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Root-Bernstein R. Biased, Bitopic, Opioid–Adrenergic Tethered Compounds May Improve Specificity, Lower Dosage and Enhance Agonist or Antagonist Function with Reduced Risk of Tolerance and Addiction. Pharmaceuticals (Basel) 2022; 15:ph15020214. [PMID: 35215326 PMCID: PMC8876737 DOI: 10.3390/ph15020214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/02/2022] [Accepted: 02/07/2022] [Indexed: 01/03/2023] Open
Abstract
This paper proposes the design of combination opioid–adrenergic tethered compounds to enhance efficacy and specificity, lower dosage, increase duration of activity, decrease side effects, and reduce risk of developing tolerance and/or addiction. Combinations of adrenergic and opioid drugs are sometimes used to improve analgesia, decrease opioid doses required to achieve analgesia, and to prolong the duration of analgesia. Recent mechanistic research suggests that these enhanced functions result from an allosteric adrenergic binding site on opioid receptors and, conversely, an allosteric opioid binding site on adrenergic receptors. Dual occupancy of the receptors maintains the receptors in their high affinity, most active states; drops the concentration of ligand required for full activity; and prevents downregulation and internalization of the receptors, thus inhibiting tolerance to the drugs. Activation of both opioid and adrenergic receptors also enhances heterodimerization of the receptors, additionally improving each drug’s efficacy. Tethering adrenergic drugs to opioids could produce new drug candidates with highly desirable features. Constraints—such as the locations of the opioid binding sites on adrenergic receptors and adrenergic binding sites on opioid receptors, length of tethers that must govern the design of such novel compounds, and types of tethers—are described and examples of possible structures provided.
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Ghasemi M, Claunch J, Niu K. Pathologic role of nitrergic neurotransmission in mood disorders. Prog Neurobiol 2018; 173:54-87. [PMID: 29890213 DOI: 10.1016/j.pneurobio.2018.06.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/30/2018] [Accepted: 06/05/2018] [Indexed: 02/08/2023]
Abstract
Mood disorders are chronic, recurrent mental diseases that affect millions of individuals worldwide. Although over the past 40 years the biogenic amine models have provided meaningful links with the clinical phenomena of, and the pharmacological treatments currently employed in, mood disorders, there is still a need to examine the contribution of other systems to the neurobiology and treatment of mood disorders. This article reviews the current literature describing the potential role of nitric oxide (NO) signaling in the pathophysiology and thereby the treatment of mood disorders. The hypothesis has arisen from several observations including (i) altered NO levels in patients with mood disorders; (ii) antidepressant effects of NO signaling blockers in both clinical and pre-clinical studies; (iii) interaction between conventional antidepressants/mood stabilizers and NO signaling modulators in several biochemical and behavioral studies; (iv) biochemical and physiological evidence of interaction between monoaminergic (serotonin, noradrenaline, and dopamine) system and NO signaling; (v) interaction between neurotrophic factors and NO signaling in mood regulation and neuroprotection; and finally (vi) a crucial role for NO signaling in the inflammatory processes involved in pathophysiology of mood disorders. These accumulating lines of evidence have provided a new insight into novel approaches for the treatment of mood disorders.
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Affiliation(s)
- Mehdi Ghasemi
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01655, USA.
| | - Joshua Claunch
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01655, USA
| | - Kathy Niu
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01655, USA
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Whittington RA, Virág L, Gratuze M, Petry FR, Noël A, Poitras I, Truchetti G, Marcouiller F, Papon MA, El Khoury N, Wong K, Bretteville A, Morin F, Planel E. Dexmedetomidine increases tau phosphorylation under normothermic conditions in vivo and in vitro. Neurobiol Aging 2015; 36:2414-28. [PMID: 26058840 DOI: 10.1016/j.neurobiolaging.2015.05.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Revised: 04/19/2015] [Accepted: 05/05/2015] [Indexed: 10/23/2022]
Abstract
There is developing interest in the potential association between anesthesia and the onset and progression of Alzheimer's disease. Several anesthetics have, thus, been demonstrated to induce tau hyperphosphorylation, an effect mostly mediated by anesthesia-induced hypothermia. Here, we tested the hypothesis that acute normothermic administration of dexmedetomidine (Dex), an intravenous sedative used in intensive care units, would result in tau hyperphosphorylation in vivo and in vitro. When administered to nontransgenic mice, Dex-induced tau hyperphosphorylation persisting up to 6 hours in the hippocampus for the AT8 epitope. Pretreatment with atipamezole, a highly specific α2-adrenergic receptor antagonist, blocked Dex-induced tau hyperphosphorylation. Furthermore, Dex dose-dependently increased tau phosphorylation at AT8 in SH-SY5Y cells, impaired mice spatial memory in the Barnes maze and promoted tau hyperphosphorylation and aggregation in transgenic hTau mice. These findings suggest that Dex: (1) increases tau phosphorylation, in vivo and in vitro, in the absence of anesthetic-induced hypothermia and through α2-adrenergic receptor activation, (2) promotes tau aggregation in a mouse model of tauopathy, and (3) impacts spatial reference memory.
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Affiliation(s)
- Robert A Whittington
- Department of Anesthesiology, Columbia University, College of Physicians and Surgeons, New York, NY, USA.
| | - László Virág
- Department of Anesthesiology, Columbia University, College of Physicians and Surgeons, New York, NY, USA
| | - Maud Gratuze
- Département de Psychiatrie et Neurosciences, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Franck R Petry
- Département de Psychiatrie et Neurosciences, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Anastasia Noël
- Département de Psychiatrie et Neurosciences, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Isabelle Poitras
- Département de Psychiatrie et Neurosciences, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Geoffrey Truchetti
- Département de Psychiatrie et Neurosciences, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - François Marcouiller
- Département de Psychiatrie et Neurosciences, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Marie-Amélie Papon
- Département de Psychiatrie et Neurosciences, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Noura El Khoury
- Département de Psychiatrie et Neurosciences, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Kevin Wong
- Department of Anesthesiology, Columbia University, College of Physicians and Surgeons, New York, NY, USA
| | - Alexis Bretteville
- Département de Psychiatrie et Neurosciences, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | | | - Emmanuel Planel
- Département de Psychiatrie et Neurosciences, Faculté de Médecine, Université Laval, Québec, Québec, Canada; Neurosciences, CHUL, CRCHU, Québec, Québec, Canada
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Hellyer PW, Bai L, Supon J, Quail C, Wagner AE, Mama KR, Magnusson KR. Comparison of opioid and alpha–2 adrenergic receptor binding in horse and dog brain using radioligand autoradiography. Vet Anaesth Analg 2003; 30:172-82. [PMID: 14498849 DOI: 10.1046/j.1467-2995.2003.00143.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To test the hypothesis that the distribution, density, and subtype of opioid and alpha (alpha)-2 adrenergic receptors within the central nervous system (CNS) are significantly different between horse and dog. STUDY DESIGN Prospective experimental study. ANIMALS Three dogs (3 years of age) and three horses (2-5 years of age). Animals were opioid- and alpha-2 agonist-free at the time of euthanasia. METHODS Brain tissue was obtained at 126 days post-surgery from dogs and 72 days post-surgery from horses. The brains were removed, sectioned coronally into 1-cm slabs, frozen in methylbutane, which was cooled by liquid nitrogen, and stored at -70 degrees C. Receptor autoradiography was performed using established techniques. [3H]DAMGO, [3H]U-69593, and [3H]RX821002 were used for mu ( micro )-opioid, kappa (kappa)-opioid, and alpha-2 adrenergic-binding assays, respectively. Species differences were analyzed separately for each major brain region by repeated measures anova for subregions followed by Fisher's protected Latin square design (LSD). p < 0.05 was considered significant. RESULTS There was higher binding of micro -opioid receptors in the frontal cortex, left somatosensory cortex, colliculus (mid-brain), and granule cell layer of the cerebellum of horses than that of dogs. There was higher binding to kappa-opioid receptors in the frontal cortex of dogs compared to horses, whereas binding to kappa-opioid receptors in the cerebellum was higher in horses. Binding to alpha-2 adrenergic receptors in the mid-brain was significantly higher in dogs than in horses. There was higher binding of alpha-2 adrenergic receptors in the dorsomedial and dorsolateral periaqueductal grey of dogs as compared to that of horses. CONCLUSION The results of this study show that the distribution of these receptors is different between horses and dogs. Further work is needed to understand the relevance of these differences to clinical responses to opioids and alpha-2 adrenergic agonists in these species.
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Affiliation(s)
- Peter W Hellyer
- Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
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Abstract
Pain management has become an increasingly well researched area in medicine over recent years, and there have been advances in a number of areas. While opioids remain an integral part of pain-management strategies, there is now an emphasis on the use of adjuvant drugs, such as paracetamol and anti-inflammatory agents, which through physiological or pharmacological synergism, both enhance pain control and reduce opioid use. The management of neuropathic pain continues to be a challenge. Anti-epileptics and antidepressants, together with clonidine and ketamine, provide the foundations for treatment. Another area of interest has been the widespread use of patient-controlled analgesia and the administration of some drugs, especially opioids, by means other than traditional oral and parenteral routes. The number of new drugs that have reached the stage of clinical trials has been small, yet they offer exciting possibilities. The epibatidine analogue ABT-594 and zinconitide both offer novel approaches to the management of neuropathic pain states, while selective cyclo-oxygenase-2 inhibitors and nitroaspirins may see advances in the management of nociceptive pain states.
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Affiliation(s)
- R D MacPherson
- Department of Anaesthesia and Pain Management, Royal North Shore Hospital, St. Leonards, NSW 2065, Australia.
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