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Yildiz Pehlivan D, Kara AY, Koyu A, Simsek F. Enhancing fentanyl antinociception and preventing tolerance with α-2 adrenoceptor agonists in rats. Behav Brain Res 2024; 457:114726. [PMID: 37865211 DOI: 10.1016/j.bbr.2023.114726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/06/2023] [Accepted: 10/17/2023] [Indexed: 10/23/2023]
Abstract
Fentanyl (FEN) is a potent opioid analgesic used for pain management. Opioid analgesic tolerance poses a significant challenge to the clinical utility of opioid agonists. Preventing the development of tolerance to opioid analgesia is crucial for improving its efficacy and safety. The noradrenergic system is involved in pain regulation. This study examined the effects of α-2 adrenoceptor (AR) agonists, dexmedetomidine (DEX), and xylazine (XYL) on FEN tolerance and antinociception, and their impact on μ-opioid receptor (MOR) expression in the posterior horn of the spinal cord (SC). Male rats were divided into six groups and treated with different drug combinations for three consecutive days. Analgesia tests and motor performance assessments were conducted, followed by SC analysis using immunohistochemistry (IHC). Analgesia tests revealed the development of FEN tolerance on the second day, but the groups receiving combined drugs did not develop tolerance. Instead, FEN antinociception was enhanced, with a prolonged duration of its effects. None of the drugs caused sedation or motor impairment, and SC morphology appeared normal. MOR expression levels did not differ significantly between the groups based on IHC analysis. These findings suggest that changes in the secondary messenger system may play a role in the early development of FEN tolerance. Combining drugs can prevent tolerance, while enhancing FEN's antinociceptive effects. These results have promising implications for chronic pain management; however, further research is needed to explore the molecular effects of α-2 AR agonists on FEN tolerance. Overall, this study sheds light on the mechanism of FEN tolerance and identifies potential avenues for future research.
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Affiliation(s)
- Deniz Yildiz Pehlivan
- Izmir Katip Celebi University, Faculty of Medicine, Department of Physiology, Izmir, Turkey
| | - Ali Yucel Kara
- Izmir Katip Celebi University, Faculty of Medicine, Department of Physiology, Izmir, Turkey.
| | - Ahmet Koyu
- Izmir Katip Celebi University, Faculty of Medicine, Department of Physiology, Izmir, Turkey
| | - Fatma Simsek
- Izmir Katip Celebi University, Faculty of Medicine, Department of Histology and Embryology, Izmir, Turkey
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2
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Badshah I, Anwar M, Murtaza B, Khan MI. Molecular mechanisms of morphine tolerance and dependence; novel insights and future perspectives. Mol Cell Biochem 2023:10.1007/s11010-023-04810-3. [PMID: 37470850 DOI: 10.1007/s11010-023-04810-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 07/06/2023] [Indexed: 07/21/2023]
Abstract
Drug addiction is a devastating condition that poses a serious burden on the society. The use of some drugs like morphine for their tremendous analgesic properties is also accompanied with developing tolerance, dependence and the withdrawal symptoms. These symptoms are frequently severe enough to reinforce the person in recovery to start over the use of drug again and hinder the clinical use of drugs like morphine for chronic pain. Research into opioid receptors and related molecular pathways has seen resurgence in the wake of the growing opioid epidemic. The current study provides a comprehensive scientific exploration of the molecular mechanisms and underlying signalling in morphine tolerance and dependence. It also critically evaluates current therapeutic approaches, shedding light on their efficacy and limitations, and future prospects. The graphical abstract depicts an overview of the pathways involved in the emergence of morphine-related tolerance and dependence including NMDA, Nitric oxide, and PPAR, as well as behavioural sensitization along with present and future innovative treatment strategies including stem cell therapy that have been discussed in the current manuscript.
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Affiliation(s)
- Ismail Badshah
- Riphah Institute of Pharmaceutical Sciences, G-7/4 Campus, Islamabad, Pakistan
| | - Maira Anwar
- Riphah Institute of Pharmaceutical Sciences, G-7/4 Campus, Islamabad, Pakistan
| | - Babar Murtaza
- Riphah Institute of Pharmaceutical Sciences, G-7/4 Campus, Islamabad, Pakistan.
| | - Muhammad Imran Khan
- Department of Biomedical Sciences, Pak Austria Fachhochschule: Institute of Applied Sciences and Technology, Haripur, Khyber Pakhtunkhwa, Pakistan.
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Deng M, Zhang Z, Xing M, Liang X, Li Z, Wu J, Jiang S, Weng Y, Guo Q, Zou W. LncRNA MRAK159688 facilitates morphine tolerance by promoting REST-mediated inhibition of mu opioid receptor in rats. Neuropharmacology 2022; 206:108938. [PMID: 34982972 DOI: 10.1016/j.neuropharm.2021.108938] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/17/2021] [Accepted: 12/28/2021] [Indexed: 12/11/2022]
Abstract
Morphine tolerance (MT) caused by the long-term use of morphine is a major medical problem. The molecular mechanism of morphine tolerance remains elusive. Here, we established a morphine tolerance model in rats and verified whether the long noncoding RNA (lncRNA) MRAK159688 is involved in morphine tolerance and its specific molecular mechanism. We show the significant upregulation of MRAK159688 expression in the spinal cord of morphine-tolerant rats. Overexpression of MRAK159688 by a lentivirus reduces the analgesic efficacy of morphine and induces pain behavior. Downregulation of MRAK159688 using a small interfering RNA (siRNA) attenuates the formation of morphine tolerance, partially reverses the development of morphine tolerance and alleviates morphine-induced hyperalgesia. MRAK159688 is located in the nucleus and cytoplasm of neurons, and it colocalizes with repressor element-1 silencing transcription factor (REST) in the nucleus. MRAK159688 potentiates the expression and function of REST, thereby inhibiting the expression of mu opioid receptor (MOR) and subsequently inducing morphine tolerance. Moreover, REST overexpression blocks the effects of MRAK159688 siRNA on relieving morphine tolerance. In general, chronic morphine administration-mediated upregulation of MRAK159688 in the spinal cord contributes to morphine tolerance and hyperalgesia by promoting REST-mediated inhibition of MOR. MRAK159688 downregulation may represent a novel RNA-based therapy for morphine tolerance.
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Affiliation(s)
- Meiling Deng
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Zengli Zhang
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China; Department of Anesthesiology, Tianjin Medical University Cancer Institute & Hospital, Tianjin, 300000, China
| | - Manyu Xing
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Xia Liang
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China; Department of Anesthesiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, 510120, Guangdong, China
| | - Zhengyiqi Li
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Jing Wu
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Shasha Jiang
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Yingqi Weng
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Qulian Guo
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Wangyuan Zou
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
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Abstract
Opioid drugs are analgesics increasingly being prescribed to control pain associated with a wide range of causes. Usage of pregnant women has dramatically increased in the past decades. Neonates born to these women are at risk for neonatal abstinence syndrome (also referred to as neonatal opioid withdrawal syndrome). Negative birth outcomes linked with maternal opioid use disorder include compromised fetal growth, premature birth, reduced birthweight, and congenital defects. Such infants require lengthier hospital stays necessitating rising health care costs, and they are at greater risk for neurobehavioral and other diseases. Thus, it is essential to understand the genesis of such disorders. As the primary communication organ between mother and conceptus, the placenta itself is susceptible to opioid effects but may be key to understanding how these drugs affect long-term offspring health and potential avenue to prevent later diseases. In this review, we will consider the evidence that placental responses are regulated through an endogenous opioid system. However, maternal consumption of opioid drugs can also bind and act through opioid receptors express by trophoblast cells of the placenta. Thus, we will also discuss the current human and rodent studies that have examined the effects of opioids on the placenta. These drugs might affect placental hormones associated with maternal recognition of pregnancy, including placental lactogens and human chorionic gonadotropin in rodents and humans, respectively. A further understanding of how such drugs affect the placenta may open up new avenues for early diagnostic and remediation approaches.
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Affiliation(s)
- Cheryl S Rosenfeld
- Correspondence: Biomedical Sciences, University of Missouri, Columbia, MO 65211, USA. E-mail:
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Zhou J, Ma R, Jin Y, Fang J, Du J, Shao X, Liang Y, Fang J. Molecular mechanisms of opioid tolerance: From opioid receptors to inflammatory mediators (Review). Exp Ther Med 2021; 22:1004. [PMID: 34345286 PMCID: PMC8311239 DOI: 10.3892/etm.2021.10437] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 04/19/2021] [Indexed: 12/14/2022] Open
Abstract
Opioids are considered the most effective analgesics for the treatment of both acute and chronic pain. However, prolonged opioid use can induce a certain level of tolerance to its analgesic effects, leading to a reduction in its effectiveness, addiction and abuse. A better understanding of the mechanisms underlying opioid tolerance may provide insights into this phenomenon and aid in the development of novel methods to combat the side effects of opioid tolerance. The present review focused on two major contributors to tolerance, opioid receptors and inflammatory mediators. The molecular mechanisms involved in the desensitization of the opioid receptors were briefly described, including their phosphorylation, internalisation and recycling. Subsequently, the effects of Toll like receptor 4/NOD-like receptor family pyrin domain containing 3-mediated proinflammatory responses in opioid tolerance were discussed, aiming in supporting the identification of novel therapeutic targets.
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Affiliation(s)
- Jie Zhou
- Department of Acupuncture and Moxibustion, The Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310005, P.R. China
| | - Ruijie Ma
- Department of Acupuncture and Moxibustion, The Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310005, P.R. China
| | - Ying Jin
- Department of Rehabilitation in Traditional Chinese Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310000, P.R. China
| | - Junfan Fang
- The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, P.R. China
| | - Junying Du
- The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, P.R. China
| | - Xiaomei Shao
- The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, P.R. China
| | - Yi Liang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, P.R. China
| | - Jianqiao Fang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, P.R. China
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Abstract
Humans are social animals: social isolation hurts people both psychologically and physically. Strong, positive social bonds help people to live longer and healthier lives compared with their more isolated peers. Opioid use disorder is associated with feelings of social isolation, an increased risk of suicide and, at the community level, lower social capital. I propose a psychobiological mechanistic explanation that contributes to the association between opioid use and social isolation. The endogenous opioid system plays a central role in the formation and maintenance of social bonds across the life span and has been investigated primarily through the framework of the brain opioid theory of social attachment. In primates, maternal-infant bonding and social play are both impaired by the administration of naltrexone (an opioid antagonist), and in humans, the chronic use of opioids appears to be particularly (relative to other drugs) corrosive to close relationships. Social isolation may play a role in the development and exacerbation of opioid use disorder. Taken together, work on the brain’s opioid system suggests a possible mechanistic basis for bidirectional causal links between social isolation and opioid use disorder. Evaluation of this hypothesis would benefit from longitudinal psychosocial and neuropsychopharmacological investigations.
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Affiliation(s)
- Nina C Christie
- Department of Psychology, University of Southern California, Los Angeles, CA, USA., USC Brain and Creativity Institute, University of Southern California, Los Angeles, CA, USA
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Zhang P, Bu J, Wu X, Deng L, Chi M, Ma C, Shi X, Wang G. Upregulation of μ-Opioid Receptor in the Rat Spinal Cord Contributes to the α2-Adrenoceptor Agonist Dexmedetomidine-Induced Attenuation of Chronic Morphine Tolerance in Cancer Pain. J Pain Res 2020; 13:2617-2627. [PMID: 33116804 PMCID: PMC7573317 DOI: 10.2147/jpr.s274225] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 09/04/2020] [Indexed: 11/23/2022] Open
Abstract
Background Sustained morphine treatment for cancer pain has been limited due to analgesic tolerance. Opioid receptor internalization and desensitization mediated by downregulation of mu-opioid receptor (MOR) expression have been confirmed as one of the mechanisms of chronic morphine tolerance. In addition to the opiate system, the α2-adrenergic system is involved in the development of morphine tolerance. Several studies reported that co-administration of α2-adrenoceptor agonist dexmedetomidine inhibits morphine tolerance in normal or neuropathic pain animals. However, the effect of dexmedetomidine on morphine tolerance has not been studied in cancer pain. Therefore, we investigated the effect of intrathecal injection of dexmedetomidine on the development of morphine tolerance in cancer pain and on the expression of MOR in the spinal cord of morphine-tolerant cancer pain rats. Methods The model was established using a rat’s right hind paw injection of Walker 256 cancer cells. Subcutaneous morphine (10mg/kg) was administrated twice daily for 7 days; meanwhile, the rats received intrathecal α2-adrenoceptor agonist dexmedetomidine (10μ/kg) or antagonist MK-467 (0.25mg/kg) in test groups. Rats receiving drug vehicle served as the control group. Antinociception was detected by von Frey filaments and hot-plate tests. The expression of MOR in the spinal cord was examined through real-time reverse transcription polymerase chain reaction and Western blotting. The data were analyzed via analysis of variance followed by Student t-test with Bonferroni correction. Results Seven-day chronic morphine administration elicited notable analgesic tolerance in the rats with cancer pain. Co-administration of α2-adrenoceptor agonist dexmedetomidine enhanced morphine analgesia and attenuated morphine tolerance, which could be blocked by α2-adrenoceptor antagonist MK-467. Furthermore, pre-treatment of dexmedetomidine significantly upregulated MOR protein expression without a notable change in MOR mRNA expression in the spinal cord. Conclusion Our findings suggest that intrathecal injection of dexmedetomidine enhanced morphine analgesia and attenuated morphine tolerance in cancer pain, potentially by upregulating MOR expression in the spinal cord. The α2-adrenoceptor agonist may provide a more versatile analgesia option for morphine treatment for cancer pain.
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Affiliation(s)
- Pinyi Zhang
- Department of Anesthesiology, Harbin Medical University Cancer Hospital, Harbin, People's Republic of China
| | - Jianlong Bu
- Department of Thoracic Surgery, Harbin Medical University Cancer Hospital, Harbin, People's Republic of China
| | - Xiaohong Wu
- Department of Anesthesiology, Harbin Medical University Cancer Hospital, Harbin, People's Republic of China
| | - Lin Deng
- Department of Anesthesiology, Harbin Medical University Cancer Hospital, Harbin, People's Republic of China
| | - Meng Chi
- Department of Anesthesiology, Harbin Medical University Cancer Hospital, Harbin, People's Republic of China
| | - Chao Ma
- Department of Anesthesiology, The Fourth Hospital of Harbin Medical University, Harbin, People's Republic of China
| | - Xiaoding Shi
- Department of Anesthesiology, Harbin Medical University Cancer Hospital, Harbin, People's Republic of China
| | - Guonian Wang
- Department of Anesthesiology, The Fourth Hospital of Harbin Medical University, Harbin, People's Republic of China
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Costa AR, Sousa M, Wilson SP, Reguenga C, Teixeira-Pinto A, Tavares I, Martins I. Shift of µ-opioid Receptor Signaling in the Dorsal Reticular Nucleus Is Implicated in Morphine-induced Hyperalgesia in Male Rats. Anesthesiology 2020; 133:628-44. [PMID: 32568844 DOI: 10.1097/ALN.0000000000003412] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
BACKGROUND Increased descending pain facilitation accounts for opioid-induced hyperalgesia, but the underlying mechanisms remain elusive. Given the role of µ-opioid receptors in opioid-induced hyperalgesia in animals, the authors hypothesized that the dorsal reticular nucleus, a medullary pain facilitatory area, is involved in opioid-induced hyperalgesia through altered µ-opioid receptor signaling. METHODS The authors used male Wistar rats (n = 5 to 8 per group), chronically infused with morphine, to evaluate in the dorsal reticular nucleus the expressions of the µ-opioid receptor and phosphorylated cAMP response element-binding, a downstream marker of excitatory µ-opioid receptor signaling. The authors used pharmacologic and gene-mediated approaches. Nociceptive behaviors were evaluated by the von Frey and hot-plates tests. RESULTS Lidocaine fully reversed mechanical and thermal hypersensitivity induced by chronic morphine. Morphine-infusion increased µ-opioid receptor, without concomitant messenger RNA changes, and phosphorylated cAMP response element-binding levels at the dorsal reticular nucleus. µ-opioid receptor knockdown in morphine-infused animals attenuated the decrease of mechanical thresholds and heat-evoked withdrawal latencies compared with the control vector (von Frey [mean ± SD]: -17 ± 8% vs. -40 ± 9.0%; P < 0.001; hot-plate: -10 ± 5% vs. -32 ± 10%; P = 0.001). µ-opioid receptor knockdown in control animals induced the opposite (von Frey: -31 ± 8% vs. -17 ± 8%; P = 0.053; hotplate: -24 ± 6% vs. -3 ± 10%; P = 0.001). The µ-opioid receptor agonist (D-ALA2,N-ME-PHE4,GLY5-OL)-enkephalin acetate (DAMGO) decreased mechanical thresholds and did not affect heat-evoked withdrawal latencies in morphine-infused animals. In control animals, DAMGO increased both mechanical thresholds and heat-evoked withdrawal latencies. Ultra-low-dose naloxone, which prevents the excitatory signaling of the µ-opioid receptor, administered alone, attenuated mechanical and thermal hypersensitivities, and coadministered with DAMGO, restored DAMGO analgesic effects and decreased phosphorylated cAMP response element-binding levels. CONCLUSIONS Chronic morphine shifted µ-opioid receptor signaling from inhibitory to excitatory at the dorsal reticular nucleus, likely enhancing descending facilitation during opioid-induced hyperalgesia in the rat.
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Abstract
The opioid crisis is a major threat of the 21st century, with a remarkable juxtaposition of use and abuse. Opioids are the most potent and efficacious class of analgesics, but despite their proven therapeutic efficacy, they have recently been degraded to third-line therapy for the management of chronic pain in clinics. The reason behind this is the development of potential side effects and tolerance after repeated dosing. Opioid tolerance is the major limiting factor leading to the withdrawal of treatment, severe side effects due to dose escalation, and sometimes even death of the patients. Every day more than 90 people die due to opioids overdose in America, and a similar trend has been seen across the globe. Over the past two decades, researchers have been trying to dissect the neurobiological mechanism of opioid tolerance. Research on opioid tolerance shifted toward central nervous system-based adaptations because tolerance is much more than just a cellular phenomenon. Thus, neurobiological adaptations associated with opioid tolerance are important to understand in order to find newer pain therapeutics. These adaptations are associated with alterations in ascending and descending pain pathways, reward circuitry modulations, receptor desensitization and down-regulation, receptor internalization, heterodimerization, and altered epigenetic regulation. The present Review is focused on novel circuitries associated with opioid tolerance in different areas of the brain, such as periaqueductal gray, rostral ventromedial medulla, dorsal raphe nucleus, ventral tegmental area, and nucleus accumbens. Understanding the neurobiological modulations associated with chronic opioid exposure and tolerance will pave the way for the development of novel pharmacological tools for safer and better management of chronic pain in patients.
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Affiliation(s)
- Ankit Uniyal
- Neuroscience & Pain Research Laboratory, Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University Varanasi-221005, Uttar Pradesh, India
| | - Anagha Gadepalli
- Neuroscience & Pain Research Laboratory, Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University Varanasi-221005, Uttar Pradesh, India
| | - Akhilesh
- Neuroscience & Pain Research Laboratory, Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University Varanasi-221005, Uttar Pradesh, India
| | - Vinod Tiwari
- Neuroscience & Pain Research Laboratory, Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University Varanasi-221005, Uttar Pradesh, India
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Garlet QI, Souza CF, Rodrigues P, Descovi SN, Martinez-Rodríguez G, Baldisserotto B, Heinzmann BM. GABAa receptor subunits expression in silver catfish (Rhamdia quelen) brain and its modulation by Nectandra grandiflora Nees essential oil and isolated compounds. Behav Brain Res 2019; 376:112178. [PMID: 31454673 DOI: 10.1016/j.bbr.2019.112178] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 08/21/2019] [Accepted: 08/23/2019] [Indexed: 11/23/2022]
Abstract
Studies using silver catfish (Rhamdia quelen) as experimental models are often applied to screen essential oils (EO) with GABAergic-mediated effects. However, the expression of GABAa receptors in the silver catfish brain remains unknown. Thus, we assessed whether silver catfish express GABAa receptor subunits associated with sedation/anesthetic process and/or neurological diseases. Additionally, we evaluated the brain expression of GABAa receptor subunits in fish sedated with Nectandra grandiflora EO and its isolated compounds, the fish anesthetic (+)-dehydrofukinone (DHF), and dehydrofukinone epoxide (DFX), eremophil-11-en-10-ol (ERM) and selin-11-en-4-α-ol (SEL), which have GABAa-mediated anxiolytic-like effects in mice. The expression of the subunits gabra1, gabra2, gabra3, gabrb1, gabrd and gabrg2 in the silver catfish brain were assessed after a 24h-sedation bath by real time PCR. Since qPCR data rarely describes mechanisms of action, which are usually found through interactions with receptors, we also performed an antagonist-driven experiment using flumazenil (FMZ). Real-time PCR detected the mRNA expression of all targeted genes in R. quelen brain. The expression of gabra1 was decreased in fish sedated with ERM; EO increased gabra2, gabra3, gabrb1 and gabrg2 expression; SEL increased gabrb1, gabrd and gabrg2 expression. EO and compounds DFX, SEL and ERM induced sustained sedation in fish and FMZ-bath prompted the recovery from ERM- and DFX-induced sedation. Our results suggest that the EO, SEL, ERM and DFX sedative effects involve interaction with the GABAergic system. Our findings support the use of the silver catfish as robust and reliable experimental model to evaluate the efficacy of drugs with putative GABAergic-mediated effects.
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Listos J, Łupina M, Talarek S, Mazur A, Orzelska-Górka J, Kotlińska J. The Mechanisms Involved in Morphine Addiction: An Overview. Int J Mol Sci 2019; 20:ijms20174302. [PMID: 31484312 PMCID: PMC6747116 DOI: 10.3390/ijms20174302] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/23/2019] [Accepted: 08/29/2019] [Indexed: 12/22/2022] Open
Abstract
Opioid use disorder is classified as a chronic recurrent disease of the central nervous system (CNS) which leads to personality disorders, co-morbidities and premature death. It develops as a result of long-term administration of various abused substances, along with morphine. The pharmacological action of morphine is associated with its stimulation of opioid receptors. Opioid receptors are a group of G protein-coupled receptors and activation of these receptors by ligands induces significant molecular changes inside the cell, such as an inhibition of adenylate cyclase activity, activation of potassium channels and reductions of calcium conductance. Recent data indicate that other signalling pathways also may be involved in morphine activity. Among these are phospholipase C, mitogen-activated kinases (MAP kinases) or β-arrestin. The present review focuses on major mechanisms which currently are considered as essential in morphine activity and dependence and may be important for further studies.
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Affiliation(s)
- Joanna Listos
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4a St., 20-093 Lublin, Poland.
| | - Małgorzata Łupina
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4a St., 20-093 Lublin, Poland.
| | - Sylwia Talarek
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4a St., 20-093 Lublin, Poland.
| | - Antonina Mazur
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4a St., 20-093 Lublin, Poland.
| | - Jolanta Orzelska-Górka
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4a St., 20-093 Lublin, Poland.
| | - Jolanta Kotlińska
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4a St., 20-093 Lublin, Poland.
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12
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Cheng YC, Tsai RY, Sung YT, Chen IJ, Tu TY, Mao YY, Wong CS. Melatonin regulation of transcription in the reversal of morphine tolerance: Microarray analysis of differential gene expression. Int J Mol Med 2018; 43:791-806. [PMID: 30569162 PMCID: PMC6317689 DOI: 10.3892/ijmm.2018.4030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 12/11/2018] [Indexed: 12/21/2022] Open
Abstract
Tolerance and associated hyperalgesia induced by long‑term morphine administration substantially restrict the clinical use of morphine in pain treatment. Melatonin, a neurohormone released by the pineal gland, has been demonstrated to attenuate anti‑nociceptive morphine tolerance. The present study investigates differentially expressed genes in the process of morphine tolerance and altered gene expression subsequent to melatonin treatment in chronic morphine‑infused ratspinal cords. Morphine tolerance was induced in male Wistar rats by intrathecal morphine infusion (the MO group). Melatonin (the MOMa group) was administered to overcome the effects derived by morphine. The mRNA collected from L5‑S3 of the spinal cord was extracted and analysed by rat expression microarray. Principal component analysis and clustering analysis revealed that the overall gene profiles were different in morphine and melatonin treatments. Subsequent to Gene Ontology analysis, the biological processes of differentially expressed genes of MO and MOMa compared with the control group were constructed. Furthermore, a panel of genes exclusively expressed following melatonin treatment and another panel of genes with inverse expression between the MO and MOMa group were also established. Subsequent to PANTHER pathway analysis, a group of genes with inverse expression following melatonin administrated compared with morphine alone were identified. The expression levels of genes of interest were also confirmed using a reverse transcription‑quantitative polymerase chain reaction. The gene panel that was constructed suggests a potential signaling pathway in morphine tolerance development and is valuable for investigating the mechanism of morphine tolerance and the regulatory gene profiles of melatonin treatment. These results may contribute to the discovery of potential drug targets in morphine tolerance treatments in the future.
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Affiliation(s)
- Yu-Che Cheng
- Proteomics Laboratory, Department of Medical Research, Cathay General Hospital, Taipei 10630, Taiwan, R.O.C
| | - Ru-Yin Tsai
- College of Nursing and Health Sciences, Da‑Yeh University, Changhua 51591, Taiwan, R.O.C
| | - Yen-Tseng Sung
- Proteomics Laboratory, Department of Medical Research, Cathay General Hospital, Taipei 10630, Taiwan, R.O.C
| | - Ing-Jung Chen
- Department of Anesthesiology, Cathay General Hospital, Taipei 10630, Taiwan, R.O.C
| | - Tzu-Yi Tu
- Proteomics Laboratory, Department of Medical Research, Cathay General Hospital, Taipei 10630, Taiwan, R.O.C
| | - Ya-Yuan Mao
- Proteomics Laboratory, Department of Medical Research, Cathay General Hospital, Taipei 10630, Taiwan, R.O.C
| | - Chih-Shung Wong
- School of Medicine, Fu Jen Catholic University, New Taipei City 24205, Taiwan, R.O.C
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Abstract
With its medicalization as a brain-based disease, addiction has come to be regarded as amenable to biomedical treatment approaches, most commonly pharmacotherapy. Various vulnerabilities are recognized to contribute to maladaptive substance use, and have been linked to diverse neurobiological alterations that may be targeted with pharmacotherapy: withdrawal, craving and cue reactivity, and aberrant reward processing are the most significant. Here, we summarize current thinking regarding pharmacotherapy for substance-use disorders, grouping medications by the type of vulnerability they propose to address and providing insight into their neurobiological mechanisms. We also examine the limitations of the brain-based disease model in addiction treatment, especially as these shortcomings pertain to the place of pharmacotherapy in recovery. We conclude by sketching a framework whereby medications might be integrated fruitfully with other interventions, such as behavioral, existential, or peer-based treatments, targeting aspects of addiction beyond neurobiological deficits.
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Affiliation(s)
- Dakwar Elias
- New York State Psychiatric Institute, Columbia University Medical Center, New York, New York, USA
| | - Herbert D Kleber
- New York State Psychiatric institute, Columbia University Medical Center, New York, New York, USA
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O'Dell JH, Kock MD, Thompson PN, Meyer LCR. Minimum effective naltrexone dose to antagonise etorphine immobilisation and prevent the complications of renarcotisation in domestic goats. Vet Rec 2017; 181:481. [PMID: 28978715 DOI: 10.1136/vr.104435] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 08/02/2017] [Accepted: 08/28/2017] [Indexed: 11/04/2022]
Abstract
Naltrexone is used to antagonise etorphine immobilisation, but a safe and effective dose for this purpose has not been objectively determined. Eight domestic goats were immobilised with etorphine (0.07 mg/kg) eight times at ≥13 day intervals. Naltrexone at doses of 0.5, 1, 2, 5, 10, 20 and 40 mg/mg etorphine were administered intravenously 17 minutes after etorphine injection. Effectiveness of antagonism was recorded based on recovery and renarcotisation scores and clinical observations. All doses produced rapid recovery to the point of standing (median 59 seconds, range 33-157 seconds), with no significant differences in recovery times (P=0.44). The lower naltrexone doses resulted in renarcotisation in some goats: 4/8 in the 10-mg dose trial, 7/8 in the 5-mg dose trial, and 8/8 in the 2-mg, 1-mg and 0.5-mg dose trials. Lower doses resulted in more severe signs of renarcotisation. Complications of renarcotisation included increased body temperature; this occurred just before signs of renarcotisation and was greater in animals with high renarcotisation scores (P<0.01). The lowest, safest effective naltrexone dose that we used to antagonise etorphine immobilisation was 20 mg/mg etorphine, which produced rapid recovery to standing with no renarcotisation.
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Affiliation(s)
- Jacques Henry O'Dell
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - Michael David Kock
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - Peter Neil Thompson
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - Leith Carl Rodney Meyer
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
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15
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Viet CT, Dang D, Aouizerat BE, Miaskowski C, Ye Y, Viet DT, Ono K, Schmidt BL. OPRM1 Methylation Contributes to Opioid Tolerance in Cancer Patients. J Pain 2017; 18:1046-1059. [PMID: 28456745 DOI: 10.1016/j.jpain.2017.04.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/13/2017] [Accepted: 04/01/2017] [Indexed: 11/28/2022]
Abstract
Cancer patients in pain require high doses of opioids and quickly become opioid-tolerant. Previous studies have shown that chronic cancer pain as well as high-dose opioid use lead to mu-opioid receptor downregulation. In this study we explore downregulation of the mu-opioid receptor gene (OPRM1), as a mechanism for opioid tolerance in the setting of opioid use for cancer pain. We demonstrate in a cohort of 84 cancer patients that high-dose opioid use correlates with OPRM1 hypermethylation in peripheral leukocytes of these patients. We then reverse-translate our clinical findings by creating a mouse cancer pain model; we create opioid tolerance in the mouse cancer model to mimic opioid tolerance in the cancer patients. Using this model we determine the functional significance of OPRM1 methylation on cancer pain and opioid tolerance. We focus on 2 main cells within the cancer microenvironment: the cancer cell and the neuron. We show that targeted re-expression of mu-opioid receptor on cancer cells inhibits mechanical and thermal hypersensitivity, and prevents opioid tolerance, in the mouse model. The resultant analgesia and protection against opioid tolerance are likely due to preservation of mu-opioid receptor expression on the cancer-associated neurons. PERSPECTIVE We demonstrate that epigenetic regulation of OPRM1 contributes to opioid tolerance in cancer patients, and that targeted gene therapy could treat cancer-induced nociception and opioid tolerance in a mouse cancer model.
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Affiliation(s)
- Chi T Viet
- Department of Oral Maxillofacial Surgery, New York University, New York, New York; Bluestone Center for Clinical Research, New York University, New York, New York
| | - Dongmin Dang
- Department of Oral Maxillofacial Surgery, New York University, New York, New York; Bluestone Center for Clinical Research, New York University, New York, New York
| | - Bradley E Aouizerat
- Bluestone Center for Clinical Research, New York University, New York, New York; School of Nursing, University of California, San Francisco, California; Institute for Human Genetics, University of California, San Francisco, California
| | | | - Yi Ye
- Department of Oral Maxillofacial Surgery, New York University, New York, New York; Bluestone Center for Clinical Research, New York University, New York, New York
| | - Dan T Viet
- Bluestone Center for Clinical Research, New York University, New York, New York
| | - Kentaro Ono
- Department of Oral Maxillofacial Surgery, New York University, New York, New York; Bluestone Center for Clinical Research, New York University, New York, New York
| | - Brian L Schmidt
- Department of Oral Maxillofacial Surgery, New York University, New York, New York; Bluestone Center for Clinical Research, New York University, New York, New York.
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16
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Wilkerson JL, Niphakis MJ, Grim TW, Mustafa MA, Abdullah RA, Poklis JL, Dewey WL, Akbarali H, Banks ML, Wise LE, Cravatt BF, Lichtman AH. The Selective Monoacylglycerol Lipase Inhibitor MJN110 Produces Opioid-Sparing Effects in a Mouse Neuropathic Pain Model. J Pharmacol Exp Ther 2016; 357:145-56. [PMID: 26791602 DOI: 10.1124/jpet.115.229971] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 01/19/2016] [Indexed: 12/28/2022] Open
Abstract
Serious clinical liabilities associated with the prescription of opiates for pain control include constipation, respiratory depression, pruritus, tolerance, abuse, and addiction. A recognized strategy to circumvent these side effects is to combine opioids with other antinociceptive agents. The combination of opiates with the primary active constituent of cannabis (Δ(9)-tetrahydrocannabinol) produces enhanced antinociceptive actions, suggesting that cannabinoid receptor agonists can be opioid sparing. Here, we tested whether elevating the endogenous cannabinoid 2-arachidonoylglycerol through the inhibition of its primary hydrolytic enzyme monoacylglycerol lipase (MAGL), will produce opioid-sparing effects in the mouse chronic constriction injury (CCI) of the sciatic nerve model of neuropathic pain. The dose-response relationships of i.p. administration of morphine and the selective MAGL inhibitor 2,5-dioxopyrrolidin-1-yl 4-(bis(4-chlorophenyl)methyl)piperazine-1-carboxylate (MJN110) were tested alone and in combination at equieffective doses for reversal of CCI-induced mechanical allodynia and thermal hyperalgesia. The respective ED50 doses (95% confidence interval) of morphine and MJN110 were 2.4 (1.9-3.0) mg/kg and 0.43 (0.23-0.79) mg/kg. Isobolographic analysis of these drugs in combination revealed synergistic antiallodynic effects. Acute antinociceptive effects of the combination of morphine and MJN110 required μ-opioid, CB1, and CB2 receptors. This combination did not reduce gastric motility or produce subjective cannabimimetic effects in the drug discrimination assay. Importantly, combinations of MJN110 and morphine given repeatedly (i.e., twice a day for 6 days) continued to produce antiallodynic effects with no evidence of tolerance. Taken together, these findings suggest that MAGL inhibition produces opiate-sparing events with diminished tolerance, constipation, and cannabimimetic side effects.
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Affiliation(s)
- Jenny L Wilkerson
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (J.L.W., T.W.G., M.A.M., R.A.A., J.L.P., W.L.D., H.A., M.L.B., L.E.W., A.H.L.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.)
| | - Micah J Niphakis
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (J.L.W., T.W.G., M.A.M., R.A.A., J.L.P., W.L.D., H.A., M.L.B., L.E.W., A.H.L.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.)
| | - Travis W Grim
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (J.L.W., T.W.G., M.A.M., R.A.A., J.L.P., W.L.D., H.A., M.L.B., L.E.W., A.H.L.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.)
| | - Mohammed A Mustafa
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (J.L.W., T.W.G., M.A.M., R.A.A., J.L.P., W.L.D., H.A., M.L.B., L.E.W., A.H.L.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.)
| | - Rehab A Abdullah
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (J.L.W., T.W.G., M.A.M., R.A.A., J.L.P., W.L.D., H.A., M.L.B., L.E.W., A.H.L.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.)
| | - Justin L Poklis
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (J.L.W., T.W.G., M.A.M., R.A.A., J.L.P., W.L.D., H.A., M.L.B., L.E.W., A.H.L.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.)
| | - William L Dewey
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (J.L.W., T.W.G., M.A.M., R.A.A., J.L.P., W.L.D., H.A., M.L.B., L.E.W., A.H.L.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.)
| | - Hamid Akbarali
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (J.L.W., T.W.G., M.A.M., R.A.A., J.L.P., W.L.D., H.A., M.L.B., L.E.W., A.H.L.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.)
| | - Matthew L Banks
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (J.L.W., T.W.G., M.A.M., R.A.A., J.L.P., W.L.D., H.A., M.L.B., L.E.W., A.H.L.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.)
| | - Laura E Wise
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (J.L.W., T.W.G., M.A.M., R.A.A., J.L.P., W.L.D., H.A., M.L.B., L.E.W., A.H.L.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.)
| | - Benjamin F Cravatt
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (J.L.W., T.W.G., M.A.M., R.A.A., J.L.P., W.L.D., H.A., M.L.B., L.E.W., A.H.L.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.)
| | - Aron H Lichtman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (J.L.W., T.W.G., M.A.M., R.A.A., J.L.P., W.L.D., H.A., M.L.B., L.E.W., A.H.L.); and The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.)
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Laredo SA, Steinman MQ, Robles CF, Ferrer E, Ragen BJ, Trainor BC. Effects of defeat stress on behavioral flexibility in males and females: modulation by the mu-opioid receptor. Eur J Neurosci 2015; 41:434-41. [PMID: 25615538 DOI: 10.1111/ejn.12824] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/05/2014] [Indexed: 02/01/2023]
Abstract
Behavioral flexibility is a component of executive functioning that allows individuals to adapt to changing environmental conditions. Independent lines of research indicate that the mu opioid receptor (MOR) is an important mediator of behavioral flexibility and responses to psychosocial stress. The current study bridges these two lines of research and tests the extent to which social defeat and MOR affect behavioral flexibility and whether sex moderates these effects in California mice (Peromyscus californicus). Males and females assigned to social defeat or control conditions were tested in a Barnes maze. In males, defeat impaired behavioral flexibility but not acquisition. Female performance was unaffected by defeat. MOR binding in defeated and control mice in the orbitofrontal cortex (OFC), striatum and hippocampus was examined via autoradiography. Stressed males had reduced MOR binding in the OFC whereas females were unaffected. The MOR antagonist beta-funaltrexamine (1 mg/kg) impaired performance in males naïve to defeat during the reversal phase but had no effect on females. Finally, we examined the effects of the MOR agonist morphine (2.5 and 5 mg/kg) on stressed mice. As expected, morphine improved behavioral flexibility in stressed males. The stress-induced deficits in behavioral flexibility in males are consistent with a proactive coping strategy, including previous observations that stressed male California mice exhibit strong social approach and aggression. Our pharmacological data suggest that a down-regulation of MOR signaling in males may contribute to sex differences in behavioral flexibility following stress. This is discussed in the framework of coping strategies for individuals with mood disorders.
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Affiliation(s)
- Sarah A Laredo
- Department of Psychology, University of California, Davis, CA, USA; Animal Behavior Graduate Group, University of California, Davis, CA, USA
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18
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Abstract
Opioid receptors (OR) are part of the class A of G-protein coupled receptors and the target of the opiates, the most powerful analgesic molecules used in clinic. During a protracted use, a tolerance to analgesic effect develops resulting in a reduction of the effectiveness. So understanding mechanisms of tolerance is a great challenge and may help to find new strategies to tackle this side effect. This review will summarize receptor-related mechanisms that could underlie tolerance especially receptor desensitization. We will focus on the latest data obtained on molecular mechanisms involved in opioid receptor desensitization: phosphorylation, receptor uncoupling, internalization, and post-endocytic fate of the receptor.
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Affiliation(s)
- Stéphane Allouche
- Laboratoire de Signalisation, Électrophysiologie et Imagerie des Lésions D'ischémie-Reperfusion Myocardique, Université de Caen, UPRES EA 4650, IFR 146 ICORE Caen, France
| | - Florence Noble
- Centre National de la Recherche Scientifique, ERL 3649 Paris, France ; Institut National de la Santé et de la Recherche Médicale, UMR-S 1124 Paris, France ; Université Paris Descartes, Neuroplasticité et Thérapies des Addictions Paris, France
| | - Nicolas Marie
- Centre National de la Recherche Scientifique, ERL 3649 Paris, France ; Institut National de la Santé et de la Recherche Médicale, UMR-S 1124 Paris, France ; Université Paris Descartes, Neuroplasticité et Thérapies des Addictions Paris, France
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19
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Hebebrand J, Albayrak Ö, Adan R, Antel J, Dieguez C, de Jong J, Leng G, Menzies J, Mercer JG, Murphy M, van der Plasse G, Dickson SL. “Eating addiction”, rather than “food addiction”, better captures addictive-like eating behavior. Neurosci Biobehav Rev 2014; 47:295-306. [DOI: 10.1016/j.neubiorev.2014.08.016] [Citation(s) in RCA: 244] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 08/25/2014] [Accepted: 08/28/2014] [Indexed: 01/18/2023]
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20
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Linares OA, Schiesser WE, Daly A. Organ-specific microcirculatory mass transport of oxycodone in humans: clinical implications for therapeutic use. Clin J Pain 2015; 31:206-13. [PMID: 24709626 DOI: 10.1097/AJP.0000000000000105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To begin to address the problem of heterogeneity of distribution of oxycodone (OC) in humans, we developed an organ-specific microcirculatory capillary-tissue exchange 2-compartment model for studying regional OC mass transport. MATERIALS AND METHODS The model was developed in silico. It quantifies OC's organ-specific mass transport rates, clearances and recycling, and it considers the effects of blood flow on OC's convective and diffusive transport. RESULTS What is new is the finding that OC undergoes local recycling at the level of organ-specific capillary-tissue exchange units in humans. Results indicate recycled OC occurs in sufficient amounts to function as a reusable source of circulating OC; which has important implications for OC dosing. Results show the brain, which is central to OC effects only receives about 8% of OC delivered to all organs via the microcirculation. This suggests that differential regulation of receptor binding, trafficking, internalization, or desensitization in the brain likely plays a dominant role in OC's central analgesic effects. DISCUSSION Organ-specific OC mass transport kinetics provide new information for OC dosing in pain management. The model promotes patient safety in opioid prescribing because it allows predictions to be made about the relative contribution that OC recycling makes to circulating OC levels. The model indicates that pharmacologic modulation of the microcirculation may give way to site-specific delivery of opioids in the future. Our study demonstrates that translation of bench in silico research data into clinical practice, although still challenging, is feasible and can assist in OC dose regimen design for patient safety.
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21
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Suárez-Boomgaard D, Gago B, Valderrama-Carvajal A, Roales-Buján R, Van Craenenbroeck K, Duchou J, Borroto-Escuela DO, Medina-Luque J, de la Calle A, Fuxe K, Rivera A. Dopamine D₄ receptor counteracts morphine-induced changes in µ opioid receptor signaling in the striosomes of the rat caudate putamen. Int J Mol Sci 2014; 15:1481-98. [PMID: 24451133 DOI: 10.3390/ijms15011481] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 01/08/2014] [Accepted: 01/13/2014] [Indexed: 11/17/2022] Open
Abstract
The mu opioid receptor (MOR) is critical in mediating morphine analgesia. However, prolonged exposure to morphine induces adaptive changes in this receptor leading to the development of tolerance and addiction. In the present work we have studied whether the continuous administration of morphine induces changes in MOR protein levels, its pharmacological profile, and MOR-mediated G-protein activation in the striosomal compartment of the rat CPu, by using immunohistochemistry and receptor and DAMGO-stimulated [35S]GTPγS autoradiography. MOR immunoreactivity, agonist binding density and its coupling to G proteins are up-regulated in the striosomes by continuous morphine treatment in the absence of changes in enkephalin and dynorphin mRNA levels. In addition, co-treatment of morphine with the dopamine D4 receptor (D4R) agonist PD168,077 fully counteracts these adaptive changes in MOR, in spite of the fact that continuous PD168,077 treatment increases the [3H]DAMGO Bmax values to the same degree as seen after continuous morphine treatment. Thus, in spite of the fact that both receptors can be coupled to Gi/0 protein, the present results give support for the existence of antagonistic functional D4R-MOR receptor-receptor interactions in the adaptive changes occurring in MOR of striosomes on continuous administration of morphine.
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22
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Yu G, Li SH, Cui MX, Yan LD, Yong Z, Zhou PL, Su RB, Gong ZH. Multiple mechanisms underlying the long duration of action of thienorphine, a novel partial opioid agonist for the treatment of addiction. CNS Neurosci Ther 2013; 20:282-8. [PMID: 24330593 DOI: 10.1111/cns.12210] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Revised: 10/28/2013] [Accepted: 10/30/2013] [Indexed: 12/01/2022] Open
Abstract
AIMS It is considered that a long-acting therapy would be advantageous in the treatment of addiction. In a search for novel buprenorphine analogues, thienorphine was demonstrated to be an extremely long-acting orally active partial opioid agonist. This study explored the mechanisms underlying the long-lasting effects of thienorphine. METHODS The binding kinetics of [(3) H]thienorphine were measured in membrane preparations expressing cloned rat opioid receptors. Flow cytometric analysis was used to determine the effect of thienorphine on the surface opioid receptor number. The long-lasting effects of thienorphine were also confirmed at the tissue level and in vivo. RESULTS At 37°C, [(3) H]thienorphine showed rapid association with μ- and κ-opioid receptors, while its dissociation was sluggish and biphasic (K-1 = 0.21 min(-1) , K-2 = 0.0078 min(-1) for the μ-receptor; K-1 = 0.17 min(-1) , K-2 = 0.0042 min(-1) for the κ-receptor). Treatment with thienorphine for 24, 48, and 72 h downregulated surface μ-receptor in a dose- and time-dependent manner. The inhibitory effect of thienorphine on guinea pig ileum persisted for more than 120 min after prolonged washing. In vivo, thienorphine exhibited significant antagonism of morphine-induced antinociception for more than 7 days. CONCLUSIONS These results indicate that multiple factors, including persistent receptor occupation and enhanced receptor downregulation, may contribute to the long-lasting effects of thienorphine that would be beneficial for its application in addiction treatment.
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Affiliation(s)
- Gang Yu
- Beijing Institute of Pharmacology and Toxicology, Beijing, China
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23
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Murányi M, Cinar R, Kékesi O, Birkás E, Fábián G, Bozó B, Zentai A, Tóth G, Kicsi EG, Mácsai M, Dochnal R, Szabó G, Szücs M. Ligand-specific regulation of the endogenous mu-opioid receptor by chronic treatment with mu-opioid peptide agonists. Biomed Res Int 2013; 2013:501086. [PMID: 24350273 DOI: 10.1155/2013/501086] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 08/22/2013] [Accepted: 09/06/2013] [Indexed: 11/17/2022]
Abstract
Since the discovery of the endomorphins (EM), the postulated endogenous peptide agonists of the mu-opioid receptors, several analogues have been synthesized to improve their binding and pharmacological profiles. We have shown previously that a new analogue, cis-1S,2R-aminocyclohexanecarboxylic acid2-endomorphin-2 (ACHC-EM2), had elevated mu-receptor affinity, selectivity, and proteolytic stability over the parent compound. In the present work, we have studied its antinociceptive effects and receptor regulatory processes. ACHC-EM2 displayed a somewhat higher (60%) acute antinociceptive response than the parent peptide, EM2 (45%), which peaked at 10 min after intracerebroventricular (icv) administration in the rat tail-flick test. Analgesic tolerance developed to the antinociceptive effect of ACHC-EM2 upon its repeated icv injection that was complete by a 10-day treatment. This was accompanied by attenuated coupling of mu-sites to G-proteins in subcellular fractions of rat brain. Also, the density of mu-receptors was upregulated by about 40% in the light membrane fraction, with no detectable changes in surface binding. Distinct receptor regulatory processes were noted in subcellular fractions of rat brains made tolerant by the prototypic full mu-agonist peptide, DAMGO, and its chloromethyl ketone derivative, DAMCK. These results are discussed in light of the recently discovered phenomenon, that is, the “so-called biased agonism” or “functional selectivity”.
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Doll C, Pöll F, Peuker K, Loktev A, Glück L, Schulz S. Deciphering µ-opioid receptor phosphorylation and dephosphorylation in HEK293 cells. Br J Pharmacol 2013; 167:1259-70. [PMID: 22725608 DOI: 10.1111/j.1476-5381.2012.02080.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE The molecular basis of agonist-selective signalling at the µ-opioid receptor is poorly understood. We have recently shown that full agonists such as [D-Ala(2)-MePhe(4)-Gly-ol]enkephalin (DAMGO) stimulate the phosphorylation of a number of carboxyl-terminal phosphate acceptor sites including threonine 370 (Thr(370)) and serine 375 (Ser(375)), and that is followed by a robust receptor internalization. In contrast, morphine promotes a selective phosphorylation of Ser(375) without causing rapid receptor internalization. EXPERIMENTAL APPROACH Here, we identify kinases and phosphatases that mediate agonist-dependent phosphorylation and dephosphorylation of the µ-opioid receptor using a combination of phosphosite-specific antibodies and siRNA knock-down screening in HEK293 cells. KEY RESULTS We found that DAMGO-driven phosphorylation of Thr(370) and Ser(375) was preferentially catalysed by G-protein-coupled receptor kinases (GRKs) 2 and 3, whereas morphine-driven Ser(375) phosphorylation was preferentially catalysed by GRK5. On the functional level, inhibition of GRK expression resulted in enhanced µ-opioid receptor signalling and reduced receptor internalization. Analysis of GRK5-deficient mice revealed that GRK5 selectively contributes to morphine-induced Ser(375) phosphorylation in brain tissue. We also identified protein phosphatase 1γ as a µ-opioid receptor phosphatase that catalysed Thr(370) and Ser(375) dephosphorylation at or near the plasma membrane within minutes after agonist removal, which in turn facilitates receptor recycling. CONCLUSIONS AND IMPLICATIONS Together, the morphine-activated µ-opioid receptor is a good substrate for phosphorylation by GRK5 but a poor substrate for GRK2/3. GRK5 phosphorylates µ-opioid receptors selectively on Ser(375), which is not sufficient to drive significant receptor internalization.
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Affiliation(s)
- Christian Doll
- Institute of Pharmacology and Toxicology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
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Mohammed W, Alhaddad H, Marie N, Tardy F, Lamballais F, Risède P, Noble F, Baud FJ, Mégarbane B. Comparison of tolerance to morphine-induced respiratory and analgesic effects in mice. Toxicol Lett 2013; 217:251-9. [DOI: 10.1016/j.toxlet.2012.12.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2012] [Revised: 12/26/2012] [Accepted: 12/27/2012] [Indexed: 11/18/2022]
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Williams JT, Ingram SL, Henderson G, Chavkin C, von Zastrow M, Schulz S, Koch T, Evans CJ, Christie MJ. Regulation of μ-opioid receptors: desensitization, phosphorylation, internalization, and tolerance. Pharmacol Rev 2013; 65:223-54. [PMID: 23321159 DOI: 10.1124/pr.112.005942] [Citation(s) in RCA: 577] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Morphine and related µ-opioid receptor (MOR) agonists remain among the most effective drugs known for acute relief of severe pain. A major problem in treating painful conditions is that tolerance limits the long-term utility of opioid agonists. Considerable effort has been expended on developing an understanding of the molecular and cellular processes that underlie acute MOR signaling, short-term receptor regulation, and the progression of events that lead to tolerance for different MOR agonists. Although great progress has been made in the past decade, many points of contention and controversy cloud the realization of this progress. This review attempts to clarify some confusion by clearly defining terms, such as desensitization and tolerance, and addressing optimal pharmacological analyses for discerning relative importance of these cellular mechanisms. Cellular and molecular mechanisms regulating MOR function by phosphorylation relative to receptor desensitization and endocytosis are comprehensively reviewed, with an emphasis on agonist-biased regulation and areas where knowledge is lacking or controversial. The implications of these mechanisms for understanding the substantial contribution of MOR signaling to opioid tolerance are then considered in detail. While some functional MOR regulatory mechanisms contributing to tolerance are clearly understood, there are large gaps in understanding the molecular processes responsible for loss of MOR function after chronic exposure to opioids. Further elucidation of the cellular mechanisms that are regulated by opioids will be necessary for the successful development of MOR-based approaches to new pain therapeutics that limit the development of tolerance.
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Affiliation(s)
- John T Williams
- Vollum Institute, Oregon Health Sciences University, Portland, Oregon, USA
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Szentirmay AK, Király KP, Lenkey N, Lackó E, Al-Khrasani M, Friedmann T, Timár J, Gyarmati S, Tóth G, Fürst S, Riba P. Spinal interaction between the highly selective μ agonist DAMGO and several δ opioid receptor ligands in naive and morphine-tolerant mice. Brain Res Bull 2012; 90:66-71. [PMID: 22995282 DOI: 10.1016/j.brainresbull.2012.09.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 09/10/2012] [Indexed: 12/11/2022]
Abstract
Since the discovery of opioid receptor dimers their possible roles in opioid actions were intensively investigated. Here we suggest a mechanism that may involve the μ-δ opioid heterodimers. The exact role of δ opioid receptors in antinociception and in the development of opioid tolerance is still unclear. While receptor up-regulation can be observed during the development of opioid tolerance no μ receptor down-regulation could be detected within five days. In our present work we investigated how the selective δ opioid receptor agonists and antagonists influence the antinociceptive effect of the selective μ receptor agonist DAMGO in naïve and morphine-tolerant mice. We treated male NMRI mice with 200 μmol/kg subcutaneous (s.c.) morphine twice daily for three days. On the fourth day we measured the antinociceptive effect of DAMGO alone and combined with delta ligands: DPDPE, deltorphin II (agonists), TIPP and TICPψ (antagonists), respectively, administered intrathecally (i.t.) in mouse tail-flick test. In naive control mice none of the δ ligands caused significant changes in the antinociceptive action of DAMGO. The treatment with s.c. morphine resulted in approximately four-fold tolerance to i.t. DAMGO, i.e. the ED₅₀ value of DAMGO was four times as high as in naive mice. 500 and 1000 pmol/mouse of the δ₁ selective agonist DPDPE enhanced the tolerance to DAMGO while 1000 pmol/mouse of the δ₂ selective agonist deltorphin II did not influence the degree of tolerance. However, both δ antagonists TIPP and TICPψ potentiated the antinociceptive effect of i.t. DAMGO, thus they restored the potency of DAMGO to the control level. The inhibitory action of DPDPE against the antinociceptive effect of DAMGO could be antagonized by TIPP and TICPψ. We hypothesize that during the development of morphine tolerance the formation of μδ heterodimers may contribute to the spinal opioid tolerance. δ ligands may affect the dimer formation differently. Those, like DPDPE may facilitate the dimer formation hence inhibit the antinociceptive effect of DAMGO by causing virtual μ receptor down-regulation. Ligands that do not affect the dimer formation do not influence antinociception either but ligands with the presumed capability of disconnecting the dimers may decrease the spinal tolerance to DAMGO.
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Affiliation(s)
- A K Szentirmay
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad Tér 4, P.O. Box 370, H-1445 Budapest, Hungary
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Abstract
Agonists acting on µ-opioid receptors (MOR) are very effective analgesics but cause tolerance during long-term or repeated exposure. Intensive efforts have been made to find novel opioid agonists that are efficacious analgesics but can elude the signalling events that cause tolerance. µ-Opioid agonists differentially couple to downstream signalling mechanisms. Some agonists, such as enkephalins, D-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin (DAMGO), methadone and sufentanyl are efficacious at mediating G-protein and effector coupling, as well as triggering MOR regulatory events that include MOR phosphorylation, β-arrestin binding, receptor endocytosis and recycling. By contrast, morphine and closely related alkaloids can mediate efficacious MOR-effector coupling but poorly trigger receptor regulation. Several models have been proposed to relate differential MOR regulation by different opioids with their propensity to cause tolerance. Most are based on dogma that β-arrestin-2 (βarr-2) binding causes MOR desensitization and/or that MOR endocytosis and recycling are required for receptor resensitization. This review will examine some of these notions in light of recent evidence establishing that MOR dephosphorylation and resensitization do not require endocytosis. Recent evidence from opioid-treated animals also suggests that impaired MOR-effector coupling is driven, at least in part, by enhanced desensitization, as well as impaired resensitization that appears to be βarr-2 dependent. Better understanding of how chronic exposure to opioids alters receptor regulatory mechanisms may facilitate the development of effective analgesics that produce limited tolerance.
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Affiliation(s)
- Vu C Dang
- Department of Psychiatry, University of California, San Francisco, CA, USABrain & Mind Research Institute, University of Sydney, NSW, Australia
| | - MacDonald J Christie
- Department of Psychiatry, University of California, San Francisco, CA, USABrain & Mind Research Institute, University of Sydney, NSW, Australia
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Zhao J, Xin X, Xie GX, Palmer PP, Huang YG. Molecular and cellular mechanisms of the age-dependency of opioid analgesia and tolerance. Mol Pain 2012; 8:38. [PMID: 22612909 PMCID: PMC3517334 DOI: 10.1186/1744-8069-8-38] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 05/09/2012] [Indexed: 01/17/2023] Open
Abstract
The age-dependency of opioid analgesia and tolerance has been noticed in both clinical observation and laboratory studies. Evidence shows that many molecular and cellular events that play essential roles in opioid analgesia and tolerance are actually age-dependent. For example, the expression and functions of endogenous opioid peptides, multiple types of opioid receptors, G protein subunits that couple to opioid receptors, and regulators of G protein signaling (RGS proteins) change with development and age. Other signaling systems that are critical to opioid tolerance development, such as N-methyl-D-aspartic acid (NMDA) receptors, also undergo age-related changes. It is plausible that the age-dependent expression and functions of molecules within and related to the opioid signaling pathways, as well as age-dependent cellular activity such as agonist-induced opioid receptor internalization and desensitization, eventually lead to significant age-dependent changes in opioid analgesia and tolerance development.
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Affiliation(s)
- Jing Zhao
- Department of Anesthesia, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China
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Madia PA, Navani DM, Yoburn BC. [(35)S]GTPγS binding and opioid tolerance and efficacy in mouse spinal cord. Pharmacol Biochem Behav 2011; 101:155-65. [PMID: 22108651 DOI: 10.1016/j.pbb.2011.11.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 10/27/2011] [Accepted: 11/05/2011] [Indexed: 11/18/2022]
Abstract
The present study examined efficacy of a series of opioid agonists and then using chronic in vivo treatment protocols, determined tolerance to opioid agonist stimulated [(35)S]GTPγS (guanosine 5'-O-(3-[(35)S] thio)triphosphate) binding in mouse spinal cord membranes and compared it directly to spinal analgesic tolerance. The [(35)S]GTPγS binding assay was used to estimate efficacy (E(max) and τ; Operational Model of Agonism) of a series of opioid agonists for G-protein activation in mouse spinal cord. The rank order of opioid agonist efficacy determined in the [(35)S]GTPγS assay using the Operational Model and E(max) was similar. These efficacy estimates correlated with historical analgesic efficacy estimates. For tolerance studies, mice were continuously treated s.c. for 7days with morphine, oxycodone, hydromorphone, etorphine or fentanyl and [(35)S]GTPγS studies were conducted in spinal cord membranes. Other mice were tested in i.t. analgesia dose response studies (tailflick). Tolerance to DAMGO ([D-Ala(2),N-MePhe(4),Gly-ol(5)]enkephalin) or morphine stimulated [(35)S]GTPγS binding (decrease in E(max)) was observed following etorphine and fentanyl treatment only. These treatment protocols downregulate μ-opioid receptor density whereas morphine, oxycodone and hydromorphone do not. Spinal analgesic tolerance was observed following all treatment protocols examined (morphine, oxycodone and etorphine). Opioid antagonist treatment that specifically upregulates (chronic naltrexone) or downregulates (clocinnamox) μ-opioid receptor density produced a corresponding change in opioid agonist stimulated [(35)S]GTPγS binding. Although receptor downregulation and G-protein uncoupling are among potential mechanisms of opioid tolerance, the present results suggest that uncoupling in mouse spinal cord plays a minor role and that the [(35)S]GTPγS assay is particularly responsive to changes in μ-opioid receptor density.
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Affiliation(s)
- Priyanka A Madia
- Department of Pharmaceutical Sciences, College of Pharmacy and Allied Health Professions, St. John's University, 8000 Utopia Parkway, Queens, NY 11439, United States
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31
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Raehal KM, Schmid CL, Groer CE, Bohn LM. Functional selectivity at the μ-opioid receptor: implications for understanding opioid analgesia and tolerance. Pharmacol Rev 2011; 63:1001-19. [PMID: 21873412 DOI: 10.1124/pr.111.004598] [Citation(s) in RCA: 197] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Opioids are the most effective analgesic drugs for the management of moderate or severe pain, yet their clinical use is often limited because of the onset of adverse side effects. Drugs in this class produce most of their physiological effects through activation of the μ opioid receptor; however, an increasing number of studies demonstrate that different opioids, while presumably acting at this single receptor, can activate distinct downstream responses, a phenomenon termed functional selectivity. Functional selectivity of receptor-mediated events can manifest as a function of the drug used, the cellular or neuronal environment examined, or the signaling or behavioral measure recorded. This review summarizes both in vitro and in vivo work demonstrating functional selectivity at the μ opioid receptor in terms of G protein coupling, receptor phosphorylation, interactions with β-arrestins, receptor desensitization, internalization and signaling, and details on how these differences may relate to the progression of analgesic tolerance after their extended use.
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Affiliation(s)
- Kirsten M Raehal
- Molecular Therapeutics and Neuroscience, The Scripps Research Institute, Jupiter, Florida, USA
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32
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Groer CE, Schmid CL, Jaeger AM, Bohn LM. Agonist-directed interactions with specific beta-arrestins determine mu-opioid receptor trafficking, ubiquitination, and dephosphorylation. J Biol Chem 2011; 286:31731-41. [PMID: 21757712 DOI: 10.1074/jbc.m111.248310] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Morphine and other opiates mediate their effects through activation of the μ-opioid receptor (MOR), and regulation of the MOR has been shown to critically affect receptor responsiveness. Activation of the MOR results in receptor phosphorylation, β-arrestin recruitment, and internalization. This classical regulatory process can differ, depending on the ligand occupying the receptor. There are two forms of β-arrestin, β-arrestin1 and β-arrestin2 (also known as arrestin2 and arrestin3, respectively); however, most studies have focused on the consequences of recruiting β-arrestin2 specifically. In this study, we examine the different contributions of β-arrestin1- and β-arrestin2-mediated regulation of the MOR by comparing MOR agonists in cells that lack expression of individual or both β-arrestins. Here we show that morphine only recruits β-arrestin2, whereas the MOR-selective enkephalin [D-Ala(2),N-Me-Phe(4),Gly(5)-ol]enkephalin (DAMGO), recruits either β-arrestin. We show that β-arrestins are required for receptor internalization and that only β-arrestin2 can rescue morphine-induced MOR internalization, whereas either β-arrestin can rescue DAMGO-induced MOR internalization. DAMGO activation of the receptor promotes MOR ubiquitination over time. Interestingly, β-arrestin1 proves to be critical for MOR ubiquitination as modification does not occur in the absence of β-arrestin1 nor when morphine occupies the receptor. Moreover, the selective interactions between the MOR and β-arrestin1 facilitate receptor dephosphorylation, which may play a role in the resensitization of the MOR and thereby contribute to overall development of opioid tolerance.
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Affiliation(s)
- Chad E Groer
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida 33458, USA
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Le Marec T, Marie-Claire C, Noble F, Marie N. Chronic and intermittent morphine treatment differently regulates opioid and dopamine systems: a role in locomotor sensitization. Psychopharmacology (Berl) 2011; 216:297-303. [PMID: 21340469 DOI: 10.1007/s00213-011-2223-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 02/03/2011] [Indexed: 11/25/2022]
Abstract
RATIONALE Behavioral sensitization induced by repeated morphine administrations may depend on patterns of administration. However, neurobiological mechanisms involved in this sensitization are largely unknown. OBJECTIVES We compared the effects of intermittent (20 mg/kg, once daily for 7 days) and chronic (escalating doses from 5 to 40 mg/kg, three times a day for 5 days) morphine treatments in mice on locomotor activity. We also quantified, by autoradiography, mu opioid receptor (MOR) in ventral tegmental area (VTA), dopamine D1 (D1R) and D2 (D2R) receptors in striatum. RESULTS Whereas the intermittent treatment led to a long-term sensitization to locomotor effects of morphine [until withdrawal day (WD) 14], the chronic treatment induced a tolerance (WD1) followed by a transient sensitization (WD14). Binding studies demonstrated a decrease of MOR in VTA at WD1 for the chronic treatment. In contrast, striatal D1R level was decreased at WD1, and increased at WD14 for the chronic treatment. For the D2R, we observed a decrease from WD1 to WD14 for the intermittent treatment and an increase at WD1 followed by a decrease at WD14 for the chronic treatment. CONCLUSIONS These results demonstrate that chronic and intermittent morphine treatments could induce different behavioral adaptations that could be explained in part by distinct changes occurring in dopamine and opioid systems.
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MESH Headings
- Analgesics, Opioid/administration & dosage
- Analgesics, Opioid/pharmacology
- Animals
- Autoradiography
- Behavior, Animal/drug effects
- Corpus Striatum/drug effects
- Corpus Striatum/metabolism
- Dose-Response Relationship, Drug
- Drug Administration Schedule
- Drug Tolerance
- Male
- Mice
- Morphine/administration & dosage
- Morphine/pharmacology
- Motor Activity/drug effects
- Receptors, Dopamine D1/drug effects
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D2/drug effects
- Receptors, Dopamine D2/metabolism
- Receptors, Opioid, mu/metabolism
- Time Factors
- Ventral Tegmental Area/drug effects
- Ventral Tegmental Area/metabolism
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Affiliation(s)
- Thierry Le Marec
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8206, Paris, France
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Quillinan N, Lau EK, Virk M, von Zastrow M, Williams JT. Recovery from mu-opioid receptor desensitization after chronic treatment with morphine and methadone. J Neurosci 2011; 31:4434-43. [PMID: 21430144 DOI: 10.1523/JNEUROSCI.4874-10.2011] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Chronic treatment with morphine results in a decrease in μ-opioid receptor sensitivity, an increase in acute desensitization, and a reduction in the recovery from acute desensitization in locus ceruleus neurons. With acute administration, morphine is unlike many other opioid agonists in that it does not mediate robust acute desensitization or induce receptor trafficking. This study compares μ-opioid receptor desensitization and trafficking in brain slices taken from rats treated for 6-7 d with a range of doses of morphine (60, 30, and 15 mg · kg(-1) · d(-1)) and methadone (60, 30, and 5 mg · kg(-1) · d(-1)) applied by subcutaneous implantation of osmotic minipumps. Mice were treated with 45 mg · kg(-1) · d(-1). In morphine-treated animals, recovery from acute [Met](5)enkephalin-induced desensitization and receptor recycling was diminished. In contrast, recovery and recycling were unchanged in slices from methadone-treated animals. Remarkably the reduced recovery from desensitization and receptor recycling found in slices from morphine-treated animals were not observed in animals lacking β-arrestin-2. Furthermore, pharmacological inhibition of G-protein receptor kinase 2 (GRK2), although not affecting the ability of [Met](5)enkephalin to induce desensitization, acutely reversed the delay in recovery from desensitization produced by chronic morphine treatment. These results characterize a previously unidentified function of the GRK/arrestin system in mediating opioid regulation in response to chronic morphine administration. They also suggest that the GRK/arrestin system, rather than serving as a primary mediator of acute desensitization, controls recovery from desensitization by regulating receptor reinsertion to the plasma membrane after chronic treatment with morphine. The sustained GRK/arrestin-dependent desensitization is another way in which morphine and methadone are distinguished.
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Vázquez Moyano M, Uña Orejón R. [Anesthesia in drug addiction]. Rev Esp Anestesiol Reanim 2011; 58:97-109. [PMID: 21427826 DOI: 10.1016/s0034-9356(11)70008-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The growing social problem of drug abuse has increased the likelihood that anesthesiologists will find acute or chronic drug users among patients requiring anesthesia for elective or emergency surgery. We must therefore be aware of the effects drugs have on the organism and their possible pharmacokinetic and pharmacodynamic interactions with anesthetic agents in order to prevent complications during surgery and postoperative recovery. Such knowledge is required for the management of abstinence syndrome or overdose, which pose the greatest potential dangers for the hospitalized drug addict.
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Affiliation(s)
- M Vázquez Moyano
- Servicio de Anestesiologáa, Reanimación y Terapéutica del Dolor, Hospital Universitario La Paz, Madrid.
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Abstract
Our laboratory embarked on research to discover proteins the interaction of which with the mu opioid receptor (MOPr) is required for its function and regulation. We performed yeast two-hybrid screens, using the carboxy tail of the human MOPr as bait and a human brain library. This yielded a number of proteins that seemed to bind to the MOPr C-tail. The one we chose to study in detail was filamin A (FLNA). Evidence was obtained that there was indeed protein-protein binding between the C-tail of MOPr and FLNA. A human melanoma cell line (M2) lacking the gene for FLNA and a control cell line (A7) which differed from M2 only in having been transfected with the gene for FLNA and expressing the FLNA protein were made available to us. We transfected these cell lines with the gene for MOPr and used them in our studies. The absence of FLNA strongly reduced MOPr downregulation as well as desensitization of adenylyl cyclase inhibition and G protein activation. A recent finding, published here for the first time, is that FLNA is required for the activation by mu opioid agonists of the MAP kinase p38. Deletion studies indicated that the MOPr binding site on FLNA is in the 24th repeat, close to its C-terminal. It was further found that FLNA lacking the N-terminal actin binding domain is as capable as full length FLNA to restore cells to control status, suggesting that actin binding is not required. A surprising finding was that upregulation of MOPr by morphine and some agonist analogs occurs in M2 cells lacking FLNA, whereas normal receptor downregulation takes place in A7 cells.
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Madia PA, Dighe SV, Sirohi S, Walker EA, Yoburn BC. Dosing protocol and analgesic efficacy determine opioid tolerance in the mouse. Psychopharmacology (Berl) 2009; 207:413-22. [PMID: 19816677 DOI: 10.1007/s00213-009-1673-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Accepted: 09/01/2009] [Indexed: 11/27/2022]
Abstract
RATIONALE Analgesic efficacy of opioids and dosing protocol have been shown to influence analgesic tolerance. OBJECTIVE This study tested the hypothesis that there is an inverse relationship between analgesic efficacy and tolerance following continuous infusion of opioid analgesics. Furthermore, it was hypothesized that analgesic efficacy plays a minor role in determining the magnitude of tolerance following intermittent or acute administration, and that acute and intermittent administration of opioid agonists produces less tolerance than continuous infusion. MATERIALS AND METHODS Analgesic (tailflick) efficacy (tau) of etorphine, methadone, oxycodone, and hydrocodone was determined using the operational model of agonism. To induce tolerance, mice were injected with opioid agonists once (acute), once per day for 7 days (intermittent) or continuously infused for 7 days. Dose-response studies were conducted using morphine following treatment. RESULTS The order of analgesic efficacy was etorphine > methadone > oxycodone congruent with hydrocodone. Infusion of the higher analgesic efficacy drug etorphine produced significantly less tolerance than the lower analgesic efficacy drugs oxycodone, methadone, and hydrocodone at equi-effective doses. In general, intermittent and acute treatment produced less tolerance compared to continuous infusion even at similar daily doses. CONCLUSION Taken together, intermittent and acute opioid agonist administration produces minimal tolerance compared to continuous infusion. Furthermore, there is an inverse relationship between analgesic efficacy and tolerance following continuous infusion. These results suggest that opioid analgesic tolerance may be increased when sustained release dosing formulations or continuous infusions are employed clinically.
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Affiliation(s)
- Priyanka A Madia
- Department of Pharmaceutical Sciences, College of Pharmacy and Allied Health Professions, St. John's University, 8000 Utopia Parkway, Queens, NY 11439, USA
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38
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Wang JF, Wang ZY, Wu N, Yan HT, Li J. Effects of aquaporin4 deficiency on opioid receptors characteristics in naive and chronic morphine-treated mice. Neurosci Lett 2009; 457:111-4. [DOI: 10.1016/j.neulet.2009.03.060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Revised: 03/13/2009] [Accepted: 03/13/2009] [Indexed: 10/21/2022]
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Dighe SV, Madia PA, Sirohi S, Yoburn BC. Continuous morphine produces more tolerance than intermittent or acute treatment. Pharmacol Biochem Behav 2009; 92:537-42. [PMID: 19248799 DOI: 10.1016/j.pbb.2009.02.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 01/30/2009] [Accepted: 02/13/2009] [Indexed: 10/21/2022]
Abstract
Dosing protocol and analgesic efficacy have been proposed to be important determinants of the magnitude of opioid tolerance. The present study examined the effect of acute, intermittent and continuous treatment with the low analgesic efficacy agonist morphine on analgesic tolerance. Mice were implanted s.c. with a 25 mg morphine pellet for 1-7 days. Other mice were implanted s.c. with two 25 mg, or one 75 mg morphine pellet for 7 days. The release of morphine from subcutaneous implanted pellets was quantitated using a spectrophotometric assay. In other studies, mice were injected with morphine once (18.5-185 mg/kg/day; approximately 10-100 times ED(50) for morphine analgesia) or once/day for 7 days. Controls were implanted with a placebo pellet or injected with saline. Analysis of drug release from a 25 mg pellet indicated that release was greatest during the first 24 h, declined and then remained relatively constant. The amount of morphine released over 7 days by a 75 mg pellet (23.9 mg) was more than that of a single 25 mg pellet (15.4 mg) but less than two 25 mg pellets (30.8 mg). Following treatment, morphine cumulative dose-response studies were conducted (tail flick). Continuous treatment with morphine using pellet implantation produced a dose-dependent shift in the morphine ED(50) by 3.3, 5.8 and 8.5 fold for one 25 mg pellet, one 75 mg pellet and two 25 mg pellets, respectively. Acute and intermittent morphine administration produced substantially less analgesic tolerance than continuous release of morphine by implant pellets. The maximum shift in the ED(50) was 1.6 for acute treatment and 2.7 for 7 day intermittent treatment; despite a larger total daily dose. The present results indicate that continuous treatment with morphine results in greater analgesic tolerance than acute or intermittent morphine treatment even at comparable daily doses. These results are consistent with the suggestion that intermittent dosing has reduced risk of producing opioid tolerance.
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Affiliation(s)
- Shveta V Dighe
- Department of Pharmaceutical Sciences, College of Pharmacy and Allied Health Professions, St. John's University, 8000 Utopia Parkway, Queens, NY 11439, USA
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Gao Y, Li F, Wu N, Su R, Liu Y, Lu X, Liu Y, Li J. Effect of agmatine on DAMGO-induced mu-opioid receptor down-regulation and internalization via activation of IRAS, a candidate for imidazoline I1 receptor. Eur J Pharmacol 2008; 599:18-23. [DOI: 10.1016/j.ejphar.2008.09.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2008] [Revised: 09/04/2008] [Accepted: 09/18/2008] [Indexed: 11/20/2022]
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41
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Dumas EO, Pollack GM. Opioid tolerance development: a pharmacokinetic/pharmacodynamic perspective. AAPS J 2008; 10:537-51. [PMID: 18989788 DOI: 10.1208/s12248-008-9056-1] [Citation(s) in RCA: 165] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Accepted: 07/14/2008] [Indexed: 01/15/2023]
Abstract
The opioids are commonly used to treat acute and severe pain. Long-term opioid administration eventually reaches a dose ceiling that is attributable to the rapid onset of analgesic tolerance coupled with the slow development of tolerance to the untoward side effects of respiratory depression, nausea and decreased gastrointestinal motility. The need for effective-long term analgesia remains. In order to develop new therapeutics and novel strategies for use of current analgesics, the processes that mediate tolerance must be understood. This review highlights potential pharmacokinetic (changes in metabolite production, metabolizing enzyme expression, and transporter function) and pharmacodynamic (receptor type, location and functionality; alterations in signaling pathways and cross-tolerance) aspects of opioid tolerance development, and presents several pharmacodynamic modeling strategies that have been used to characterize time-dependent attenuation of opioid analgesia.
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Affiliation(s)
- Emily O Dumas
- Division of Pharmacotherapy and Experimental Therapeutics, School of Pharmacy, The University of North Carolina at Chapel Hill, CB #7360, Kerr Hall 2311, Chapel Hill, NC 27599-7360, USA.
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Goicoechea C, Sánchez E, Cano C, Jagerovic N, Martín MI. Analgesic activity and pharmacological characterization of N-[1-phenylpyrazol-3-yl]-N-[1-(2-phenethyl)-4-piperidyl] propenamide, a new opioid agonist acting peripherally. Eur J Pharmacol 2008; 595:22-9. [DOI: 10.1016/j.ejphar.2008.07.052] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 07/10/2008] [Accepted: 07/23/2008] [Indexed: 11/30/2022]
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Kitanaka N, Kitanaka J, Hall FS, Tatsuta T, Morita Y, Takemura M, Wang XB, Uhl GR. Alterations in the levels of heterotrimeric G protein subunits induced by psychostimulants, opiates, barbiturates, and ethanol: Implications for drug dependence, tolerance, and withdrawal. Synapse 2008; 62:689-99. [PMID: 18566973 DOI: 10.1002/syn.20543] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Neuronal adaptations have been found to occur in multiple brain regions after chronic intake of abused drugs, and are therefore thought to underlie drug dependence, tolerance, and withdrawal. Pathophysiological changes in drug responsiveness as well as behavioral sequelae of chronic drug exposure are thought to depend largely upon the altered state of heterotrimeric GTP binding protein (G protein)-coupled receptor (GPCR)-G protein interactions. Responsiveness of GPCR-related intracellular signaling systems to drugs of abuse is heterogeneous, depending on the types of intracellular effectors to which the specific Galpha protein subtypes are coupled and GPCR-G protein coupling efficiency, factors influenced by the class of drug, expression levels of G protein subunits, and drug treatment regimens. To enhance understanding of the molecular mechanisms that underlie the development of pathophysiological states resulting from chronic intake of abused drugs, this review focuses on alterations in the expression levels of G protein subunits induced by various drugs of abuse. Changes in these mechanisms appear to be specific to particular drugs of abuse, and specific conditions of drug treatment.
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Affiliation(s)
- Nobue Kitanaka
- Department of Pharmacology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, Japan.
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Kumar P, Sunkaraneni S, Sirohi S, Dighe SV, Walker EA, Yoburn BC. Hydromorphone efficacy and treatment protocol impact on tolerance and mu-opioid receptor regulation. Eur J Pharmacol 2008; 597:39-45. [PMID: 18789923 DOI: 10.1016/j.ejphar.2008.08.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Revised: 08/18/2008] [Accepted: 08/21/2008] [Indexed: 11/26/2022]
Abstract
This study examined the antinociceptive (analgesic) efficacy of hydromorphone and hydromorphone-induced tolerance and regulation of mu-opioid receptor density. Initially s.c. hydromorphone's time of peak analgesic (tail-flick) effect (45 min) and ED50 using standard and cumulative dosing protocols (0.22 mg/kg, 0.37 mg/kg, respectively) were determined. The apparent analgesic efficacy (tau) of hydromorphone was then estimated using the operational model of agonism and the irreversible mu-opioid receptor antagonist clocinnamox. Mice were injected with clocinnamox (0.32-25.6 mg/kg, i.p.) and 24 h later, the analgesic potency of hydromorphone was determined. The tau value for hydromorphone was 35, which suggested that hydromorphone is a lower analgesic efficacy opioid agonist. To examine hydromorphone-induced tolerance, mice were continuously infused s.c. with hydromorphone (2.1-31.5 mg/kg/day) for 7 days and then morphine cumulative dose response studies were performed. Other groups of mice were injected with hydromorphone (2.2-22 mg/kg/day) once, or intermittently every 24 h for 7 days. Twenty-four hours after the last injection, mice were tested using morphine cumulative dosing studies. There was more tolerance with infusion treatments compared to intermittent treatment. When compared to higher analgesic efficacy opioids, hydromorphone infusions induced substantially more tolerance. Finally, the effect of chronic infusion (31.5 mg/kg/day) and 7 day intermittent (22 mg/kg/day) hydromorphone treatment on spinal cord mu-opioid receptor density was determined. Hydromorphone did not produce any change in mu-opioid receptor density following either treatment. These results support suggestions that analgesic efficacy is correlated with tolerance magnitude and regulation of mu-opioid receptors when opioid agonists are continuously administered. Taken together, these studies indicate that analgesic efficacy and treatment protocol are important in determining tolerance and regulation of mu-opioid receptors.
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Affiliation(s)
- Priyank Kumar
- Department of Pharmaceutical Sciences, College of Pharmacy and Allied Health Professions, St. John's University, 8000 Utopia Parkway, Queens, NY 11439, USA
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Arttamangkul S, Quillinan N, Low MJ, von Zastrow M, Pintar J, Williams JT. Differential activation and trafficking of micro-opioid receptors in brain slices. Mol Pharmacol 2008; 74:972-9. [PMID: 18612077 DOI: 10.1124/mol.108.048512] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The activation of G protein-coupled receptors results in a cascade of events that include acute signaling, desensitization, and internalization, and it is thought that not all agonists affect each process to the same extent. The early steps in opioid receptor signaling, including desensitization, have been characterized electrophysiologically using brain slice preparations, whereas most previous studies of opioid receptor trafficking have been conducted in heterologous cell models. This study used transgenic mice that express an epitope-tagged (FLAG) micro-opioid receptor (FLAGMOR) targeted to catecholamine neurons by regulatory elements from the tyrosine hydroxylase gene. Brain slices from these mice were used to study tagged MOR receptors in neurons of the locus ceruleus. Activation of the FLAGMOR with [Met5]enkephalin (ME) produced a hyperpolarization that desensitized acutely to the same extent as native MOR in slices from wild-type mice. A series of opioid agonists were then used to study desensitization and receptor trafficking in brain slices, which was monitored with a monoclonal antibody against the FLAG epitope (M1) conjugated to Alexa 594. Three patterns of receptor trafficking and desensitization were observed: 1) ME, etorphine, and methadone resulted in both receptor desensitization and internalization; 2) morphine and oxymorphone caused significant desensitization without evidence for internalization; and 3) oxycodone was ineffective in both processes. These results show that two distinct forms of signaling were differentially engaged depending on the agonist used to activate the receptor, and they support the hypothesis that ligand-specific regulation of opioid receptors occurs in neurons maintained in brain slices from adult animals.
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Affiliation(s)
- Seksiri Arttamangkul
- Vollum Institute, L474, Department of Behavioral Neuroscience, Oregon Health Sciences University, 3181 W Sam Jackson Park Dr., Portland, OR 97239, USA
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Sirohi S, Dighe SV, Walker EA, Yoburn BC. The analgesic efficacy of fentanyl: relationship to tolerance and mu-opioid receptor regulation. Pharmacol Biochem Behav 2008; 91:115-20. [PMID: 18640146 DOI: 10.1016/j.pbb.2008.06.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Revised: 06/18/2008] [Accepted: 06/24/2008] [Indexed: 11/19/2022]
Abstract
This study determined if fentanyl analgesic efficacy predicts the magnitude of tolerance and mu-opioid receptor regulation. To estimate efficacy, mice were injected i.p. with saline or clocinnamox (CCAM), an irreversible mu-opioid receptor antagonist, (0.32-25.6 mg/kg) and 24 h later fentanyl cumulative dose-response studies were conducted. CCAM dose dependently shifted the fentanyl dose-response function to the right. The apparent efficacy (tau) of fentanyl, based on the operational model of agonism, was estimated as 58, indicating that fentanyl is a high analgesic efficacy agonist. Next, mice were infused with fentanyl (1, 2 or 4 mg/kg/day) for 7 days. Controls were implanted with placebo pellets. At the end of 7 days, morphine cumulative dose-response studies or mu-opioid receptor saturation binding studies were conducted. Fentanyl infusions dose dependently decreased morphine potency with the highest fentanyl dose reducing morphine potency by approximately 6 fold. Chronic infusion with fentanyl (4 mg/kg/day) significantly reduced mu-opioid receptor density by 28% without altering affinity, whereas lower infusion doses had no effect. Taken together, the present results strengthen the proposal that opioid analgesic efficacy predicts mu-opioid receptor regulation and the magnitude of tolerance.
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Affiliation(s)
- Sunil Sirohi
- Department of Pharmaceutical Sciences, College of Pharmacy and Allied Health Professions, St. John's University, 8000 Utopia Parkway, Queens, NY 11439, USA
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Abstract
A large range of neuroadaptations develop in response to chronic opioid exposure and these are thought to be more or less critical for expression of the major features of opioid addiction: tolerance, withdrawal and processes that may contribute to compulsive use and relapse. This review considers these adaptations at different levels of organization in the nervous system including tolerance at the mu-opioid receptor itself, cellular tolerance and withdrawal in opioid-sensitive neurons, systems tolerance and withdrawal in opioid-sensitive nerve networks, as well as synaptic plasticity in opioid sensitive nerve networks. Receptor tolerance appears to involve enhancement of mechanisms of receptor regulation, including desensitization and internalization. Adaptations causing cellular tolerance are more complex but several important processes have been identified including upregulation of cAMP/PKA and cAMP response element-binding signalling and perhaps the mitogen activated PK cascades in opioid sensitive neurons that might not only influence tolerance and withdrawal but also synaptic plasticity during cycles of intoxication and withdrawal. The potential complexity of network, or systems adaptations that interact with opioid-sensitive neurons is great but some candidate neuropeptide systems that interact with mu-opioid sensitive neurons may play a role in tolerance and withdrawal, as might activation of glial signalling. Implication of synaptic forms of learning such as long term potentiation and long term depression in opioid addiction is still in its infancy but this ultimately has the potential to identify specific synapses that contribute to compulsive use and relapse.
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Affiliation(s)
- M J Christie
- Pain Management Research Institute and Kolling Institute, University of Sydney, Royal North Shore Hospital, St Leonards, NSW, Australia.
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Abstract
Agonist-selective actions of opioids on the desensitization of mu-opioid receptors (MORs) have been well characterized, but few if any studies have examined agonist-dependent recovery from desensitization. The outward potassium current induced by several opioids was studied using whole-cell voltage-clamp recordings in locus ceruleus neurons. A brief application of the irreversible opioid antagonist beta-chlornaltrexamine (beta-CNA) was applied immediately after treatment of slices with saturating concentrations of opioid agonists. This approach permitted the measurement of desensitization and recovery from desensitization using multiple opioid agonists, including [Met](5)enkephalin (ME), [d-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin (DAMGO), etorphine, fentanyl, methadone, morphine, morphine-6-glucuronide, oxycodone, and oxymorphone. The results indicate that desensitization protects receptors from irreversible antagonism with beta-CNA. The amount of desensitization was measured as the decrease in current during a 10-min application of a saturating agonist concentration and was a good predictor of the extent of receptor protection from irreversible inactivation with beta-CNA. After desensitization with ME or DAMGO and treatment with beta-CNA, there was an initial profound inhibition of MOR-induced current that recovered significantly after 45 min. There was, however, no recovery of MOR-mediated current with time after treatment with agonists that did not cause desensitization, such as oxycodone. These results demonstrate that desensitization prevents irreversible inactivation of receptors by beta-CNA.
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Affiliation(s)
- Michael S Virk
- Vollum Institute, L474, Oregon Health Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97239.
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Onoprishvili I, Simon EJ. Chronic morphine treatment up-regulates mu opioid receptor binding in cells lacking filamin A. Brain Res 2007; 1177:9-18. [PMID: 17897634 PMCID: PMC2175075 DOI: 10.1016/j.brainres.2007.08.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 05/31/2007] [Accepted: 08/09/2007] [Indexed: 11/19/2022]
Abstract
We investigated the effects of morphine and other agonists on the human mu opioid receptor (MOP) expressed in M2 melanoma cells, lacking the actin cytoskeleton protein filamin A and in A7, a subclone of the M2 melanoma cells, stably transfected with filamin A cDNA. The results of binding experiments showed that after chronic morphine treatment (24 h) of A7 cells, MOP-binding sites were down-regulated to 63% of control, whereas, unexpectedly, in M2 cells, MOP binding was up-regulated to 188% of control naive cells. Similar up-regulation was observed with the agonists methadone and levorphanol. The presence of antagonists (naloxone or CTAP) during chronic morphine treatment inhibited MOP down-regulation in A7 cells. In contrast, morphine-induced up-regulation of MOP in M2 cells was further increased by these antagonists. Chronic morphine desensitized MOP in A7 cells, i.e., it decreased DAMGO-induced stimulation of GTPgammaS binding. In M2 cells DAMGO stimulation of GTPgammaS binding was significantly greater than in A7 cells and was not desensitized by chronic morphine. Pertussis toxin treatment abolished morphine-induced receptor up-regulation in M2 cells, whereas it had no effect on morphine-induced down-regulation in A7 cells. These results indicate that, in the absence of filamin A, chronic treatment with morphine, methadone or levorphanol leads to up-regulation of MOP, to our knowledge, the first instance of opioid receptor up-regulation by agonists in cell culture.
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MESH Headings
- Blotting, Western
- Cell Line
- Cell Line, Tumor
- Contractile Proteins/deficiency
- Contractile Proteins/physiology
- Data Interpretation, Statistical
- Diprenorphine/pharmacology
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- Filamins
- Guanosine 5'-O-(3-Thiotriphosphate)/metabolism
- Humans
- Ligands
- Melanoma/genetics
- Melanoma/pathology
- Microfilament Proteins/deficiency
- Microfilament Proteins/physiology
- Morphine/pharmacology
- Narcotic Antagonists/metabolism
- Narcotic Antagonists/pharmacology
- Narcotics/pharmacology
- Pertussis Toxin/pharmacology
- Radioligand Assay
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/drug effects
- Receptors, Opioid, mu/metabolism
- Tubulin/pharmacology
- Up-Regulation/drug effects
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Affiliation(s)
- Irma Onoprishvili
- Department of Psychiatry, New York University School of Medicine, New York, NY
| | - Eric J. Simon
- Department of Psychiatry, New York University School of Medicine, New York, NY
- Department of Pharmacology, New York University School of Medicine, New York, NY
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Abstract
Chronic opioid antagonist treatment up-regulates opioid receptors and produces functional supersensitivity. Although opioid antagonists vary from neutral to inverse, the role of antagonist efficacy in mediating the chronic effects of opioid antagonists is not known. In this study, the effects of two putative inverse agonists (naltrexone, naloxone) and a putative neutral antagonist (6beta-naltrexol) were examined. Initially, peak effect (40 min, naltrexone and naloxone; 70 min, 6beta-naltrexol) and relative potency to antagonize morphine analgesia were determined (relative potencies = 1, 2, and 16, 6beta-naltrexol, naloxone, and naltrexone, respectively). Next, mice were infused for 7 days with naloxone (0.1-10 mg/kg/day), naltrexone (10 or 15 mg s.c. pellet), or 6beta-naltrexol (0.2-20 mg/kg/day), and spinal micro-opioid receptor density was examined, or morphine analgesia dose-response studies were conducted. All antagonists up-regulated mu-opioid receptors (60-122%) and induced supersensitivity (1.8-2.0-fold increase in morphine potency). There were no differences in antagonist potency to produce up-regulation or supersensitivity. These data suggest that opioid antagonist-induced mu-opioid receptor up-regulation and supersensitivity require occupancy of the receptor and that antagonist efficacy is not critical. Finally, the ED(50) to precipitate withdrawal jumping was examined in morphine-dependent mice. Naltrexone, naloxone, and 6beta-naltrexol produced withdrawal jumping, although potencies relative to 6beta-naltrexol were 211, 96, and 1, respectively. Thus, antagonist potency to precipitate opioid withdrawal was related to inverse agonist efficacy. Overall, the estimated relative potency of the opioid antagonists was a function of the outcome measured, and inverse agonist activity was not required for mu-opioid receptor up-regulation and supersensitivity.
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Affiliation(s)
- Sunil Sirohi
- Department of Pharmaceutical Sciences, College of Pharmacy and Allied Health Professions, St. John's University, Queens, New York 11439, USA
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