Gene Symbol: Oprk1
Description: opioid receptor, kappa 1
Alias: kappa-type opioid receptor, K-OR-1, KOR-1
Species: rat
Products:     Oprk1

Top Publications

  1. Teodorov E, Modena C, Sukikara M, Felicio L. Preliminary study of the effects of morphine treatment on opioid receptor gene expression in brain structures of the female rat. Neuroscience. 2006;141:1225-31 pubmed
    ..In chronic treatment, both Oprk1 and Oprm1 expression levels, that encoded kappa and mu-opioid receptor respectively, showed significant decreases ..
  2. Teodorov E, Bernardi M, Ferrari M, Fior Chadi D, Felicio L. Plasticity of opioid receptors in the female periaqueductal gray: multiparity-induced increase in the activity of genes encoding for mu and kappa receptors and a post-translational decrease in delta receptor expression. J Mol Neurosci. 2011;43:175-81 pubmed publisher
    ..This study addresses the effects of multiple reproductive experiences on ?-, ?- and ?-opioid receptor (Oprm1, Oprk1, and Oprd1 respectively) gene activity and ?, ? and ? protein expression (MOR, KOR and DOR respectively) in the ..
  3. Mostari P, Ieda N, Deura C, Minabe S, Yamada S, Uenoyama Y, et al. dynorphin-kappa opioid receptor signaling partly mediates estrogen negative feedback effect on LH pulses in female rats. J Reprod Dev. 2013;59:266-72 pubmed
    ..The treatment also did not affect mRNA levels of Pdyn and Oprk1 (KOR gene) in the ARC-median eminence region, but significantly increased the ARC kisspeptin immunoreactivity...
  4. Cortez A, Charntikov S, Der Ghazarian T, Horn L, Crawford C, McDougall S. Age-dependent effects of kappa-opioid receptor stimulation on cocaine-induced stereotyped behaviors and dopamine overflow in the caudate-putamen: an in vivo microdialysis study. Neuroscience. 2010;169:203-13 pubmed publisher
    ..This lack of functional maturity may explain why kappa-opioid receptor agonists frequently induce different behavioral effects in young and adult rats. ..
  5. Feng Y, Johansson J, Shao R, Mannerås Holm L, Billig H, Stener Victorin E. Electrical and manual acupuncture stimulation affect oestrous cyclicity and neuroendocrine function in an 5?-dihydrotestosterone-induced rat polycystic ovary syndrome model. Exp Physiol. 2012;97:651-62 pubmed publisher
    ..s. versus control animals). The mRNA expression of the opioid receptors Oprk1 and Oprm1 in the hypothalamic arcuate nucleus was lower in the EA group than in untreated control rats...
  6. Valdez G, Harshberger E. ? opioid regulation of anxiety-like behavior during acute ethanol withdrawal. Pharmacol Biochem Behav. 2012;102:44-7 pubmed publisher
  7. Cunha T, Souza G, Domingues A, Carreira E, Lotufo C, Funez M, et al. Stimulation of peripheral kappa opioid receptors inhibits inflammatory hyperalgesia via activation of the PI3K?/AKT/nNOS/NO signaling pathway. Mol Pain. 2012;8:10 pubmed publisher
    ..This study extends a previously study of our group suggesting that PI3K?/AKT/nNOS/NO is an important analgesic pathway in primary nociceptive neurons. ..
  8. Brust T, Morgenweck J, Kim S, Rose J, Locke J, Schmid C, et al. Biased agonists of the kappa opioid receptor suppress pain and itch without causing sedation or dysphoria. Sci Signal. 2016;9:ra117 pubmed
    ..Moreover, the findings suggest that biased KOR agonists may present a means to treat pain and intractable itch without the side effects of dysphoria and sedation and with reduced abuse potential. ..
  9. Lucas L, Dragisic T, Duwaerts C, Swiatkowski M, Suzuki H. Effects of recovery from immobilization stress on striatal preprodynorphin- and kappa opioid receptor-mRNA levels of the male rat. Physiol Behav. 2011;104:972-80 pubmed publisher

More Information


  1. Rosin A, Lindholm S, Franck J, Georgieva J. Downregulation of kappa opioid receptor mRNA levels by chronic ethanol and repetitive cocaine in rat ventral tegmentum and nucleus accumbens. Neurosci Lett. 1999;275:1-4 pubmed
    ..In the NAc, the strongest decrease was observed in the 'binge' cocaine group. This profound decrease of KOR mRNA in regions important for brain reward suggests a potential role of the KOR system in the abuse of cocaine and ethanol. ..
  2. Herraez Baranda L, Carretero J, Gonzalez Sarmiento R, Laorden M, Milanes M, Rodriguez R. Evidence of involvement of the nNOS and the kappa-opioid receptor in the same intracellular network of the rat periaqueductal gray that controls morphine tolerance and dependence. Brain Res Mol Brain Res. 2005;137:166-73 pubmed
    ..Besides, we examined the colocalization of both molecules. Our results point to an involvement of KOR and nNOS in the same intracellular network that controls the development of morphine tolerance and dependence. ..
  3. McLaughlin J, Xu M, Mackie K, Chavkin C. Phosphorylation of a carboxyl-terminal serine within the kappa-opioid receptor produces desensitization and internalization. J Biol Chem. 2003;278:34631-40 pubmed
    ..These results demonstrate that GRK-mediated phosphorylation of serine 369 mediates rat KOR desensitization and internalization. ..
  4. Scarpellini C, Gargaglioni L, Branco L, Bicego K. Role of preoptic opioid receptors in the body temperature reduction during hypoxia. Brain Res. 2009;1286:66-74 pubmed publisher
    ..Our results indicate the kappa-opioid receptor in the AVPO is important for the reduction of Tb during hypoxia while the mu and delta receptors are involved in the increase of Tb during normoxia post-hypoxia. ..
  5. Tryoen Toth P, Gaveriaux Ruff C, Maderspach K, Labourdette G. Regulation of kappa-opioid receptor mRNA level by cyclic AMP and growth factors in cultured rat glial cells. Brain Res Mol Brain Res. 1998;55:141-50 pubmed
    ..The regulation of KOR mRNA level under the effect of extracellular signals suggests that opioids take part in dynamic processes in glial cells, possibly related to glial-neuron communication. ..
  6. Nishi M, Takeshima H, Fukuda K, Kato S, Mori K. cDNA cloning and pharmacological characterization of an opioid receptor with high affinities for kappa-subtype-selective ligands. FEBS Lett. 1993;330:77-80 pubmed
    ..RNA blot hybridization analysis indicated that ROR-D mRNA is distributed in cerebrum and brainstem but not in cerebellum. ..
  7. Peng P, Huang L, Li J, Fan R, Zhang S, Wang Y, et al. Distribution of kappa-opioid receptor in the pulmonary artery and its changes during hypoxia. Anat Rec (Hoboken). 2009;292:1062-7 pubmed publisher
    ..05). The present study has provided evidence for the first time of the precise location of kappa-ORs in PAs and PASMCs of rats and that hypoxia upregulates expression of kappa-ORs. ..
  8. Lee J, Joshi S, Chan J, Wong Y. Differential coupling of mu-, delta-, and kappa-opioid receptors to G alpha16-mediated stimulation of phospholipase C. J Neurochem. 1998;70:2203-11 pubmed
    ..5- to almost 17-fold. These findings suggest that the promiscuous G alpha16 can in fact discriminate among different receptors and that such preferential interaction might in part be due to the abundance of receptors. ..
  9. Simonin F, Valverde O, Smadja C, Slowe S, Kitchen I, Dierich A, et al. Disruption of the kappa-opioid receptor gene in mice enhances sensitivity to chemical visceral pain, impairs pharmacological actions of the selective kappa-agonist U-50,488H and attenuates morphine withdrawal. EMBO J. 1998;17:886-97 pubmed
    ..Together, our data demonstrate that the KOR-encoded receptor plays a modulatory role in specific aspects of opioid function. ..
  10. Drake C, De Oliveira A, Harris J, Connor D, Winkler C, Aicher S. Kappa opioid receptors in the rostral ventromedial medulla of male and female rats. J Comp Neurol. 2007;500:465-76 pubmed
    ..Altering the balance between pre- and postsynaptic receptive sites may underlie differences in the effects of KOR agonists on nociceptive responses in males and females. ..
  11. Jarosz P. The effect of kappa opioid receptor antagonism on energy expenditure in the obese Zucker rat. Biol Res Nurs. 2007;8:294-9 pubmed
    ..Reduction in body weight as a result of KOR inhibition in this study was related to a decrease in food intake but not related to an increase in energy expended or activity. ..
  12. Tian F, Zheng X, Li J, Zhang S, Feng N, Guo H, et al. κ-Opioid Receptor Stimulation Improves Endothelial Function via Akt-stimulated NO Production in Hyperlipidemic Rats. Sci Rep. 2016;6:26807 pubmed publisher
    ..Its mechanism is related to the preservation of eNOS phosphorylation through activation of the PI3K/Akt signaling pathway and downregulation of iNOS expression/activity. ..
  13. Polter A, Bishop R, Briand L, Graziane N, Pierce R, Kauer J. Poststress block of kappa opioid receptors rescues long-term potentiation of inhibitory synapses and prevents reinstatement of cocaine seeking. Biol Psychiatry. 2014;76:785-93 pubmed publisher
    ..ORs antagonists reverse the neuroadaptations underlying stress-induced drug-seeking behavior and may be useful in the treatment of cocaine addiction. ..
  14. Xiu J, Liu J, Li H, Fu L, Ding D, Han D. The effects of ?-opioid receptor on stretch-induced electrophysiological changes in infarcted rat hearts. Am J Med Sci. 2013;345:129-35 pubmed publisher
    ..01). The ?-OR could influence the stretch-induced electrophysiological changes and play an antiarrhythmic role in stretch-induced arrhythmias after acute MI. ..
  15. Anderson R, Agoglia A, Morales M, Varlinskaya E, Spear L. Stress, ? manipulations, and aversive effects of ethanol in adolescent and adult male rats. Neuroscience. 2013;249:214-22 pubmed publisher
  16. Zhang Z, Zhang C, Zhou M, Xu F. Activation of opioid ?-receptors, but not ?- or ?-receptors, switches pulmonary C-fiber-mediated rapid shallow breathing into an apnea in anesthetized rats. Respir Physiol Neurobiol. 2012;183:211-7 pubmed publisher
    ..Our results suggest that activating ?-receptors is capable of turning the PCF-mediated RSB into an apnea, at least partly, via facilitating PCFs' activity and this switching effect appears independent of the released histamine. ..
  17. Joshi S, Su X, Porreca F, Gebhart G. kappa -opioid receptor agonists modulate visceral nociception at a novel, peripheral site of action. J Neurosci. 2000;20:5874-9 pubmed
    ..The present results support the existence of a non-kappa-opioid receptor site of action localized in the colon. ..
  18. Przybysz K, Werner D, Diaz M. Age-dependent regulation of GABA transmission by kappa opioid receptors in the basolateral amygdala of Sprague-Dawley rats. Neuropharmacology. 2017;117:124-133 pubmed publisher
  19. Luz P, Saraiva R, Almeida T, Fregoneze J, De Castro e Silva E. Blockade of central kappa-opioid receptors inhibits the antidipsogenic effect of interleukin-1beta. Neuropeptides. 2009;43:93-103 pubmed publisher
  20. Parks G, Wang L, Wang Z, Civelli O. Identification of neuropeptide receptors expressed by melanin-concentrating hormone neurons. J Comp Neurol. 2014;522:3817-33 pubmed publisher
    ..Surprisingly, several receptors thought to regulate MCH neurons displayed minimal colocalization with MCH, suggesting that they may not directly regulate the MCH system. ..
  21. Lin J, Wang H, Li J, Wang Q, Zhang S, Feng N, et al. ?-Opioid receptor stimulation modulates TLR4/NF-?B signaling in the rat heart subjected to ischemia-reperfusion. Cytokine. 2013;61:842-8 pubmed publisher
    ..These data provide evidence for the first time that ?-opioid receptor stimulation inhibits TLR4/NF-?B signaling in the rat heart subjected to MI/R. ..
  22. Liu N, Chakrabarti S, Schnell S, Wessendorf M, Gintzler A. Spinal synthesis of estrogen and concomitant signaling by membrane estrogen receptors regulate spinal ?- and ?-opioid receptor heterodimerization and female-specific spinal morphine antinociception. J Neurosci. 2011;31:11836-45 pubmed publisher
    ..We suggest that KOR/MOR is a molecular switch that shifts the function of KOR and thereby endogenous dynorphin from pronociceptive to antinociceptive. KOR/MOR could thus serve as a novel molecular target for pain management in women. ..
  23. Hirota K, Okawa H, Appadu B, Grandy D, Devi L, Lambert D. Stereoselective interaction of ketamine with recombinant mu, kappa, and delta opioid receptors expressed in Chinese hamster ovary cells. Anesthesiology. 1999;90:174-82 pubmed
    ..Ketamine (100 microM) reversed DAMGO (mu) and spiradoline (kappa) inhibition of formation of cyclic adenosine monophosphate. Ketamine interacts stereoselectively with recombinant mu and kappa opioid receptors. ..
  24. Jordan B, Devi L. G-protein-coupled receptor heterodimerization modulates receptor function. Nature. 1999;399:697-700 pubmed
    ..Furthermore, the kappa-delta heterodimer synergistically binds highly selective agonists and potentiates signal transduction. Thus, heterodimerization of these GPCRs represents a novel mechanism that modulates their function. ..
  25. Leventhal L, Silva R, Rossi G, Pasternak G, Bodnar R. Morphine-6beta-glucuronide-induced hyperphagia: characterization of opioid action by selective antagonists and antisense mapping in rats. J Pharmacol Exp Ther. 1998;287:538-44 pubmed
  26. Mousa S, Shaqura M, Schäper J, Huang W, Treskatsch S, Habazettl H, et al. Identification of mu- and kappa-opioid receptors as potential targets to regulate parasympathetic, sympathetic, and sensory neurons within rat intracardiac ganglia. J Comp Neurol. 2010;518:3836-47 pubmed publisher
    ..Thus, they may well play a role within the complex network for the integration of the heart's neuronal in- and output. ..
  27. Fassini A, Scopinho A, Resstel L, Corrêa F. κ-opioid receptors in the infralimbic cortex modulate the cardiovascular responses to acute stress. Exp Physiol. 2015;100:377-87 pubmed publisher
    ..In conclusion, κ-opioid receptors in the IL modulate pressor and tachycardiac responses caused by RS, suggesting a facilitatory role of this structure in this aversive situation. ..
  28. Peart J, Gross E, Gross G. Effect of exogenous kappa-opioid receptor activation in rat model of myocardial infarction. J Cardiovasc Pharmacol. 2004;43:410-5 pubmed
    ..These data demonstrate that KOR activation provides a similar degree of infarct size reduction as DOR activation. KOR agonists also reduced arrhythmogenesis; however, these responses appear to be independent of KOR activation. ..
  29. Berg K, Rowan M, Gupta A, Sanchez T, Silva M, Gomes I, et al. Allosteric interactions between ? and ? opioid receptors in peripheral sensory neurons. Mol Pharmacol. 2012;81:264-72 pubmed publisher
  30. Meng F, Xie G, Thompson R, Mansour A, Goldstein A, Watson S, et al. Cloning and pharmacological characterization of a rat kappa opioid receptor. Proc Natl Acad Sci U S A. 1993;90:9954-8 pubmed
    ..These observations indicate that we have cloned a cDNA encoding a rat kappa receptor of the kappa 1 subtype. ..
  31. Sahley T, Anderson D, Chernicky C. Bi-phasic intensity-dependent opioid-mediated neural amplitude changes in the chinchilla cochlea: partial blockade by an N-Methyl-D-Aspartate (NMDA)-receptor antagonist. Eur J Pharmacol. 2008;580:100-15 pubmed
    ..The role played by lateral efferent opioid neuromodulation at cochlear NMDA receptors, is discussed. ..
  32. Yu G, Yan H, Gong Z. Effects of acute and repeated morphine treatment on ?-opioid receptor protein levels in mesocorticolimbic system. J Recept Signal Transduct Res. 2014;34:44-7 pubmed publisher
    ..These results, along with those reported previously, suggested that morphine dependence may be associated with regionally specific changes in ?-opioid receptor expression in mesocorticolimbic system. ..
  33. Chakrabarti S, Liu N, Gintzler A. Formation of mu-/kappa-opioid receptor heterodimer is sex-dependent and mediates female-specific opioid analgesia. Proc Natl Acad Sci U S A. 2010;107:20115-9 pubmed publisher
    ..Spinal cord MOR/KOR heterodimers represent a unique pharmacological target for female-specific pain control. ..
  34. Chen Y, Mestek A, Liu J, Yu L. Molecular cloning of a rat kappa opioid receptor reveals sequence similarities to the mu and delta opioid receptors. Biochem J. 1993;295 ( Pt 3):625-8 pubmed
  35. Chao C, Gekker G, Hu S, Sheng W, Shark K, Bu D, et al. kappa opioid receptors in human microglia downregulate human immunodeficiency virus 1 expression. Proc Natl Acad Sci U S A. 1996;93:8051-6 pubmed
    ..These findings suggest that kappa opioid agonists have immunomodulatory activity in the brain, and that these compounds could have potential in the treatment of HIV-1-associated encephalopathy. ..
  36. Fuentealba J, Gysling K, Andrés M. Increased locomotor response to amphetamine induced by the repeated administration of the selective kappa-opioid receptor agonist U-69593. Synapse. 2007;61:771-7 pubmed
    ..These results suggest that long-term effect of KOR activation results in facilitation of amphetamine-induced DA extracellular levels in the NAc accompanied by sensitization of amphetamine-induced increase in locomotor activity. ..
  37. Silva R, Grossman H, Hadjimarkou M, Rossi G, Pasternak G, Bodnar R. Dynorphin A(1-17)-induced feeding: pharmacological characterization using selective opioid antagonists and antisense probes in rats. J Pharmacol Exp Ther. 2002;301:513-8 pubmed
    ..These converging antagonist and AS ODN data firmly implicate the kappa(1)-opioid receptor and the KOR-1 and KOR-3/ORL-1 opioid receptor genes in the mediation of dynorphin-induced feeding. ..
  38. Peart J, Gross E, Reichelt M, Hsu A, Headrick J, Gross G. Activation of kappa-opioid receptors at reperfusion affords cardioprotection in both rat and mouse hearts. Basic Res Cardiol. 2008;103:454-63 pubmed publisher
    ..In summary, kappa-ORs afford cardioprotection primarily when activated prior to and not after reperfusion. This protection may involve activation of the PI3 kinase (PI3K) pathway and mitochondrial (mito) K (ATP) channels. ..
  39. Groblewski P, Zietz C, Willuhn I, Phillips P, Chavkin C. Repeated stress exposure causes strain-dependent shifts in the behavioral economics of cocaine in rats. Addict Biol. 2015;20:297-301 pubmed publisher
    ..Thus, R-FSS exposure had strain-dependent effects on cocaine responding during the threshold procedure, and the stress effects on cocaine valuation exhibited by Wistar, but not WKY, required intact KOR signaling. ..
  40. Berger A, Williams A, McGinnis M, Walker B. Affective cue-induced escalation of alcohol self-administration and increased 22-kHz ultrasonic vocalizations during alcohol withdrawal: role of kappa-opioid receptors. Neuropsychopharmacology. 2013;38:647-54 pubmed publisher
    ..Taken together, this study implicates negative affective states induced by both alcohol withdrawal and conditioned stimuli as being produced, in part, by activity of the DYN/KOR system. ..
  41. Ploj K, Nylander I. Long-term effects on brain opioid and opioid receptor like-1 receptors after short periods of maternal separation in rats. Neurosci Lett. 2003;345:195-7 pubmed
  42. Chen X, Zhao S, Xia Y, Xiong Z, Li Y, Tao L, et al. G protein coupled receptor kinase-2 upregulation causes ?-opioid receptor desensitization in diabetic heart. Biochem Biophys Res Commun. 2017;482:658-664 pubmed publisher
  43. Vujić V, Stanojevic S, Dimitrijević M. Methionine-enkephalin stimulates hydrogen peroxide and nitric oxide production in rat peritoneal macrophages: interaction of mu, delta and kappa opioid receptors. Neuroimmunomodulation. 2004;11:392-403 pubmed
    ..It is concluded that both negative and positive functional interaction between delta, mu and kappa opioid receptors regulate the influence of MET on H(2)O(2) and NO production in rat peritoneal macrophages. ..
  44. Seale S, Feng Q, Agarwal A, El Alfy A. Neurobehavioral and transcriptional effects of acrylamide in juvenile rats. Pharmacol Biochem Behav. 2012;101:77-84 pubmed publisher
    ..Second, in sciatic nerves, acrylamide repressed the expression of the opioid receptor gene Oprk1 that is known to play a role in neuropathic pain regulation...
  45. Fan L, Tien L, Tanaka S, Ma T, Chudapongse N, Sinchaisuk S, et al. Changes in the brain kappa-opioid receptor levels of rats in withdrawal from physical dependence upon butorphanol. Neuroscience. 2003;121:1063-74 pubmed
  46. Liu H, Tian Y, Ji B, Lu H, Xin Q, Jiang Y, et al. Heterodimerization of the kappa opioid receptor and neurotensin receptor 1 contributes to a novel ?-arrestin-2-biased pathway. Biochim Biophys Acta. 2016;1863:2719-2738 pubmed publisher
  47. Rabkin S. Endogenous kappa opioids mediate the action of brain angiotensin II to increase blood pressure. Neuropeptides. 2007;41:411-9 pubmed
  48. Sedki F, Eigenmann K, Gelinas J, Schouela N, Courchesne S, Shalev U. A role for kappa-, but not mu-opioid, receptor activation in acute food deprivation-induced reinstatement of heroin seeking in rats. Addict Biol. 2015;20:423-32 pubmed publisher
    ..These results support the hypothesis that activation of KOR, but not MOR, is critically involved in stress-induced reinstatement of drug seeking. ..
  49. Bi J, Tsai N, Lin Y, Loh H, Wei L. Axonal mRNA transport and localized translational regulation of kappa-opioid receptor in primary neurons of dorsal root ganglia. Proc Natl Acad Sci U S A. 2006;103:19919-24 pubmed
  50. Reyes B, Chavkin C, van Bockstaele E. Subcellular targeting of kappa-opioid receptors in the rat nucleus locus coeruleus. J Comp Neurol. 2009;512:419-31 pubmed publisher
    ..These data add to the growing literature showing that kappaORs can modulate diverse afferent signaling to the LC. ..
  51. Knoll A, Muschamp J, Sillivan S, Ferguson D, Dietz D, Meloni E, et al. Kappa opioid receptor signaling in the basolateral amygdala regulates conditioned fear and anxiety in rats. Biol Psychiatry. 2011;70:425-33 pubmed publisher
  52. Herraez Baranda L, Carretero J, Gonzalez Sarmiento R, Rodriguez R. Kappa opioid receptor is expressed in the rat cerebellar cortex. Cell Tissue Res. 2005;320:223-8 pubmed
    ..This work contributes to the deeper knowledge of the mechanisms that are involved in cerebellar function and may lead to a better understanding of the relationships between nociceptive activity and drug abuse potential. ..
  53. Carr G, Bangasser D, Bethea T, Young M, Valentino R, Lucki I. Antidepressant-like effects of kappa-opioid receptor antagonists in Wistar Kyoto rats. Neuropsychopharmacology. 2010;35:752-63 pubmed publisher
    ..These results support the use of the WKY rat as a model of affective disorders potentially involving KOR overactivity and provide more evidence that KOR antagonists could potentially be used as novel antidepressants. ..
  54. Karkhanis A, Rose J, Weiner J, Jones S. Early-Life Social Isolation Stress Increases Kappa Opioid Receptor Responsiveness and Downregulates the Dopamine System. Neuropsychopharmacology. 2016;41:2263-74 pubmed publisher
  55. Zhang L, Li J, Shi Q, Fan R, Kaye A, Wang Y, et al. Role of ?-opioid receptor in hypoxic pulmonary artery hypertension and its underlying mechanism. Am J Ther. 2013;20:329-36 pubmed publisher
    ..This increase of ?-OR expression was both enhanced by U50,488H and abolished by nor-BNI. The results demonstrate that U50,488H attenuates HPH through both the stimulation and upregulation of ?-ORs. ..
  56. Nealey K, Smith A, Davis S, Smith D, Walker B. ?-opioid receptors are implicated in the increased potency of intra-accumbens nalmefene in ethanol-dependent rats. Neuropharmacology. 2011;61:35-42 pubmed publisher
  57. Minami M, Toya T, Katao Y, Maekawa K, Nakamura S, Onogi T, et al. Cloning and expression of a cDNA for the rat kappa-opioid receptor. FEBS Lett. 1993;329:291-5 pubmed
    ..Northern blot analysis demonstrated that kappa-opioid receptor mRNA is expressed in a regionally specific manner in rat brain. ..
  58. Teodorov E, Camarini R, Bernardi M, Felicio L. Treatment with steroid hormones and morphine alters general activity, sexual behavior, and opioid gene expression in female rats. Life Sci. 2014;104:47-54 pubmed publisher
    ..5mg/kg morphine once per day for 6days. We evaluated general activity, sexual behavior, Oprm1, Oprd1, and Oprk1 gene expression, and ? opioid receptor (MOR), ? opioid receptor (DOR), and ? opioid receptor (KOR) protein ..
  59. Wu G, Huang W, Zhang H, Li Q, Zhou J, Shu H. Inhibitory effects of processed Aconiti tuber on morphine-induced conditioned place preference in rats. J Ethnopharmacol. 2011;136:254-9 pubmed publisher
    ..1) PAT dose-dependently inhibited morphine-induced CPP. (2) The inhibition of PAT on morphine-induced CPP was probably due to activation of KOR by increasing dynorphin release in rats' NAc. ..
  60. Jolivalt C, Jiang Y, Freshwater J, Bartoszyk G, Calcutt N. Dynorphin A, kappa opioid receptors and the antinociceptive efficacy of asimadoline in streptozotocin-induced diabetic rats. Diabetologia. 2006;49:2775-85 pubmed
    ..Using selective peripheral KOR agonists to take advantage of elevated peripheral KOR expression may provide a novel therapeutic approach for painful diabetic neuropathy. ..
  61. Appleyard S, McLaughlin J, Chavkin C. Tyrosine phosphorylation of the kappa -opioid receptor regulates agonist efficacy. J Biol Chem. 2000;275:38281-5 pubmed
    ..Thus, tyrosine phosphorylation may provide an important mechanism for modulation of G protein-coupled receptor signaling. ..
  62. Yukhananov R, Handa R. Alterations in kappa opioid receptor mRNA levels in the paraventricular nucleus of the hypothalamus by stress and sex steroids. Neuroreport. 1996;7:1690-4 pubmed
    ..Taken together, these data indicate that kOR mRNA levels are under estrogenic control and up-regulated in a stressor specific fashion. ..
  63. Rostamzadeh F, Najafipour H, Yeganeh Hajahmadi M, Esmaeili Mahani S, Joukar S, Iranpour M. Heterodimerization of apelin and opioid receptors and cardiac inotropic and lusitropic effects of apelin in 2K1C hypertension: Role of pERK1/2 and PKC. Life Sci. 2017;191:24-33 pubmed publisher
    ..However, the role of interaction between KOR and apelin receptors (APJ) on the cardiac contractility effects of apelin and in regulation of pERK1/2 and PKC in the heart of renovascular hypertensive (2K1C) rats is unknown...
  64. Nakahara T, Uenoyama Y, Iwase A, Oishi S, Nakamura S, Minabe S, et al. Chronic peripheral administration of kappa-opioid receptor antagonist advances puberty onset associated with acceleration of pulsatile luteinizing hormone secretion in female rats. J Reprod Dev. 2013;59:479-84 pubmed
  65. Schank J, Goldstein A, Rowe K, King C, Marusich J, Wiley J, et al. The kappa opioid receptor antagonist JDTic attenuates alcohol seeking and withdrawal anxiety. Addict Biol. 2012;17:634-47 pubmed publisher
    ..Our results provide additional evidence for the involvement of KOR in regulation of alcohol-related behaviors and provide support for KOR antagonists, including JDTic, to be evaluated as medications for alcoholism. ..
  66. Jongkamonwiwat N, Phansuwan Pujito P, Sarapoke P, Chetsawang B, Casalotti S, Forge A, et al. The presence of opioid receptors in rat inner ear. Hear Res. 2003;181:85-93 pubmed
    ..These findings are the first report of the presence of all three classical opioid receptors in the inner ear and suggest that these receptors may have both presynaptic and postsynaptic roles. ..