expression. Pain. 2004;108:67-75 pubmed
    ..05, t-test). In summary, antinociception during early inflammation is apparently not limited by the number of opioid-containing leukocytes but by OR availability. ..
  6. Agu R, Vu Dang H, Jorissen M, Kinget R, Verbeke N. Metabolism and absorption enhancement of methionine enkephalin in human nasal epithelium. Peptides. 2004;25:563-9 pubmed
    The objective of this study was to investigate absorption enhancing approaches for systemic delivery of methionine enkephalin via the nose...
  7. Desiderio D, Zhu X. Quantitative analysis of methionine enkephalin and beta-endorphin in the pituitary by liquid secondary ion mass spectrometry and tandem mass spectrometry. J Chromatogr A. 1998;794:85-96 pubmed
    ..S.) for quantification. The measurement of methionine enkephalin (ME) and of beta-endorphin1-31 (BE) in the human pituitary is described...
  8. Zagon I, McLaughlin P. Opioids and differentiation in human cancer cells. Neuropeptides. 2005;39:495-505 pubmed
    ..The absence of effects on cancer cell differentiation by a variety of other opioids supports the previously reported lack of growth effects of these compounds. ..
  9. Zagon I, McLaughlin P. Opioid growth factor receptor is unaltered with the progression of human pancreatic and colon cancers. Int J Oncol. 2006;29:489-94 pubmed
    ..This information will be relevant in the design of therapeutic modalities, the diagnosis and prognosis of neoplasia, as well as understanding of the processes and mechanisms of carcinogenesis. ..
  10. McLaughlin P, Verderame M, Hankins J, Zagon I. Overexpression of the opioid growth factor receptor downregulates cell proliferation of human squamous carcinoma cells of the head and neck. Int J Mol Med. 2007;19:421-8 pubmed
    ..These data indicate that the OGF receptor is integral to cell replication of SCCHN, and support treatment modalities that amplify OGFr in order to decrease the growth of these neoplasias. ..
  11. Goldenberg D, Zagon I, Fedok F, Crist H, McLaughlin P. Expression of opioid growth factor (OGF)-OGF receptor (OGFr) axis in human nonmedullary thyroid cancer. Thyroid. 2008;18:1165-70 pubmed publisher
    ..In the present study we examined the presence and distribution of OGF and OGFr in nonmedullary thyroid cancer, including papillary, follicular, and anaplastic, as well as thyroid tissue from patients with nonmalignant disease...
  12. Zagon I, Roesener C, Verderame M, Ohlsson Wilhelm B, Levin R, McLaughlin P. Opioid growth factor regulates the cell cycle of human neoplasias. Int J Oncol. 2000;17:1053-61 pubmed
    ..The data on blockade of OGF-OGFr during log phase growth suggest a requisite escorting of the growth peptide and its receptor through the cell cycle. ..
  13. Mousa S, Straub R, Schafer M, Stein C. Beta-endorphin, Met-enkephalin and corresponding opioid receptors within synovium of patients with joint trauma, osteoarthritis and rheumatoid arthritis. Ann Rheum Dis. 2007;66:871-9 pubmed
    ..These findings are consistent with the notion that, with prolonged and enhanced inflammation, the immune and peripheral nervous systems upregulate sensory nerves expressing ORs and their ligands to counterbalance pain and inflammation. ..
  14. Kraemer W, Kim S, Bush J, Nindl B, Volek J, Spiering B, et al. Influence of the menstrual cycle on proenkephalin peptide F responses to maximal cycle exercise. Eur J Appl Physiol. 2006;96:581-6 pubmed
    ..Pre-exercise arousal mechanisms potentially related to analgesia may also be involved to prepare untrained women for the stress of maximal exercise. ..
  15. Poras H, Bonnard E, Fournié Zaluski M, Roques B. Modulation of disulfide dual ENKephalinase inhibitors (DENKIs) activity by a transient N-protection for pain alleviation by oral route. Eur J Med Chem. 2015;102:58-67 pubmed publisher
    ..This demonstrates that DENKIs are able to relieve pain at its source thanks to the increase of enkephalin levels. ..
  16. Gabrilovac J, Marotti T. Gender-related differences in murine T- and B-lymphocyte proliferative ability in response to in vivo [Met(5)]enkephalin administration. Eur J Pharmacol. 2000;392:101-8 pubmed
    ..This finding may be relevant to the potential use of [Met(5)]enkephalin in adjuvant therapy for immunocompromised states, such as acquired immunodeficiency syndrome (AIDS) or malignancies. ..
  17. Daunton N, Tang F, Corcoran M, Fox R, Man S. Chronic exposure to hypergravity affects thyrotropin-releasing hormone levels in rat brainstem and cerebellum. Biol Signals Recept. 1998;7:337-44 pubmed
  18. Marzioni M, Alpini G, Saccomanno S, De Minicis S, Glaser S, Francis H, et al. Endogenous opioids modulate the growth of the biliary tree in the course of cholestasis. Gastroenterology. 2006;130:1831-47 pubmed
    ..The increase in opioid peptide synthesis in the course of cholestasis aims to limit the excessive growth of the biliary tree in the course of cholestasis by the interaction with the deltaOR expressed by cholangiocytes. ..
  19. Schroeder J, Schneider J. GABA-opioid interactions in the globus pallidus: [D-Ala2]-Met-enkephalinamide attenuates potassium-evoked GABA release after nigrostriatal lesion. J Neurochem. 2002;82:666-73 pubmed
    ..DALA-induced inhibition of pallidal GABA release after a dopamine-depleting lesion, suggests that enkephalin may attenuate GABA release in the GP specifically after striatal dopamine loss. ..
  20. Donahue R, McLaughlin P, Zagon I. Cell proliferation of human ovarian cancer is regulated by the opioid growth factor-opioid growth factor receptor axis. Am J Physiol Regul Integr Comp Physiol. 2009;296:R1716-25 pubmed publisher
    ..These data are the first to report that the OGF-OGFr system is a native biological regulator of cell proliferation in human ovarian cancer. This information will be important in designing treatment strategies for this deadly disease. ..
  21. Mosnaim A, Saavedra R, Wolf M. Bacitracin-sensitive aminopeptidase(s) degradation of methionine(5)-enkephalin by human brain putamen and hippocampus preparations: inhibition by phenothiazine drugs. Am J Ther. 2009;16:512-6 pubmed publisher
    ..Whether their development could find useful pharmacologic applications remains to be explored. ..
  22. Kokrashvili Z, Rodriguez D, Yevshayeva V, Zhou H, Margolskee R, Mosinger B. Release of endogenous opioids from duodenal enteroendocrine cells requires Trpm5. Gastroenterology. 2009;137:598-606, 606.e1-2 pubmed publisher
    ..These cells are likely to secrete the bioactive peptides into the intestinal lumen in response to dietary factors; release of the opioid peptides requires the Trpm5 ion channel. ..
  23. Ciesla A, Mach T, Pierzchała Koziec K, Skwara P, Szczepanski W. Met-enkephalin in the liver as a marker of hepatocellular damage in chronic viral hepatitis type B and C. Adv Med Sci. 2006;51:261-4 pubmed
    ..The degree of necroinflammatory activity in the liver as well as sex and age of patients with chronic hepatitis do not correlate with changes in opioid system. ..
  24. Torii M, Kubo K, Sasaki T. Differential effects of beta-endorphin and Met- and Leu-enkephalin on steroid hormone-induced lordosis in ovariectomized female rats. Pharmacol Biochem Behav. 1997;58:837-42 pubmed
  25. Aira Z, Barrenetxea T, Buesa I, Garcia del Caño G, Azkue J. Dopamine D1-like Receptors Regulate Constitutive, ?-Opioid Receptor-Mediated Repression of Use-Dependent Synaptic Plasticity in Dorsal Horn Neurons: More Harm than Good?. J Neurosci. 2016;36:5661-73 pubmed publisher
    ..We show that the ability of MOR to oppose LTP is rapidly impaired by sustained D1LR activation via a mechanism involving sustained MOR activation. ..
  26. Piva M, Moreno J, Jenkins F, Smith J, Thomas J, Montgomery C, et al. In vitro modulation of cytokine expression by enkephalin-derived peptides. Neuroimmunomodulation. 2005;12:339-47 pubmed
    ..YG, the minimal molecular requirement for enhancement and suppression of immune responses by these metabolites, appears to mediate exclusively an across-the-board suppression via low-affinity, nonclassical, nonopioid receptors. ..
  27. Hebb A, Zacharko R. Central D-Ala2-Met5-enkephalinamide mu/delta-opioid receptor activation blocks behavioral sensitization to cholecystokinin in CD-1 mice. Brain Res. 2003;970:20-34 pubmed
    ..These data imply that while CCK induces relatively protracted and exaggerated behavioral disturbances, mu/delta opioid-receptor activation may block CCK-induced behavioral sensitization and change the course of psychopathology. ..
  28. Vertes Z, Sandor A, Kovacs K, Oszter A, Kornyei J, Kovacs S, et al. Epidermal growth factor influenced by opioid peptides in immature rat uterus. J Endocrinol Invest. 2000;23:502-8 pubmed
    ..The present results suggest a novel multiple interaction between estrogen and two probably paracrine hormones, EGF and opioid peptide, in the regulation of growth and development of the uterus. ..
  29. Duplan H, Li R, Vue C, Zhou H, Emorine L, Herman J, et al. Grafts of immortalized chromaffin cells bio-engineered to improve met-enkephalin release also reduce formalin-evoked c-fos expression in rat spinal cord. Neurosci Lett. 2004;370:1-6 pubmed
    ..The use of such expandable cell lines, for chronic spinal delivery of opiates, could offer an attractive and safe alternative strategy based on ex vivo gene therapy for the control of opioid-sensitive chronic pain. ..
  30. Rada P, Barson J, Leibowitz S, Hoebel B. Opioids in the hypothalamus control dopamine and acetylcholine levels in the nucleus accumbens. Brain Res. 2010;1312:1-9 pubmed publisher
  31. Zhang S, Wang N, Xu J, Gao Q, Lin G, Bruce I, et al. Kappa-opioid receptors mediate cardioprotection by remote preconditioning. Anesthesiology. 2006;105:550-6 pubmed
    ..Activation of cardiac kappa-opioid receptors is involved in the cardioprotection induced by remote preconditioning, and the mitochondrial permeability transition pore may participate in the postreceptor pathway. ..
  32. Zagon I, Sassani J, McLaughlin P. Re-epithelialization of the rabbit cornea is regulated by opioid growth factor. Brain Res. 1998;803:61-8 pubmed
    ..These results show that an opioid peptide, OGF, plays a direct role in the repair of injury to the corneal epithelium in the rabbit and acts as a receptor-mediated and constitutively expressed inhibitory molecule. ..
  33. Liu J, Laferriere A, Moss I. Repeated prenatal cocaine increases met-enkephalin immunoreactivity in respiratory-related medulla of developing swine. Brain Res Bull. 2000;51:419-24 pubmed
    ..These findings support a modulatory role of met-enkephalin in the normal development of respiratory control, and an involvement of this peptide in the attenuation of respiration by repeated prenatal exposure to cocaine. ..
  34. Mulabegović N, Rakanović Todić M. [Pharmacodynamic properties of a combination of met-enkephalin and alpha 1-13 adrenocorticotropic hormone]. Med Arh. 2008;62:41-4 pubmed
    ..Adverse reactions registered for so long with ENKORTEN were mild, reversible and usually developed during and immediately after drug application. ..
  35. Sollertinskaia T. [Comparative study of neurochemical compensation of brain dysfunctions in mammals]. Zh Evol Biokhim Fiziol. 2003;39:546-58 pubmed
  36. Ballet S, Mauborgne A, Hamon M, Cesselin F, Collin E. Altered opioid-mediated control of the spinal release of dynorphin and met-enkephalin in polyarthritic rats. Synapse. 2000;37:262-72 pubmed
  37. Terashvili M, Wu H, Leitermann R, Sun H, Clithero A, Tseng L. Differential mechanisms of antianalgesia induced by endomorphin-1 and endomorphin-2 in the ventral periaqueductal gray of the rat. J Pharmacol Exp Ther. 2005;312:1257-65 pubmed
  38. Bosi G, Shinn A, Giari L, Sayyaf Dezfuli B. Enteric neuromodulators and mucus discharge in a fish infected with the intestinal helminth Pomphorhynchus laevis. Parasit Vectors. 2015;8:359 pubmed publisher
    ..The mucous cells hyperplasia and enhanced mucus secretion in the helminth-infected intestines could be elicited by the increase in the number of ECs which release these regulatory substances. ..
  39. Bujdosó E, Jászberényi M, Farkas J, Toth G, Wollemann M, Telegdy G. Behavioral and neuroendocrine actions of the Met-enkephalin-related peptide MERF. Horm Behav. 2003;43:302-11 pubmed
    ..MERF also appears to activate the paraventricular CRH neurons, but dopaminergic transmission does not seem to play a significant role in its hypothalamic action. ..
  40. Cao Z, Liu L, Van Winkle D. Met5-enkephalin-induced cardioprotection occurs via transactivation of EGFR and activation of PI3K. Am J Physiol Heart Circ Physiol. 2005;288:H1955-64 pubmed
    ..We conclude that ME-induced cardioprotection is mediated via Src-dependent EGFR transactivation and activation of the PI3K and MAPK pathways. ..
  41. Hong Y, Dai P, Jiang J, Zeng X. Dual effects of intrathecal BAM22 on nociceptive responses in acute and persistent pain--potential function of a novel receptor. Br J Pharmacol. 2004;141:423-30 pubmed
    ..The name suggested for this novel receptor, its potential physiological function and its ligand are discussed. British Journal of Pharmacology (2004) 141, 423-430. doi:10.1038/sj.bjp.0705637 ..
  42. Sizemore R, Piva M, Moore L, Gordonov N, Heilman E, Godfrey H. Modulation of delayed-type hypersensitivity responses in hairless guinea pigs by peptides derived from enkephalin. Neuroimmunomodulation. 2004;11:141-8 pubmed
    ..We conclude that the immunoactivity of met-enkephalin resides in its first two amino acids and suggest that cleavage of enkephalin molecules to YG occurs in serum and/or on the cell surface. ..
  43. Zagon I, Verderame M, Allen S, McLaughlin P. Cloning, sequencing, expression and function of a cDNA encoding a receptor for the opioid growth factor, [Met(5)]enkephalin. Brain Res. 1999;849:147-54 pubmed
    ..The molecular organization of the OGFr has no homology to classical opioid receptors. These results provide molecular validity for the interaction of OGF and OGFr in the regulation of growth processes. ..
  44. Bergasa N, Boyella V. Liver derived endogenous opioids may interfere with the therapeutic effect of interferon in chronic hepatitis C. Med Hypotheses. 2008;70:556-9 pubmed
    ..If this hypothesis is correct, the study of opiate antagonists in combination with antiviral therapy in patients with hepatitis C expressing MEIR in their livers merits consideration. ..
  45. Lee H, Smith M, Smith B, Grussendorf J, Xu L, Gillies R, et al. Anticonvulsant Met-enkephalin analogues containing backbone spacers reveal alternative non-opioid signaling in the brain. ACS Chem Biol. 2009;4:659-71 pubmed publisher
    ..In summary, the results obtained with the analogues containing backbone spacers suggest a novel mechanism for seizure control in the brain that involves alternative non-opioid signaling. ..
  46. Jakas A, Horvat S. Reactivity and oxidative potential of fructose and glucose in enkephalin-sugar model systems. Amino Acids. 2008;34:329-32 pubmed
    ..Glucose showed higher level of reactivity than fructose with respect to the extent of glycated product formation. The presence of fructose in the incubation mixtures makes Met residue more susceptible to oxidation than glucose. ..
  47. Malendowicz L, Rebuffat P, Tortorella C, Nussdorfer G, Ziolkowska A, Hochol A. Effects of met-enkephalin on cell proliferation in different models of adrenocortical-cell growth. Int J Mol Med. 2005;15:841-5 pubmed
  48. Roman E, Ploj K, Gustafsson L, Meyerson B, Nylander I. Variations in opioid peptide levels during the estrous cycle in Sprague-Dawley rats. Neuropeptides. 2006;40:195-206 pubmed
    ..These findings are discussed in relation to the possible role of interactions between sex steroids and opioid peptide mechanisms during the normal estrous cycle. ..
  49. Gonzalez Nunez V, Toth G, Rodriguez R. Endogenous heptapeptide Met-enkephalin-Gly-Tyr binds differentially to duplicate delta opioid receptors from zebrafish. Peptides. 2007;28:2340-7 pubmed
    ..Our results prove that although the MEGY peptide acts as an agonist on ZFOR1 and ZFOR4, there are subtle pharmacological differences between these two delta opioid receptors from zebrafish. ..
  50. Westlund K. Gene therapy for pancreatitis pain. Gene Ther. 2009;16:483-92 pubmed publisher
    ..As innovative means of significantly reducing pancreatic inflammation and preserving tissue architecture, they may extend their clinical usefulness for pancreatitis and pancreatic cancer pain patients. ..
  51. Dimitrijevic M, Stanojevic S, Kovacević Jovanović V, Miletic T, Vujić Redzić V, Radulovic J. Modulation of humoral immune responses in the rat by centrally applied Met-Enk and opioid receptor antagonists: functional interactions of brain OP1, OP2 and OP3 receptors. Immunopharmacology. 2000;49:255-62 pubmed
    ..In contrast, the central immunoenhancing effect of Met-Enk appears to be mediated through OP(3)-independent OP(1) receptors. ..
  52. Rougeot C, Messaoudi M, Hermitte V, Rigault A, Blisnick T, Dugave C, et al. Sialorphin, a natural inhibitor of rat membrane-bound neutral endopeptidase that displays analgesic activity. Proc Natl Acad Sci U S A. 2003;100:8549-54 pubmed
    ..Furthermore, our study provides evidence that it is a physiological modulator of pain perception after injury and might be the progenitor of a new class of therapeutic molecules. ..
  53. Vats I, Chaudhary S, Karar J, Nath M, Pasha Q, Pasha S. Endogenous peptide: Met-enkephalin-Arg-Phe, differently regulate expression of opioid receptors on chronic treatment. Neuropeptides. 2009;43:355-62 pubmed publisher
    ..Further, the interaction was such that the induction was mainly observed at molecular/expression level and not at pharmacological level to affect antinociception. ..
  54. Assis M, Hansen C, Lux Lantos V, Cancela L. Sensitization to amphetamine occurs simultaneously at immune level and in met-enkephalin of the nucleus accumbens and spleen: an involved NMDA glutamatergic mechanism. Brain Behav Immun. 2009;23:464-73 pubmed publisher
    ..A glutamate mechanism is implied in the long-term amphetamine-induced effects at immune level and in the met-enkephalin from NAc and spleen. ..
  55. Nikitin V, Kozyrev S. Selective involvement of opioids in the mechanisms of synapse-specific plasticity in the common snail during the acquisition of sensitization. Neurosci Behav Physiol. 2005;35:125-32 pubmed
  56. Hauser K, Houdi A, Turbek C, Elde R, Maxson W. Opioids intrinsically inhibit the genesis of mouse cerebellar granule neuron precursors in vitro: differential impact of mu and delta receptor activation on proliferation and neurite elongation. Eur J Neurosci. 2000;12:1281-93 pubmed
    ..The data additionally suggest that perinatal exposure to opiate drugs of abuse directly interfere with cerebellar maturation by disrupting normal opioid signalling and inhibiting the proliferation of granule neuron precursors. ..
  57. Brehmer A, Schrödl F, Neuhuber W. Correlated morphological and chemical phenotyping in myenteric type V neurons of porcine ileum. J Comp Neurol. 2002;453:1-9 pubmed
    ..These results further support the concept of a close correlation between morphologically defined neuronal type and chemical coding and, it is likely, also function in the enteric nervous system of larger mammals. ..
  58. Meneray M, Fields T, Bennett D. Gi/Go couple met-enkephalin to inhibition of cholinergic and beta-adrenergic stimulation of lacrimal secretion. Cornea. 2000;19:92-8 pubmed
    ..The effector coupled by the G proteins is not AC. However, we suggest a role for met-enkephalin in G-protein-coupled modulation of ion channels important for cholinergic and beta-adrenergic stimulation of lacrimal secretion. ..
  59. Zhu W, Pan Z. Mu-opioid-mediated inhibition of glutamate synaptic transmission in rat central amygdala neurons. Neuroscience. 2005;133:97-103 pubmed
    ..This study provides evidence for the presynaptic regulation of glutamate synaptic transmission by mu-opioid receptors in CeA neurons. ..
  60. Jackson K, Farias M, Stanfill A, Caffrey J. Delta opioid receptors inhibit vagal bradycardia in the sinoatrial node. J Cardiovasc Pharmacol Ther. 2001;6:385-93 pubmed
    ..These data suggest that the vagolytic effect of MEAP involves the activation of delta opiate receptors within the sinoatrial node. ..
  61. Hanif K, Fahim M, Pavar M, Bansal V, Pasha S. Hypotensive effect of novel chimeric peptides of met-enkephalin and FMRFa. Regul Pept. 2005;125:155-61 pubmed
  62. Hwang S, Steineckert B, Yasothornsrikul S, Sei C, Toneff T, Rattan J, et al. Molecular cloning of endopin 1, a novel serpin localized to neurosecretory vesicles of chromaffin cells. Inhibition of basic residue-cleaving proteases by endopin 1. J Biol Chem. 1999;274:34164-73 pubmed
    ..These results suggest a role for the novel serpin, endopin 1, in regulating basic residue-cleaving proteases within neurosecretory vesicles of chromaffin cells. ..
  63. Zeng X, Huang H, Hong Y. Effects of intrathecal BAM22 on noxious stimulus-evoked c-fos expression in the rat spinal dorsal horn. Brain Res. 2004;1028:170-9 pubmed
  64. Cao Z, Liu L, Van Winkle D. Activation of delta- and kappa-opioid receptors by opioid peptides protects cardiomyocytes via KATP channels. Am J Physiol Heart Circ Physiol. 2003;285:H1032-9 pubmed
    ..7 for HMR-1098 and ME + HMR-1098, respectively (P < 0.01). We conclude that opioid peptide-induced cardioprotection is mediated by delta- and kappa-receptors and involves sarcolemmal and mitochondrial ATP-sensitive K+ channels. ..
  65. Monville C, Torres E, Dunnett S. Validation of the l-dopa-induced dyskinesia in the 6-OHDA model and evaluation of the effects of selective dopamine receptor agonists and antagonists. Brain Res Bull. 2005;68:16-23 pubmed
    ..g. using grafts while blocking the unwanted adverse effects of the drugs. ..
  66. Xu H, Izrailev S, Agrafiotis D. Conformational sampling by self-organization. J Chem Inf Comput Sci. 2003;43:1186-91 pubmed
    ..When compared to a conventional distance geometry algorithm based on the same set of geometric constraints, our method is faster and generates conformations that are more diverse and more energetically favorable. ..
  67. Salzet M, Tasiemski A. Involvement of pro-enkephalin-derived peptides in immunity. Dev Comp Immunol. 2001;25:177-85 pubmed
    ..The focus of this review is to describe how the pro-enkephalin derived peptides participate in immune processes. ..
  68. Wasowicz K, Podlasz P, Czaja K, Łakomy M. Uterus-innervating neurones of paracervical ganglion in the pig: immunohistochemical characteristics. Folia Morphol (Warsz). 2002;61:15-20 pubmed
    ..The results pointed to some species-related differences in immunohistochemical coding of neurones of paracervical ganglion responsible for uterus innervation. ..
  69. Klocek M, Sassani J, Donahue R, McLaughlin P, Zagon I. Regulation of Tenon's capsule fibroblast cell proliferation by the opioid growth factor and the opioid growth factor receptor axis. Invest Ophthalmol Vis Sci. 2010;51:5054-61 pubmed publisher
    ..The OGF-OGFr system is a native biological regulator of cell proliferation in RTCFs and may offer a means of improving the success of glaucoma filtration surgery in a safe and nontoxic manner. ..
  70. Bergasa N, Liau S, Homel P, Ghali V. Hepatic Met-enkephalin immunoreactivity is enhanced in primary biliary cirrhosis. Liver. 2002;22:107-13 pubmed
    ..These results suggest that the human liver in cholestasis may be a source of endogenous opioids. ..
  71. Mosnaim A, Nguyen T, Tse R, Puente J, Couceyro P, Wolf M. In vitro methionine5-enkephalin degradation kinetics by human brain preparations. Neurochem Res. 2008;33:81-6 pubmed
    ..A better understanding of the mechanisms regulating brain MET metabolism may contribute to the rational design of pharmacological strategies based in the modulation of its bioavailability. ..
  72. Tjesic Drinkovic D, Stambuk N, Tjesic Drinkovic D, Konjevoda P, Gotovac N, Curković T, et al. Met-enkephalin effects on histamine-induced bronchoconstriction in guinea pigs. Coll Antropol. 2005;29:689-92 pubmed
    ..Estimated ED50 dose was 0.235 mg/kg. Further studies are needed to define practical and therapeutical use of the presented observations in respiratory pharmacology. ..
  73. Nakamura M, Sekino Y, Manabe T. GABAergic interneurons facilitate mossy fiber excitability in the developing hippocampus. J Neurosci. 2007;27:1365-73 pubmed
    ..These results suggested that GABA released from interneurons acted on axonal GABA(A) receptors on mossy fibers and contributed at least partially to the activity- and age-dependent facilitation in the hippocampus. ..
  74. Sollertinskaia T. [The role of neuropeptides in brain asymmetry]. Zh Evol Biokhim Fiziol. 2003;39:94-103 pubmed
  75. Li C, Davis B, Smith D. Opioid modulation of taste responses in the nucleus of the solitary tract. Brain Res. 2003;965:21-34 pubmed
    ..These data suggest that endogenous opiates play an inhibitory role in gustatory processing within the medulla. ..
  76. Gupta D, Gintzler A. Influence of ovarian sex steroids on spinal methionine-enkephalin release: comparison with dynorphin reveals asymmetrical regulation. J Pharmacol Exp Ther. 2003;304:738-44 pubmed
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    ..Met-enkephalin (Type Entrez Proteins; Value A61445; Service Entrez Proteins). ..