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Kor Antagonist

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
Miriam Aceves, Eric Bancroft, Alejandro R Aceves, Michelle Hook
Opioids are frequently used for the treatment of pain following spinal cord injury (SCI). Unfortunately, we have shown that morphine administered in the acute phase of SCI results in significant, adverse secondary consequences including compromised locomotor and sensory recovery. Similarly, we showed that selective activation of the κ-opioid receptor (KOR), even at a dose 32-fold lower than morphine, is sufficient to attenuate recovery of locomotor function. In the current study, we tested whether activation of the KOR is necessary to produce morphine's adverse effects using nor-Binaltorphimine (norBNI), a selective KOR antagonist...
October 13, 2016: Journal of Neurotrauma
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
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
Simone Ronsisvalle, Giuseppina Aricò, Federica Panarello, Angelo Spadaro, Lorella Pasquinucci, Maria S Pappalardo, Carmela Parenti, Nicole Ronsisvalle
The hypothesis that central analgesia with reduced side effects is obtainable by occupying an 'allosteric' site in the MOR ligand binding domain requires the development of new ligands with peculiar pharmacological profile to be used as tools. New benzomorphan derivatives, analogues of LP1, a multitarget MOR agonist/DOR antagonist, were designed to examine in depth MOR ligand binding domain. Compound 5, bearing a diphenylic N-substituent on the benzomorphan nucleus, showed an affinity (Ki(μ)=0.5±0.2nM) comparable to that of LP1 and a better selectivity versus DOR and KOR...
November 1, 2016: Bioorganic & Medicinal Chemistry
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
Katsuya Ohbuchi, Chika Miyagi, Yasuyuki Suzuki, Yasuharu Mizuhara, Keita Mizuno, Yuji Omiya, Masahiro Yamamoto, Eiji Warabi, Yuka Sudo, Akinobu Yokoyama, Kanako Miyano, Takatsugu Hirokawa, Yasuhito Uezono
Processed Aconiti tuber (PAT) is used to treat pain associated with various disorders. Although it has been demonstrated that the κ opioid receptor (KOR) signaling pathway is a mediator of the analgesic effect of PAT, active components affecting opioid signaling have not yet been identified. In this study, we explored candidate components of PAT by pharmacokinetic analysis and identified ignavine, which is a different structure from aconitine alkaloids. A receptor binding assay of opioid receptors showed that ignavine specifically binds the μ opioid receptor (MOR), not the KOR...
2016: Scientific Reports
Feng Mei, Sonia R Mayoral, Hiroko Nobuta, Fei Wang, Caroline Desponts, Daniel S Lorrain, Lan Xiao, Ari J Green, David Rowitch, Jennifer Whistler, Jonah R Chan
UNLABELLED: Remyelinating therapies seek to promote restoration of function and normal cellular architecture following demyelination in diseases, such as multiple sclerosis (MS). Functional screening for small molecules or novel targets for remyelination is a major hurdle to the identification and development of rational therapeutics for MS. Recent findings and technical advances provide us with a unique opportunity to provide insight into the cell autonomous mechanisms for remyelination and address this unmet need...
July 27, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Sun Wook Moon, Eui Ho Park, Hye Rim Suh, Duk Hwan Ko, Yang In Kim, Hee Chul Han
The systemic administration of opioids can be used for their strong analgesic effect. However, extensive activation of opioid receptors (ORs) beyond the targeted tissue can cause dysphoria, pruritus, and constipation. Therefore, selective activation of peripheral ORs present in the afferent fibers of the targeted tissue can be considered a superior strategy in opioid analgesia to avoid potential adverse effects. The purpose of this study was to clarify the role of peripheral kappa opioid receptors (kORs) in arthritic pain for the possible use of peripheral ORs as a target in anti-nociceptive therapy...
October 1, 2016: Brain Research
Chad M Kormos, Moses G Gichinga, Scott P Runyon, James B Thomas, S Wayne Mascarella, Ann M Decker, Hernán A Navarro, F Ivy Carroll
The potent and selective KOR antagonist JDTic was derived from the N-substituted trans-3,4-dimethyl-4-(3-hydroxyphenyl)piperidine class of pure opioid antagonists. In previous studies we reported that compounds that did not have a hydroxyl on the 3-hydroxyphenyl group and did not have methyl groups at the 3- and 4-position of the piperidine ring were still potent and selective KOR antagonists. In this study we report JDTic analogs 2, 3a-b, 4a-b, and 5, where the 3-hydroxyphenyl ring has been replaced by a 2-, 3-, or 4-pyridyl or 3-thienyl group and do not have the 3-methyl or 3,4-dimethyl groups, remain potent and selective KOR antagonists...
August 15, 2016: Bioorganic & Medicinal Chemistry
Tanvir Khaliq, Todd D Williams, Sanjeewa N Senadheera, Jane V Aldrich
Selective kappa opioid receptor (KOR) antagonists may have therapeutic potential as treatments for substance abuse and mood disorders. Since [D-Trp]CJ-15,208 (cyclo[Phe-d-Pro-Phe-d-Trp]) is a novel potent KOR antagonist in vivo, it is imperative to evaluate its pharmacokinetic properties to assist the development of analogs as potential therapeutic agents, necessitating the development and validation of a quantitative method for determining its plasma levels. A method for quantifying [D-Trp]CJ-15,208 was developed employing high performance liquid chromatography-tandem mass spectrometry in mouse plasma...
August 15, 2016: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Dwight A Williams, Yi Zheng, Bethany G David, Yunyun Yuan, Saheem A Zaidi, David L Stevens, Krista L Scoggins, Dana E Selley, William L Dewey, Hamid I Akbarali, Yan Zhang
The 6β-N-heterocyclic naltrexamine derivative, NAP, has been demonstrated to be a peripherally selective mu opioid receptor modulator. To further improve peripheral selectivity of this highly potent ligand, its pyridal ring was quaterinized with benzyl bromide to produce BNAP. In radioligand binding assay, the Ki of BNAP for MOR was 0.76 ± 0.09 nM and was >900-fold more selective for MOR than DOR. The Ki for KOR was 3.46 ± 0.05 nM. In [(35)S]GTPγS ligand stimulated assay, BNAP showed low agonist efficacy with 14...
August 17, 2016: ACS Chemical Neuroscience
Adam L Halberstadt, James Hyun, Michael A Ruderman, Susan B Powell
N-allylnormetazocine (NANM; SKF 10,047) is a benzomorphan opioid that produces psychotomimetic effects. (+)-NANM is the prototypical agonist for the sigma-1 (σ1) receptor, and there is a widespread belief that the hallucinogenic effects of NANM and other benzomorphan derivatives are mediated by interactions with σ1 sites. However, NANM is also an agonist at the κ opioid receptor (KOR) and binds to the PCP site located within the channel pore of the NMDA receptor, interactions that could potentially contribute to the effects of NANM...
September 2016: Pharmacology, Biochemistry, and Behavior
Lorella Pasquinucci, Rita Turnaturi, Giuseppina Aricò, Carmela Parenti, Paschalina Pallaki, Zafiroula Georgoussi, Simone Ronsisvalle
The benzomorphan scaffold has great potential as lead structure and the nature of the N-substituent is able to influence affinity, potency, and efficacy at all three opioid receptors. Building upon these considerations, we synthesized a new series of LP1 analogues by introducing naphthyl or heteroaromatic rings in propanamide side chain of its N-substituent (9-15). In vitro competition-binding assays in HEK293 cells stably expressing MOR, DOR or KOR showed that in compound 9 the 1-naphthyl ring led to the retention of MOR affinity (Ki(MOR)=38±4nM) displaying good selectivity versus DOR and KOR...
June 15, 2016: Bioorganic & Medicinal Chemistry
Steven G Grinnell, Michael Ansonoff, Gina F Marrone, Zhigang Lu, Ankita Narayan, Jin Xu, Grace Rossi, Susruta Majumdar, Ying-Xian Pan, Daniel L Bassoni, John Pintar, Gavril W Pasternak
Buprenorphine has long been classified as a mu analgesic, although its high affinity for other opioid receptor classes and the orphanin FQ/nociceptin ORL1 receptor may contribute to its other actions. The current studies confirmed a mu mechanism for buprenorphine analgesia, implicating several subsets of mu receptor splice variants. Buprenorphine analgesia depended on the expression of both exon 1-associated traditional full length 7 transmembrane (7TM) and exon 11-associated truncated 6 transmembrane (6TM) MOR-1 variants...
October 2016: Synapse
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