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Yuan L, Luo L, Ma X, Wang W, Yu K, Shi H, Chen J, Chen D, Xu T. Chronic morphine induces cyclic adenosine monophosphate formation and hyperpolarization-activated cyclic nucleotide-gated channel expression in the spinal cord of mice. Neuropharmacology 2020; 176:108222. [PMID: 32659289 DOI: 10.1016/j.neuropharm.2020.108222] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/31/2020] [Accepted: 06/23/2020] [Indexed: 12/23/2022]
Abstract
Chronic morphine exposure persistently activates Gαi/o protein-coupled receptors and enhances adenylyl cyclase (AC) activity, which can increase cyclic adenosine monophosphate (cAMP) production. Direct binding of cAMP to the cytoplasmic site on hyperpolarization-activated cyclic nucleotide-gated (HCN) channels increases the probability of channel opening. HCN channels play a prominent role in chronic pain the disease that shares some common mechanisms with opioid tolerance. This compensatory AC activation may be responsible for the induction of morphine-induced analgesic tolerance. We investigated spinal cAMP formation and expression of HCN2 in the spinal cord, and observed the effect of AC inhibition on the induction of morphine analgesic tolerance. We found that chronic morphine-induced antinociceptive tolerance increased spinal cAMP formation and the expression of spinal HCN2. Inhibition of spinal AC partially blocked chronic morphine-induced cAMP formation and prevented the induction of morphine-induced analgesic tolerance. Inhibition of HCN2 also showed a partial preventive effect on morphine-induced tolerance, hypothermia tolerance and also the right-shift of the dose-response curve. We conclude that repeated morphine treatment increases AC activity and cAMP formation, and also spinal HCN2 expression, blockade of AC or HCN2 can prevent the development of morphine-induced analgesic tolerance.
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Affiliation(s)
- Lin Yuan
- Department of Anesthesiology, Tongzhou People's Hospital, Nantong, 226300, China
| | - Limin Luo
- Department of Anesthesiology, Affiliated Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai, 200233, China
| | - Xiaqing Ma
- Department of Anesthesiology, Affiliated Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai, 200233, China
| | - Wenying Wang
- Department of Anesthesiology, Affiliated Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai, 200233, China
| | - Kangkang Yu
- Department of Pathology, Tongzhou People's Hospital, Nantong, 226300, China
| | - Haibo Shi
- Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, 200233, China
| | - Jian Chen
- Department of Orthopaedics, Tongzhou People's Hospital, Nantong, 226300, China.
| | - Dake Chen
- Department of Oncology, Tongzhou People's Hospital, Nantong, 226300, China.
| | - Tao Xu
- Department of Anesthesiology, Tongzhou People's Hospital, Nantong, 226300, China; Department of Anesthesiology, Affiliated Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai, 200233, China.
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2
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Mesenchymal stem cells from bone marrow attenuated the chronic morphine-induced cAMP accumulation in vitro. Neurosci Lett 2018; 698:76-80. [PMID: 30605704 DOI: 10.1016/j.neulet.2018.12.046] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 12/10/2018] [Accepted: 12/30/2018] [Indexed: 12/31/2022]
Abstract
Even though opioid tolerance is both a common and a major challenge in medicine, treatment with opioids is currently the primary method used to treat acute and chronic pain. The cAMP accumulation induced by chronic morphine is regarded as one of the molecular mechanisms leading to its tolerance and dependence characteristics. In the present study, we differentiated SH-SY5Y cells into neuron-like cells by retinoic acid (RA), pretreated these cells with morphine, and tested their cAMP levels under different conditions, including co-culture with bone marrow-derived human mesenchymal stem cells from bone marrow (hMSCs-BM) at various hMSCs-BM/SH-SY5Y ratios (1:5, 1:25, and 1:125), by direct cell-to-cell contact or without cell-to-cell contact, and by conditioned medium (CM) from hMSCs-BM. We found that chronic treatment with 10 μM morphine led to cAMP upregulation in those RA-differentiated SH-SY5Y cells while the morphine induced-cAMP accumulation was significantly attenuated by co-culturing with hMSCs-BM by direct cell-to-cell contact at a lower cell ratio (1:25) and a higher cell ratio (1:5). However, at neither the low or higher cell ratios could hMSCs-BM inhibit morphine-induced cAMP accumulation in RA-differentiated SH-SY5Y cells without cell-to-cell contact. In summary, hMSCs-BM can successfully inhibit morphine-induced cAMP up-regulation in RA-differentiated SH-SY5Y cells by cell-to-cell contact at a higher ratio, suggesting that hMSCs-BM may serve as valuable therapeutics to minimize the risk of drug abuse and addiction in the treatment of morphine tolerance and dependence.
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Baranowska-Bosiacka I, Listos J, Gutowska I, Machoy-Mokrzyńska A, Kolasa-Wołosiuk A, Tarnowski M, Puchałowicz K, Prokopowicz A, Talarek S, Listos P, Wąsik A, Chlubek D. Effects of perinatal exposure to lead (Pb) on purine receptor expression in the brain and gliosis in rats tolerant to morphine analgesia. Toxicology 2016; 339:19-33. [DOI: 10.1016/j.tox.2015.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 10/08/2015] [Accepted: 10/12/2015] [Indexed: 02/08/2023]
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A new method to effectively and rapidly generate neurons from SH-SY5Y cells. Neurosci Lett 2015; 610:43-7. [PMID: 26497914 DOI: 10.1016/j.neulet.2015.10.047] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/07/2015] [Accepted: 10/18/2015] [Indexed: 11/22/2022]
Abstract
It is well known that neurons differentiated from SH-SY5Y cells can serve as cell models for neuroscience research; i.e., neurotoxicity and tolerance to morphine in vitro. To differentiate SH-SY5Y cells into neurons, RA (retinoic acid) is commonly used to produce the inductive effect. However, the percentage of neuronal cells produced from SH-SY5Y cells is low, either from the use of RA treatment alone or from the combined application of RA and other chemicals. In the current study, we used CM-hNSCs (conditioned medium of human neural stem cells) as the combinational inducer with RA to prompt neuronal differentiation of SH-SY5Y cells. We found that neuronal differentiation was improved and that neurons were greatly increased in the differentiated SH-SY5Y cells using a combined treatment of CM-hNSCs and RA compared to RA treatment alone. The neuronal percentage was higher than 80% (about 88%) on the 3rd day and about 91% on the 7th day examined after a combined treatment with CM-hNSCs and RA. Cell maturation and neurite growth of these neuronal cells were also improved. In addition, the use of CM-hNSCs inhibited the apoptosis of RA-treated SH-SY5Y cells in culture. We are the first to report the use of CM-hNSCs in combination with RA to induce neuronal differentiation of RA-treated SH-SY5Y cells. Our method can rapidly and effectively promote the neuronal production of SH-SY5Y cells in culture conditions.
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Bian JM, Wu N, Su RB, Li J. Phosphatidylethanolamine-binding protein is not involved in µ-opioid receptor-mediated regulation of extracellular signal-regulated kinase. Mol Med Rep 2015; 11:3368-74. [PMID: 25573435 PMCID: PMC4368089 DOI: 10.3892/mmr.2015.3161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 11/25/2014] [Indexed: 12/18/2022] Open
Abstract
Stimulation of the µ‑opioid receptor activates extracellular signal‑regulated kinase (ERK), however, the mechanism by which this occurs remains to be elucidated. Phosphatidylethanolamine‑binding protein (PEBP) has been reported to act as a negative regulator of the ERK cascade (Raf‑MEK‑ERK) by binding to Raf‑1 kinase. In the present study, the role of PEBP in µ‑opioid receptor‑mediated ERK activation was investigated in Chinese hamster ovary/µ cells and SH‑SY5Y cells, as well as in human embryonic kidney 293 cells expressing other types of G protein‑coupled receptors. The acute activation of µ‑opioid receptors by morphine or (D‑Ala2, MePhe4, Gly5‑ol) enkephalin induced a rapid activation of ERK. Prolonged morphine treatment did not affect the phosphorylation level of ERK compared with control cells, but the phosphorylation level of ERK decreased markedly when cells were precipitated with naloxone following chronic morphine treatment. For the phosphorylation of PEBP, no change was identified under the designated drug treatment and exposure duration. A total of two other types of G protein‑coupled receptors, including Gs‑coupled dopamine D1 receptors and Gq‑coupled adrenergic α1A receptors were also investigated and only the activation of adrenergic α1A receptors induced an upregulated phosphorylation of PEBP, which was protein kinase C activity dependent. Thus, PEBP did not have a significant role in µ‑opioid receptor‑mediated regulation of ERK.
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Affiliation(s)
- Jia-Ming Bian
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, P.R. China
| | - Ning Wu
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, P.R. China
| | - Rui-Bin Su
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, P.R. China
| | - Jin Li
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, P.R. China
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Shen CH, Tsai RY, Wong CS. Role of neuroinflammation in morphine tolerance: effect of tumor necrosis factor-α. ACTA ACUST UNITED AC 2013; 50:178-82. [PMID: 23385041 DOI: 10.1016/j.aat.2012.12.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 07/30/2012] [Accepted: 12/04/2012] [Indexed: 02/07/2023]
Abstract
Opioids have been used as potent analgesics in clinics for decades; however, their long-term administration leads to tolerance. Two possible mechanisms for drug tolerance are postulated as within-system and between-systems adaptation. The within-system tolerance is involved in the signal transduction of opioid receptors, including downregulation of opioid receptors, uncoupling of G-protein from opioid receptors, and β-arrestin recruitment to opioid receptors, which causes receptor desensitization and internalization/endocytosis. The between-systems tolerance comprehends the glutamatergic receptor system and glial activation with the release of proinflammatory cytokines, and thus the analgesic effect of morphine is reduced. Tumor necrosis factor-α (TNF-α) is a vital proinflammatory cytokine and exerts either a neurotoxic or neuroprotective effect on different diseases of the central nervous system. TNF-α has also been demonstrated to correlate with neuronal plasticity via activation of spinal glial cells and enhancement of glutamatergic transmission. Previous studies had revealed an increased expression of TNF-α in morphine tolerance. This review article focuses on the role of TNF-α in neuroinflammation and the glutamatergic receptor system in morphine tolerance. It may provide another adjuvant therapy for morphine tolerance, which extends the effectiveness of opioids in clinical pain management.
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Affiliation(s)
- Ching-Hui Shen
- Department of Anesthesiology, Veterans General Hospital, Taichung, Taiwan
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7
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Slade GD, Conrad MS, Diatchenko L, Rashid NU, Zhong S, Smith S, Rhodes J, Medvedev A, Makarov S, Maixner W, Nackley AG. Cytokine biomarkers and chronic pain: association of genes, transcription, and circulating proteins with temporomandibular disorders and widespread palpation tenderness. Pain 2011; 152:2802-2812. [PMID: 22000099 DOI: 10.1016/j.pain.2011.09.005] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 08/29/2011] [Accepted: 09/08/2011] [Indexed: 12/22/2022]
Abstract
For reasons unknown, temporomandibular disorder (TMD) can manifest as localized pain or in conjunction with widespread pain. We evaluated relationships between cytokines and TMD without or with widespread palpation tenderness (TMD-WPT or TMD+WPT, respectively) at protein, transcription factory activity, and gene levels. Additionally, we evaluated the relationship between cytokines and intermediate phenotypes characteristic of TMD and WPT. In a case-control study of 344 females, blood samples were analyzed for levels of 22 cytokines and activity of 48 transcription factors. Intermediate phenotypes were measured by quantitative sensory testing and questionnaires asking about pain, health, and psychological status. Single nucleotide polymorphisms (SNPs) coding cytokines and transcription factors were genotyped. TMD-WPT cases had elevated protein levels of proinflammatory cytokine monocyte chemotactic protein (MCP-1) and antiinflammatory cytokine interleukin (IL)-1ra, whereas TMD+WPT cases had elevated levels of proinflammatory cytokine IL-8. MCP-1, IL-1ra, and IL-8 were differentially associated with experimental pain, self-rated pain, self-rated health, and psychological phenotypes. TMD-WPT and TMD+WPT cases had inhibited transcription activity of the antiinflammatory cytokine transforming growth factor β1 (TGFβ1). Interactions were observed between TGFβ1 and IL-8 SNPs: an additional copy of the TGFβ1 rs2241719 minor T allele was associated with twice the odds of TMD+WPT among individuals homozygous for the IL-8 rs4073 major A allele, and half the odds of TMD+WPT among individuals heterozygous for rs4073. These results demonstrate how pro- and antiinflammatory cytokines contribute to the pathophysiology of TMD and WPT in genetically susceptible people. Furthermore, they identify MCP-1, IL-1ra, IL-8, and TGFβ1 as potential diagnostic markers and therapeutic targets for pain in patients with TMD.
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Affiliation(s)
- Gary D Slade
- Center for Neurosensory Disorders, School of Dentistry, University of North Carolina, Chapel Hill, NC 27599, USA Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27599, USA Attagene, Inc, Morrisville, NC 27560, USA
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8
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Intrathecal Etanercept Partially Restores Morphine's Antinociception in Morphine-Tolerant Rats via Attenuation of the Glutamatergic Transmission. Anesth Analg 2011; 113:184-90. [DOI: 10.1213/ane.0b013e318217f7eb] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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9
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Shen CH, Tsai RY, Shih MS, Lin SL, Tai YH, Chien CC, Wong CS. Etanercept restores the antinociceptive effect of morphine and suppresses spinal neuroinflammation in morphine-tolerant rats. Anesth Analg 2010; 112:454-9. [PMID: 21081778 DOI: 10.1213/ane.0b013e3182025b15] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND In the present study we examined the effect of the tumor necrosis factor (TNF)-α antagonist etanercept on the antinociceptive effect of morphine in morphine-tolerant rats. METHODS Male Wistar rats were implanted with 2 intrathecal catheters, and 1 was connected to a mini-osmotic pump for either morphine (15 μg/h) or saline (1 μL/h) infusion for 5 days. On day 5, either etanercept (5 μg, 25 μg, and 50 μg/10 μL) or saline (10 μL) was injected via the other catheter after morphine infusion was discontinued. Three hours later, morphine (15 μg/10 μL, intrathecally) was given and tail-flick latency was measured to evaluate the antinociceptive effect of morphine. Rats were then killed and their spinal cords were removed for quantitative real-time polymerase chain reaction and immunohistochemistry to measure proinflammatory cytokines expression. RESULTS We found that acute etanercept (50 μg) treatment preserved a significant antinociceptive effect of morphine in morphine-tolerant rats. In addition, the expression of TNFα mRNA was increased by 2.5-fold, interleukin (IL)-1β mRNA increased by 13-fold and IL-6 mRNA by 111-fold in the dorsal spinal cord of morphine-tolerant rats. The increase in TNFα, IL-1β, and IL-6 mRNA expression was blocked by 50 μg etanercept pretreatment. The immunohistochemistry analysis revealed that 50 μg etanercept suppressed proinflammatory cytokines expression and neuroinflammation in the microglia. CONCLUSIONS The present study demonstrates that etanercept restores the antinociceptive effect of morphine in morphine-tolerant rats by inhibition of proinflammatory cytokine TNF-α, IL-1β, and IL-6 expression and spinal neuroinflammation. The results suggest that etanercept could also be an adjuvant therapy for morphine tolerance, which extends the effectiveness of opioids in clinical pain management.
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Affiliation(s)
- Ching-Hui Shen
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan
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10
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Del Borgo MP, Blanchfield JT, Toth I. Internalisation of the mu-opioid receptor by endomorphin-1 and leu-enkephalin is dependant on aromatic amino acid residues. Bioorg Med Chem 2008; 16:4341-6. [PMID: 18329886 DOI: 10.1016/j.bmc.2008.02.074] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Revised: 02/21/2008] [Accepted: 02/22/2008] [Indexed: 11/26/2022]
Abstract
The opioid receptor system in the central nervous system controls a number of physiological processes, most notably pain. However, most opioids currently available have a variety of side-effects as well as exhibiting tolerance. Tolerance is most likely to be a complex phenomenon, however, the role of receptor internalisation is thought to play a crucial role. In this study, we examined the role of aromaticity in ligand-mediated receptor internalisation of the mu-opioid receptor (MOPR). These studies show that the amount of receptor internalisation may be dependant on the amphiphilicity of the ligand. Specifically, deletion of the C-terminus aromatic residues of endomorphin 1, particularly tryptophan reduces receptor-mediated internalisation whilst the addition of tryptophan within the enkephalin sequence increases receptor internalisation and decreases tolerance.
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Affiliation(s)
- Mark P Del Borgo
- School of Molecular and Microbial Sciences, University of Queensland, St. Lucia, 4072 Qld, Australia
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11
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Marie N, Aguila B, Hasbi A, Davis A, Jauzac P, Allouche S. Different kinases desensitize the human delta-opioid receptor (hDOP-R) in the neuroblastoma cell line SK-N-BE upon peptidic and alkaloid agonists. Cell Signal 2008; 20:1209-20. [PMID: 18395423 DOI: 10.1016/j.cellsig.2008.02.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Revised: 02/13/2008] [Accepted: 02/15/2008] [Indexed: 11/25/2022]
Abstract
In a previous work, we described a differential desensitization of the human delta-opioid receptor (hDOP-R) by etorphine (a non-selective and alkaloid agonist) and delta-selective and peptidic agonists (DPDPE ([D-Pen(2,5)]enkephalin) and deltorphin I (Tyr-D-Ala-Phe-Asp-Val-Val-Gly-NH(2))) in the neuroblastoma cell line SK-N-BE (Allouche et al., Eur. J. Pharmacol., 371, 235, 1999). In the present study, we explored the putative role of different kinases in this differential regulation. First, selective chemical inhibitors of PKA, PKC and tyrosine kinases were used and we showed a significant reduction of etorphine-induced opioid receptor desensitization by the bisindolylmaleimide I (PKC inhibitor) while genistein (tyrosine kinase inhibitor) was potent to impair desensitization induced by the different agonists. When the PKA was inhibited by H89 pretreatment, no modification of opioid receptor desensitization was observed whatever the agonist used. Second, we further studied the role of G protein-coupled receptor kinases (GRKs) and by using western-blot experiments we observed that only the GRK2 isoform was expressed in the SK-N-BE cells. Next, the neuroblastoma cells were transfected with the wild type GRK2 or its dominant negative mutant GRK2-K220R and the inhibition on cAMP level was determined in naïve and agonist-pretreated cells. We showed that over-expression of GRK2-K220R totally abolished etorphine-induced receptor desensitization while no effect was observed with peptidic agonists and over-expression of GRK2 selectively impaired cAMP inhibition promoted by etorphine suggesting that this kinase was involved in the regulation of hDOP-R activated only by etorphine. Third, correlation between functional experiments and phosphorylation of the hDOP-R after agonist activation was assessed by western-blot using the specific anti-phospho-DOP-R Ser(363) antibody. While all agonists were potent to increase phosphorylation of opioid receptor, we showed no impairment of receptor phosphorylation level after PKC inhibitor pretreatment. Upon agonist activation, no enhancement of receptor phosphorylation was observed when the GRK2 was over-expressed while the GRK2-K220R partially reduced the hDOP-R Ser(363) phosphorylation only after peptidic agonists pretreatment. In conclusion, hDOP-R desensitization upon etorphine exposure relies on the GRK2, PKC and tyrosine kinases while DPDPE and deltorphin I mediate desensitization at least via tyrosine kinases. Although the Ser(363) was described as the primary phosphorylation site of the mouse DOP-R, we observed no correlation between desensitization and phosphorylation of this amino acid.
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Affiliation(s)
- Nicolas Marie
- Université de Caen, Laboratoire de biologie moléculaire et cellulaire de la signalisation, UPRES-EA 3919, IFR 146 ICORE, avenue côte de Nacre, 14032 Caen, France
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12
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Role of receptor internalization in opioid tolerance and dependence. Pharmacol Ther 2007; 117:199-206. [PMID: 18076994 DOI: 10.1016/j.pharmthera.2007.10.003] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Accepted: 10/25/2007] [Indexed: 12/01/2022]
Abstract
Agonist-induced mu-opioid receptor (MOPr) internalization has long been suggested to contribute directly to functional receptor desensitization and opioid tolerance. In contrast, recent evidence suggests that opioid receptor internalization could in fact reduce opioid tolerance in vivo, but the mechanisms that are responsible for the internalization-mediated protection against opioid tolerance are controversely discussed. One prevailing hypothesis is, that receptor internalization leads to decreased receptor signaling and therefore to reduced associated compensatory changes in downstream signaling systems that are involved in the development of opioid tolerance. However, numerous studies have demonstrated that desensitized and internalized mu-opioid receptors are rapidly recycled to the cell surface in a reactivated state, thus counteracting receptor desensitization and opioid tolerance. Further studies revealed agonist-selective differences in the ability to induce opioid receptor internalization. Recently it has been demonstrated that the endocytotic efficacies of opioids are negatively correlated to the induced opioid tolerance. Thus, clearer understanding of the role of opioid receptor trafficking in the regulation of opioid tolerance and dependence will help in the treatment of patients suffering from chronic pain or drug dependence.
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Marie N, Aguila B, Allouche S. Tracking the opioid receptors on the way of desensitization. Cell Signal 2006; 18:1815-33. [PMID: 16750901 DOI: 10.1016/j.cellsig.2006.03.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Accepted: 03/21/2006] [Indexed: 11/24/2022]
Abstract
Opioid receptors belong to the super family of G-protein coupled receptors (GPCRs) and are the targets of numerous opioid analgesic drugs. Prolonged use of these drugs results in a reduction of their effectiveness in pain relief also called tolerance, a phenomenon well known by physicians. Opioid receptor desensitization is thought to play a major role in tolerance and a lot of work has been dedicated to elucidate the molecular basis of desensitization. As described for most of GPCRs, opioid receptor desensitization involves their phosphorylation by kinases and their uncoupling from G-proteins realized by arrestins. More recently, opioid receptor trafficking was shown to contribute to desensitization. In this review, our knowledge on the molecular mechanisms of desensitization and recent progress on the role of opioid receptor internalization, recycling or degradation in desensitization will be reported. A better understanding of these regulatory mechanisms would be helpful to develop new analgesic drugs or new strategies for pain treatment by limiting opioid receptor desensitization and tolerance.
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Affiliation(s)
- Nicolas Marie
- Neuropsychopharmacologie des addictions, CNRS 7157, INSERM U705, Université Paris V, France
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14
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Wang ZJ, Wang LX. Phosphorylation: A molecular switch in opioid tolerance. Life Sci 2006; 79:1681-91. [PMID: 16831450 DOI: 10.1016/j.lfs.2006.05.023] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 04/26/2006] [Accepted: 05/24/2006] [Indexed: 02/07/2023]
Abstract
Protein phosphorylation is a key posttranslational modification mechanism controlling the conformation and activity of many proteins. Increasing evidence has implicated an essential role of phosphorylation by several major protein kinases in promoting and maintaining opioid tolerance. We review some of the most recent studies on protein kinase C (PKC), cyclic AMP dependent protein kinase A (PKA), calcium/calmodulin-dependent protein kinase II (CaMKII), protein kinase G (PKG), and G protein receptor kinase (GRK). These kinases act as the molecular switches to modulate opioid tolerance. Pharmacological interventions at one or more of the protein kinases and phosphatases may provide valuable strategies to improve opioid analgesia by attenuating tolerance to these drugs.
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Affiliation(s)
- Zaijie Jim Wang
- Department of Biopharmaceutical Sciences and Cancer Center, University of Illinois, Chicago, IL 60612, USA.
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15
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Webster DE, Lu J, Chen SN, Farnsworth NR, Wang ZJ. Activation of the mu-opiate receptor by Vitex agnus-castus methanol extracts: implication for its use in PMS. JOURNAL OF ETHNOPHARMACOLOGY 2006; 106:216-21. [PMID: 16439081 DOI: 10.1016/j.jep.2005.12.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2005] [Accepted: 12/19/2005] [Indexed: 05/06/2023]
Abstract
The dried ripe fruit of Vitex agnus-castus L. (VAC) is widely used for the treatment of premenstrual syndrome (PMS). A previous study reported that extracts of VAC showed affinity to opiate receptors; however, functional activity was not determined. We tested two different VAC extracts in receptor binding and functional assays. Our objectives were: (1) to confirm the opiate affinity; (2) to rule out interference by free fatty acids (FFA); (3) to determine the mode of action of VAC at the mu-opiate receptor. Methanol extracts of VAC were prepared either before (VAC-M1) or after (VAC-M2) extraction with petroleum ether to remove fatty acids. Both extracts showed significant affinities to the mu-opiate receptor, as indicated by the concentration-dependent displacement of [3H]DAMGO binding in Chinese hamster ovary (CHO)-human mu-opiate receptor (hMOR) cells. The IC50 values were estimated to be 159.8 microg/ml (VAC-M1) and 69.5 microg/ml (VAC-M2). Since the defatted extract not only retained, but exhibited a higher affinity (p<0.001), it argued against significant interference by fatty acids. In an assay to determine receptor activation, VAC-M1 and VAC-M2 stimulated [35S]GTPgammaS binding by 41 and 61% (p<0.001), respectively. These results suggested for the first time that VAC acted as an agonist at the mu-opiate receptor, supporting its beneficial action in PMS.
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MESH Headings
- Animals
- Binding, Competitive
- CHO Cells
- Cell Membrane/drug effects
- Cell Membrane/metabolism
- Cricetinae
- Cricetulus
- Dose-Response Relationship, Drug
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/metabolism
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- Female
- Fruit
- Guanosine 5'-O-(3-Thiotriphosphate)/metabolism
- Methanol
- Plant Extracts/metabolism
- Plant Extracts/pharmacology
- Plant Extracts/therapeutic use
- Premenstrual Syndrome/drug therapy
- Premenstrual Syndrome/metabolism
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
- Solvents
- Transfection
- Vitex
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Affiliation(s)
- D E Webster
- Department of Biopharmaceutical Sciences, College of Pharmacy, 833 South Woods Street, Room 335, University of Illinois, Chicago, IL 60612, USA
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Lu J, Jeon E, Lee BS, Onyuksel H, Wang ZJ. Targeted drug delivery crossing cytoplasmic membranes of intended cells via ligand-grafted sterically stabilized liposomes. J Control Release 2005; 110:505-13. [PMID: 16356575 DOI: 10.1016/j.jconrel.2005.10.025] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2005] [Revised: 10/19/2005] [Accepted: 10/25/2005] [Indexed: 11/15/2022]
Abstract
In this study, we tested whether sterically stabilized liposomes (SSL) with surface ligands specific for the mu opioid receptor (MOR) can actively target MOR-expressing cells. Dermorphin, a selective MOR agonist, was conjugated to DSPE-PEG(3400) to obtain DSPE-PEG(3400)-dermorphin. Dermorphin-grafted SSL (dermorphin-SSL) was prepared by thin-film rehydration-extrusion and post-insertion method. DSPE-PEG(3400)-dermorphin and dermorphin-SSL retained the affinity to MOR as determined by receptor binding assay using [(3)H]DAMGO, whereas plain SSL without surface ligands showed no binding to the receptor. Cellular uptake of cholesteryl BODIPY encapsulated dermorphin-SSL was studied by microplate spectrofluorometry as well as fluorescent and confocal microscopy. Significant fluorescence signal was observed inside CHO-hMOR cells after the treatment with dermorphin-SSL, indicative of MOR-mediated endocytosis. In contrast, no uptake of dermorphin-SSL was found in naive CHO cells or CHO-hDOR cells that lack MOR. Taken together, these results demonstrate that dermorphin-SSL delivery system is capable of targeting intracellular components of MOR-expressing cells. Such a system may be applied to carry pharmaceutical agents to achieve region-specific delivery of analgesics and/or to attenuate side effects associated with opioids.
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Affiliation(s)
- Jian Lu
- Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois, Chicago, IL 60612-7231, USA
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17
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Guang W, Wang H, Su T, Weinstein IB, Wang JB. Role of mPKCI, a Novel μ-Opioid Receptor Interactive Protein, in Receptor Desensitization, Phosphorylation, and Morphine-Induced Analgesia. Mol Pharmacol 2004. [DOI: 10.1124/mol.66.5.1285] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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18
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Liu ZH, He Y, Jin WQ, Chen XJ, Shen QX, Chi ZQ. Effect of chronic treatment of ohmefentanyl stereoisomers on cyclic AMP formation in Sf9 insect cells expressing human mu-opioid receptors. Life Sci 2004; 74:3001-8. [PMID: 15051423 DOI: 10.1016/j.lfs.2003.10.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2003] [Accepted: 10/21/2003] [Indexed: 10/26/2022]
Abstract
The binding affinity of ohmefentanyl stereoisomers for mu-opioid receptors and the effect of chronic ohmefentanyl stereoisomers pretreatments on intracellular cAMP formation were investigated in Sf9 insect cells expressing human mu-opioid receptors (Sf9-mu cells). Competitive assay of [3H]ohmefentanyl binding revealed that these isomers had high affinity for micro-opioid receptors in Sf9-mu cells. Isomer F9204 had the highest affinity for mu-opioid receptors with the Ki value of 1.66 +/- 0.28 nM. After pretreated Sf9-mu cells with increasing concentrations of these isomers for 6 h, addition of naloxone (1 microM) precipitated an overshoot of foskolin-stimulated cAMP accumulation. The ability of these isomers to induce cAMP overshoot differed greatly with the order of F9202>F9205>F9208>F9206>F9204>F9207. Of these isomers, F9202 was 2.7-fold less potent than F9204 in receptor binding affinity, but 71.5-fold more potent in ability to induce cAMP overshoot. These results suggested that there was a significant stereo-structural difference among ohmefentanyl stereoisomers in ability to induce naloxone-precipitated cAMP overshoot in Sf9-mu cells.
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Affiliation(s)
- Zhong-Hua Liu
- 2nd Department of Pharmacology, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201203, China
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19
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Stirnweiss J, Hartrodt B, Greksch G, Stürzebecher U, Böhmer FD, Neubert K, Liebmann C. Tyr-c[D-Orn-Tyr(Bzl)-Pro-Gly]: a novel antiproliferative acting somatostatin receptor agonist with mu-opioid receptor-sensitizing properties. Br J Pharmacol 2003; 140:13-22. [PMID: 12967930 PMCID: PMC1574013 DOI: 10.1038/sj.bjp.0705416] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
(1) Here, we introduce a beta-casomorphin-5-derived cyclic pentapeptide, cCD-2 (Tyr-cyclo[d-Orn-Tyr(Bzl)-Pro-Gly]), which inhibits the cell growth of a variety of human cancer cell lines. (2) This opioid-derived peptide possesses only low affinity for mu-receptors, but enhances the agonist binding to mu-receptors in vitro and potentiates the analgesic effect of morphin in vivo. The molecular mechanism of mu-receptor sensitization by cCD-2 is not yet known. (3) The antiproliferative effect of cCD-2 is independent of mu-, delta-, and kappa-receptors. (4) Using SH-SY5Y cells as model, we can demonstrate that cCD-2 specifically binds to somatostatin receptors and stimulates the activity of protein tyrosine phosphatases, which are early downstream targets of SST receptors. (5) In SH-SY5Y cells, cCD-2 specifically increases the activity of the cytosolic PTP SHP-2, stimulates the activity of mitogen-activated protein kinase (MAPK), and elevates the expression of the cyclin-dependent kinase inhibitor p21 (WAF1/Cip1), suggesting the involvement of SSTR1 receptor subtype in cCD-2 action in this cell type. (6) In COS-7 cells, for comparison, we found a stimulation of SHP-2 as well as SHP-1 in response to cCD-2. The activation of SHP-1, which is attributed to the SSTR2 receptor and negatively regulates the EGF receptor, corresponds with the ability of cCD-2 to inhibit the EGF-induced MAPK activation in COS-7 cells. (7) Our results show that in SH-SY5Y cells cCD-2 inhibits cell growth via the SSTR1 receptor-signalling pathway but may, in other cells, also use other SSTR subtypes and their signalling mechanisms. (8) cCD-2 represents a novel type of opioid-derived antiproliferative SST receptor agonist, which possesses low mu-receptor affinity but may induce mu-receptor sensitization and is structurally different from the hitherto known SST receptor agonists.
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MESH Headings
- Cell Division/drug effects
- Cell Division/physiology
- Cell Line, Tumor
- Dose-Response Relationship, Drug
- Endorphins/chemistry
- Endorphins/metabolism
- Endorphins/pharmacology
- Growth Inhibitors/chemistry
- Growth Inhibitors/metabolism
- Growth Inhibitors/pharmacology
- Humans
- Narcotic Antagonists/pharmacology
- Pain Measurement/drug effects
- Pain Measurement/methods
- Peptide Fragments/chemistry
- Peptide Fragments/metabolism
- Peptide Fragments/pharmacology
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/antagonists & inhibitors
- Receptors, Opioid, mu/metabolism
- Receptors, Somatostatin/agonists
- Receptors, Somatostatin/metabolism
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Affiliation(s)
- Jörg Stirnweiss
- Institute of Biochemistry and Biophysics, Biological and Pharmaceutical Faculty, Friedrich-Schiller-University Jena, Philosophenweg 12, Jena D-07743, Germany
| | - Bianka Hartrodt
- Department of Biochemistry and Biotechnology, Institute of Biochemistry, University of Halle, Halle D-06120, Germany
| | - Gisela Greksch
- Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Magdeburg, Magdeburg D-39120, Germany
| | - Uta Stürzebecher
- Institute of Biochemistry and Biophysics, Biological and Pharmaceutical Faculty, Friedrich-Schiller-University Jena, Philosophenweg 12, Jena D-07743, Germany
| | - Frank-D Böhmer
- Institute of Molecular Cell Biology, Medical Faculty, Friedrich-Schiller-University Jena, Jena D-07747, Germany
| | - Klaus Neubert
- Department of Biochemistry and Biotechnology, Institute of Biochemistry, University of Halle, Halle D-06120, Germany
| | - Claus Liebmann
- Institute of Biochemistry and Biophysics, Biological and Pharmaceutical Faculty, Friedrich-Schiller-University Jena, Philosophenweg 12, Jena D-07743, Germany
- Author for correspondence:
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20
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Liu XH, Huang DA, Yang FY, Hao YS, Du GG, Li PF, Li G. A new cytokine: the possible effect pathway of methionine enkephalin. World J Gastroenterol 2003; 9:169-73. [PMID: 12508376 PMCID: PMC4728236 DOI: 10.3748/wjg.v9.i1.169] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate experimentally the effects of methionine enkephalin on signal transduction of mouse myeloma NS-1 cells.
METHODS: The antigen determinate of delta opioid receptor was designed in this lab and the polypeptide fragment of antigen determinate with 12 amino acids residues was synthesized. Monoclonal antibody against this peptide fragment was prepared. Proliferation of Mouse NS-1 cells treated with methionine enkephalin of 1 × 10-6 mol·L-1 was observed. The activities of protein kinase A (PKA) and protein kinase C (PKC) were measured and thereby the mechanism of effect of methionine enkephalin was postulated.
RESULTS: The results demonstrated that methionine enkephalin could enhance the proliferation of NS-1 cells and the effect of methionine enkephalin could be particularly blocked by monoclonal antibody. The activity of PKA was increased in both cytosol and cell membrane. With reference to PKC, the intracellular activity of PKC in NS-1 cells was elevated at 1 × 10-7 mol·L-1 and then declined gradually as the concentration of methionine enkephalin was raised. The effects of methionine enkephalin might be reversed by both naloxone and monoclonal antibody.
CONCLUSION: Coupled with the findings, it in-dicates that the signal transduction systems via PKA and PKC are involved in the effects of methionine enkephalin by binding with the traditional opioid receptors, and therefore resulting in different biological effects.
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MESH Headings
- Animals
- Antibodies, Monoclonal/immunology
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Cytokines
- Enkephalin, Methionine/metabolism
- Enkephalin, Methionine/pharmacology
- Mice
- Mice, Inbred BALB C
- Naloxone/pharmacology
- Narcotic Antagonists/pharmacology
- Protein Kinase C/metabolism
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, delta/immunology
- Receptors, Opioid, delta/metabolism
- Signal Transduction/drug effects
- Tumor Cells, Cultured
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Affiliation(s)
- Xin-Hua Liu
- Department of Biochemistry and Molecular Biology, Health Science Center, Peking University, Beijing 100083, China
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21
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Chronic morphine induces downregulation of spinal glutamate transporters: implications in morphine tolerance and abnormal pain sensitivity. J Neurosci 2002. [PMID: 12223586 DOI: 10.1523/jneurosci.22-18-08312.2002] [Citation(s) in RCA: 292] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Tolerance to the analgesic effects of an opioid occurs after its chronic administration, a pharmacological phenomenon that has been associated with the development of abnormal pain sensitivity such as hyperalgesia. In the present study, we examined the role of spinal glutamate transporters (GTs) in the development of both morphine tolerance and associated thermal hyperalgesia. Chronic morphine administered through either intrathecal boluses or continuous infusion induced a dose-dependent downregulation of GTs (EAAC1 and GLAST) in the rat's superficial spinal cord dorsal horn. This GT downregulation was mediated through opioid receptors because naloxone blocked such GT changes. Morphine-induced GT downregulation reduced the ability to maintain in vivo glutamate homeostasis at the spinal level, because the hyperalgesic response to exogenous glutamate was enhanced, including an increased magnitude and a prolonged time course, in morphine-treated rats with reduced spinal GTs. Moreover, the downregulation of spinal GTs exhibited a temporal correlation with the development of morphine tolerance and thermal hyperalgesia. Consistently, the GT inhibitor l-trans-pyrrolidine-2-4-dicarboxylate (PDC) potentiated, whereas the positive GT regulator riluzole reduced, the development of both morphine tolerance and thermal hyperalgesia. The effects from regulating spinal GT activity by PDC were at least in part mediated through activation of the NMDA receptor (NMDAR), because the noncompetitive NMDAR antagonist MK-801 blocked both morphine tolerance and thermal hyperalgesia that were potentiated by PDC. These results indicate that spinal GTs may contribute to the neural mechanisms of morphine tolerance and associated abnormal pain sensitivity by means of regulating regional glutamate homeostasis.
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22
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Bushell T, Endoh T, Simen AA, Ren D, Bindokas VP, Miller RJ. Molecular components of tolerance to opiates in single hippocampal neurons. Mol Pharmacol 2002; 61:55-64. [PMID: 11752206 DOI: 10.1124/mol.61.1.55] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined the effect of acute and chronic opioid treatment on synaptic transmission and mu-opioid receptor (MOR) endocytosis in cultures of naïve rat hippocampal neurons. Opioid agonists that activate MOR inhibited synaptic transmission at inhibitory but not excitatory autapses. [D-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin (DAMGO), morphine, and methadone were all effective at blocking inhibitory transmission. These same drugs also reduced the amplitude of voltage-dependent Ca(2+) currents in inhibitory but not excitatory neurons. Chronic treatment with all three opioids reduced the subsequent effects of a challenge with either the same drug or one of the others in individual autaptic neurons. Chronic treatment with DAMGO or methadone produced internalization of enhanced yellow fluorescent protein-tagged MOR expressed in hippocampal neurons within hours, whereas morphine produced internalization much more slowly, even when accompanied by overexpression of beta-arrestin-2. We conclude that DAMGO, methadone, and morphine all produce tolerance in single hippocampal neurons. Morphine-induced tolerance does not necessarily seem to involve receptor endocytosis.
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Affiliation(s)
- T Bushell
- Department of Neurobiology, Pharmacology, and Physiology, University of Chicago, Chicago, Illinois 60637, USA
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23
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Abstract
This paper is the twenty-third installment of the annual review of research concerning the opiate system. It summarizes papers published during 2000 that studied the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects, although stress-induced analgesia is included. The specific topics covered this year include stress; tolerance and dependence; learning, memory, and reward; eating and drinking; alcohol and other drugs of abuse; sexual activity, pregnancy, and development; mental illness and mood; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; gastrointestinal, renal, and hepatic function; cardiovascular responses; respiration and thermoregulation; and immunological responses.
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Affiliation(s)
- A L Vaccarino
- Department of Psychology, University of New Orleans, New Orleans, LA 70148, USA.
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24
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Lutfy K, Hossain SM, Khaliq I, Maidment NT. Orphanin FQ/nociceptin attenuates the development of morphine tolerance in rats. Br J Pharmacol 2001; 134:529-34. [PMID: 11588106 PMCID: PMC1572978 DOI: 10.1038/sj.bjp.0704279] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2001] [Revised: 07/05/2001] [Accepted: 07/05/2001] [Indexed: 11/09/2022] Open
Abstract
1. Recent evidence from studies in mice lacking the opioid receptor-like (ORL-1) receptor and from experiments using antibodies raised against orphanin FQ/nociceptin (OFQ/N) suggest that this peptide may be involved in morphine tolerance. In the present study we sought to investigate if administration of exogenous OFQ/N would modulate the development of tolerance to the antinociceptive effect of morphine. 2. Rats were treated for 3 days with either saline or morphine (10 mg kg(-1), s.c.) followed, 15 and 75 min later, by two intracerebroventricular injections of either artificial cerebrospinal fluid (aCSF) or OFQ/N. The dose of OFQ/N was doubled each day (7.5, 15, 30 nmol). On day 4, rats were tested on a hot plate apparatus before and 30, 60 and 90 min after morphine administration. 3. Repeated OFQ/N treatment did not affect basal nociceptive responses or morphine-induced antinociception. However, the same treatment significantly attenuated the development of morphine tolerance. 4. Since learning and memory could contribute to the development of morphine tolerance, in subsequent studies, we examined the effect of OFQ/N administered in the CA3 region of the hippocampus, where OFQ/N has been shown to block LTP and impair spatial memory. A greater attenuation of morphine tolerance with no alteration of baseline hot plate latency or morphine-induced antinociception was observed when OFQ/N was administered in this area of the rat brain. 5. Taken together, our results demonstrate that OFQ/N may act in the hippocampus to attenuate morphine tolerance.
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Affiliation(s)
- K Lutfy
- Department of Psychiatry and Biobehavioral Sciences, Neuropsychiatric Institute, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles, California, CA 90024, USA.
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25
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Loghin F, Popa DS, Socaciu C. Influence of glutethimide on rat brain mononucleotides by sub-chronic codeine treatment. J Cell Mol Med 2001; 5:409-16. [PMID: 12067475 PMCID: PMC6740115 DOI: 10.1111/j.1582-4934.2001.tb00176.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
It was investigated the in vivo effect of glutethimide on the intracellular neuroadaptation characteristic for m-opioid receptor tolerance induced by chronic codeine treatment and reflected by increased levels of adenylyl cyclase (AC) and cAMP-dependent protein kinase (PKA). AC activity was appreciated by cyclic-AMP (cAMP) formation, the levels of adenine and guanine nucleotides in brain extracts being assayed using a high performance liquid chromatographic method. The concomitant chronic administration of codeine and glutethimide resulted in a pronounced and long-lasting energetic depletion of the neurons, consistent with the high risk of overdose, and increase of cAMP's stable metabolite, 5'-AMP. This increase is persistent even after withdrawal and suggests an interference with the adenylyl cyclase system involved in the development of tolerance of opioid receptor and in relapse and provides a possible explanation of addiction and fast increase of doses observed in humans abusing this combination.
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Affiliation(s)
- F Loghin
- Department of Toxicology, University of Medicine and Pharmacy Iuliu Hatieganu, 13, Emil Isac, 3400 Cluj-Napoca, Romania.
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