leucine enkephalin


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

Top Publications

  1. Kramer H, Andria M, Kushner S, Esposito D, Hiller J, Simon E. Mutation of tyrosine 318 (Y318F) in the delta-opioid receptor attenuates tyrosine phosphorylation, agonist-dependent receptor internalization, and mitogen-activated protein kinase activation. Brain Res Mol Brain Res. 2000;79:55-66 pubmed
    ..These findings implicate tyrosine phosphorylation of Y318 in receptor signalling and agonist-mediated regulation. ..
  2. Qin L, Liu Y, Qian X, Hong J, Block M. Microglial NADPH oxidase mediates leucine enkephalin dopaminergic neuroprotection. Ann N Y Acad Sci. 2005;1053:107-20 pubmed
    Here, we report that leucine enkephalin (LE) is neuroprotective to dopaminergic (DA) neurons at femtomolar concentrations through anti-inflammatory properties...
  3. Armstead W. Role of NOC/oFQ in impaired opioid-induced pial artery dilation following brain injury. Brain Res. 2000;869:231-5 pubmed
    ..2+/-1, 6+/-1, and 7+/-2%) under non-brain injury conditions. Similar inhibition by NOC/oFQ was observed for leucine enkephalin and dynorphin...
  4. Gu X, Ying J, Min B, Cain J, Davis P, Willey P, et al. Parallel synthesis and biological evaluation of different sizes of bicyclo[2,3]-Leu-enkephalin analogues. Biopolymers. 2005;80:151-63 pubmed
    ..Binding affinities and bioassay studies show ligands with micromolar binding affinities and antagonist bioactivities for the [6,5]- and [7,5]-bicyclo-Leu-enkephalin analogues. ..
  5. Singh V, Bajpai K, Narayan P, Yadav V, Dhawan V, Haq W, et al. Delta-opioid receptor antagonist inhibits immunomodulation by Met-enkephalin analogs. Neuroimmunomodulation. 1999;6:355-60 pubmed
    ..These observations suggest that analogs (1) and (2) of Met-enkephalin stimulate T cell proliferation predominantly via delta-opioid receptor present on T cells. ..
  6. Chen X, Steill J, Oomens J, Polfer N. Oxazolone versus macrocycle structures for Leu-enkephalin b2-b4: insights from infrared multiple-photon dissociation spectroscopy and gas-phase hydrogen/deuterium exchange. J Am Soc Mass Spectrom. 2010;21:1313-21 pubmed publisher
    ..This indicates that the chemistry of "head-to-tail" cyclization depends on subtle differences in the sequence as well as the size of the b fragment. ..
  7. Thorlin T, Eriksson P, Ronnback L, Hansson E. Receptor-activated Ca2+ increases in vibrodissociated cortical astrocytes: a nonenzymatic method for acute isolation of astrocytes. J Neurosci Res. 1998;54:390-401 pubmed
  8. Lodyga Chruscinska E, Micera G, Sanna D, Olczak J, Zabrocki J, Kozlowski H, et al. Effect of the tetrazole cis-amide bond surrogate on the complexing ability of some enkephalin analogues toward Cu(II) ions. J Inorg Biochem. 1999;76:1-11 pubmed
    ..The data indicate that Cu(II) ions are strongly trapped inside a bent peptide backbone. However, the coordination mode involving the tetrazole ring nitrogen does not prevent the hydrolysis process under strongly basic conditions. ..
  9. Zhang Y, Wu Y, Hao Y, Dun Y, Yang S. Role of endogenous opioid peptides in protection of ischemic preconditioning in rat small intestine. Life Sci. 2001;68:1013-9 pubmed
    ..It was shown that the release of leu-enkephalin was markedly increased during preconditioning. These results suggested that EOP might play an important role in PC in rat small intestine. ..

More Information

Publications116 found, 100 shown here

  1. Nikitin V, Kozyrev S, Shevelkin A. [Selectivity of opioid peptide effects on excitability and various sensory inputs in LPl1 and PPl1 command neurons participating in defensive behavior of the snail Helix lucorum]. Ross Fiziol Zh Im I M Sechenova. 2002;88:22-31 pubmed
    ..Experimental results show selective opioid peptides' effects on excitability and plasticity of L-RPII neural inputs with site- and modality-specifics. ..
  2. Hashimoto Y, Hasegawa H, Waki I. High sensitivity and broad dynamic range infrared multiphoton dissociation for a quadrupole ion trap. Rapid Commun Mass Spectrom. 2004;18:2255-9 pubmed
    ..An optimized method for gas introduction enables the trapping efficiency to remain constant during the accumulation period, which permits a broad dynamic range measurement. ..
  3. Molotkovskaya I, Malyukova I, Zakharova L. Opioid agonist modulation of cytoplasmic free Ca2+ level in concanavalin A-stimulated mouse lymphocytes. Biochemistry (Mosc). 1999;64:546-51 pubmed
    ..The effects of opioids were antagonized by naloxone. These data indicate that functionally active opioid receptors expressed on lymphocytes could be involved in early stages of mitogen activation. ..
  4. Hook S, Camberis M, Prout M, Konig M, Zimmer A, van Heeke G, et al. Preproenkephalin is a Th2 cytokine but is not required for Th2 differentiation in vitro. Immunol Cell Biol. 1999;77:385-90 pubmed
    ..Lymphocytes from these mice could be driven into a Th2 phenotype, suggesting that cultures containing IL-4 do not require PPNK for Th2 differentiation. ..
  5. Kaminski T, Siawrys G, Bogacka I, Okrasa S, Przala J. The regulation of steroidogenesis by opioid peptides in porcine theca cells. Anim Reprod Sci. 2003;78:71-84 pubmed
    ..In view of these findings we suggest that opioid peptides derived from three major opioid precursors may directly participate in the regulation of porcine theca cell steroidogenesis. ..
  6. Naito A, Nishimura K. Conformational analysis of opioid peptides in the solid states and the membrane environments by NMR spectroscopy. Curr Top Med Chem. 2004;4:135-45 pubmed
    ..Since the membrane bound structures of opioid peptides differ from those of the solution states, membrane association is an important process for exerting the affinity and the selectivity to the specific opioid receptors. ..
  7. Takayanagi I, Konno F, Goromaru N, Koike K, Kanematsu K, Fujii I, et al. Some pharmacological properties of a newly synthesized morphine derivative, (-)-6 beta-acetylthiomorphine. Arch Int Pharmacodyn Ther. 1988;294:71-84 pubmed
    ..Results suggested that AcS-morphine is weaker than morphine in its dependence liability, though it seems almost certain that AcS-morphine does have this liability. ..
  8. Teskey G, Kavaliers M. Effects of opiate agonists and antagonists on aggressive encounters and subsequent opioid-induced analgesia, activity and feeding responses in male mice. Pharmacol Biochem Behav. 1988;31:43-52 pubmed
  9. Schomburg E, Steffens H, Wada N. Parallel nociceptive reflex pathways with negative and positive feedback functions to foot extensors in the cat. J Physiol. 2001;536:605-13 pubmed
    ..e. it mediates a positive feedback. ..
  10. Sahlin E, Beisler A, Woltman S, Weber S. Fabrication of microchannel structures in fluorinated ethylene propylene. Anal Chem. 2002;74:4566-9 pubmed
    ..A microreactor coupled to an electrochemical flow cell detects the biuret complex of the natively electroinactive peptide des-Tyr-Leu-enkephalin. ..
  11. Hothi S, Randall D, Titheradge M. [Leu]enkephalin stimulates carbohydrate metabolism in isolated hepatocytes and kidney tubule fragments by interaction with angiotensin II receptors. Biochem J. 1989;257:705-10 pubmed
  12. Jiang C, Son L, Lu C, You Z, Wang Y, Sun L, et al. Analgesic effect of interferon-alpha via mu opioid receptor in the rat. Neurochem Int. 2000;36:193-6 pubmed
    ..The evidence is consistent with the hypothesis that multiple actions of cytokines, such as immunoregulatory and neuroregulatory effects, might be mediated by distinct domains of cytokines interacting with different receptors. ..
  13. Bernkop Schnurch A, Obermair K, Greimel A, Palmberger T. In vitro evaluation of the potential of thiomers for the nasal administration of Leu-enkephalin. Amino Acids. 2006;30:417-23 pubmed
    ..According to these results thiolated polycarbophil might be a promising excipient for nasal administration of Leu-enkephalin. ..
  14. Wojtkiewicz J, Rytel L, Makowska K, Gonkowski S. Co-localization of zinc transporter 3 (ZnT3) with sensory neuromediators and/or neuromodulators in the enteric nervous system of the porcine esophagus. Biometals. 2017;30:393-403 pubmed publisher
    ..Co-localization of ZnT3 with substance P (SP), leucine enkephalin (LENK) and calcitonin gene-related peptide (CGRP) was studied using standard double-immunofluorescence ..
  15. Andersson L, Muller R, Vlatakis G, Mosbach K. Mimics of the binding sites of opioid receptors obtained by molecular imprinting of enkephalin and morphine. Proc Natl Acad Sci U S A. 1995;92:4788-92 pubmed
    ..Enantioselective recognition of the L-enantiomer of phenylalanylglycine anilide, a truncated analogue of the N-terminal end of enkephalin, was observed. ..
  16. Walker G, Langoth N, Bernkop Schnurch A. Peptidase activity on the surface of the porcine buccal mucosa. Int J Pharm. 2002;233:141-7 pubmed
    ..We suggest that compared with the existing in vitro metabolism methods, the analysis of peptide or protein metabolism on intact buccal mucosa could better predict the degradation of the drug as it crosses the tissue. ..
  17. Hack S, Bagley E, Chieng B, Christie M. Induction of delta-opioid receptor function in the midbrain after chronic morphine treatment. J Neurosci. 2005;25:3192-8 pubmed
    ..These results suggest that induction of DOPr-mediated actions in PAG by chronic morphine requires prolonged MOPr stimulation and expression of beta-arrestin-2. ..
  18. Chen J, Zhao X, Yue G, Wang Z. Influence of acute and chronic treadmill exercise on rat plasma lactate and brain NPY, L-ENK, DYN A1-13. Cell Mol Neurobiol. 2007;27:1-10 pubmed
    ..And this high level might reduce energy expenditure and thus contribute to the stimulation of brain NPY neurons. ..
  19. Jessing M, Brandt M, Jensen K, Christensen J, Boas U. Thiophene backbone amide linkers, a new class of easily prepared and highly acid-labile linkers for solid-phase synthesis. J Org Chem. 2006;71:6734-41 pubmed
    ..Tert-butyl based protecting groups, tert-butyl esters, tert-butyl ethers, and Boc groups, as well as dimethyl acetals were relatively stable to these mild conditions for release of the peptides. ..
  20. Buzas B, Toth G, Cavagnero S, Hruby V, Borsodi A. Synthesis and binding characteristics of the highly delta-specific new tritiated opioid peptide, [3H]deltorphin II. Life Sci. 1992;50:PL75-8 pubmed
    ..The highly delta selective binding properties of this new radioligand suggest that it could serve as an excellent tool for investigating the delta opioid receptors in various species. ..
  21. Chiesa R, Silva W, Renaud F. Pharmacological characterization of an opioid receptor in the ciliate Tetrahymena. J Eukaryot Microbiol. 1993;40:800-4 pubmed
    ..We suggest that the opioid receptor coupled to phagocytosis in Tetrahymena is mu-like in some of its pharmacological characteristics and may serve as a model system for studies on opioid receptor function and evolution. ..
  22. Connelly C, Martinez R, Schupsky J, Porreca F, Raffa R. Etonitazene-induced antinociception in mu1 opioid receptor deficient CXBK mice: evidence for a role for mu2 receptors in supraspinal antinociception. Life Sci. 1994;54:PL369-74 pubmed
    ..These findings suggest that mu2 opioid receptors are important contributors to opioid-induced supraspinal antinociception in mice. ..
  23. Ghaddar G, Ruchon A, Carpentier M, Marcinkiewicz M, Seidah N, Crine P, et al. Molecular cloning and biochemical characterization of a new mouse testis soluble-zinc-metallopeptidase of the neprilysin family. Biochem J. 2000;347:419-29 pubmed
    ..This distribution of NL1 mRNA suggests that it could be involved in sperm formation or other processes related to fertility. ..
  24. Abbood A, Smadja C, Taverna M, Herrenknecht C. Hydrophilic interaction liquid chromatography for dalargin separation from its structural analogues and side products. J Chromatogr A. 2017;1498:155-162 pubmed publisher
    ..Then, by coupling the HILIC column with ESI-MS, using the optimal separation conditions, it was possible to identify Dalargin and to propose the amino-acids sequence of its side-products. ..
  25. Soper Hopper M, Eschweiler J, Ruotolo B. Ion Mobility-Mass Spectrometry Reveals a Dipeptide That Acts as a Molecular Chaperone for Amyloid ?. ACS Chem Biol. 2017;12:1113-1120 pubmed publisher
    ..Previously, we discovered and structurally characterized a complex between amyloid ? 1-40 and the neuropeptide leucine enkephalin. This work identified leucine enkephalin as a potentially useful starting point for the discovery of peptide-..
  26. Bhargava H, Ramarao P. Antagonism of kappa opioid mediated effects in the rat by cyclo(Leu-Gly). Life Sci. 1989;45:2521-8 pubmed
    ..c.) given once a day for 4 days. It is concluded that cyclo(Leu-Gly) antagonizes acute actions of U-50,488H and that such effects of cyclo(Leu-Gly) are not mediated via a direct action on kappa-opioid receptors. ..
  27. Castagnola M, Cassiano L, Messana I, Paci M, Rossetti D, Giardina B. Effect of 2,2,2-trifluoroethanol on capillary zone electrophoretic peptide separations. J Chromatogr A. 1996;735:271-81 pubmed
    ..Fourth, the structural properties of 2,2,2-trifluoroethanol are particularly useful for an improvement in the separation of large apolar peptides. Finally, the use of trifluoroethanol strongly stabilizes the capillary coating. ..
  28. Kuniyoshi A, Kodama R, Moraes L, Duzzi B, Iwai L, Lima I, et al. In vitro cleavage of bioactive peptides by peptidases from Bothrops jararaca venom and its neutralization by bothropic antivenom produced by Butantan Institute: Major contribution of serine peptidases. Toxicon. 2017;137:114-119 pubmed publisher
  29. Koyanagawa H, Musha T, Kanda A, Kimura T, Satoh S. Inhibition of vagal transmission by cardiac sympathetic nerve stimulation in the dog: possible involvement of opioid receptor. J Pharmacol Exp Ther. 1989;250:1092-6 pubmed
  30. Hens J, Gajda M, Scheuermann D, Adriaensen D, Timmermans J. The longitudinal smooth muscle layer of the pig small intestine is innervated by both myenteric and submucous neurons. Histochem Cell Biol. 2002;117:481-92 pubmed
    ..The two major populations are descending nitrergic neurons and ascending tachykinergic motor neurons, but also other subpopulations with specific projection patterns and neurochemical features have been identified. ..
  31. Bolger G, Marcus K, Thibou R, Skolnick P, Weissman B. Enhancement of [3H]DAGO1 binding to rat brain by low concentrations of monovalent cations. Can J Physiol Pharmacol. 1987;65:2338-45 pubmed
    ..3H]etorphine binding increased and was unchanged, and both [3H]bremazocine and [3H]naloxone binding increased by 50 mM Na+ in 5 mM and 50 mM Tris-HCl, respectively.(ABSTRACT TRUNCATED AT 250 WORDS) ..
  32. Kawabata K. Paraganglia of the gallbladder: a report of two cases with an immunohistochemical study. Pathol Res Pract. 1999;195:781-6 pubmed
    ..These structures, which slightly resembled adrenal medulla or retroperitoneal paraganglia, might be misunderstood as an infiltration of primary or metastatic carcinoma into the subserosal connective tissue...
  33. Cox M, Welch S. The antinociceptive effect of Delta9-tetrahydrocannabinol in the arthritic rat. Eur J Pharmacol. 2004;493:65-74 pubmed
    ..We hypothesize that the elevated idyn A level in arthritic rats contributes to hyperalgesia by interaction with N-methyl-D-aspartate receptors, and that Delta9-THC induces antinociception by decreasing idyn A release. ..
  34. Skobowiat C, Gonkowski S, Janiuk I, Całka J, Majewski M. The relationship and co-localization of vasoactive intestinal peptide (VIP)- and Leu5-enkephalin (LENK)-immunoreactivity in the female genital tract of the pig. Pol J Vet Sci. 2009;12:347-53 pubmed
    ..The great number of specific co-localization between VIP and LENK in nerve processes of the porcine female genital organs may indicate a functional regulatory interaction between the neuropeptides studied, requiring further study. ..
  35. Tomic A, Kovacevic B, Tomic S. Concerted nitrogen inversion and hydrogen bonding to Glu451 are responsible for protein-controlled suppression of the reverse reaction in human DPP III. Phys Chem Chem Phys. 2016;18:27245-27256 pubmed
    ..Therefore we propose that the functional significance of DPP III is dual: to lower the energy barrier of the peptide hydrolysis and to suppress the reverse reaction. ..
  36. Kakidani H, Furutani Y, Takahashi H, Noda M, Morimoto Y, Hirose T, et al. Cloning and sequence analysis of cDNA for porcine beta-neo-endorphin/dynorphin precursor. Nature. 1982;298:245-9 pubmed
    ..This precursor protein, like adrenal preproenkephalin and the corticotropin/beta-lipotropin precursor, comprises multiple repetitive units and a cysteine-containing amino-terminal sequence preceded by a signal peptide. ..
  37. Zhu X, Wang C, Cheng Z, Wu Y, Zhou D, Pei G. The carboxyl terminus of mouse delta-opioid receptor is not required for agonist-dependent activation. Biochem Biophys Res Commun. 1997;232:513-6 pubmed
    ..Their membrane localization and ability to mediate signal transduction were also studied. We conclude that the C-terminus of delta OR is not essential for plasma membrane targeting, ligand specificity, and agonist-dependent activation. ..
  38. Wu S, Li Y, Shi J. Temporal changes of preproenkephalin mRNA and leu-enkephalin-like immunoreactivity in the neurons of the caudal spinal trigeminal nucleus and upper cervical cord after noxious stimuli. J Hirnforsch. 1998;39:217-22 pubmed
  39. Osman A, Gomma M, Saad A. A possible role for an enkephalinergic system in the internal defense mechanism of Biomphalaria alexandrina exposed to Schistosoma mansoni. J Egypt Soc Parasitol. 2003;33:841-61 pubmed
    ..alexandrina, associated with susceptibility and resistance to S. mansoni infection, the results suggest the role of such opioid system in molecular signaling within the host and in host-parasite interactions. ..
  40. Albo F, Antonangeli R, Cavazza A, Marini M, Roda L, Rossi P. Neuropeptide degradation in naive and steroid-treated allergic saliva. Int Immunopharmacol. 2001;1:1777-88 pubmed
  41. Aburi M, Smith P. A conformational analysis of leucine enkephalin as a function of pH. Biopolymers. 2002;64:177-88 pubmed
    ..Further study indicated that the unfolded state of the peptide was not random in nature and consisted of one major unfolded backbone arrangement stabilized by a persistent hydrophobic interaction between the side chains of Tyr and Leu. ..
  42. Yaşar F, Arkin H, Celik T, Berg B, Meirovitch H. Efficiency of the multicanonical simulation method as applied to peptides of increasing size: the heptapeptide deltorphin. J Comput Chem. 2002;23:1127-34 pubmed
    ..These latter results are compared with conformational coverage obtained by the Monte Carlo minimization method of Li and Scheraga. ..
  43. Cai X, Dass C. Structural characterization of methionine and leucine enkephalins by hydrogen/deuterium exchange and electrospray ionization tandem mass spectrometry. Rapid Commun Mass Spectrom. 2005;19:1-8 pubmed
    Conformational changes in two endogenous opioid active pentapeptides methionine enkephalin (Met-enk) and leucine enkephalin (Leu-enk) induced by trifluoroethanol (TFE) were identified using hydrogen/deuterium exchange (HDX), coupled with ..
  44. Mensah Brown E, Garey L. The superior colliculus of the camel: a neuronal-specific nuclear protein (NeuN) and neuropeptide study. J Anat. 2006;208:239-50 pubmed
    ..Such pain inhibition could be important in relation to the camel's life in the harsh environment of its native deserts, often living in very high temperatures with no shade and a diet consisting largely of thorny branches. ..
  45. Herburger A, van der Linde C, Beyer M. Photodissociation spectroscopy of protonated leucine enkephalin. Phys Chem Chem Phys. 2017;19:10786-10795 pubmed publisher
    Protonated leucine enkephalin (YGGFL) was studied by ultraviolet photodissociation (UVPD) from 225 to 300 nm utilizing an optical parametric oscillator tunable wavelength laser system (OPO)...
  46. Cutler D, Mundey M, Mason R. Electrophysiological effects of opioid receptor activation on Syrian hamster suprachiasmatic nucleus neurones in vitro. Brain Res Bull. 1999;50:119-25 pubmed
  47. Wen D, Hu X, Wang Y, Luo J, Lin W, Jia L, et al. Effects of aqueous extracts from Panax ginseng and Hippophae rhamnoides on acute alcohol intoxication: An experimental study using mouse model. J Ethnopharmacol. 2016;192:67-73 pubmed publisher
    ..AEPH can markedly increase the levels of ADH, ALDH, decrease EO activity in liver and decrease the concentration of ?-EP and LENK in the brain to against acute alcohol intoxication in mice. ..
  48. Dezfuli B, Giari L, Simoni E, Shinn A, Bosi G. Immunohistochemistry, histopathology and ultrastructure of Gasterosteus aculeatus tissues infected with Glugea anomala. Dis Aquat Organ. 2004;58:193-202 pubmed
    ..Specifically, the protozoan induces a response in the stickleback nervous system, the reaction of which is revealed through the application of immunohistochemical techniques...
  49. Zolotarev I, Sokolov O, Kost N, Vas kovskiĭ B, Miasoedov N, Zozulia A. [Leu-enkephalin homogeneously labeled with tritium in studying the Selank inhibiting effect on the enkephalin-degrading enzymes of human plasma]. Bioorg Khim. 2004;30:234-40 pubmed
    ..The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 3; see also http://www.maik.ru. ..
  50. la Cour Jansen T, Dijkstra A, Watson T, Hirst J, Knoester J. Modeling the amide I bands of small peptides. J Chem Phys. 2006;125:44312 pubmed
    ..5 cm(-1). The correlation of the intensities for this model with intensities from DFT calculations is 0.94. ..
  51. Smith K, Berridge K. Opioid limbic circuit for reward: interaction between hedonic hotspots of nucleus accumbens and ventral pallidum. J Neurosci. 2007;27:1594-605 pubmed
    ..This pattern reveals differences between limbic opioid circuits that control reward "liking" and "wanting" functions. ..
  52. Walters A, Ondo W, Zhu W, Le W. Does the endogenous opiate system play a role in the Restless Legs Syndrome? A pilot post-mortem study. J Neurol Sci. 2009;279:62-5 pubmed publisher
    ..In addition, other opioid rich areas need to be explored as well as areas implicated in the pathogenesis of RLS such as the red nucleus and raphe nucleus. ..
  53. Coupar I. The peristaltic reflex in the rat ileum: evidence for functional mu- and delta-opiate receptors. J Pharm Pharmacol. 1995;47:643-6 pubmed
    ..The same response is subserved by mu-opiate receptors and either of these opiate-receptor subtypes could be activated by endogenous enkephalins. ..
  54. Porter A, Wattchow D, Hunter A, Costa M. Abnormalities of nerve fibers in the circular muscle of patients with slow transit constipation. Int J Colorectal Dis. 1998;13:208-16 pubmed
    ..No difference was detected in the density or distribution of nerve fibres using the other antisera. Excitatory nerve fibres are present in the circular muscle in STC but they are deficient in tachykinins and enkephalin. ..
  55. Hoang V, Uchenna A, Mark J, Renaat K, Norbert V. Characterization of human nasal primary culture systems to investigate peptide metabolism. Int J Pharm. 2002;238:247-56 pubmed
    ..The degradation kinetics of a model peptide, leucine enkephalin (Tyr-Gly-Gly-Phe-Leu, Leu-Enk), was determined in four nasal cell culture systems: immersion, air-liquid ..
  56. Boas U, Brask J, Christensen J, Jensen K. The ortho backbone amide linker (o-BAL) is an easily prepared and highly acid-labile handle for solid-phase synthesis. J Comb Chem. 2002;4:223-8 pubmed
    ..The very convenient synthesis of 4,6-dimethoxy-2-hydroxybenzaldehyde combined with the benign properties of the o-BAL handle may make it the preferred regioisomer. ..
  57. Teskey G, Kavaliers M. Modifications of social conflict-induced analgesic and activity responses in male mice receiving chronic opioid agonist and antagonist treatments. Pharmacol Biochem Behav. 1991;38:485-93 pubmed
    ..Levorphanol also induced a marked decrease in locomotor activity over days 3-7 postimplantation, with no evidence of the development of tolerance or withdrawal following termination of infusion.(ABSTRACT TRUNCATED AT 250 WORDS) ..
  58. Vargish T, Beamer K. Delta and Mu receptor agonists correlate with greater depression of cardiac function than morphine sulfate in perfused rat hearts. Circ Shock. 1989;27:245-51 pubmed
    ..The data suggest that all three delta agonists and DAGO are capable of depressing heart rate, cardiac output, and stroke volume at concentrations between 10(3) and 10(4) lower than those used in studies with morphine sulfate. ..
  59. Castagnola M, Rossetti D, Cassiano L, Misiti F, Pennacchietti L, Giardina B, et al. Determination of peptide dissociation constants and Stokes radius at different protonation stages by capillary electrophoresis. Electrophoresis. 1996;17:1925-30 pubmed
    ..Thus, not only can peptide dissociation constants be measured, but information about Stokes radius modifications linked to proton loss can also be obtained with picomoles of peptide. ..
  60. Milligan G, MacEwan D, Mercouris M, Mullaney I. Inverse agonism at adrenergic and opioid receptors: studies with wild type and constitutively active mutant receptors. Receptors Channels. 1997;5:209-13 pubmed
    ..In the stable cells lines this effect was prevented by co-incubation with neutral antagonists but could not be reproduced by an adenylyl cyclase P-site ligand which also inhibited basal adenylyl cyclase levels. ..
  61. Doi M, Asano A, Komura E, Ueda Y. The structure of an endomorphin analogue incorporating 1-aminocyclohexane-1-carboxlylic acid for proline is similar to the beta-turn of Leu-enkephalin. Biochem Biophys Res Commun. 2002;297:138-42 pubmed
    ..Selectivity for the opioid mu-receptor was fairly well conserved by [Chx(2)]EM, suggesting that the folded form is important for mu-selectivity. ..
  62. Hirose N, Murakawa K, Takada K, Oi Y, Suzuki T, Nagase H, et al. Interactions among mu- and delta-opioid receptors, especially putative delta1- and delta2-opioid receptors, promote dopamine release in the nucleus accumbens. Neuroscience. 2005;135:213-25 pubmed
  63. Shabanov P, Lebedev A, Nozdrachev A. Extrahypothalamic corticoliberin receptors regulate the reinforcing effects of self-stimulation. Dokl Biol Sci. 2006;406:14-7 pubmed
  64. Liu D, Chen Z, Xu H. Effects of leucine-enkephalin on catalase activity and hydrogen peroxide levels in the haemolymph of the Pacific Oyster (Crassostrea gigas). Molecules. 2008;13:864-70 pubmed
    ..The data strongly suggests an involvement of opioid peptides in the regulation of the antioxidant defence systems of Crassostrea gigas. ..
  65. Hoshi N, Hitomi J, Kusakabe T, Fukuda T, Hirota M, Suzuki T. Distinct morphological and immunohistochemical features and different growth rates among four human neuroblastomas heterotransplanted into nude mice. Med Mol Morphol. 2008;41:151-9 pubmed publisher
    ..These results indicate that human neuroblastoma cells have different biological characteristics and reduced growth rate with differentiation in terms of ultrastructure and of peptide production abilities. ..
  66. Yung K, Tang F, Fielding R, Du Y, Vacca Galloway L. Alteration in the levels of thyrotropin releasing hormone, substance P and enkephalins in the spinal cord, brainstem, hypothalamus and midbrain of the Wobbler mouse at different stages of the motoneuron disease. Neuroscience. 1992;50:209-22 pubmed
    ..undertaken to quantify selected neuropeptides (thyrotropin releasing hormone, substance P, methionine and leucine enkephalin) in the cervical spinal cord and other regions of the central nervous system of Wobbler mice by ..
  67. Larsimont V, Prokai L, Hochhaus G. Leucine enkephalin-tyrosinase reaction products--identification and biological activity. Biochim Biophys Acta. 1994;1222:95-100 pubmed
    b>Leucine enkephalin (1 mM) was reacted with mushroom tyrosinase under reductive conditions (ascorbic acid, 50 mM)...
  68. Armstead W. Relationship between opioids and prostaglandins in hypoxia-induced vasodilation of pial arteries in the newborn pig. Proc Soc Exp Biol Med. 1996;212:135-41 pubmed
    Previously, it has been observed that methionine enkephalin and leucine enkephalin contribute to hypoxia-induced pial artery dilation in the newborn pig...
  69. Bakalkin G, Yakovleva T, Terenius L. The Leu-enkephalin-encoding sequence DNA-binding factor (LEF) is the transcription factor YY1. Biochem Biophys Res Commun. 1997;231:135-9 pubmed
  70. Salvadori S, Temussi P. Antagonism in opioid peptides: the role of conformation. Curr Top Med Chem. 2004;4:145-57 pubmed
    ..The most significant achievements in the design of opioid antagonists are classified according to the relative importance of chemical constitution, conformation and chirality. ..
  71. Mosnaim A, Puente J, Ranade V, Hoang C, Wolf M. Inhibition of human plasma leucine5-enkephalin aminopeptidase hydrolysis by various endogenous peptides and a select number of clinically used drugs. Am J Ther. 2004;11:459-65 pubmed
    ..Whether their development could find useful pharmacological applications remains to be explored. ..
  72. Polfer N, Bohrer B, Plasencia M, Paizs B, Clemmer D. On the dynamics of fragment isomerization in collision-induced dissociation of peptides. J Phys Chem A. 2008;112:1286-93 pubmed publisher
    ..It is demonstrated here that cyclic and linear a4 structures can interconvert freely as a result of collisional activation, implying that isomerization takes place prior to dissociation. ..
  73. Yung K, Tang F, Vacca Galloway L. Decrease of enkephalins in cerebellum during Wobbler mouse motoneuron disease. Brain Res. 1992;599:175-80 pubmed
    ..The data imply that early changes in enkephalin (also shown for leucine enkephalin in the spinal cord and brainstem) may be important to the etiology of the Wobbler disorder...
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