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Galambos AR, Papp ZT, Boldizsár I, Zádor F, Köles L, Harsing LG, Al-Khrasani M. Glycine Transporter 1 Inhibitors: Predictions on Their Possible Mechanisms in the Development of Opioid Analgesic Tolerance. Biomedicines 2024; 12:421. [PMID: 38398023 PMCID: PMC10886540 DOI: 10.3390/biomedicines12020421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 02/06/2024] [Accepted: 02/07/2024] [Indexed: 02/25/2024] Open
Abstract
The development of opioid tolerance in patients on long-term opioid analgesic treatment is an unsolved matter in clinical practice thus far. Dose escalation is required to restore analgesic efficacy, but at the price of side effects. Intensive research is ongoing to elucidate the underlying mechanisms of opioid analgesic tolerance in the hope of maintaining opioid analgesic efficacy. N-Methyl-D-aspartate receptor (NMDAR) antagonists have shown promising effects regarding opioid analgesic tolerance; however, their use is limited by side effects (memory dysfunction). Nevertheless, the GluN2B receptor remains a future target for the discovery of drugs to restore opioid efficacy. Mechanistically, the long-term activation of µ-opioid receptors (MORs) initiates receptor phosphorylation, which triggers β-arrestin-MAPKs and NOS-GC-PKG pathway activation, which ultimately ends with GluN2B receptor overactivation and glutamate release. The presence of glutamate and glycine as co-agonists is a prerequisite for GluN2B receptor activation. The extrasynaptic localization of the GluN2B receptor means it is influenced by the glycine level, which is regulated by astrocytic glycine transporter 1 (GlyT1). Enhanced astrocytic glycine release by reverse transporter mechanisms as a consequence of high glutamate levels or unconventional MOR activation on astrocytes could further activate the GluN2B receptor. GlyT1 inhibitors might inhibit this condition, thereby reducing opioid tolerance.
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Affiliation(s)
- Anna Rita Galambos
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvá-rad tér 4, H-1445 Budapest, Hungary; (A.R.G.); (Z.T.P.); (I.B.); (F.Z.)
| | - Zsolt Tamás Papp
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvá-rad tér 4, H-1445 Budapest, Hungary; (A.R.G.); (Z.T.P.); (I.B.); (F.Z.)
| | - Imre Boldizsár
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvá-rad tér 4, H-1445 Budapest, Hungary; (A.R.G.); (Z.T.P.); (I.B.); (F.Z.)
| | - Ferenc Zádor
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvá-rad tér 4, H-1445 Budapest, Hungary; (A.R.G.); (Z.T.P.); (I.B.); (F.Z.)
| | - László Köles
- Department of Oral Biology, Semmelweis University, H-1089 Budapest, Hungary;
| | - Laszlo G. Harsing
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvá-rad tér 4, H-1445 Budapest, Hungary; (A.R.G.); (Z.T.P.); (I.B.); (F.Z.)
| | - Mahmoud Al-Khrasani
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvá-rad tér 4, H-1445 Budapest, Hungary; (A.R.G.); (Z.T.P.); (I.B.); (F.Z.)
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Thakral M, Walker RL, Saunders K, Shortreed SM, Parchman M, Hansen RN, Ludman E, Sherman KJ, Dublin S, Von Korff M. Comparing Pain and Depressive Symptoms of Chronic Opioid Therapy Patients Receiving Dose Reduction and Risk Mitigation Initiatives With Usual Care. THE JOURNAL OF PAIN 2017; 19:111-120. [PMID: 29038060 DOI: 10.1016/j.jpain.2017.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/30/2017] [Accepted: 09/30/2017] [Indexed: 01/30/2023]
Abstract
Dose reduction and risk mitigation initiatives have been recommended to reduce opioid-related risks among patients receiving chronic opioid therapy (COT), but questions remain over whether these initiatives worsen pain control and quality of life. In 2014 to 2015, we interviewed 1,588 adult COT patients within a health care system in Washington State and compared those who received dose reduction and risk mitigation initiatives in primary care clinics (intervention) with patients in comparable health care settings without initiatives (control). The primary outcomes were pain assessed using the pain, enjoyment, and general activity (PEG) scale, a 3-item scale to assess global pain intensity and interference, with secondary measures including depression (Patient Health Questionnaire-8 scale). Generalized estimating equations for linear regression models were used to estimate differences in mean scores between intervention and control sites. Estimated differences, adjusted for patient characteristics and weighted for nonresponse, between patients at intervention and control clinics were not clinically significant for the PEG (-.03, 95% confidence interval = -.25 to .19) or Patient Health Questionnaire-8 (-.64, 95% confidence interval = -1.19 to -.08). We found no evidence that COT patients in clinics with dose reduction and risk mitigation initiatives had clinically meaningful differences in pain intensity, interference with activities and enjoyment of life, or depressive symptoms compared with control health care settings. PERSPECTIVE This article evaluates the effect of dose reduction and risk mitigation initiatives, such as those recently recommended by the Centers for Disease Control and Prevention, to reduce risks associated with COT on global pain and interference, depressive symptoms, and perceived pain relief and bothersomeness of side effects.
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Affiliation(s)
- Manu Thakral
- Kaiser Permanente Washington Health Research Institute, Seattle, Washington; Department of Psychosocial and Community Health, School of Nursing, University of Washington, Seattle, Washington.
| | - Rod L Walker
- Kaiser Permanente Washington Health Research Institute, Seattle, Washington
| | - Kathleen Saunders
- Kaiser Permanente Washington Health Research Institute, Seattle, Washington
| | - Susan M Shortreed
- Kaiser Permanente Washington Health Research Institute, Seattle, Washington; Department of Biostatistics, University of Washington, Seattle, Washington
| | - Michael Parchman
- Kaiser Permanente Washington Health Research Institute, Seattle, Washington
| | - Ryan N Hansen
- Kaiser Permanente Washington Health Research Institute, Seattle, Washington; Departments of Pharmacy and Health Services, University of Washington, Seattle, Washington
| | - Evette Ludman
- Kaiser Permanente Washington Health Research Institute, Seattle, Washington
| | - Karen J Sherman
- Kaiser Permanente Washington Health Research Institute, Seattle, Washington; Department of Epidemiology, University of Washington, Seattle, Washington
| | - Sascha Dublin
- Kaiser Permanente Washington Health Research Institute, Seattle, Washington; Department of Epidemiology, University of Washington, Seattle, Washington
| | - Michael Von Korff
- Kaiser Permanente Washington Health Research Institute, Seattle, Washington
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De Pinto M, Cahana A. Medical management of acute pain in patients with chronic pain. Expert Rev Neurother 2013; 12:1325-38. [PMID: 23234394 DOI: 10.1586/ern.12.123] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The number of patients with chronic pain has increased over the years, as well as the number of patients who manage chronic pain with opioids. As prescribed opioid use has increased, so has its abuse and misuse. It has also been estimated that the number of people using opioids illicitly has doubled worldwide over the last 20 years. Management of chronic pain with opioids is associated with pathophysiological phenomena such as tolerance, dependence and hyperalgesia. They can become a problem when chronic pain patients present for a surgical procedure. Furthermore, patients who are on opioids on a regular basis require higher amounts during the perioperative period. The perioperative management of the chronic pain patient is difficult and complex. Developing an appropriate plan that can fulfill patients' and surgical team's needs requires skills and experience. The aim of this review is to describe the options available for the optimal perioperative management of acute pain in patients with a history of chronic pain.
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Affiliation(s)
- Mario De Pinto
- Department of Anesthesiology and Pain Medicine, University of Washington, Pain Relief Service, Harborview Medical Center, 325 9th Avenue, Seattle, WA 98104, Box 359724, USA.
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Dunbar SA, Karamian I, Zhang J. Ketorolac prevents recurrent withdrawal induced hyperalgesia but does not inhibit tolerance to spinal morphine in the rat. Eur J Pain 2012; 11:1-6. [PMID: 16448827 DOI: 10.1016/j.ejpain.2005.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Revised: 11/29/2005] [Accepted: 12/13/2005] [Indexed: 10/25/2022]
Abstract
Chronic use of opioid is associated with pro-nociceptive phenomena such as hyperalgesia or tolerance. The interaction between opioid and non-steroidal anti-inflammatory drugs (NSAIDs) with respect to opioid-associated hyperalgesia and tolerance remains largely unknown. This study examines the effect of subcutaneous or intrathecal administration of ketorolac, an NSAID, on recurrent withdrawal induced hyperalgesia and tolerance to spinal morphine in rats. Animals were infused with morphine intrathecally, and daily subcutaneous naloxone was used for recurrent withdrawal purpose. We observed that escape latencies on hot box were decreased in animals subjected to withdrawal, and this decrease was reversed by subcutaneous ketorolac pretreatment. In addition, we observed that recurrent withdrawal did not significantly affect the magnitude of spinal morphine tolerance. Compared to controls, all morphine infused animals showed similar changes in their dose responses to spinal morphine, effective dose 50 values and tolerance ratios; and these changes were not affected by the ketorolac given subcutaneously. The effect of ketorolac on tolerance was further examined by directly delivering ketorolac to the spinal cord, and again we observed similar changes in the daily latency, percentage of area under the curve and percentage of maximal possible effects among groups infused with morphine, regardless of intrathecal ketorolac treatment. Together, our results demonstrate that recurrent withdrawal is associated with hyperalgesia but this has no effect on the tolerance development; ketorolac protects against recurrent withdrawal induced hyperalgesia without significantly altering spinal morphine tolerance.
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MESH Headings
- Analgesics, Opioid/adverse effects
- Animals
- Anti-Inflammatory Agents, Non-Steroidal/pharmacology
- Anti-Inflammatory Agents, Non-Steroidal/therapeutic use
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Drug Interactions/physiology
- Drug Tolerance/physiology
- Hyperalgesia/chemically induced
- Hyperalgesia/drug therapy
- Hyperalgesia/physiopathology
- Injections, Spinal
- Ketorolac/pharmacology
- Ketorolac/therapeutic use
- Male
- Morphine/adverse effects
- Morphine Dependence/metabolism
- Morphine Dependence/physiopathology
- Naloxone/adverse effects
- Narcotic Antagonists/adverse effects
- Pain Measurement/drug effects
- Pain, Intractable/chemically induced
- Pain, Intractable/drug therapy
- Pain, Intractable/physiopathology
- Rats
- Rats, Sprague-Dawley
- Spinal Cord/drug effects
- Spinal Cord/metabolism
- Spinal Cord/physiopathology
- Substance Withdrawal Syndrome/drug therapy
- Substance Withdrawal Syndrome/physiopathology
- Substance Withdrawal Syndrome/prevention & control
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Affiliation(s)
- Stuart A Dunbar
- Department of Anesthesiology, Pain Management Center, Baystate Medical Center, Tufts University, 3400 Main Street, Springfield, MA 01199, USA.
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Wilson NM, Jung H, Ripsch MS, Miller RJ, White FA. CXCR4 signaling mediates morphine-induced tactile hyperalgesia. Brain Behav Immun 2011; 25:565-73. [PMID: 21193025 PMCID: PMC3039030 DOI: 10.1016/j.bbi.2010.12.014] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 12/17/2010] [Accepted: 12/18/2010] [Indexed: 01/15/2023] Open
Abstract
Morphine and related compounds are the first line of therapy in the treatment of moderate to severe pain. Over time, individuals taking opioids can develop an increasing sensitivity to noxious stimuli, even evolving into a painful response to previously non-noxious stimuli (opioid-induced hyperalgesia; OIH). The mechanism underlying OIH is not well understood although complex intracellular neural mechanisms, including opioid receptor desensitization and down-regulation, are believed to be major mechanisms underlying OIH. However, OIH may also be associated with changes in gene expression. A growing body of evidence suggests that cellular exposure to mu agonists upregulate chemokines/receptors and recent work from our laboratory implicates chemokine upregulation in a variety of neuropathic pain behaviors. Here we characterized the degree to which chemokines/receptors signaling is increased in primary afferent neurons of the dorsal root ganglion (DRG) following chronic morphine sulfate treatment and correlated these changes with tactile hyperalgesic behavior in rodents. We demonstrate that mRNA expression of the chemokine, stromal-derived factor-1 (SDF1/CXCL12) is upregulated following morphine treatment in sensory neurons of the rat. The release of SDF1 was found to be constitutive when compared with the activity dependent release of the C-C chemokine, monocyte chemoattractant protein-1 (MCP1/CCL2) in a line of F11 neuroblastoma-sensory neuron hybrid cells. We further determined that there is pronounced CXCR4 expression in satellite glial cells and following morphine treatment, increased functional CXCR4 expression in sensory neurons of the DRG. Moreover, intraperitoneal administration of the specific CXCR4 antagonist, AMD3100, completely reversed OIH in the rat. Taken together; the data suggest that opioid-induced SDF1/CXCR4 signaling is central to the development of long lasting OIH and that receptor antagonists represent a promising novel approach to the management of the side effects associated with the use of opioids for chronic pain management.
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Affiliation(s)
- Natalie M. Wilson
- Department of Pharmacology, Loyola University, Chicago, Maywood, Illinois 60153
| | - Hosung Jung
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University, Chicago, IL 60611
| | - Matthew S. Ripsch
- Department of Anesthesia, Indiana University, Indianapolis, IN 46208
| | - Richard J. Miller
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University, Chicago, IL 60611
| | - Fletcher A. White
- Department of Anesthesia, Program in Medical Neurosciences, Stark Neurosciences Research Institute, Indiana University, Indianapolis, IN 46208
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Abstract
Although methadone is not a new medication, its use in pain management has increased rapidly over the past decade. This article reviews the unique pharmacologic properties of methadone, including its long-acting nature, highly variable clearance rate, and its antagonism of the N-methyl-D-aspartate receptor. We discuss potential benefits and risks of methadone over other opioid medications. Preclinical studies suggest methadone may reduce abuse potential, tolerance development, and sensitization of nociceptive pathways. Pharmacologic properties of methadone suggest potential greater risk of dangerous or fatal side effects from overdose, QT interval prolongation, and drug interactions. However, clinical studies have yet to confirm that methadone produces either better clinical outcomes or higher rates of adverse events than other opioid analgesics. Clinicians who understand the special properties of methadone and follow recommended precautionary prescribing and monitoring practices can safely and effectively use methadone for pain treatment.
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Affiliation(s)
- Jodie A Trafton
- Center for Health Care Evaluation, VA Palo Alto and Stanford University School of Medicine, 795 Willow Road (152-MPD), Menlo Park, CA 94025, USA.
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Liang D, Shi X, Qiao Y, Angst MS, Yeomans DC, Clark JD. Chronic morphine administration enhances nociceptive sensitivity and local cytokine production after incision. Mol Pain 2008; 4:7. [PMID: 18294378 PMCID: PMC2279109 DOI: 10.1186/1744-8069-4-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Accepted: 02/22/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The chronic use of opioids prior to surgery leads to lowered pain thresholds and exaggerated pain levels after these procedures. Several mechanisms have been proposed to explain this heightened sensitivity commonly termed opioid-induced hyperalgesia (OIH). Most of these proposed mechanisms involve plastic events in the central or peripheral nervous systems. Alterations in the abundance of peripheral mediators of nociception have not previously been explored. RESULTS In these experiments mice were treated with saline (control) or ascending daily doses of morphine to generate a state of OIH followed by hind paw incision. In other experiments morphine treatment was initiated at the time of incision. Both mechanical allodynia and peri-incisional skin cytokine levels were measured. Myeloperoxidase (MPO) assays were used to determine neutrophil activity near the wounds. The cytokine production inhibitor pentoxifylline was used to determine the functional significance of the excess cytokines in previously morphine treated animals. Mice treated chronically treated with morphine prior to incision were found to have enhanced skin levels of IL-1beta, IL-6, G-CSF, KC and TNFalpha after incision at one or more time points compared to saline pretreated controls. The time courses of individual cytokines followed different patterns. There was no discernable effect of chronic morphine treatment on wound area neutrophil infiltration. Pentoxifylline reduced cytokine levels and reversed the excess mechanical sensitization caused by chronic morphine administration prior to incision. Morphine treatment initiated at the time of incision did not lead to a generalized enhancement of cytokine production or nociceptive sensitization in excess of the levels observed after incision alone. CONCLUSION The enhanced level of nociceptive sensitization seen after incision in animals chronically exposed to morphine is associated with elevated levels of several cytokines previously reported to be relevant to this incisional pain model. The cytokines may be functional in supporting nociceptive sensitization because pentoxifylline reverses both peri-incisional skin cytokine levels and OIH. Opioid administration beginning at the time of incision does not seem to have the same cytokine enhancing effect. Approaches to postoperative pain control involving a reduction of cytokines may be an effective way to control excessive pain in patients chronically using opioids prior to surgical procedures.
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Affiliation(s)
- DeYong Liang
- Department of Anesthesia, Stanford University School of Medicine, Stanford, CA, USA.
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Spinal mu-opioid receptor-expressing dorsal horn neurons: role in nociception and morphine antinociception. J Neurosci 2008; 28:904-13. [PMID: 18216198 DOI: 10.1523/jneurosci.4452-07.2008] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The role of spinal cord mu-opioid receptor (MOR)-expressing dorsal horn neurons in nociception and morphine analgesia is incompletely understood. Using intrathecal dermorphin-saporin (Derm-sap) to selectively destroy MOR-expressing dorsal horn neurons, we sought to determine the role of these neurons in (1) normal baseline reflex nocifensive responses to noxious thermal stimulation (hotplate, tail flick) and to persistent noxious chemical stimulation (formalin) and (2) the antinociceptive activity of intrathecal and systemic morphine in the same tests. Lumbar intrathecal Derm-sap (500 ng) produced (1) partial loss of lamina II MOR-expressing dorsal horn neurons, (2) no effect on MOR-expressing dorsal root ganglion neurons, and (3) no change in baseline tail-flick and hotplate reflex nocifensive responses. Derm-sap treatment attenuated the antinociceptive action of both intrathecal and systemic morphine on hotplate responses. Derm-sap treatment had two effects in the formalin test: (1) increased baseline nocifensive responding and (2) reduced antinociceptive action of systemic morphine. We conclude that MOR-expressing dorsal horn neurons (1) are not essential for determining nocifensive reflex responsiveness to noxious thermal stimuli, (2) are necessary for full antinociceptive action of morphine (intrathecal or systemic) in these tests, and (3) play a significant role in the endogenous modulation of reflex nocifensive responses to persistent pain in the formalin test. Thus, one would predict that altering the activity of MOR-expressing dorsal horn neurons would be antinociceptive and of interest in the search for new approaches to management of chronic pain.
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Okura T, Komiyama N, Morita Y, Kimura M, Yamada S. Different effects of morphine and morphine-6β-glucuronide on formalin-evoked spinal glutamate release in conscious and freely moving rats. Neurosci Lett 2007; 415:169-73. [PMID: 17267124 DOI: 10.1016/j.neulet.2007.01.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Revised: 01/08/2007] [Accepted: 01/08/2007] [Indexed: 10/23/2022]
Abstract
The aim of this study was to investigate comparatively the role of spinal glutamate in the antinociceptive effect of morphine and morphine-6beta-glucuronide (M6G). The glutamate concentration in the spinal microdialysates and flinching behavior were simultaneously measured in conscious and freely moving rats after the intraplanter injection of formalin. The subcutaneous administration of morphine (0.3-3mg/kg) in these rats suppressed dose dependently both flinching behavior and spinal glutamate release induced by formalin. Similarly, the subcutaneous administration of M6G at doses of 0.1-3mg/kg suppressed the formalin-induced flinching behavior in the dose-dependent manner, but it did not cause a dose-related inhibition of spinal glutamate release. The inhibitory effects of morphine on the formalin-induced flinching behavior and spinal glutamate release were markedly attenuated by repeated treatment with this drug for 5 days in rats. Thus, there was a significant (P<0.05) correlation between antinociception and inhibitory effect on glutamate release of morphine in rats. These results suggest a significant difference between morphine and M6G in the participation of spinal glutamate for the antinociceptive effect.
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Affiliation(s)
- Takashi Okura
- Department of Pharmacokinetics and Pharmacodynamics and Center of Excellence (COE) Research Program in the 21st Century, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
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10
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Dunbar SA, Karamian I, Yeatman A, Zhang J. Effects of recurrent withdrawal on spinal GABA release during chronic morphine infusion in the rat. Eur J Pharmacol 2006; 535:152-6. [PMID: 16540107 DOI: 10.1016/j.ejphar.2006.02.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2005] [Revised: 11/17/2005] [Accepted: 02/07/2006] [Indexed: 11/18/2022]
Abstract
Chronic opioid administration is associated with altered nociception. The mechanisms underlying these changes are not fully understood. Nociceptive transmission within the spinal cord is modulated by both excitatory and inhibitory neurotransmitters. Using spinal microdialysis, the effects of recurrent withdrawal on the release of gamma-aminobutyric acid (GABA), at rest or after naloxone stimulation, was investigated in rats chronically exposed to morphine. For comparison purpose, the release of glutamate was investigated in parallel. We observed that chronic morphine treatment alone significantly inhibited resting GABA release; and recurrent withdrawal appeared to reverse this effect. Recurrent withdrawal also significantly elevated resting glutamate levels. In addition, we observed that only acute withdrawal moderately increased stimulated GABA release. In contrast, both acute and recurrent withdrawal markedly increased stimulated glutamate release. These observed changes in GABA release offer direct evidence that GABA may contribute to the altered nociceptive response mediated by opioids.
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Affiliation(s)
- Stuart A Dunbar
- Department of Anesthesiology, Baystate Medical Center, Tufts University, 3400 Main Street, Springfield, MA 01199, USA.
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11
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Trafton JA, Minkel J, Humphreys K. Determining effective methadone doses for individual opioid-dependent patients. PLoS Med 2006; 3:e80. [PMID: 16448216 PMCID: PMC1360079 DOI: 10.1371/journal.pmed.0030080] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Accepted: 12/08/2005] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Randomized clinical trials of methadone maintenance have found that on average high daily doses are more effective for reducing heroin use, and clinical practice guidelines recommend 60 mg/d as a minimum dosage. Nevertheless, many clinicians report that some patients can be stably maintained on lower methadone dosages to optimal effect, and clinic dosing practices vary substantially. Studies of individual responses to methadone treatment may be more easily translated into clinical practice. METHODS AND FINDINGS A volunteer sample of 222 opioid-dependent US veterans initiating methadone treatment was prospectively observed over the year after treatment entry. In the 168 who achieved at least 1 mo of heroin abstinence, methadone dosages on which patients maintained heroin-free urine samples ranged from 1.5 mg to 191.2 mg (median = 69 mg). Among patients who achieved heroin abstinence, higher methadone dosages were predicted by having a diagnosis of posttraumatic stress disorder or depression, having a greater number of previous opioid detoxifications, living in a region with lower average heroin purity, attending a clinic where counselors discourage dosage reductions, and staying in treatment longer. These factors predicted 42% of the variance in dosage associated with heroin abstinence. CONCLUSIONS Effective and ineffective methadone dosages overlap substantially. Dosing guidelines should focus more heavily on appropriate processes of dosage determination rather than solely specifying recommended dosages. To optimize therapy, methadone dosages must be titrated until heroin abstinence is achieved.
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Affiliation(s)
- Jodie A Trafton
- Center for Health Care Evaluation, VA Palo Alto Health Care System and Stanford University School of Medicine, Menlo Park, California, United States of America.
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12
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Lin JA, Lee MS, Wu CT, Yeh CC, Lin SL, Wen ZH, Wong CS. Attenuation of morphine tolerance by intrathecal gabapentin is associated with suppression of morphine-evoked excitatory amino acid release in the rat spinal cord. Brain Res 2005; 1054:167-73. [PMID: 16054118 DOI: 10.1016/j.brainres.2005.06.058] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Revised: 06/17/2005] [Accepted: 06/25/2005] [Indexed: 11/18/2022]
Abstract
This study was designed to investigate the effect of acute and chronic intrathecal (i.t.) injection of gabapentin (GBP) on the antinociceptive effect of morphine and tolerance development using a tail-flick latency test. Levels of excitatory amino acids (EAA) in i.t. CSF dialysates were also measured by high performance liquid chromatography. Male Wistar rats were implanted with either one or two i.t. catheters for drug injection or pump infusion and with a microdialysis probe for CSF dialysate collection. The effect of acute GBP (10 microg i.t.) injection on the morphine dose response was examined in both naïve rats and rats made tolerant by continuous infusion of morphine (15 microg/h i.t.) for 5 days. At such a low dose (10 microg i.t.), GBP did not enhance morphine's antinociception in naïve rats. In morphine-tolerant rats, however, acute GBP (10 microg i.t.) injection potentiated morphine's antinociception and yielded a 14.6-fold shift in morphine's dose-response curve. When GBP (10 microg/h i.t.) was co-infused with morphine (15 microg/h i.t.) to examine its effect on the development of morphine tolerance, GBP attenuated the development of morphine tolerance. The effect of GBP and morphine on CSF glutamate and aspartate levels was examined in naïve rats, and the effect of morphine challenge on CSF glutamate and aspartate levels was examined in rats previously infused for 5 days with morphine alone or morphine plus GBP. Acute injection of GBP (10 microg i.t.), morphine (50 microg i.t.), or GBP (10 microg i.t.) followed by morphine (50 microg i.t.) 30 min later had no significant effect on CSF EAA concentration in naïve rats; however, in tolerant rats, morphine challenge (50 microg i.t.) increased aspartate and glutamate levels to 221 +/- 22% and 296 +/- 43%, respectively, of those before morphine challenge, and this phenomenon was inhibited by GBP co-infusion. Our results show that GBP, at a dose without enhanced effect on morphine's antinociception in naïve rats, not only potentiates morphine's antinociceptive effect in morphine-tolerant rats but also attenuates the development of morphine tolerance. The mechanism of the effect of GBP on morphine tolerance might be via suppression of the EAA concentration in spinal CSF dialysate.
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Affiliation(s)
- Jui-An Lin
- Department of Anesthesiology, Tri-Service General Hospital, National Defense Medical Center, #325, Chenggung Road, Section 2, Neihu 114, Taipei, Taiwan
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Gu G, Kondo I, Hua XY, Yaksh TL. Resting and evoked spinal substance P release during chronic intrathecal morphine infusion: parallels with tolerance and dependence. J Pharmacol Exp Ther 2005; 314:1362-9. [PMID: 15908510 DOI: 10.1124/jpet.105.087718] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Spinal opiate analgesia is associated with presynaptic inhibition of release of excitatory neurotransmitters/neuromodulators, e.g., substance P (SP), from primary afferent terminals. Chronic intrathecal (i.t.) administration of opiates such as morphine results in an initial analgesia followed by tolerance and a state of dependence. In this study, we examined the resting and evoked neurokinin 1 receptor (NK1r) internalization, indicative of endogenous SP release, in dorsal horn neurons of the lumbar spinal cord by immunocytochemistry during chronic i.t. infusion of morphine in rats. Noxious mechanical stimulation (compression) applied to unilateral hind paw evoked a significant increase in NK1r internalization in lamina I neurons in the ipsilateral dorsal horn. Intrathecal morphine infusion (40 nmol/microl/h) for 1 day possessed similar analgesic efficacy as acute morphine and blocked compression-induced spinal NK1r internalization. After 5 days of morphine infusion, thermal escape latencies were the same as in preinfusion animals or saline-infused controls, and compression-evoked NK1r internalization was no longer suppressed. Systemic administration of naloxone to rats on day 6 of morphine infusion resulted in prominent withdrawal behaviors and a concomitant increase in NK1r internalization in dorsal horn. The naloxone-induced internalization was blocked by NK1r antagonist L-703,606 [cis-2-(diphenylmethyl)-N-[(2-iodophenyl)methyl]-1 azabicyclo[2.2.2]octan-3-amine] or pretreatment with capsaicin, confirming that the internalization is due to the endogenous SP release from the primary afferents. We conclude that inability to suppress release of excitatory neurotransmitters/neuromodulators from primary afferents by morphine after chronic exposure is an important component in spinal morphine tolerance, and excessive release from these afferents contributes to the spinal morphine withdrawal syndrome.
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Affiliation(s)
- Guibao Gu
- Department of Anesthesiology, University of California-San Diego, La Jolla, 92093-0818, USA
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Abstract
This paper is the 26th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2003 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology, Doctoral Sub-Program, Queens College, City University of New York, 65-30 Kissena Blvd., Flushing, NY 11367, USA.
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Abstract
Clinical reports suggest that opioids, intended to abolish pain, can unexpectedly produce hyperalgesia. This paradoxical effect may be mechanistically related to tolerance induced by increasing doses of opioids. Two case reports illustrate a syndrome characterized by increasing pain pursued by escalating opioid doses, which results in a worsening of the clinical picture. Several experimental data may help explain the course of this challenging clinical condition. In escalating opioid doses rapidly, a risk of opioid-induced hyperalgesia should be recognized, as higher doses of opioids may stimulate rather than inhibit the central nervous system by different mechanisms. Alternative procedures should be taken into consideration to break this cycle, should it occur. More data are needed to detect this condition, as currently no diagnostic information on specific markers, clinical or biochemical, exists.
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Affiliation(s)
- Sebastiano Mercadante
- Anesthesia and Intensive Care Unit & Pain Relief and Palliative Care Unit, La Maddalena Cancer Center, Palermo, Italy
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