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Kappa opioid receptor

Shehla Akbar, Fazal Subhan, Nasiara Karim, Muhammad Shahid, Nisar Ahmad, Gowhar Ali, Wajahat Mahmood, Khwaja Fawad
BACKGROUND: Diabetic neuropathy is the most prevalent, persistent and debilitating complication of diabetes mellitus often coupled with vulvodynia that may present as an isolated symptom or as a part of constellation of other neuropathic abnormalities. OBJECTIVE: Flavonoids have selective affinity for GABA receptors and 6-methoxyflavanone (6-MeOF) is a positive allosteric modulator of GABA responses at human recombinant GABAA receptors. GABAergic and opioidergic system inhibition have been shown to facilitate neuropathic pain...
October 17, 2016: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Mst Parvin Mostari, Nahoko Ieda, Chikaya Deura, Shiori Minabe, Shunji Yamada, Yoshihisa Uenoyama, Kei-Ichiro Maeda, Hiroko Tsukamura
Figure 3(a) have been corrected.
2016: Journal of Reproduction and Development
D Reiss, R A Ceredig, T Secher, J Boué, F Barreau, G Dietrich, C Gavériaux-Ruff
BACKGROUND: Opiates act through opioid receptors to diminish pain. Here, we investigated whether mu (MOR) and delta (DOR) receptor endogenous activity assessed in the whole mouse body or in particular at peripheral receptors on primary nociceptive neurons, control colonic pain. METHODS: We compared global MOR and DOR receptor knockout (KO) mice, mice with a conditional deletion of MOR and DOR in Nav1.8-positive nociceptive primary afferent neurons (cKO), and control floxed mice of both genders for visceral sensitivity...
October 17, 2016: European Journal of Pain: EJP
Santhanalakshmi Sundaramurthy, Balasubramaniam Annamalai, Devadoss J Samuvel, Toni S Shippenberg, Lankupalle D Jayanthi, Sammanda Ramamoorthy
Kappa opioid receptor (KOR) agonists produce dysphoria and psychotomimesis. While KOR agonists produce pro-depressant-like effects, KOR antagonists produce anti-depressant-like effects in rodent models. The cellular mechanisms and downstream effector(s) by which KOR ligands produce these effects are not clear. KOR agonists modulate serotonin (5-HT) transmission in the brain regions implicated in mood and motivation regulation. Presynaptic serotonin transporter (SERT) activity is critical in the modulation of synaptic 5-HT and, subsequently, in mood disorders...
October 12, 2016: Neuropharmacology
Zhengxin Cai, Song Ye Li, Richard Pracitto, Antonio Navarro, Anupama Shirali, Jim Ropchan, Yiyun Henry Huang
Kappa opioid receptor (KOR) antagonists are potential drug candidates for diseases such as treatment-refractory depression, anxiety, and addictive disorders. PET imaging radiotracers for KOR can be used in occupancy study to facilitate drug development, and to investigate the roles of KOR in health and diseases. We have previously developed two 11C-labeled antagonist radiotracers with high affinity and selectivity toward KOR. What is limiting their wide applications is the short half-life of 11C. Herein, we report the synthesis of a first 18F-labeled KOR antagonist radiotracer and the initial PET imaging study in a non-human primate...
October 14, 2016: ACS Chemical Neuroscience
Marcelina Jasmine Silva, Andrea Rubinstein
Buprenorphine, a semisynthetic thebaine derivative, is a unique opioid, as it has activity at multiple receptors, including mu (partial agonist), kappa (antagonist), OLR-1 (agonist), and delta (antagonist). Because buprenorphine's pharmacology is relatively complex, misconceptions about its actions are common. Most other opioids act solely or predominately as full mu receptor agonists. Common practice at many institutions calls for the cessation of regular buprenorphine use 48-72 hours prior to surgery. This practice is based on three foundational theories that have come from scant data about the properties of buprenorphine: (1) that buprenorphine is only a partial mu agonist and therefore is not a potent analgesic; (2) because buprenorphine has a ceiling effect on respiratory depression, it also has a ceiling effect on analgesia; and (3) that buprenorphine acts as a "blockade" to the analgesic effects of other opiates when coadministered due to its strong binding affinity...
October 13, 2016: Journal of Pain & Palliative Care Pharmacotherapy
Eiko Yokota, Yuko Koyanagi, Kiyofumi Yamamoto, Yoshiyuki Oi, Noriaki Koshikawa, Masayuki Kobayashi
The insular cortex (IC) plays a principal role in the regulation of pain processing. Although opioidergic agonists depress cortical excitatory synaptic transmission, little is known about opioidergic roles in inhibitory synaptic transmission. In the IC, the opioid receptors differentially regulate the excitatory propagation: agonists of the mu (MOR), delta (DOR), and kappa (KOR) exhibit suppressive, facilitative, and little effects, respectively. Thus, we aimed to examine the effects of opioid receptor agonists on unitary inhibitory postsynaptic currents (uIPSCs) in the IC...
October 7, 2016: Neuroscience
S Michael Owens, Gerald T Pollard, James L Howard, Timothy R Fennell, Rodney W Snyder, F Ivy Carroll
JDTic is a potent and selective κ-opioid receptor (KOR) antagonist that reverses U50,488-induced diuresis in rats. It partitions into brain with a duration of action lasting for weeks. In a search for KOR antagonists that do not accumulate in the brain, we compared single doses of five methylated JDTic analogs (RTI-97, -194, -212, -240, and -241) for reversal of U50,488 diuresis and pharmacokinetic (PK) properties. All six compounds showed potent and selective KOR antagonism in a [(35)S]GTPγS binding assay...
October 4, 2016: ACS Chemical Neuroscience
William A Carlezon, Andrew D Krystal
Kappa-opioid receptor (KOR) antagonists are currently being considered for the treatment of a variety of neuropsychiatric conditions, including depressive, anxiety, and substance abuse disorders. A general ability to mitigate the effects of stress, which can trigger or exacerbate these conditions, may explain their putative efficacy across such a broad array of conditions. The discovery of their potentially therapeutic effects evolved from preclinical research designed to characterize the molecular mechanisms by which experience causes neuroadaptations in the nucleus accumbens (NAc), a key element of brain reward circuitry...
October 2016: Depression and Anxiety
Ashlee Van't Veer, Karen L Smith, Bruce M Cohen, William A Carlezon, Anita J Bechtholt
INTRODUCTION: Studies in laboratory animals and humans indicate that endogenous opioids play an important role in regulating the rewarding value of various drugs, including ethanol (EtOH). Indeed, opioid antagonists are currently a front-line treatment for alcoholism in humans. Although roles for mu- and delta-opioid receptors have been characterized, the contribution of kappa-opioid receptors (KORs) is less clear. There is evidence that changes in KOR system function can decrease or increase EtOH drinking, depending on test conditions...
September 2016: Brain and Behavior
Aishwarya Vijay, Shuo Wang, Patrick Worhunsky, Ming-Qiang Zheng, Nabeel Nabulsi, Jim Ropchan, Suchitra Krishnan-Sarin, Yiyun Huang, Evan D Morris
Opioid receptors may play critical roles in alcoholism and other addictions, addiction withdrawal, and depression and are considered pharmacological targets for treatment of these conditions. Sex differences have been demonstrated in mu (MOR) and delta (DOR) opioid receptors in humans, in vivo. In addition, sex differences have been observed in efficacy of treatment targeting kappa opioid receptors (KOR). Our goal in the present study was to compare the availability of KOR (1) between healthy control (HC) men and women...
2016: American Journal of Nuclear Medicine and Molecular Imaging
Jai Shankar K Yadlapalli, Benjamin M Ford, Amit Ketkar, Anqi Wan, Narasimha R Penthala, Robert L Eoff, Paul L Prather, Maxim Dobretsov, Peter A Crooks
: This study determined the antinociceptive effects of morphine and morphine-6-O-sulfate (M6S) in both normal and diabetic rats, and evaluated the comparative role of mu-opioid receptors (mu-ORs) and delta-opioid receptors (delta-ORs) in the antinociceptive action of these opioids. In vitro characterization of mu-OR and delta-OR-mediated signaling by M6S and morphine in stably transfected Chinese hamster ovary (CHO-K1) cells showed that M6S exhibited a 6-fold higher affinity for delta-ORs and modulated G-protein and adenylyl cyclase activity via delta-ORs more potently than morphine...
September 13, 2016: Pharmacological Research: the Official Journal of the Italian Pharmacological Society
Shalini Dogra, Ajeet Kumar, Deepmala Umrao, Amogh A Sahasrabuddhe, Prem N Yadav
Psychotomimetic and prodepressive effect by kappa opioid receptor (KOR) activation in rodents and human is widely known. Significantly, recent clinical investigations demonstrated the salutary effects of KOR antagonists in patients with treatment resistant depression, indicating essential role of KOR signaling in refractory depression. This study was undertaken to reveal the molecular determinant of KOR mediated depression and antidepressant response of KOR antagonist. We observed that chronic KOR activation by U50488, a selective KOR agonist, significantly increased depression like symptoms (behavioral despair, anhedonia and sociability) in C57BL/6J mice, which were blocked by KOR antagonist norBNI and antidepressant imipramine, but not by fluoxetine or citalopram...
2016: Scientific Reports
Sara M Hall, Lindsay LeBaron, Cyf Ramos-Colon, Chaoling Qu, Jennifer Yanhua Xie, Frank Porreca, Josephine Lai, Yeon Sun Lee, Victor J Hruby
Dynorphin A (Dyn A) is a unique endogenous ligand that possesses well-known neuroinhibitory effects via opioid receptors with a preference for the kappa receptor but also neuroexcitatory effects, which cause hyperalgesia. We have shown that the neuroexcitatory effects are mediated through bradykinin (BK) receptors and that intrathecal ( administration of our lead ligand 1, [des-Arg(7)]-Dyn A-(4-11), which shows good binding affinity (IC50 = 150 nM) at the BK receptors, blocks Dyn A-induced hyperalgesia in naïve animals and reverses thermal and tactile hypersensitivities in a dose-dependent manner in nerve-injured animals...
September 27, 2016: ACS Chemical Neuroscience
Raehanna J Jamshidi, Laura C Sullivan, Blaine A Jacobs, Teresa A Chavera, Kelly A Berg, William P Clarke
A single administration of the kappa opioid receptor (KOR) antagonist, norbinaltorphimine (norBNI), produces long-term reduction in KOR function in heterologous expression systems and brain that is mediated by activation of c-Jun N-terminal Kinase (JNK). In this study, we examined the long-term effects of norBNI on adult rat peripheral sensory neurons in vivo and ex vivo. Following a single intraplantar ( injection of norBNI into the hindpaw, peripheral KOR-mediated antinociception in the ipsilateral, but not the contralateral, hindpaw was abolished for at least 9 days...
September 7, 2016: Journal of Pharmacology and Experimental Therapeutics
Hyun Jung Kim, Hyungwoo Kim, Myeong Ho Jung, Young Kyu Kwon, Byung Joo Kim
Berberine is traditionally used to treat gastrointestinal (GI) motility disorders. The interstitial cells of Cajal (ICCs) are the pacemaker cells of the gastrointestinal tract, which are responsible for the production of gut movements. The present study aimed to investigate the effects of berberine on pacemaker potentials (PPs) in cultured ICC clusters from the mouse small intestine, and sought to identify the receptors involved and the underlying mechanisms of action. All experiments were performed on cultured ICCs, and a whole‑cell patch‑clamp configuration was used to record PPs from ICC clusters (current clamp mode)...
October 2016: Molecular Medicine Reports
Bin Mei, Wanhong Li, Xinqi Cheng, Xuesheng Liu, Erwei Gu, Ye Zhang
BACKGROUND: Remote precoditioning of trauma (RPCT) confers cardioprotective effects against myocardial ischemia/reperfusion injury, which are mediated by spinal opioid receptors. The aim of this study was to identify the roles of opioid receptor subtypes in the cardioprotective effect of RPCT and possible mechanisms. METHODS: In this study, 192 Sprague-Dawley rats were allocated to 12 groups. Except for the sham group, rats in all groups were subjected to myocardial ischemia reperfusion...
September 2, 2016: Cardiology Journal
Roger Negrete, María Salud García Gutiérrez, Jorge Manzanares, Rafael Maldonado
Joint pain is a major clinical problem mainly associated to osteoarthritis, and characterized by articular cartilage degradation resulting in a complex chronic pain state that includes nociceptive, emotional and cognitive manifestations. Memory impairment, depressive- and anxiety-like symptoms have been reported to be associated with chronic pain, leading to a decrease of life quality. In this study, we evaluated the involvement of the endogenous dynorphin/kappa opioid receptor (KOR) system on the nociceptive, emotional, cognitive, neurochemical and epigenetic manifestations of joint pain...
August 24, 2016: Neuropharmacology
Haiqing Liu, Yanjun Tian, Bingyun Ji, Hai Lu, Qing Xin, Yunlu Jiang, Liangcai Ding, Jingmei Zhang, Jing Chen, Bo Bai
Together with its endogenous ligands (dynorphin), the kappa opioid receptor (KOR) plays an important role in modulating various physiological and pharmacological responses, with a classical G protein-coupled pathway mediating analgesia and non-G protein-dependent pathway, especially the β-arrestin-dependent pathway, eliciting side effects of dysphoria, aversion, drug-seeking in addicts, or even relapse to addiction. Although mounting evidence has verified a functional overlap between dynorphin/KOR and neurotensin/neurotensin receptor 1 (NTSR1) systems, little is known about direct interaction between the two receptors...
August 12, 2016: Biochimica et Biophysica Acta
Eva Tudurí, Daniel Beiroa, Johannes Stegbauer, Johan Fernø, Miguel López, Carlos Diéguez, Rubén Nogueiras
Pancreatic insulin-secreting β-cells express opioid receptors, whose activation by opioid peptides modulates hormone secretion. Opioid receptors are also expressed in multiple brain regions including the hypothalamus, where they play a role in feeding behavior and energy homeostasis, but their potential role in central regulation of glucose metabolism is unknown. Here, we investigate whether central opioid receptors participate in the regulation of insulin secretion and glucose homeostasis in vivo. C57BL/6J mice were acutely treated by intracerebroventricular (i...
November 2016: Neuropharmacology
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