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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
Anna E Mechling, Tanzil Arefin, Hsu-Lei Lee, Thomas Bienert, Marco Reisert, Sami Ben Hamida, Emmanuel Darcq, Aliza Ehrlich, Claire Gaveriaux-Ruff, Maxime J Parent, Pedro Rosa-Neto, Jürgen Hennig, Dominik von Elverfeldt, Brigitte Lina Kieffer, Laura-Adela Harsan
Connectome genetics seeks to uncover how genetic factors shape brain functional connectivity; however, the causal impact of a single gene's activity on whole-brain networks remains unknown. We tested whether the sole targeted deletion of the mu opioid receptor gene (Oprm1) alters the brain connectome in living mice. Hypothesis-free analysis of combined resting-state fMRI diffusion tractography showed pronounced modifications of functional connectivity with only minor changes in structural pathways. Fine-grained resting-state fMRI mapping, graph theory, and intergroup comparison revealed Oprm1-specific hubs and captured a unique Oprm1 gene-to-network signature...
October 11, 2016: Proceedings of the National Academy of Sciences of the United States of America
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
Hooman Djaladat, Siamak Daneshmand
Gastrointestinal (GI) complications are among the most common complications following radical cystectomy and urinary diversion. The most common is postoperative ileus, although its precise pathophysiology is not completely understood. Enhanced recovery after surgery (ERAS) protocols include evidence-based steps to optimize postoperative recovery and shorten hospital stay, mainly through expedited GI function recovery. They include avoiding bowel preparation and postoperative nasogastric tube, early feeding, non-narcotic pain management, and the use of cholinergic and mu-receptor opioid antagonists...
July 2016: Current Urology Reports
David W Fabi
Hip fracture is one of the most common injuries among the elderly and, because the population is aging, it is expected to remain a major clinical challenge and public health problem for the foreseeable future. The clinical importance of early mobilization and prompt participation in physical therapy after hip fracture surgery is now widely recognized. Because postoperative pain can impair mobility and delay physical therapy, much attention is now being paid to finding more effective ways of controlling pain after hip fracture...
May 2016: Journal of Orthopaedic Trauma
Justyna Piekielna, Rossella De Marco, Luca Gentilucci, Maria Camilla Cerlesi, Girolamo Calo', Csaba Tömböly, Roberto Artali, Anna Janecka
The study reports the synthesis and biological evaluation of two opioid analogs, a monomer and a dimer, obtained as products of the solid-phase, side-chain to side-chain cyclization of the pentapeptide Tyr-d-Lys-Phe-Phe-AspNH2 . The binding affinities to the mu, delta, and kappa opioid receptors, as well as results obtained in a calcium mobilization functional assay are reported. Tyr-[d-Lys-Phe-Phe-Asp]2 -NH2 1 was a potent and selective full agonist of mu with sub-nanomolar affinity, while the dimer (Tyr-[d-Lys-Phe-Phe-Asp]2 -NH2 )2 2 showed a significant mixed mu/kappa affinity, acting as an agonist at the mu...
May 2016: Biopolymers
Hongsheng Wang, John E Coligan, Herbert C Morse
Most natural IgM antibodies are encoded by germline Ig sequences and are produced in large quantities by both mice and humans in the absence of intentional immunization. Natural IgM are reactive with many conserved epitopes, including those shared by microorganisms and autoantigens. As a result, these antibodies play important roles in clearing intruding pathogens, as well as apoptotic/necrotic cells and otherwise damaged tissues. While natural IgM binds to target structures with low affinity due to a lack of significant selection by somatic hypermutation, its pentameric structure with 10 antigen-binding sites enables these antibodies to bind multivalent target antigens with high avidity...
2016: Frontiers in Immunology
Gina F Marrone, Steven G Grinnell, Zhigang Lu, Grace C Rossi, Valerie Le Rouzic, Jin Xu, Susruta Majumdar, Ying-Xian Pan, Gavril W Pasternak
The clinical management of severe pain depends heavily on opioids acting through mu opioid receptors encoded by the Oprm1 gene, which undergoes extensive alternative splicing. In addition to generating a series of prototypic seven transmembrane domain (7TM) G protein-coupled receptors (GPCRs), Oprm1 also produces a set of truncated splice variants containing only six transmembrane domains (6TM) through which selected opioids such as IBNtxA (3'-iodobenzoyl-6β-naltrexamide) mediate a potent analgesia without many undesirable effects...
March 29, 2016: Proceedings of the National Academy of Sciences of the United States of America
Lawrence Toll, Michael R Bruchas, Girolamo Calo', Brian M Cox, Nurulain T Zaveri
The NOP receptor (nociceptin/orphanin FQ opioid peptide receptor) is the most recently discovered member of the opioid receptor family and, together with its endogenous ligand, N/OFQ, make up the fourth members of the opioid receptor and opioid peptide family. Because of its more recent discovery, an understanding of the cellular and behavioral actions induced by NOP receptor activation are less well developed than for the other members of the opioid receptor family. All of these factors are important because NOP receptor activation has a clear modulatory role on mu opioid receptor-mediated actions and thereby affects opioid analgesia, tolerance development, and reward...
April 2016: Pharmacological Reviews
G Bot, L A Chahl
Opioid drugs such as morphine have powerful reinforcing effects which lead to drug-seeking behaviour. Both dopamine- and substance P-containing neurones have been implicated in reward. In the present study twocolour immunohistochemistry was used to investigate whether Fos protein was induced in dopaminergic (tyrosine hydroxylase) and substance P-containing neurones of guinea-pig brain following intracerebroventricular administration of the predominantly mu-receptor agonist, morphine, and the kappa-receptor agonist, U50,488H, which have been reported to produce rewarding and aversive effects, respectively...
October 1998: Addiction Biology
Maria J Simon, A Higuera-Matas, D Roura-Martinez, M Ucha, R Santos-Toscano, C Garcia-Lecumberri, E Ambrosio, A Puerto
Intracranial self-stimulation (ICSS) of the lateral hypothalamus (LH) is involved in the activation of neuroanatomical systems that are also associated with the processing of natural and other artificial rewarding stimuli. Specific components of this behavior (hedonic impact, learning, and motor behavior) may involve changes in different neurotransmitters, such as dopamine and opioids. In this study, quantitative autoradiography was used to examine changes in mu-opioid and D1/D2-dopamine receptor expression in various anatomical regions related to the motor and mesolimbic reward systems after intracranial self-stimulation of the LH...
January 2016: Neurobiology of Learning and Memory
A V Solin, Yu D Lyashev
It was established in experiments on rats, that injection of opioid peptides DAGO (a selective igonist of opioid mu-receptors), DSLET (a selective agonist of opioid delta-receptors) or dynorpiin A (1-13) (a selective agonist of opioid kappa-receptors) decreased the stress-induced activatin of lipid peroxidation in liver tissue and plasma. A selective agonist of opioid mu-receptors) AGO manifested the most expressed activity. The using of investigating peptides caused the increase of superoxiddismutase activity in liver tissue...
August 2015: Rossiĭskii Fiziologicheskiĭ Zhurnal Imeni I.M. Sechenova
Timothy J Wiegand
Buprenorphine represents a safe and effective therapy for treating opioid dependence, alleviating craving and withdrawal symptoms in opioid-dependent patients. Buprenorphine has a "blocking" effect against the action of other opioids at the mu-receptor, preventing not only opioid-induced euphoria, but CNS and respiratory depressant effects as well. Buprenorphine was approved for the treatment of opioid dependence in 2002 after the passage of Drug Abuse Treatment Act 2000 (DATA 2000) which allowed clinicians to treat opioid-dependent patients with specifically named opioid agonist therapies in an office setting...
March 2016: Journal of Medical Toxicology: Official Journal of the American College of Medical Toxicology
Donatella Marazziti, Silvio Presta, Stefano Baroni, Francesco Mungai, Armando Piccinni, Federico Mucci, Liliana Dell'Osso
Alcoholism is an increasing problem all over the world, and nowadays especially amongst teenagers. Although several drug treatments have been proposed for this condition, only a few have demonstrated a significant efficacy. Nalmefene, a novel compound that combines opioids mu-receptors antagonism and kappa-receptors partial agonism, was recently approved by the European Medicine Agency for the treatment of alcoholism. This drug can be very helpful in reducing the alcohol intake, and, as such, it can be considered one of the first and fundamental steps towards alcohol abstinence...
2015: Current Medicinal Chemistry
Gina F Marrone, Susruta Majumdar, Gavril W Pasternak
Receptor binding provides a valuable approach for characterization of drugs and their receptors. There are three major families of opioid receptors: mu, delta, and kappa. Highly selective radioligands are available for all three classes of traditional receptors. Of the three, the mu receptor undergoes extensive alternative splicing, generating a number of traditional mu receptor subtypes as well as a nontraditional, truncated set of variants associated with exon 11. These exon 11-associated truncated variants are not readily labeled with current radioligands...
2015: Methods in Molecular Biology
H N David, M Dhilly, M Degoulet, G Poisnel, C Meckler, N Vallée, J-É Blatteau, J-J Risso, M Lemaire, D Debruyne, J H Abraini
We investigated the effects of the noble gas argon on the expression of locomotor sensitization to amphetamine and amphetamine-induced changes in dopamine release and mu-opioid neurotransmission in the nucleus accumbens. We found (1) argon blocked the increase in carrier-mediated dopamine release induced by amphetamine in brain slices, but, in contrast, potentiated the decrease in KCl-evoked dopamine release induced by amphetamine, thereby suggesting that argon inhibited the vesicular monoamine transporter-2; (2) argon blocked the expression of locomotor and mu-opioid neurotransmission sensitization induced by repeated amphetamine administration in a short-term model of sensitization in rats; (3) argon decreased the maximal number of binding sites and increased the dissociation constant of mu-receptors in membrane preparations, thereby indicating that argon is a mu-receptor antagonist; (4) argon blocked the expression of locomotor sensitization and context-dependent locomotor activity induced by repeated administration of amphetamine in a long-term model of sensitization...
2015: Translational Psychiatry
Bishal Gyawali, Naomi Hayashi, Hiroaki Tsukuura, Kazunori Honda, Tomoya Shimokata, Yuichi Ando
Opioid-induced constipation (OIC) is a very troublesome, difficult to manage and a nearly universal complication of chronic opioid use to control pain associated with advanced illness. Some studies have reported that OIC is so intolerable in some patients that they skip their opioid medications and bear pain instead of OIC. Laxatives have commonly been used as a prophylaxis and treatment of OIC but they are frequently ineffective because the commonly available laxatives do not target the underlying mechanism of OIC, which is the blockade of peripheral mu-receptors...
2015: Scandinavian Journal of Gastroenterology
Zhiheng Chen, Yamei Tang, Huai Tao, Cunyan Li, Xianghui Zhang, Yong Liu
It has been reported that kappa opioid receptor (KOR) is expressed in the paraventricular nucleus of thalamus (PVT), a brain region associated with arousal, drug reward and stress. Although intra-PVT infusion of KOR agonist was found to inhibit drug-seeking behavior, it is still unclear whether endogenous KOR agonists directly regulate PVT neuron activity. Here, we investigated the effect of the endogenous KOR agonist dynorphin-A (Dyn-A) on the excitability of mouse PVT neurons at different developmental ages...
October 2015: Neuropharmacology
Houssam G Kotrach, Jean Bourbeau, Dennis Jensen
Few therapies exist for the relief of dyspnea in restrictive lung disorders. Accumulating evidence suggests that nebulized opioids selective for the mu-receptor subtype may relieve dyspnea by modulating intrapulmonary opioid receptor activity. Our respective primary and secondary objectives were to test the hypothesis that nebulized fentanyl (a mu-opioid receptor agonist) relieves dyspnea during exercise in the presence of abnormal restrictive ventilatory constraints and to identify the physiological mechanisms of this improvement...
June 1, 2015: Journal of Applied Physiology
Felicity C Veal, Gregory M Peterson
Persistent pain affects the elderly disproportionally, occurring in 50% of elderly community-dwelling patients and 80% of aged care residents. The management of pain in the elderly and frail patient is complicated because of the risks posed by changes in pharmacokinetics and pharmacodynamics, polypharmacy, and drug-disease interactions. Trials evaluating the efficacy of analgesics have often excluded elderly patients and universally excluded frail patients; therefore, the true efficacy and side-effect profiles in these population groups are largely unknown, especially for long-term use...
June 2015: Drugs & Aging
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