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Farinella R, Falchi F, Tavanti A, Tuoni C, Di Nino MG, Filippi L, Ciantelli M, Rizzato C, Campa D. The genetic variant SLC2A1 -rs1105297 is associated with the differential analgesic response to a glucose-based treatment in newborns. Pain 2024; 165:657-665. [PMID: 37703430 PMCID: PMC10859852 DOI: 10.1097/j.pain.0000000000003051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 07/21/2023] [Accepted: 07/27/2023] [Indexed: 09/15/2023]
Abstract
ABSTRACT Neonatal pain is a critical issue in clinical practice. The oral administration of glucose-based solutions is currently one of the most common and effective nonpharmacologic strategies for neonatal pain relief in daily minor procedures. However, a varying degree of analgesic efficacy has been reported for this treatment. Environmental, maternal, and genetic factors may explain this variability and potentially allow for a personalized analgesic approach, maximizing therapeutic efficacy and preventing side effects. We investigated the exposome (ie, the set of clinical and anthropometric variables potentially affecting the response to the therapy) and the genetic variability of the noradrenaline transporter gene (solute carrier family 6 member 2 [ SLC6A2 ]) and 2 glucose transporter genes (solute carrier family 2 member 1 [ SLC2A1 ] and 2 [ SLC2A2 ]) in relation to the neonatal analgesic efficacy of a 33% glucose solution. The study population consisted in a homogeneous sample of more than 1400 healthy term newborns. No association for the exposome was observed, whereas a statistically significant association between the G allele of SLC2A1 -rs1105297 and a fourfold decreased probability of responding to the therapy was identified after multiple-testing correction (odds ratio of 3.98, 95% confidence interval 1.95-9.17; P = 4.05 × 10 -4 ). This allele decreases the expression of SLC2A1-AS1 , causing the upregulation of SLC2A1 in the dorsal striatum, which has been suggested to be involved in reward-related processes through the binding of opioids to the striatal mu-opioid receptors. Altogether, these results suggest the involvement of SLC2A1 in the analgesic process and highlight the importance of host genetics for defining personalized analgesic treatments.
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Affiliation(s)
| | - Fabio Falchi
- Department of Biology, University of Pisa, Pisa, Italy
| | | | - Cristina Tuoni
- Division of Neonatology, Santa Chiara Hospital, Pisa, Italy
| | | | - Luca Filippi
- Neonatology and Neonatal Intensive Care Unit, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Massimiliano Ciantelli
- Neonatology and Neonatal Intensive Care Unit, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
- Centro Di Formazione e Simulazione Neonatale “NINA”, Azienda Ospedaliero-Universitaria Pisana, Pisa, Italy
| | - Cosmeri Rizzato
- Department of Translational Research and of New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Daniele Campa
- Department of Biology, University of Pisa, Pisa, Italy
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Quantitative Systems Pharmacology and Biased Agonism at Opioid Receptors: A Potential Avenue for Improved Analgesics. Int J Mol Sci 2022; 23:ijms23095114. [PMID: 35563502 PMCID: PMC9104178 DOI: 10.3390/ijms23095114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/01/2022] [Accepted: 05/02/2022] [Indexed: 11/25/2022] Open
Abstract
Chronic pain is debilitating and represents a significant burden in terms of personal and socio-economic costs. Although opioid analgesics are widely used in chronic pain treatment, many patients report inadequate pain relief or relevant adverse effects, highlighting the need to develop analgesics with improved efficacy/safety. Multiple evidence suggests that G protein-dependent signaling triggers opioid-induced antinociception, whereas arrestin-mediated pathways are credited with modulating different opioid adverse effects, thus spurring extensive research for G protein-biased opioid agonists as analgesic candidates with improved pharmacology. Despite the increasing expectations of functional selectivity, translating G protein-biased opioid agonists into improved therapeutics is far from being fully achieved, due to the complex, multidimensional pharmacology of opioid receptors. The multifaceted network of signaling events and molecular processes underlying therapeutic and adverse effects induced by opioids is more complex than the mere dichotomy between G protein and arrestin and requires more comprehensive, integrated, network-centric approaches to be fully dissected. Quantitative Systems Pharmacology (QSP) models employing multidimensional assays associated with computational tools able to analyze large datasets may provide an intriguing approach to go beyond the greater complexity of opioid receptor pharmacology and the current limitations entailing the development of biased opioid agonists as improved analgesics.
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Manohar S, Adler HJ, Radziwon K, Salvi R. Interaction of auditory and pain pathways: Effects of stimulus intensity, hearing loss and opioid signaling. Hear Res 2020; 393:108012. [PMID: 32554129 DOI: 10.1016/j.heares.2020.108012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 04/24/2020] [Accepted: 05/29/2020] [Indexed: 11/19/2022]
Abstract
Moderate intensity sounds can reduce pain sensitivity (i.e., audio-analgesia) whereas intense sounds can induce aural pain, evidence of multisensory interaction between auditory and pain pathways. To explore auditory-pain pathway interactions, we used the tail-flick (TF) test to assess thermal tail-pain sensitivity by measuring the latency of a rat to remove its tail from 52 °C water. In Experiment 1, TF latencies were measured in ambient noise and broadband noise (BBN) presented from 80 to 120 dB SPL. TF latencies gradually increased from ambient to 90 dB SPL (audio-analgesia), but then declined. At 120 dB, TF latencies were significantly shorter than normal, evidence for audio-hyperalgesia near the aural threshold for pain. In Experiment II, the opioid pain pathway was modified by treating rats with a high dose of fentanyl known to induce post-treatment hyperalgesia. TF latencies in ambient noise were normal 10-days post-fentanyl. However, TF latencies became shorter than normal from 90 to 110 dB indicating that fentanyl pre-treatment had converted audio-analgesia to audio-hyperalgesia. In Experiment III, we tested the hypothesis that hearing loss could alter pain sensitivity by unilaterally exposing rats to an intense noise that induced a significant hearing loss. TF latencies in ambient noise gradually declined from 1- to 4-weeks post-exposure indicating that noise-induced hearing loss had increased pain sensitivity. Our results suggest that auditory and pain pathways interact in ways that depend on intensity, hearing loss and opioid pain signaling, results potentially relevant to pain hyperacusis.
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Affiliation(s)
- Senthilvelan Manohar
- Center for Hearing and Deafness, 137 Cary Hall, University at Buffalo, Buffalo, NY, 14214, USA
| | - Henry J Adler
- Center for Hearing and Deafness, 137 Cary Hall, University at Buffalo, Buffalo, NY, 14214, USA
| | - Kelly Radziwon
- Center for Hearing and Deafness, 137 Cary Hall, University at Buffalo, Buffalo, NY, 14214, USA
| | - Richard Salvi
- Center for Hearing and Deafness, 137 Cary Hall, University at Buffalo, Buffalo, NY, 14214, USA.
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4
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Zarkowski PA. Relative prevalence of 10 types of pharmacodynamic interactions in psychiatric treatment. Int J Psychiatry Med 2020; 55:82-104. [PMID: 31470752 DOI: 10.1177/0091217419870669] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To assess the relative prevalence and factors affecting the prescription of medication combinations with a theoretical efficacy limiting pharmacodynamic interaction, defined as two medications with opposing indications and side effects or antagonistic action at the primary receptor of mechanism of action. METHOD One hundred sixteen combinations were identified for 10 types of pharmacodynamic interactions. PubMed was searched for each combination to assess the quality of evidence either supporting clinical use or verifying reduced efficacy. Micromedex was searched to determine the presence of warnings to prescribers of reduced efficacy. The prevalence in clinical practice was determined by computer review of the Genoa Healthcare database for all prescribers at 10 participating community mental health centers. The expected prevalence was calculated as the product of the probability of each medication prescribed alone and was compared with the actual prevalence of the combination using the test of proportions. RESULTS The frequency of prescription of eight combinations met the Bonferroni corrected level of significance of p < 0.001. Four were combinations of amphetamine and D2 antagonists and each were prescribed less often than chance, p = 0.0001 consistent with epidemiological studies and multiple animal studies verifying an efficacy limiting interaction. Despite epidemiological studies indicating increased risk of accidents, alprazolam and amphetamine were prescribed more often than chance, p = 0.0001. Micromedex generated warnings for efficacy limiting interactions for five other combinations, but with no subsequent change in prescription frequency. CONCLUSIONS Neither presence of medical evidence nor warnings from Micromedex consistently affect the prescription of combinations with pharmacodynamic efficacy limiting interactions.
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Affiliation(s)
- Paul A Zarkowski
- Department of Psychiatry and Behavioral Sciences, Harborview Medical Center, University of Washington, Seattle, WA, USA
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5
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Gene knockout animal models of depression, anxiety and obsessive compulsive disorders. Psychiatr Genet 2019; 29:191-199. [DOI: 10.1097/ypg.0000000000000238] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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6
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Noradrenaline induces peripheral antinociception by endogenous opioid release. Pharmacol Rep 2018; 70:784-788. [DOI: 10.1016/j.pharep.2018.02.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 02/07/2018] [Accepted: 02/21/2018] [Indexed: 11/20/2022]
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Andreoli M, Marketkar T, Dimitrov E. Contribution of amygdala CRF neurons to chronic pain. Exp Neurol 2017; 298:1-12. [PMID: 28830762 DOI: 10.1016/j.expneurol.2017.08.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 08/03/2017] [Accepted: 08/18/2017] [Indexed: 12/30/2022]
Abstract
We investigated the role of amygdala corticotropin-releasing factor (CRF) neurons in the perturbations of descending pain inhibition caused by neuropathic pain. Forced swim increased the tail-flick response latency in uninjured mice, a phenomenon known as stress-induced analgesia (SIA) but did not change the tail-flick response latency in mice with neuropathic pain caused by sciatic nerve constriction. Neuropathic pain also increased the expression of CRF in the central amygdala (CeAmy) and ΔFosB in the dorsal horn of the spinal cord. Next, we injected the CeAmy of CRF-cre mice with cre activated AAV-DREADD (Designer Receptors Exclusively Activated by Designer Drugs) vectors. Activation of CRF neurons by DREADD/Gq did not affect the impaired SIA but inhibition of CRF neurons by DREADD/Gi restored SIA and decreased allodynia in mice with neuropathic pain. The possible downstream circuitry involved in the regulation of SIA was investigated by combined injections of retrograde cre-virus (CAV2-cre) into the locus ceruleus (LC) and cre activated AAV-diphtheria toxin (AAV-FLEX-DTX) virus into the CeAmy. The viral injections were followed by a sciatic nerve constriction ipsilateral or contralateral to the injections. Ablation of amygdala projections to the LC on the side of injury but not on the opposite side, completely restored SIA, decreased allodynia and decreased ΔFosB expression in the spinal cord in mice with neuropathic pain. The possible lateralization of SIA impairment to the side of injury was confirmed by an experiment in which unilateral inhibition of the LC decreased SIA even in uninjured mice. The current view in the field of pain research attributes the process of pain chronification to abnormal functioning of descending pain inhibition. Our results demonstrate that the continuous activity of CRF neurons brought about by persistent pain leads to impaired SIA, which is a symptom of dysregulation of descending pain inhibition. Therefore, an over-activation of amygdala CRF neurons is very likely an important contributing factor for pain chronification.
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Affiliation(s)
- Matthew Andreoli
- Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, Unites States.
| | - Tanvi Marketkar
- Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, Unites States.
| | - Eugene Dimitrov
- Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, Unites States.
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8
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Wang YX, Mao XF, Li TF, Gong N, Zhang MZ. Dezocine exhibits antihypersensitivity activities in neuropathy through spinal μ-opioid receptor activation and norepinephrine reuptake inhibition. Sci Rep 2017; 7:43137. [PMID: 28230181 PMCID: PMC5322378 DOI: 10.1038/srep43137] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 01/19/2017] [Indexed: 01/17/2023] Open
Abstract
Dezocine is the number one opioid painkiller prescribed and sold in China, occupying 44% of the nation’s opioid analgesics market today and far ahead of the gold-standard morphine. We discovered the mechanisms underlying dezocine antihypersensitivity activity and assessed their implications to antihypersensitivity tolerance. Dezocine, given subcutaneously in spinal nerve-ligated neuropathic rats, time- and dose-dependently produced mechanical antiallodynia and thermal antihyperalgesia, significantly increased ipsilateral spinal norepinephrine and serotonin levels, and induced less antiallodynic tolerance than morphine. Its mechanical antiallodynia was partially (40% or 60%) and completely (100%) attenuated by spinal μ-opioid receptor (MOR) antagonism or norepinephrine depletion/α2-adrenoceptor antagonism and combined antagonism of MORs and α2-adenoceptors, respectively. In contrast, antagonism of spinal κ-opioid receptors (KORs) and δ-opioid receptors (DORs) or depletion of spinal serotonin did not significantly alter dezocine antiallodynia. In addition, dezocine-delayed antiallodynic tolerance was accelerated by spinal norepinephrine depletion/α2-adenoceptor antagonism. Thus dezocine produces antihypersensitivity activity through spinal MOR activation and norepinephrine reuptake inhibition (NRI), but apparently not through spinal KOR and DOR activation, serotonin reuptake inhibition or other mechanisms. Our findings reclassify dezocine as the first analgesic of the recently proposed MOR-NRI, and reveal its potential as an alternative to as well as concurrent use with morphine in treating pain.
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Affiliation(s)
- Yong-Xiang Wang
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai 200240, China
| | - Xiao-Fang Mao
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai 200240, China
| | - Teng-Fei Li
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai 200240, China
| | - Nian Gong
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai 200240, China
| | - Ma-Zhong Zhang
- Department of Anesthesiology and Pediatric Clinical Pharmacology Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, 1678 Dongfang Road, Shanghai 200127, China
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9
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Mannangatti P, Sundaramurthy S, Ramamoorthy S, Jayanthi LD. Differential effects of aprepitant, a clinically used neurokinin-1 receptor antagonist on the expression of conditioned psychostimulant versus opioid reward. Psychopharmacology (Berl) 2017; 234:695-705. [PMID: 28013351 PMCID: PMC5266628 DOI: 10.1007/s00213-016-4504-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 12/08/2016] [Indexed: 01/29/2023]
Abstract
RATIONALE Neurokinin-1 receptor (NK1R) signaling modulates behaviors associated with psychostimulants and opioids. Psychostimulants, such as amphetamine (AMPH) and cocaine, bind to monoamine transporters and alter their functions. Both dopamine and norepinephrine transporters are regulated by NK1R activation suggesting a role for NK1R mediated catecholamine transporter regulation in psychostimulant-mediated behaviors. OBJECTIVES The effect of in vivo administration of aprepitant (10 mg/kg) on the expression of AMPH (0.5 and 2 mg/kg) and cocaine (5 and 20 mg/kg)-induced conditioned place preference (CPP) as well as locomotor activation was examined in C57BL/6J mice. The effect of aprepitant on morphine (1 and 5 mg/kg)-induced CPP was also examined to identify the specific actions of aprepitant on psychostimulant versus opioid-induced behaviors. RESULTS Aprepitant administration significantly attenuated the CPP expression and locomotor activation produced by AMPH and cocaine. In contrast, aprepitant significantly enhanced the expression of CPP produced by morphine while significantly suppressing the locomotor activity of the mice conditioned with morphine. Aprepitant by itself did not induce significant CPP or conditioned place aversion or locomotor activation or suppression. CONCLUSIONS Attenuation of AMPH or cocaine-induced CPP and locomotor activation by aprepitant suggests a role for NK1R signaling in psychostimulant-mediated behaviors. Stimulation of morphine-induced CPP expression and suppression of locomotor activity of morphine-conditioned mice suggest differential effects of NK1R antagonism on conditioned psychostimulant versus opioid reward. Collectively, these findings indicate that clinically used NK1R antagonist, aprepitant may serve as a potential therapeutic agent in the treatment of psychostimulant abuse.
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Affiliation(s)
| | | | | | - Lankupalle D Jayanthi
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, 23298, USA.
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10
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Deng L, Lee WH, Xu Z, Makriyannis A, Hohmann AG. Prophylactic treatment with the tricyclic antidepressant desipramine prevents development of paclitaxel-induced neuropathic pain through activation of endogenous analgesic systems. Pharmacol Res 2016; 114:75-89. [PMID: 27773824 DOI: 10.1016/j.phrs.2016.10.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 08/10/2016] [Indexed: 12/19/2022]
Abstract
Neuropathic pain impacts approximately 3-4.5% of the global population and remains an unresolved health problem. The management of neuropathic pain has two distinct goals-prevention of development and control of established neuropathic pain. We examined the impact of both prophylactic and therapeutic treatments with the tricyclic antidepressant desipramine on the development and maintenance of toxic neuropathic pain induced by the chemotherapeutic agent paclitaxel. We also investigated the involvement of endogenous analgesic (i.e., endogenous opioid and endocannabinoid) systems in the antinociceptive actions of desipramine in these two distinct phases of neuropathic pain. Chronic subcutaneous infusion of desipramine via osmotic pumps suppressed both the development and maintenance of paclitaxel-induced neuropathic pain. However, only prophylactic desipramine treatment blocked the development of neuropathic pain throughout the three month observation interval; neuropathic pain did not return. The opioid receptor antagonist naloxone blocked the antinociceptive effects of both prophylactic and therapeutic desipramine treatments throughout the entire timecourse of desipramine-induced antinociception. By contrast, cannabinoid CB1 and CB2 receptor antagonists partially attenuated the antinociceptive actions of desipramine in a manner that was restricted to the development phase of paclitaxel-induced neuropathic pain only. Paclitaxel decreased cell viability in TMD231 tumor cells in an MTT assay in vitro. Notably, desipramine (1nM-1μM) alone did not alter tumor cell viability and did not prevent the cytotoxic effects of paclitaxel under identical conditions. The highest concentration of desipramine (10μM) reduced tumor cell viability alone and enhanced the cytotoxic effects of paclitaxel. Our study identifies a previously unrecognized preemptive analgesic strategy that prevents development of paclitaxel-induced neuropathic pain, and also dissects receptor mechanisms underlying desipramine-induced antinociceptive effects. This information may be applied to improve current therapeutic strategies with the goal of preventing and managing neuropathic pain induced by chemotherapeutic treatment.
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Affiliation(s)
- Liting Deng
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA; Interdisciplinary Biochemistry Graduate Program, Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA
| | - Wan-Hung Lee
- Interdisciplinary Biochemistry Graduate Program, Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA
| | - Zhili Xu
- Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - Alexandros Makriyannis
- Center for Drug Discovery, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
| | - Andrea G Hohmann
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA; Interdisciplinary Biochemistry Graduate Program, Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA; Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA.
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11
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Cheng Y, El-Kattan A, Zhang Y, Ray AS, Lai Y. Involvement of Drug Transporters in Organ Toxicity: The Fundamental Basis of Drug Discovery and Development. Chem Res Toxicol 2016; 29:545-63. [DOI: 10.1021/acs.chemrestox.5b00511] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Yaofeng Cheng
- Pharmaceutical
Candidate Optimization, Bristol-Myers Squibb Company, 3551 Lawrenceville
Road, Princeton, New Jersey 08540, United States
| | - Ayman El-Kattan
- Department
of Pharmacokinetics, Dynamics and Metabolism, Pfizer Inc., 610 Main
Street, Cambridge, Massachusetts 02139, United States
| | - Yan Zhang
- Drug
Metabolism and Biopharmaceutics, Incyte Corporation, 1801 Augustine
Cutoff, Wilmington, Delaware 19803, United States
| | - Adrian S. Ray
- Department
of Drug Metabolism, Gilead Sciences, Inc., 333 Lakeside Drive, Foster City, California 94404, United States
| | - Yurong Lai
- Pharmaceutical
Candidate Optimization, Bristol-Myers Squibb Company, 3551 Lawrenceville
Road, Princeton, New Jersey 08540, United States
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12
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Brouwer BA, de Greef BTA, Hoeijmakers JGJ, Geerts M, van Kleef M, Merkies ISJ, Faber CG. Neuropathic Pain due to Small Fiber Neuropathy in Aging: Current Management and Future Prospects. Drugs Aging 2016; 32:611-21. [PMID: 26239827 PMCID: PMC4548010 DOI: 10.1007/s40266-015-0283-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Over the last 10 years, the diagnosis small fiber neuropathy (SFN) has gained recognition worldwide. Patients often suffer from severe neuropathic pain that may be difficult to treat. A substantial subset of patients with SFN is aged 65 years or older, and these patients often exhibit comorbidities and usage of multiple drugs, making neuropathic pain treatment more challenging. In this review, we highlight relevant pathophysiological aspects and discuss currently used therapeutic strategies for neuropathic pain. Possible pitfalls in neuropathic pain treatment in the elderly will be underlined.
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Affiliation(s)
- Brigitte A Brouwer
- Department of Anesthesiology and Pain Medicine, Maastricht University Medical Center, 6202 AZ, Maastricht, The Netherlands
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13
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Dual allosteric modulation of opioid antinociceptive potency by α2A-adrenoceptors. Neuropharmacology 2015; 99:285-300. [PMID: 26254859 DOI: 10.1016/j.neuropharm.2015.08.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Revised: 07/09/2015] [Accepted: 08/04/2015] [Indexed: 12/31/2022]
Abstract
Opioid and α2-adrenoceptor (AR) agonists are analgesic when administered in the spinal cord and show a clinically beneficial synergistic interaction when co-administered. However, α2-AR antagonists can also inhibit opioid antinociception, suggesting a complex interaction between the two systems. The α2A-AR subtype is necessary for spinal adrenergic analgesia and synergy with opioids for most agonist combinations. Therefore, we investigated whether spinal opioid antinociception and opioid-adrenergic synergy were under allosteric control of the α2A-AR. Drugs were administered intrathecally in wild type (WT) and α2A-knock-out (KO) mice and antinociception was measured using the hot water tail immersion or substance P behavioral assays. The α2A-AR agonist clonidine was less effective in α2A-KO mice in both assays. The absence of the α2A-AR resulted in 10-70-fold increases in the antinociceptive potency of the opioid agonists morphine and DeltII. In contrast, neither morphine nor DeltII synergized with clonidine in α2A-KO mice, indicating that the α2AAR has both positive and negative modulatory effects on opioid antinociception. Depletion of descending adrenergic terminals with 6-OHDA resulted in a significant decrease in morphine efficacy in WT but not in α2A-KO mice, suggesting that endogenous norepinephrine acts through the α2A-AR to facilitate morphine antinociception. Based on these findings, we propose a model whereby ligand-occupied versus ligand-free α2A-AR produce distinct patterns of modulation of opioid receptor activation. In this model, agonist-occupied α2A-ARs potentiate opioid analgesia, while non-occupied α2A-ARs inhibit opioid analgesia. Exploiting such interactions between the two receptors could lead to the development of better pharmacological treatments for pain management.
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14
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Castor MGM, Santos RAS, Duarte IDG, Romero TRL. Angiotensin-(1-7) through Mas receptor activation induces peripheral antinociception by interaction with adrenoreceptors. Peptides 2015; 69:80-5. [PMID: 25895850 DOI: 10.1016/j.peptides.2015.04.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/06/2015] [Accepted: 04/07/2015] [Indexed: 11/17/2022]
Abstract
Angiotensin-(1-7) [Ang-(1-7)] develops its functions interacting with Mas receptor. Mas receptor was recently identified in the DRG and its activation by Ang-(1-7) resulted in peripheral antinociception against PGE2 hyperalgesia in an opioid-independent pathway. Nevertheless, the mechanism by which Ang-(1-7) induce peripheral antinociception was not yet elucidated. Considering that endogenous noradrenaline could induce antinociceptive effects by activation of the adrenoceptors the aim of this study was verify if the Ang-(1-7) is able to induce peripheral antinociception by interacting with the endogenous noradrenergic system. Hyperalgesia was induced by intraplantar injection of prostaglandin E2 (2μg). Ang-(1-7) was administered locally into the right hindpaw alone and after either agents, α2-adrenoceptor antagonist, yohimbine (5, 10 and 20 μg/paw), α2C-adrenoceptor antagonist rauwolscine (10, 15 and 20 μg/paw), α1-adrenoceptor antagonist prazosin (0.5, 1 and 2 μg/paw), β-adrenoceptor antagonist propranolol (150, 300 and 600 ng/paw). Noradrenaline (NA) reuptake inhibitor reboxetine (30 μg/paw) was administered prior to Ang-(1-7) low dose (20 ng) and guanetidine 3 days prior to experiment (30 mg/kg/animal, once a day), depleting NA storage. Intraplantar Ang-(1-7) induced peripheral antinociception against hyperalgesia induced by PGE2. This effect was reversed, in dose dependent manner, by intraplantar injection of yohimbine, rauwolscine, prazosin and propranolol. Reboxetine intensified the antinociceptive effects of low-dose of Ang-(1-7) and guanethidine, which depletes peripheral sympathomimetic amines, reversed almost 70% the Ang-(1-7)-induced peripheral antinociception. Then, this study provides evidence that Ang-(1-7) induce peripheral antinociception stimulating an endogenous noradrenaline release that activates peripheral adrenoceptors inducing antinociception.
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Affiliation(s)
- Marina G M Castor
- Department of Pharmacology, Institute of Biological Sciences, UFMG, Av. Antônio Carlos, 6627, 31.270-100 Belo Horizonte, Brazil
| | - Robson A S Santos
- Department of Physiology and Biophysics, Institute of Biological Sciences, UFMG, Av. Antônio Carlos, 6627, 31.270-100 Belo Horizonte, Brazil
| | - Igor D G Duarte
- Department of Pharmacology, Institute of Biological Sciences, UFMG, Av. Antônio Carlos, 6627, 31.270-100 Belo Horizonte, Brazil
| | - Thiago R L Romero
- Department of Pharmacology, Institute of Biological Sciences, UFMG, Av. Antônio Carlos, 6627, 31.270-100 Belo Horizonte, Brazil.
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Granovsky Y. Conditioned pain modulation: a predictor for development and treatment of neuropathic pain. Curr Pain Headache Rep 2014; 17:361. [PMID: 23943407 DOI: 10.1007/s11916-013-0361-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Psychophysical evaluation of endogenous pain inhibition via conditioned pain modulation (CPM) represents a new generation of laboratory tests for pain assessment. In this review we discuss recent findings on CPM in neuropathic pain and refer to psychophysical, neurophysiological, and methodological aspects of its clinical implications. Typically, chronic neuropathic pain patients express less efficient CPM, to the extent that incidence of acquiring neuropathic pain (e.g. post-surgery) and its intensity can be predicted by a pre-surgery CPM assessment. Moreover, pre-treatment CPM evaluation may assist in the correct choice of serotonin-noradrenalin reuptake inhibitor analgesic agents for individual patients. Evaluation of pain modulation capabilities can serve as a step forward in individualizing pain medicine.
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Affiliation(s)
- Yelena Granovsky
- Department of Neurology, Rambam Health Care Campus, Laboratory of Clinical Neurophysiology, Faculty of Medicine, Technion, P.O. Box 9602, Haifa, Israel.
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Kinoshita J, Takahashi Y, Watabe AM, Utsunomiya K, Kato F. Impaired noradrenaline homeostasis in rats with painful diabetic neuropathy as a target of duloxetine analgesia. Mol Pain 2013; 9:59. [PMID: 24279796 PMCID: PMC4222693 DOI: 10.1186/1744-8069-9-59] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 11/22/2013] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Painful diabetic neuropathy (PDN) is a serious complication of diabetes mellitus that affects a large number of patients in many countries. The molecular mechanisms underlying the exaggerated nociception in PDN have not been established. Recently, duloxetine (DLX), a serotonin and noradrenaline re-uptake inhibitor, has been recommended as one of the first-line treatments of PDN in the United States Food and Drug Administration, the European Medicines Agency and the Japanese Guideline for the Pharmacologic Management of Neuropathic pain. Because selective serotonin re-uptake inhibitors show limited analgesic effects in PDN, we examined whether the potent analgesic effect of DLX contributes toward improving the pathologically aberrant noradrenaline homeostasis in diabetic models. RESULTS In streptozotocin (STZ) (50 mg/kg, i.v.)-induced diabetic rats that exhibited robust mechanical allodynia and thermal hyperalgesia, DLX (10 mg/kg, i.p.) significantly and markedly increased the nociceptive threshold. The analgesic effect of DLX was nullified by the prior administration of N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) (50 mg/kg, i.p.), which drastically eliminated dopamine-beta-hydroxylase- and norepinephrine transporter-immunopositive fibers in the lumbar spinal dorsal horn and significantly reduced the noradrenaline content in the lumbar spinal cord. The treatment with DSP-4 alone markedly lowered the nociceptive threshold in vehicle-treated non-diabetic rats; however, this pro-nociceptive effect was occluded in STZ-treated diabetic rats. Furthermore, STZ-treated rats exhibited a higher amount of dopamine-beta-hydroxylase- and norepinephrine transporter-immunopositive fibers in the dorsal horn and noradrenaline content in the spinal cord compared to vehicle-treated rats. CONCLUSIONS Impaired noradrenaline-mediated regulation of the spinal nociceptive network might underlie exaggerated nociception in PDN. DLX might exert its analgesic effect by selective enhancement of noradrenergic signals, thus counteracting this situation.
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Affiliation(s)
- Jun Kinoshita
- Department of Neuroscience, Jikei University School of Medicine, Minato, Tokyo 105-8461, Japan.
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17
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Fentress HM, Klar R, Krueger JJ, Sabb T, Redmon SN, Wallace NM, Shirey-Rice JK, Hahn MK. Norepinephrine transporter heterozygous knockout mice exhibit altered transport and behavior. GENES, BRAIN, AND BEHAVIOR 2013; 12:749-59. [PMID: 24102798 PMCID: PMC3852905 DOI: 10.1111/gbb.12084] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 07/26/2013] [Accepted: 09/06/2013] [Indexed: 01/07/2023]
Abstract
The norepinephrine (NE) transporter (NET) regulates synaptic NE availability for noradrenergic signaling in the brain and sympathetic nervous system. Although genetic variation leading to a loss of NET expression has been implicated in psychiatric and cardiovascular disorders, complete NET deficiency has not been found in people, limiting the utility of NET knockout mice as a model for genetically driven NET dysfunction. Here, we investigate NET expression in NET heterozygous knockout male mice (NET(+/-) ), demonstrating that they display an approximately 50% reduction in NET protein levels. Surprisingly, these mice display no significant deficit in NET activity assessed in hippocampal and cortical synaptosomes. We found that this compensation in NET activity was due to enhanced activity of surface-resident transporters, as opposed to surface recruitment of NET protein or compensation through other transport mechanisms, including serotonin, dopamine or organic cation transporters. We hypothesize that loss of NET protein in the NET(+/-) mouse establishes an activated state of existing surface NET proteins. The NET(+/-) mice exhibit increased anxiety in the open field and light-dark box and display deficits in reversal learning in the Morris water maze. These data suggest that recovery of near basal activity in NET(+/-) mice appears to be insufficient to limit anxiety responses or support cognitive performance that might involve noradrenergic neurotransmission. The NET(+/-) mice represent a unique model to study the loss and resultant compensatory changes in NET that may be relevant to behavior and physiology in human NET deficiency disorders.
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Affiliation(s)
- H M Fentress
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA
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18
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Shen F, Tsuruda PR, Smith JAM, Obedencio GP, Martin WJ. Relative contributions of norepinephrine and serotonin transporters to antinociceptive synergy between monoamine reuptake inhibitors and morphine in the rat formalin model. PLoS One 2013; 8:e74891. [PMID: 24098676 PMCID: PMC3787017 DOI: 10.1371/journal.pone.0074891] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 08/07/2013] [Indexed: 01/21/2023] Open
Abstract
Multimodal analgesia is designed to optimize pain relief by coadministering drugs with distinct mechanisms of action or by combining multiple pharmacologies within a single molecule. In clinical settings, combinations of monoamine reuptake inhibitors and opioid receptor agonists have been explored and one currently available analgesic, tapentadol, functions as both a µ-opioid receptor agonist and a norepinephrine transporter inhibitor. However, it is unclear whether the combination of selective norepinephrine reuptake inhibition and µ-receptor agonism achieves an optimal antinociceptive synergy. In this study, we assessed the pharmacodynamic interactions between morphine and monoamine reuptake inhibitors that possess different affinities and selectivities for norepinephrine and serotonin transporters. Using the rat formalin model, in conjunction with measurements of ex vivo transporter occupancy, we show that neither the norepinephrine-selective inhibitor, esreboxetine, nor the serotonin-selective reuptake inhibitor, fluoxetine, produce antinociceptive synergy with morphine. Atomoxetine, a monoamine reuptake inhibitor that achieves higher levels of norepinephrine than serotonin transporter occupancy, exhibited robust antinociceptive synergy with morphine. Similarly, a fixed-dose combination of esreboxetine and fluoxetine which achieves comparable levels of transporter occupancy potentiated the antinociceptive response to morphine. By contrast, duloxetine, a monoamine reuptake inhibitor that achieves higher serotonin than norepinephrine transporter occupancy, failed to potentiate the antinociceptive response to morphine. However, when duloxetine was coadministered with the 5-HT3 receptor antagonist, ondansetron, potentiation of the antinociceptive response to morphine was revealed. These results support the notion that inhibition of both serotonin and norepinephrine transporters is required for monoamine reuptake inhibitor and opioid-mediated antinociceptive synergy; yet, excess serotonin, acting via 5-HT3 receptors, may reduce the potential for synergistic interactions. Thus, in the rat formalin model, the balance between norepinephrine and serotonin transporter inhibition influences the degree of antinociceptive synergy observed between monoamine reuptake inhibitors and morphine.
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Affiliation(s)
- Fei Shen
- Departments of Pharmacology, Theravance Inc., South San Francisco, California, United States of America
- * E-mail:
| | - Pamela R. Tsuruda
- Departments of Molecular and Cell Biology, Theravance Inc., South San Francisco, California, United States of America
| | - Jacqueline A. M. Smith
- Departments of Molecular and Cell Biology, Theravance Inc., South San Francisco, California, United States of America
| | - Glenmar P. Obedencio
- Departments of Molecular and Cell Biology, Theravance Inc., South San Francisco, California, United States of America
| | - William J. Martin
- Departments of Pharmacology, Theravance Inc., South San Francisco, California, United States of America
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Schreiber S, Barak Y, Hostovsky A, Baratz-Goldstein R, Volis I, Rubovitch V, Pick CG. Interaction of different antidepressants with acute and chronic methadone in mice, and possible clinical implications. J Mol Neurosci 2013; 52:598-604. [PMID: 24057890 DOI: 10.1007/s12031-013-0115-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 09/03/2013] [Indexed: 01/04/2023]
Abstract
We studied the interaction of a single dose of different antidepressant medications with a single (acute) dose or implanted mini-pump (chronic) methadone administration in mice, using the hotplate assay. For the acute experiment, subthreshold doses of six antidepressant drugs were administered separately with a single dose of methadone. The addition of a subthreshold dose of desipramine or clomipramine to methadone produced significant augmentation of the methadone effect with each drug (p < 0.05). Fluvoxamine given at a fixed subthreshold dose induced a synergistic effect only with a low methadone dose. Escitalopram, reboxetine and venlafaxine given separately, each at a fixed subthreshold dose, induced no interaction. Possible clinical implications of these findings are that while escitalopram, reboxetine and venlafaxine do not affect methadone's antinociception in mice and are safe to be given together with methadone when indicated, fluvoxamine, clomipramine and desipramine considerably augment methadone-induced effects and should be avoided in this population due to the risk of inducing opiate overdose. For the chromic experiment, when a subthreshold dose of either escitalopram, desipramine or clomipramine was injected to mice following 2 weeks of methadone administration with the mini-pump, none of the antidepressant drugs strengthened methadone's analgesic effect. Further studies are needed before possible clinical implications can be drawn.
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Affiliation(s)
- Shaul Schreiber
- Department of Psychiatry, Tel Aviv Sourasky Medical Center, Tel Aviv University, Tel Aviv, 64239, Israel,
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20
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Michot B, Bourgoin S, Kayser V, Hamon M. Effects of tapentadol on mechanical hypersensitivity in rats with ligatures of the infraorbital nerve versus the sciatic nerve. Eur J Pain 2012; 17:867-80. [PMID: 23229959 DOI: 10.1002/j.1532-2149.2012.00259.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2012] [Indexed: 12/16/2022]
Abstract
BACKGROUND Convergent data showed that neuropathic pain has specific characteristics at cephalic versus extra-cephalic level, where single-targeted drugs differentially alleviate pain. Because the novel analgesic drug, tapentadol, is acting at two targets, μ-opioid receptors (as agonist) and noradrenaline reuptake (as inhibitor), we tested its effects on neuropathic pain at both cephalic and extra-cephalic levels. METHODS Sprague-Dawley rats underwent unilateral constriction injury (CCI) to the infraorbital nerve (ION; cephalic territory) or the sciatic nerve (SN; extra-cephalic territory), and alleviation of nerve lesion-induced mechanical allodynia/hyperalgesia was assessed after acute or repeated (for 4 days) treatment with tapentadol compared with morphine and/or reboxetine (noradrenaline reuptake inhibitor) 2 weeks after surgery. Possible changes in the expression of the neuroinflammatory markers activating transcription factor 3 (ATF3), interleukin-6 (IL-6) and brain-derived neurotrophic factor (BDNF) by repeated tapentadol treatment were quantified by real-time reverse transcription polymerase chain reaction in ganglia and central tissues. RESULTS Acute administration of tapentadol (1-10 mg/kg, i.p.) significantly reduced allodynia in both CCI-SN and CCI-ION rats. Although morphine (3 mg/kg, s.c.) or reboxetine (10 mg/kg, i.p.) alone was only marginally active, the combination of both drugs produced supra-additive effects like those observed with tapentadol. In contrast to repeated morphine whose effects vanished, the anti-allodynic effects of tapentadol remained unchanged after a 4-day treatment. However, the latter treatment with tapentadol did not affect nerve lesion-evoked overexpression of ATF3, IL-6 and BDNF transcripts. CONCLUSIONS The dual synergistic pharmacological properties of tapentadol, which result in clear-cut anti-neuropathic pain effects at both cephalic and extra-cephalic levels, probably involve mechanisms downstream of nerve injury-induced neuroinflammatory reaction.
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Affiliation(s)
- B Michot
- INSERM U894-CPN, Université Pierre et Marie Curie, Paris, France
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21
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Arnold LM, Hirsch I, Sanders P, Ellis A, Hughes B. Safety and efficacy of esreboxetine in patients with fibromyalgia: a fourteen-week, randomized, double-blind, placebo-controlled, multicenter clinical trial. ACTA ACUST UNITED AC 2012; 64:2387-97. [PMID: 22275142 DOI: 10.1002/art.34390] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To evaluate the efficacy, tolerability, and safety of multiple fixed dosages of esreboxetine for the treatment of fibromyalgia. METHODS Patients meeting the American College of Rheumatology criteria for fibromyalgia were randomized to receive esreboxetine at dosages of 4 mg/day (n=277), 8 mg/day (n=284), or 10 mg/day (n=283) or matching placebo (n=278) for 14 weeks. The primary efficacy outcomes were the weekly mean pain score and the Fibromyalgia Impact Questionnaire (FIQ) total score at week 14. Secondary efficacy measures included scores for the Patient's Global Impression of Change (PGIC) scale, the Global Fatigue Index (GFI), and the 36-item Short-Form health survey (SF-36; physical function scale only) at week 14. The safety profile of esreboxetine was evaluated based on adverse events and other safety measures. RESULTS Patients receiving all dosages of esreboxetine demonstrated statistically significant improvements in the pain score (P≤0.025), the FIQ score (P≤0.023), and the PGIC score (P≤0.007) compared with patients in the placebo group. Additionally, patients receiving esreboxetine at dosages of 4 mg/day and 8 mg/day showed statistically significant improvements in the GFI score compared with those receiving placebo (P=0.001). No significant differences in SF-36 physical function scores were observed between patients receiving esreboxetine (any dosage) and those receiving placebo. Adverse events were mostly mild to moderate in severity; insomnia, constipation, dry mouth, nausea, dizziness, hot flush, headache, hyperhidrosis, and palpitations were reported most frequently. CONCLUSION Esreboxetine was generally well tolerated and was associated with significant improvements in pain, FIQ, PGIC, and fatigue scores compared with placebo. The lack of a dose-response relationship in both the efficacy and safety analyses suggests that esreboxetine at a dosage of 4 mg/day would offer clinical benefit with the least risk of drug exposure.
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Affiliation(s)
- Lesley M Arnold
- University of Cincinnati College of Medicine, Cincinnati, Ohio 45219, USA.
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22
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Evidence that behavioral phenotypes of morphine in β-arr2-/- mice are due to the unmasking of JNK signaling. Neuropsychopharmacology 2012; 37:1953-62. [PMID: 22491351 PMCID: PMC3376327 DOI: 10.1038/npp.2012.42] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The altered behavioral effects of morphine, but not most other mu agonists, in mice lacking β-arrestin 2, suggest that this scaffolding protein regulates the signaling cascade of this commonly used analgesic. One of the cascades that could be regulated by β-arrestin 2 is cJun-N-terminal kinase (JNK), which binds with β-arrestin 2 and modulates the analgesic effects of morphine. Using neurons lacking β-arrestin 2 (β-arr2-/-) to examine this interaction, we found that β-arr2-/- neurons show altered intracellular distribution of JNK and cJun, and that morphine, but not fentanyl, increased the nuclear localization of the phosphorylated, therefore activated, form of cJun, a JNK target in dorsal root ganglia neurons. This suggests that deleting β-arrestin 2 affects the JNK cascade. We therefore examined whether some of the behavioral phenotypes of mice lacking β-arrestin 2 could be a result of altered JNK signaling. Indeed, two different JNK inhibitors reversed the enhanced analgesic effect of morphine, a known phenotype of β-arr2-/- mice, to +/+ levels. Both the reduced locomotor effect of morphine and the psychomotor sensitization to repeated morphine administration in β-arr2-/- mice were also returned to +/+ levels by inhibiting JNK. In contrast, the behavioral effects of fentanyl were neither genotype-dependent nor affected by JNK inhibition. Furthermore, a PKC inhibitor had a similar effect as inhibiting JNK in reducing the enhanced analgesic effect of morphine in β-arr2-/- mice to +/+ levels. In summary, removing β-arrestin 2 reveals mu receptor activation of the JNK cascade in a ligand-specific manner explaining several behavioral phenotypes of β-arr2-/- mice.
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23
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Mu, Delta, and Kappa opioid receptor agonists induce peripheral antinociception by activation of endogenous noradrenergic system. J Neurosci Res 2012; 90:1654-61. [DOI: 10.1002/jnr.23050] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 01/17/2012] [Accepted: 02/10/2012] [Indexed: 01/25/2023]
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Differential adaptive changes on serotonin and noradrenaline transporters in a rat model of peripheral neuropathic pain. Neurosci Lett 2012; 515:181-6. [PMID: 22480692 DOI: 10.1016/j.neulet.2012.03.050] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 03/16/2012] [Accepted: 03/19/2012] [Indexed: 11/21/2022]
Abstract
Serotonin and noradrenaline reuptake inhibitors have shown to produce antinociceptive effects in several animal models of neuropathic pain. In the present work, we have analyzed the density of brain and spinal serotonin and noradrenaline transporters (5-HTT and NAT) in a rat model of neuropathic pain, the spinal nerve ligation (SNL). Quantitative autoradiography revealed a significant decrease in the density of 5-HTT ([(3)H]citalopram binding) at the level of the lumbar spinal cord following 2 weeks of neuropathic surgery (lamina V, -40%: 6.01±0.64 nCi/mg tissue in sham-animals vs 3.59±1.56 in SNL-animals; lamina X, -30%: 9.10±2.00 vs 6.40±1.93 and lamina IX, -22%: 12.01±2.41 vs 9.42±1.58). By contrast, NAT density ([(3)H]nisoxetine binding) was significantly increased (lamina I-II, +34%: 2.20±0.45 vs 2.96±0.65; lamina V, +57%: 1.34±0.28 vs 2.11±0.66; and lamina IX, +58%: 2.39±0.71 vs 3.78±1.10). At supraspinal structures, SNL induced adaptive changes only in the density of 5-HTT (septal nuclei, +33%: 10.18±2.03 vs 13.53±1.14; CA3 field of hippocampus, +18%: 6.94±1.01 vs 8.21±0.81; paraventricular thalamic nucleus, +21%: 15.18±1.88 vs 18.35±2.08; lateral hypothalamic area, +40%: 12.68±1.90 vs 17.8±2.55; ventromedial hypothalamic nuclei, +19%: 7.16±0.92 vs 8.55±0.40; and dorsal raphe nucleus, +15%: 35.22±3.88 vs 40.68±3.11). Thus, we demonstrate, in the SNL model of neuropathic pain, the existence of opposite changes in the spinal expression of 5-HTT (down-regulation) and NAT (up-regulation), and the presence of supraspinal adaptive changes (up-regulation) only on 5-HTT density. These findings may help understanding the pathogeny of neuropathic pain and the differential analgesic action of antidepressants targeting 5-HTT and/or NAT transporters.
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Schröder W, Vry J, Tzschentke TM, Jahnel U, Christoph T. Differential contribution of opioid and noradrenergic mechanisms of tapentadol in rat models of nociceptive and neuropathic pain. Eur J Pain 2012; 14:814-21. [DOI: 10.1016/j.ejpain.2010.05.005] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 04/28/2010] [Accepted: 05/10/2010] [Indexed: 11/15/2022]
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Miller LK, Hou X, Rodriguiz RM, Gagnidze K, Sweedler JV, Wetsel WC, Devi LA. Mice deficient in endothelin-converting enzyme-2 exhibit abnormal responses to morphine and altered peptide levels in the spinal cord. J Neurochem 2011; 119:1074-85. [PMID: 21972895 DOI: 10.1111/j.1471-4159.2011.07513.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An increasing body of evidence suggests that endothelin-converting enzyme-2 (ECE-2) is a non-classical neuropeptide processing enzyme. Similar to other neuropeptide processing enzymes, ECE-2 exhibits restricted neuroendocrine distribution, intracellular localization, and an acidic pH optimum. However, unlike classical neuropeptide processing enzymes, ECE-2 exhibits a non-classical cleavage site preference for aliphatic and aromatic residues. We previously reported that ECE-2 cleaves a number of neuropeptides at non-classical sites in vitro; however its role in peptide processing in vivo is poorly understood. Given the recognized roles of neuropeptides in pain and opiate responses, we hypothesized that ECE-2 knockout (KO) mice might show altered pain and morphine responses compared with wild-type mice. We find that ECE-2 KO mice show decreased response to a single injection of morphine in hot-plate and tail-flick tests. ECE-2 KO mice also show more rapid development of tolerance with prolonged morphine treatment and fewer signs of naloxone-precipitated withdrawal. Peptidomic analyses revealed changes in the levels of a number of spinal cord peptides in ECE-2 KO as compared to wild-type mice. Taken together, our findings suggest a role for ECE-2 in the non-classical processing of spinal cord peptides and morphine responses; however, the precise mechanisms through which ECE-2 influences morphine tolerance and withdrawal remain unclear.
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Affiliation(s)
- Lydia K Miller
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, New York, USA
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Gursoy S, Ozdemir E, Bagcivan I, Altun A, Durmus N. Effects of alpha 2-adrenoceptor agonists dexmedetomidine and guanfacine on morphine analgesia and tolerance in rats. Ups J Med Sci 2011; 116:238-46. [PMID: 21919812 PMCID: PMC3207298 DOI: 10.3109/03009734.2011.597889] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Alpha 2 (α(2))-adrenoceptor agonists may be useful for their potential to increase or prolong opioid analgesia while attenuating the development of opioid tolerance. The purpose of this study was to investigate the effects of dexmedetomidine and guanfacine (α(2)-adrenoceptor agonists) on morphine analgesia and tolerance in rats. METHODS Adult male Wistar albino rats weighing 195-205 g were used. To constitute morphine tolerance, animals received morphine (50 mg/kg) once daily for 3 days. After the last dose of morphine had been injected on day 4, morphine tolerance was evaluated by analgesia tests. The analgesic effects of dexmedetomidine (20 ug/kg), guanfacine (0.5 mg/kg), MK-467 (0.25 mg/kg), and morphine were estimated at 30-min intervals (0, 30, 60, 90, and 120 min) by tail-flick and hot-plate analgesia tests. RESULTS Our findings indicate that dexmedetomidine and guanfacine attenuated the expression of morphine tolerance. In addition, administration of dexmedetomidine with morphine increased morphine analgesia. On the contrary, data suggested that MK-467 (an α(2)-adrenoceptor antagonist) decreased morphine analgesia and increased morphine tolerance in analgesia tests. CONCLUSION In conclusion, we observed that co-injection of dexmedetomidine or guanfacine with morphine attenuated the expression of tolerance to the analgesic effect of morphine and that dexmedetomidine enhanced the morphine analgesia.
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Affiliation(s)
- Sinan Gursoy
- Anesthesiology and Reanimation, Cumhuriyet University School of Medicine, Sivas, Turkey
| | - Ercan Ozdemir
- Department of Physiology, Cumhuriyet University School of Medicine, Sivas, Turkey
| | - Ihsan Bagcivan
- Department of Pharmacology, Cumhuriyet University School of Medicine, Sivas, Turkey
| | - Ahmet Altun
- Department of Pharmacology, Cumhuriyet University School of Medicine, Sivas, Turkey
| | - Nedim Durmus
- Department of Pharmacology, Cumhuriyet University School of Medicine, Sivas, Turkey
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Haenisch B, Bönisch H. Depression and antidepressants: Insights from knockout of dopamine, serotonin or noradrenaline re-uptake transporters. Pharmacol Ther 2011; 129:352-68. [DOI: 10.1016/j.pharmthera.2010.12.002] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 11/29/2010] [Indexed: 12/15/2022]
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29
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Arnold LM, Chatamra K, Hirsch I, Stoker M. Safety and efficacy of esreboxetine in patients with fibromyalgia: An 8-week, multicenter, randomized, double-blind, placebo-controlled study. Clin Ther 2011; 32:1618-32. [PMID: 20974319 DOI: 10.1016/j.clinthera.2010.08.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2010] [Indexed: 01/04/2023]
Abstract
BACKGROUND Esreboxetine is an investigational, highly selective norepinephrine reuptake inhibitor that has been reported to have antinociceptive effects in preclinical pain models. OBJECTIVE This study assessed the efficacy and safety profile of esreboxetine in the management of fibromyalgia. METHODS This was a multicenter, randomized, double-blind, placebo-controlled trial in patients aged ≥18 years who met American College of Rheumatology criteria for fibromyalgia. Eligible patients were required to have a score ≥40 mm on the 100-mm visual analog scale of the Short-Form McGill Pain Questionnaire at screening and randomization, and a mean score ≥4 on an 11-point pain rating scale (from 0 = no pain to 10 = worst possible pain) based on the weekly mean pain score in the week before randomization. After a 1-week baseline period and a 2-week, single-blind, placebo run-in period, patients were randomized to receive esreboxetine or placebo for 8 weeks, followed by a 1-week follow-up period. Esreboxetine dosing was started at 2 mg/d and was escalated by 2 mg/d every 2 weeks until attainment of a dose of 8 mg/d or the maximum tolerated dose. The primary efficacy outcome was the change from baseline to week 8 in weekly mean pain scores, as derived from patients' daily pain ratings on the 11-point scale. Additional primary efficacy outcomes included changes in the Fibromyalgia Impact Questionnaire (FIQ) total score and the Patient Global Impression of Change (PGIC). The safety profile was evaluated based on observed and spontaneously reported adverse events, laboratory tests, and other safety measures. RESULTS One hundred thirty-four patients were randomized to each study group, but 1 patient in the placebo group did not receive treatment. Thus, the study population consisted of 267 patients (89.5% female; 88.4% white; mean age, ∼50 years [range, 20-84 years]). Twenty-seven patients in each group discontinued the study. Adverse events were the most common reason for discontinuation in the esreboxetine group (11 patients), compared with 3 discontinuing due to adverse events in the placebo group. Patient default (withdrawal of consent and loss to follow-up) was the most common reason for discontinuation in the placebo group (13 patients), compared with 10 in the esreboxetine group. The esreboxetine group had significantly greater improvement in the weekly mean pain score compared with the placebo group (mean [SE] change from baseline: -1.55 [0.16] vs -0.99 [0.16], respectively; P = 0.006). A significantly greater percentage of patients in the esreboxetine group reported a ≥30% reduction in pain scores compared with the placebo group (37.6% [50/133] vs 22.6% [30/133]; P = 0.004). Esreboxetine was associated with significant improvement compared with placebo in the FIQ total score (mean change from baseline: -15.63 [1.56] vs -8.07 [1.54]; P < 0.001). On the PGIC, significantly more patients in the esreboxetine group than in the placebo group reported their condition much or very much improved (odds ratio = 2.42; 90% CI, 1.549-3.786; P < 0.001). Esreboxetine also was associated with significant improvements in secondary outcomes compared with placebo. These included fatigue, as reflected in scores on the Multidimensional Assessment of Fatigue (mean [SE] change from baseline: -6.39 [0.75] vs -2.82 [0.75], respectively; P < 0.001), and scores on measures of patient function and health-related quality of life, including the 36-item Short Form Health Survey (SF-36) Physical Component Summary (mean change from baseline: 4.36 [0.59] vs 1.86 [0.59]; P = 0.002), the SF-36 Mental Component Summary (mean change from baseline: 4.25 [0.83] vs 1.81 [0.83]; P = 0.019), and the Sheehan Disability Scale total score (mean change from baseline: -6.50 [0.64] vs -2.79 [0.61]; P < 0.001). Numerically more patients in the esreboxetine group than in the placebo group reported at least one adverse event (71.6% vs 57.1%), most commonly constipation (17.2% vs 5.3%), insomnia (15.7% vs 3.0%), dry mouth (15.7% vs 2.3%), and headache (10.4% vs 2.3%). CONCLUSIONS In this 8-week trial in patients with fibromyalgia, esreboxetine was associated with significant reductions in pain scores compared with placebo. It was also associated with improvements in outcomes relevant to fibromyalgia, including the PGIC, function, and fatigue. ClinicalTrials.gov identifier: NCT00357825.
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Affiliation(s)
- Lesley M Arnold
- University of Cincinnati College of Medicine, Cincinnati, Ohio 45219, USA.
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Hache G, Coudore F, Gardier AM, Guiard BP. Monoaminergic Antidepressants in the Relief of Pain: Potential Therapeutic Utility of Triple Reuptake Inhibitors (TRIs). Pharmaceuticals (Basel) 2011. [PMCID: PMC4053958 DOI: 10.3390/ph4020285] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Over 75% of depressed patients suffer from painful symptoms predicting a greater severity and a less favorable outcome of depression. Imaging, anatomical and functional studies have demonstrated the existence of common brain structures, neuronal pathways and neurotransmitters in depression and pain. In particular, the ascending serotonergic and noradrenergic pathways originating from the raphe nuclei and the locus coeruleus; respectively, send projections to the limbic system. Such pathways control many of the psychological functions that are disturbed in depression and in the perception of pain. On the other hand, the descending pathways, from monoaminergic nuclei to the spinal cord, are specifically implicated in the inhibition of nociception providing rationale for the use of serotonin (5-HT) and/or norepinephrine (NE) reuptake inhibitors (SSRIs, NRIs, SNRIs), in the relief of pain. Compelling evidence suggests that dopamine (DA) is also involved in the pathophysiology and treatment of depression. Indeed, recent insights have demonstrated a central role for DA in analgesia through an action at both the spinal and suprasinal levels including brain regions such as the periaqueductal grey (PAG), the thalamus, the basal ganglia and the limbic system. In this context, dopaminergic antidepressants (i.e., containing dopaminergic activity), such as bupropion, nomifensine and more recently triple reuptake inhibitors (TRIs), might represent new promising therapeutic tools in the treatment of painful symptoms with depression. Nevertheless, whether the addition of the dopaminergic component produces more robust effects than single- or dual-acting agents, has yet to be demonstrated. This article reviews the main pathways regulating pain transmission in relation with the monoaminergic systems. It then focuses on the current knowledge regarding the in vivo pharmacological properties and mechanism of action of monoaminergic antidepressants including SSRIs, NRIs, SNRIs and TRIs. Finally, a synthesis of the preclinical studies supporting the efficacy of these antidepressants in analgesia is also addressed in order to highlight the relative contribution of 5-HT, NE and DA to nociception.
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Affiliation(s)
- Guillaume Hache
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: 011-331-46-83-53-61
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Lin Z, Canales JJ, Björgvinsson T, Thomsen MM, Qu H, Liu QR, Torres GE, Caine SB. Monoamine transporters: vulnerable and vital doorkeepers. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 98:1-46. [PMID: 21199769 PMCID: PMC3321928 DOI: 10.1016/b978-0-12-385506-0.00001-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Transporters of dopamine, serotonin, and norepinephrine have been empirically used as medication targets for several mental illnesses in the last decades. These protein-targeted medications are effective only for subpopulations of patients with transporter-related brain disorders. Since the cDNA clonings in early 1990s, molecular studies of these transporters have revealed a wealth of information about the transporters' structure-activity relationship (SAR), neuropharmacology, cell biology, biochemistry, pharmacogenetics, and the diseases related to the human genes encoding these transporters among related regulators. Such new information creates a unique opportunity to develop transporter-specific medications based on SAR, mRNA, DNA, and perhaps transporter trafficking regulation for a number of highly relevant diseases including substance abuse, depression, schizophrenia, and Parkinson's disease.
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Affiliation(s)
- Zhicheng Lin
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA 02478, USA
| | - Juan J. Canales
- Department of Psychology, Behavioural Neuroscience, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Thröstur Björgvinsson
- Behavioral Health Partial Hospital and Psychology Internship Programs, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - Morgane M. Thomsen
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA 02478, USA
| | - Hong Qu
- Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University. Beijing, 100871 China
| | - Qing-Rong Liu
- Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, NIH/DHHS, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Gonzalo E. Torres
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - S. Barak Caine
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA 02478, USA
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Hall FS, Schwarzbaum JM, Perona MTG, Templin JS, Caron MG, Lesch KP, Murphy DL, Uhl GR. A greater role for the norepinephrine transporter than the serotonin transporter in murine nociception. Neuroscience 2010; 175:315-27. [PMID: 21129446 DOI: 10.1016/j.neuroscience.2010.11.057] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 10/27/2010] [Accepted: 11/28/2010] [Indexed: 11/16/2022]
Abstract
Norepinephrine and serotonin involvement in nociceptive functions is supported by observations of analgesic effects of norepinephrine transporter (NET) and serotonin transporter (SERT) inhibitors such as amitriptyline. However, the relative contribution of NET and SERT to baseline nociception, as well as amitriptyline analgesia, is unclear. Amitriptyline and morphine analgesia in wild-type (WT) mice and littermates with gene knockout (KO) of SERT, NET or both transporters was conducted using the hotplate and tail-flick tests. Hypoalgesia was observed in NET KO mice, and to a lesser extent in SERT KO mice. The magnitude of this hypoalgesia in NET KO mice was so profound that it limited the assessment of drug-induced analgesia. Nonetheless, the necessary exclusion of these subjects because of profound baseline hypoalgesia strongly supports the role of norepinephrine and NET in basal nociceptive behavior while indicating a much smaller role for serotonin and SERT. To further clarify the role of NET and SERT in basal nociceptive sensitivity further experiments were conducted in SERT KO and NET KO mice across a range of temperatures. NET KO mice were again found to have pronounced thermal hypoalgesia compared to WT mice in both the hotplate and tail-flick tests, while only limited effects were observed in SERT KO mice. Furthermore, in the acetic acid writhing test of visceral nociception pronounced hypoalgesia was again found in NET KO mice, but no change in SERT KO mice. As some of these effects may have resulted from developmental consequences of NET KO, the effects of the selective NET blocker nisoxetine and the selective SERT blocker fluoxetine were also examined in WT mice: only nisoxetine produced analgesia in these mice. Collectively these data suggest that NET has a far greater role in determining baseline analgesia, and perhaps other analgesic effects, than SERT in mice.
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Affiliation(s)
- F S Hall
- National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD 21224, USA.
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33
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McElligott ZA, Winder DG. Modulation of glutamatergic synaptic transmission in the bed nucleus of the stria terminalis. Prog Neuropsychopharmacol Biol Psychiatry 2009; 33:1329-35. [PMID: 19524008 PMCID: PMC2783684 DOI: 10.1016/j.pnpbp.2009.05.022] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 05/12/2009] [Accepted: 05/14/2009] [Indexed: 11/27/2022]
Abstract
Glutamate, catecholamine and neuropeptide signaling within the bed nucleus of the stria terminalis (BNST) have all been identified as key participants in anxiety-like behaviors and behaviors related to withdrawal from exposure to substances of abuse. The BNST is thought to serve as a key relay between limbic cognitive centers and reward, stress and anxiety nuclei. Human studies and animal models have demonstrated that stressors and drugs of abuse can result in long term behavioral modifications that can culminate in psychological diseases such as addiction and post-traumatic stress disorder. The ability of catecholamines and neuropeptides to influence synaptic glutamatergic transmission (stemming from cognitive centers) within the BNST may have profound consequences over these behaviors. In this review we highlight studies examining synaptic plasticity and modulation of excitatory transmission within the BNST, emphasizing how such modulation may result in alterations in anxiety and reward related behavior.
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Affiliation(s)
| | - Danny G. Winder
- Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN, USA, Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN, USA, Kennedy Center For Human Development, Vanderbilt University Medical Center, Nashville, TN, USA
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Matthies HJG, Han Q, Shields A, Wright J, Moore JL, Winder DG, Galli A, Blakely RD. Subcellular localization of the antidepressant-sensitive norepinephrine transporter. BMC Neurosci 2009; 10:65. [PMID: 19545450 PMCID: PMC2716352 DOI: 10.1186/1471-2202-10-65] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Accepted: 06/23/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Reuptake of synaptic norepinephrine (NE) via the antidepressant-sensitive NE transporter (NET) supports efficient noradrenergic signaling and presynaptic NE homeostasis. Limited, and somewhat contradictory, information currently describes the axonal transport and localization of NET in neurons. RESULTS We elucidate NET localization in brain and superior cervical ganglion (SCG) neurons, aided by a new NET monoclonal antibody, subcellular immunoisolation techniques and quantitative immunofluorescence approaches. We present evidence that axonal NET extensively colocalizes with syntaxin 1A, and to a limited degree with SCAMP2 and synaptophysin. Intracellular NET in SCG axons and boutons also quantitatively segregates from the vesicular monoamine transporter 2 (VMAT2), findings corroborated by organelle isolation studies. At the surface of SCG boutons, NET resides in both lipid raft and non-lipid raft subdomains and colocalizes with syntaxin 1A. CONCLUSION Our findings support the hypothesis that SCG NET is segregated prior to transport from the cell body from proteins comprising large dense core vesicles. Once localized to presynaptic boutons, NET does not recycle via VMAT2-positive, small dense core vesicles. Finally, once NET reaches presynaptic plasma membranes, the transporter localizes to syntaxin 1A-rich plasma membrane domains, with a portion found in cholera toxin-demarcated lipid rafts. Our findings indicate that activity-dependent insertion of NET into the SCG plasma membrane derives from vesicles distinct from those that deliver NE. Moreover, NET is localized in presynaptic membranes in a manner that can take advantage of regulatory processes targeting lipid raft subdomains.
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Affiliation(s)
- Heinrich J G Matthies
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Kest B, Smith SB, Schorscher-Petcu A, Austin JS, Ritchie J, Klein G, Rossi GC, Fortin A, Mogil JS. Gnao1 (G alphaO protein) is a likely genetic contributor to variation in physical dependence on opioids in mice. Neuroscience 2009; 162:1255-64. [PMID: 19460419 DOI: 10.1016/j.neuroscience.2009.05.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Revised: 05/14/2009] [Accepted: 05/15/2009] [Indexed: 12/17/2022]
Abstract
Chronic exposure to opioids leads to physical dependence, which manifests as the symptoms of drug withdrawal. Interindividual differences in withdrawal symptom severity are well known, and at least partially due to genetic variation. To identify genes contributing to variation in withdrawal severity, we chronically treated 30 strains of the AcB/BcA recombinant congenic mouse strain set, including their A/J and C57BL/6J (B6) progenitors, with morphine for seven days and compared jumping frequencies--a sensitive and widely used index of withdrawal magnitude--during naloxone-precipitated withdrawal (NPW). Jumping frequencies of B6 mice were more than threefold greater than values obtained in A/J mice. Visual inspection of the genomic distribution of parental haplotypes in the AcB/BcA strains identified a putative quantitative trait locus (QTL) localized to chromosome 8 (90-117 Mb), and this QTL was confirmed in a B6AF2 intercross. The most salient candidate gene within this QTL, Gnao1 (guanine nucleotide binding protein, alpha(o); G alpha(o); 96.3 Mb), was tested for functional relevance using quantitative PCR and an antisense oligodeoxynucleotide strategy. The expression of Gnao1 in the locus coeruleus was found to be upregulated in morphine-dependent B6 but not A/J mice. Antisense knockdown of Gnao1 reduced NPW jumping in B6, but not A/J, mice rendered dependent on either morphine or heroin, largely rescuing the original strain difference. These data strongly implicate the G alpha(o) protein in the locus coeruleus as contributing to interindividual variability in physical dependence on opioids in mice.
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Affiliation(s)
- B Kest
- Department of Psychology and Center for Developmental Neuroscience, The College of Staten Island, City University of New York, Staten Island, NY 10314, USA.
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Fairbanks CA, Stone LS, Wilcox GL. Pharmacological profiles of alpha 2 adrenergic receptor agonists identified using genetically altered mice and isobolographic analysis. Pharmacol Ther 2009; 123:224-38. [PMID: 19393691 DOI: 10.1016/j.pharmthera.2009.04.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Accepted: 04/09/2009] [Indexed: 12/24/2022]
Abstract
Endogenous, descending noradrenergic fibers impose analgesic control over spinal afferent circuitry mediating the rostrad transmission of pain signals. These fibers target alpha 2 adrenergic receptors (alpha(2)ARs) on both primary afferent terminals and secondary neurons, and their activation mediates substantial inhibitory control over this transmission, rivaling that of opioid receptors which share a similar pattern of distribution. The terminals of primary afferent nociceptive neurons and secondary spinal dorsal horn neurons express alpha(2A)AR and alpha(2C)AR subtypes, respectively. Spinal delivery of these agents serves to reduce their side effects, which are mediated largely at supraspinal sites, by concentrating the drugs at the spinal level. Targeting these spinal alpha(2)ARs with one of five selective therapeutic agonists, clonidine, dexmedetomidine, brimonidine, ST91 and moxonidine, produces significant antinociception that can work in concert with opioid agonists to yield synergistic antinociception. Application of several genetically altered mouse lines had facilitated identification of the primary receptor subtypes that likely mediate the antinociceptive effects of these agents. This review provides first an anatomical description of the localization of the three subtypes in the central nervous system, second a detailed account of the pharmacological history of each of the six primary agonists, and finally a comprehensive report of the specific interactions of other GPCR agonists with each of the six principal alpha(2)AR agonists featured.
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Affiliation(s)
- Carolyn A Fairbanks
- Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA
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Alpha1-adrenergic receptor-induced heterosynaptic long-term depression in the bed nucleus of the stria terminalis is disrupted in mouse models of affective disorders. Neuropsychopharmacology 2008; 33:2313-23. [PMID: 18046308 PMCID: PMC3046390 DOI: 10.1038/sj.npp.1301635] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The glutamatergic synapse in specific brain regions has been shown to be a site for convergence of stress and addictive substances. The bed nucleus of the stria terminalis (BNST), a nucleus that relays between higher order processing centers and classical reward and stress pathways, receives dense noradrenergic inputs that are known to influence behavioral paradigms of both anxiety and stress-induced relapse to drug seeking. Alpha(1)-adrenergic receptors (alpha(1)-ARs) within this region have been implicated in modulation of the HPA axis and anxiety responses. We found that application of an alpha(1)-AR agonist produced a long-term depression (LTD) of excitatory transmission in an acute mouse BNST slice preparation. This effect was mimicked by a 20 min, but not a 10 min, application of 100 microM norepinephrine (NE) in a prazosin-sensitive manner. This alpha(1)-AR LTD was independent of N-methyl-D-aspartate receptor (NMDAR) function unlike previously described alpha(1)-AR LTD in the hippocampus and visual cortex; however, it was dependent on the activation of L-type voltage gated calcium channels (VGCCs). In addition, alpha(1)-AR LTD was induced independently of the activation of mGluR5 which can also induce LTD in this region. Furthermore, alpha(1)-AR LTD was intact in mice receiving an intraperitoneal injection of cocaine but was disrupted in alpha(2a)-AR and NE transporter (NET) knockout (KO) mice. Thus a loss of this plasticity at glutamatergic synapses in BNST could contribute to affective behavioral phenotypes of these mice.
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Zhang HT, Huang Y, Masood A, Stolinski LR, Li Y, Zhang L, Dlaboga D, Jin SLC, Conti M, O'Donnell JM. Anxiogenic-like behavioral phenotype of mice deficient in phosphodiesterase 4B (PDE4B). Neuropsychopharmacology 2008; 33:1611-23. [PMID: 17700644 PMCID: PMC2728355 DOI: 10.1038/sj.npp.1301537] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Phosphodiesterase-4 (PDE4), an enzyme that catalyzes the hydrolysis of cyclic AMP and plays a critical role in controlling its intracellular concentration, has been implicated in depression- and anxiety-like behaviors. However, the functions of the four PDE4 subfamilies (PDE4A, PDE4B, PDE4C, and PDE4D) remain largely unknown. In animal tests sensitive to anxiolytics, antidepressants, memory enhancers, or analgesics, we examined the behavioral phenotype of mice deficient in PDE4B (PDE4B-/-). Immunoblot analysis revealed loss of PDE4B expression in the cerebral cortex and amygdala of PDE4B-/- mice. The reduction of PDE4B expression was accompanied by decreases in PDE4 activity in the brain regions of PDE4B-/- mice. Compared to PDE4B+/+ littermates, PDE4B-/- mice displayed anxiogenic-like behavior, as evidenced by decreased head-dips and time spent in head-dipping in the holeboard test, reduced transitions and time on the light side in the light-dark transition test, and decreased initial exploration and rears in the open-field test. Consistent with anxiogenic-like behavior, PDE4B-/- mice displayed increased levels of plasma corticosterone. In addition, these mice also showed a modest increase in the proliferation of neuronal cells in the hippocampal dentate gyrus. In the forced-swim test, PDE4B-/- mice exhibited decreased immobility; however, this was not supported by the results from the tail-suspension test. PDE4B-/- mice did not display changes in memory, locomotor activity, or nociceptive responses. Taken together, these results suggest that the PDE4B subfamily is involved in signaling pathways that contribute to anxiogenic-like effects on behavior.
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Affiliation(s)
- Han-Ting Zhang
- Department of Behavioral Medicine and Psychiatry, West Virginia University Health Sciences Center, Morgantown, WV 26506, USA.
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Chen W, Song B, Marvizón JCG. Inhibition of opioid release in the rat spinal cord by alpha2C adrenergic receptors. Neuropharmacology 2008; 54:944-53. [PMID: 18343461 DOI: 10.1016/j.neuropharm.2008.02.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2007] [Revised: 02/01/2008] [Accepted: 02/03/2008] [Indexed: 10/22/2022]
Abstract
Neurotransmitter receptors that control the release of opioid peptides in the spinal cord may play an important role in pain modulation. Norepinephrine, released by a descending pathway originating in the brainstem, is a powerful inducer of analgesia in the spinal cord. Adrenergic alpha2C receptors are present in opioid-containing terminals in the dorsal horn, where they could modulate opioid release. The goal of this study was to investigate this possibility. Opioid release was evoked from rat spinal cord slices by incubating them with the sodium channel opener veratridine in the presence of peptidase inhibitors (actinonin, captopril and thiorphan), and was measured in situ through the internalization of mu-opioid receptors in dorsal horn neurons. Veratridine produced internalization in 70% of these neurons. The alpha2 receptor agonists clonidine, guanfacine, medetomidine and UK-14304 inhibited the evoked mu-opioid receptor internalization with IC50s of 1.7 microM, 248 nM, 0.3 nM and 22 nM, respectively. However, inhibition by medetomidine was only partial, and inhibition by UK-14304 reversed itself at concentrations higher than 50 nM. None of these agonists inhibited mu-opioid receptor internalization produced by endomorphin-2, showing that they inhibited opioid release and not the internalization itself. The inhibitions produced by clonidine, guanfacine or UK-14304 were completely reversed by the selective alpha2C antagonist JP-1203. In contrast, inhibition by guanfacine was not prevented by the alpha2A antagonist BRL-44408. These results show that alpha2C receptors inhibit the release of opioids in the dorsal horn. This action may serve to shut down the opioid system when the adrenergic system is active.
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Affiliation(s)
- Wenling Chen
- Center for the Neurobiology of Stress and CURE: Digestive Diseases Research Center, Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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Leuner K, Müller WE. [Tricyclics as co-analgesics. Therapeutic options for chronic pain]. PHARMAZIE IN UNSERER ZEIT 2008; 37:220-225. [PMID: 18446905 DOI: 10.1002/pauz.200800265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Kristina Leuner
- Pharmakologisches Institut der JWG-Universität, Biozentrum Niederursel, Max-von-Laue-Str. 9, 60438 Frankfurt am Main
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41
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Candidate gene polymorphisms predicting individual sensitivity to opioids. Naunyn Schmiedebergs Arch Pharmacol 2007; 377:269-81. [DOI: 10.1007/s00210-007-0205-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Accepted: 10/18/2007] [Indexed: 11/26/2022]
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Dick IE, Brochu RM, Purohit Y, Kaczorowski GJ, Martin WJ, Priest BT. Sodium channel blockade may contribute to the analgesic efficacy of antidepressants. THE JOURNAL OF PAIN 2006; 8:315-24. [PMID: 17175203 DOI: 10.1016/j.jpain.2006.10.001] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Revised: 09/11/2006] [Accepted: 10/08/2006] [Indexed: 11/16/2022]
Abstract
UNLABELLED Sodium channel blockers such as lidocaine, lamotrigine, and carbamazepine can be effective in the treatment of neuropathic pain. Though not approved for neuropathic pain indications, tricyclic antidepressants are often considered first-line treatment for conditions such as post-herpetic neuralgia and diabetic neuropathy. Several tricyclic antidepressants have been shown to block peripheral nerve sodium channels, which may contribute to their antihyperalgesic efficacy. In this study, we compared the sodium channel-blocking potency of a number of antidepressants, including tricyclic antidepressants and selective serotonin reuptake inhibitors. All compounds tested inhibited Na(V)1.7 in a state- and use-dependent manner, with affinities for the inactivated state ranging from 0.24 micromol/L for amitriptyline to 11.6 micromol/L for zimelidine. The tricyclic antidepressants were more potent blockers of Na(V)1.7. Moreover, IC(50)s for block of the inactivated state for amitriptyline, nortriptyline, imipramine, desipramine, and maprotiline were in the range of therapeutic plasma concentrations for both the treatment of depression as well as neuropathic pain. By contrast, fluoxetine, paroxetine, mianserine, and zimelidine had IC(50)s for Na(V)1.7 outside their therapeutic concentration ranges and generally were not efficacious against post-herpetic neuralgia or diabetic neuropathy. These results suggest that block of peripheral nerve sodium channels may contribute to the antihyperalgesic efficacy of certain antidepressants. PERSPECTIVE Tricyclic antidepressants are often considered first-line treatment for neuropathic pain. Some tricyclic antidepressants block sodium channels, which may contribute to their antihyperalgesic efficacy. In the current study, we compared the potency of peripheral sodium channel blockade for several tricyclic antidepressants and selective serotonin reuptake inhibitors with their therapeutic efficacy.
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Affiliation(s)
- Ivy E Dick
- Department of Ion Channels, Merck Research Laboratories, Rahway, New Jersey 07065-0900, USA
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43
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Abstract
INTRODUCTION Neuropathic pain occurs in 1% of the population and is difficult to manage. Responses to single drugs are limited in benefit. Thirty percent will fail to respond altogether. This is a review of newer drugs and treatment paradigms. METHODS A literature review was performed pertinent to new drugs and treatment algorithms in the management of neuropathic pain. RESULTS New information on opioids (tramadol and buprenorphine) suggests benefits in the management of neuropathic pain and has increased interest in their use earlier in the course of illness. Newer antidepressants, selective noradrenaline, and serotonin reuptake inhibitors (SNRIs) have evidence for benefit and reduced toxicity without an economic disadvantage compared to tricyclic antidepressants (TCAs). Pregabalin and gabapentin are effective in diabetic neuropathy and postherpetic neuralgia. Treatment paradigms are shifting from sequential single drug trials to multiple drug therapies. Evidence is needed to justify this change in treatment approach. CONCLUSION Drug choices are now based not only on efficacy but also toxicity and drug interactions. For this reason, SNRIs and gabapentin/pregabalin have become popular though efficacy is not better than TCAs. Multiple drug therapies becoming an emergent treatment paradigm research in multiple drug therapy are needed.
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Affiliation(s)
- Mellar P Davis
- The Harry R. Horvitz Center for Palliative Medicine, Cleveland Clinic Health System, 9500 Euclid Avenue, R35, Cleveland, OH 44195, USA.
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44
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Abstract
The norepinephrine transporter (NET) terminates noradrenergic signalling by rapid re-uptake of neuronally released norepinephrine (NE) into presynaptic terminals. NET exerts a fine regulated control over NE-mediated behavioural and physiological effects including mood, depression, feeding behaviour, cognition, regulation of blood pressure and heart rate. NET is a target of several drugs which are therapeutically used in the treatment or diagnosis of disorders among which depression, attention-deficit hyperactivity disorder and feeding disturbances are the most common. Individual genetic variations in the gene encoding the human NET (hNET), located at chromosome 16q12.2, may contribute to the pathogenesis of those diseases. An increasing number of studies concerning the identification of single nucleotide polymorphisms in the hNET gene and their potential association with disease as well as the functional investigation of naturally occurring or induced amino acid variations in hNET have contributed to a better understanding of NET function, regulation and genetic contribution to disorders. This review will reflect the current knowledge in the field of NET from its initial discovery until now.
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Affiliation(s)
- H Bönisch
- Department of Pharmacology and Toxicology, University of Bonn, Reuterstr. 2b, 53115 Bonn, Germany.
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45
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Dong Z, Mao R, Han H, Cao J, Xu L. Morphine withdrawal modifies antinociceptive effects of acute morphine in rats. Biochem Biophys Res Commun 2006; 346:578-82. [PMID: 16762316 DOI: 10.1016/j.bbrc.2006.05.151] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2006] [Accepted: 05/13/2006] [Indexed: 10/24/2022]
Abstract
Repeated opioid use is known to cause tolerance of antinociceptive effects. Whether opioid abstinence modifies antinociceptive effects is unknown. Here we reported that morphine withdrawal for 18 h and 4 days after repeated morphine treatment largely reduced tail-flick latencies compared with control, while the rats showed severe withdrawal syndromes. However, the latencies and withdrawal syndromes were restored to control level at 20 days withdrawal. Similarly, antinociceptive effects of acute morphine were decreased at 18 h and further decreased at 4 days but restored to control level at 20 days withdrawal. Behavioral stress that was given to the rats at 18 h withdrawal further reduced tail-flick latencies and antinociceptive effects. Conversely, the glucocorticoid receptor antagonist RU38486 increased tail-flick latencies and antinociceptive effects at 4 days withdrawal. These results suggest that morphine withdrawal could evoke behavioral stress to modify antinociceptive effects, implicating a significant influence of opioid abstinence on chronic pain treatment.
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Affiliation(s)
- Zhifang Dong
- Key Laboratory of Animal Models and Human Disease Mechanisms, and Laboratory of Learning and Memory, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, PR China
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46
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Gilsbach R, Faron-Górecka A, Rogóz Z, Brüss M, Caron MG, Dziedzicka-Wasylewska M, Bönisch H. Norepinephrine transporter knockout-induced up-regulation of brain alpha2A/C-adrenergic receptors. J Neurochem 2006; 96:1111-20. [PMID: 16417582 DOI: 10.1111/j.1471-4159.2005.03598.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The norepinephrine transporter (NET) is responsible for the rapid removal of norepinephrine released from sympathetic neurons; this release is controlled by inhibitory alpha(2)-adrenergic receptors (alpha(2)ARs). Long-term inhibition of the NET by antidepressants has been reported to change the density and function of pre- and postsynaptic ARs, which may contribute to the antidepressant effects of NET inhibitors such as desipramine. NET-deficient (NET-KO) mice have been described to behave like antidepressant-treated mice. By means of quantitative real-time PCR we show that mRNAs encoding the alpha(2A)-adrenergic receptor (alpha(2A)AR) and the alpha(2C)-adrenergic receptor (alpha(2C)AR) are up-regulated in the brainstem, and that alpha(2C)AR mRNA is also elevated in the hippocampus and striatum of NET-KO mice. These results were confirmed at the protein level by quantitative autoradiography. The NET-KO mice showed enhanced binding of the selective alpha(2)AR antagonist [(3)H]RX821002 in several brain regions. Most robust increases (20-25%) in alpha(2)AR expression were observed in the hippocampus and in the striatum. Significant increases (16%) were also seen in the extended amygdala and thalamic structures. In an 'in vivo' test, the alpha(2)AR agonist clonidine (0.1 mg/kg) caused a significantly greater reduction of locomotor activity in NET-KO mice than in wild-type mice, showing the relevance of our findings at the functional level.
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Affiliation(s)
- R Gilsbach
- Institute of Pharmacology & Toxicology, University of Bonn, Germany
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47
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Keller NR, Diedrich A, Appalsamy M, Miller LC, Caron MG, McDonald MP, Shelton RC, Blakely RD, Robertson D. Norepinephrine transporter-deficient mice respond to anxiety producing and fearful environments with bradycardia and hypotension. Neuroscience 2006; 139:931-46. [PMID: 16515844 DOI: 10.1016/j.neuroscience.2006.01.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Revised: 11/18/2005] [Accepted: 01/15/2006] [Indexed: 10/24/2022]
Abstract
The study of anxiety and fear involves complex interrelationships between psychiatry and the autonomic nervous system. Altered noradrenergic signaling is linked to certain types of depression and anxiety disorders, and treatment often includes specific transporter blockade. The norepinephrine transporter is crucial in limiting catecholaminergic signaling. Norepinephrine transporter-deficient mice have increased circulating catecholamines and elevated heart rate and blood pressure. We hypothesized, therefore, that reduced norepinephrine clearance would heighten the autonomic cardiovascular response to anxiety and fear. In separate experiments, norepinephrine transporter-deficient (norepinephrine transporter-/-) mice underwent tactile startle and trace fear conditioning to measure hemodynamic responses. A dramatic tachycardia was observed in norepinephrine transporter-/- mice compared with controls following both airpuff or footshock stimuli, and pressure changes were also greater. Interestingly, in contrast to normally elevated home cage levels in norepinephrine transporter-deficient mice, prestimulus heart rate and blood pressure were actually higher in norepinephrine transporter+/+ animals throughout behavioral testing. Upon placement in the behavioral chamber, norepinephrine transporter-deficient mice demonstrated a notable bradycardia and depressor effect that was more pronounced in females. Power spectral analysis indicated an increase in low frequency oscillations of heart rate variability; in mice, suggesting increased parasympathetic tone. Finally, norepinephrine transporter-/- mice exhibited sexual dimorphism in freeze behavior, which was greatest in females. Therefore, while reduced catecholamine clearance amplifies immediate cardiovascular responses to anxiety- or fear-inducing stimuli in norepinephrine transporter-/- mice, norepinephrine transporter deficiency apparently prevents protracted hemodynamic escalation in a fearful environment. Conceivably, chronic norepinephrine transporter blockade with transporter-specific drugs might attenuate recognition of autonomic and somatic distress signals in individuals with anxiety disorders, possibly lessening their behavioral reactivity, and reducing the cardiovascular risk factors associated with persistent emotional arousal.
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Affiliation(s)
- N R Keller
- Autonomic Dysfunction Center, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, AA3228 MCN, Nashville, TN 37232-2195, USA.
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48
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Ozdoğan UK, Lähdesmäki J, Scheinin M. The analgesic efficacy of partial opioid agonists is increased in mice with targeted inactivation of the alpha2A-adrenoceptor gene. Eur J Pharmacol 2005; 529:105-13. [PMID: 16325800 DOI: 10.1016/j.ejphar.2005.10.029] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Revised: 10/14/2005] [Accepted: 10/21/2005] [Indexed: 11/26/2022]
Abstract
Alpha(2A)-Adrenoceptors mediate the antinociceptive effects of alpha(2)-adrenoceptor agonists in mice, and analgesic synergism between noradrenergic and opioidergic mechanisms has been reported to be lacking in mice devoid of functional alpha(2A)-adrenoceptors. We investigated whether the antinociceptive actions of opioid agonists with different efficacy would be altered in mice with targeted inactivation of the alpha(2A)-adrenoceptor gene (alpha(2A)-KO mice). The antinociceptive effects of fentanyl, morphine, buprenorphine and tramadol were assessed using conventional tail-flick and hot-plate assays. Antinociceptive responses to fentanyl were unaltered in the alpha(2A)-KO animals. Morphine analgesia was slightly accentuated in the tail-flick test. The naloxone-sensitive antinociceptive responses to both tested weak partial agonists were very markedly accentuated in both tests. For example, after 40 mg/kg tramadol administration, the tramadol-induced prolongation of tail-flick latency was 86+/-6% of the maximal possible effect (MPE) in alpha(2A)-KO and 22+/-2% of MPE in control mice; prolongation of hot-plate latency was 93+/-5% of MPE in alpha(2A)-KO mice and 8+/-2% of MPE in the controls (P<0.001 for both). The effects of alpha(2A)-KO were mimicked by pretreatment of wild-type control mice with the alpha(2)-adrenoceptor antagonists, atipamezole and yohimbine; the apparent efficacy of tramadol and buprenorphine now approached that of morphine and fentanyl. Other behavioural effects of the tested opioid agonists were not similarly influenced by alpha(2A)-KO. Antagonists of alpha(2A)-adrenoceptors may offer a novel mechanism to augment the antinociceptive actions of partial opioid agonists.
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MESH Headings
- Adrenergic Antagonists/pharmacology
- Analgesics, Opioid/adverse effects
- Analgesics, Opioid/pharmacology
- Analgesics, Opioid/therapeutic use
- Animals
- Behavior, Animal/drug effects
- Body Temperature/drug effects
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Motor Activity/drug effects
- Pain/drug therapy
- Pain Measurement
- Receptors, Adrenergic, alpha-2/genetics
- Receptors, Adrenergic, alpha-2/metabolism
- Receptors, Adrenergic, alpha-2/physiology
- Receptors, Opioid/agonists
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Affiliation(s)
- Umit Kazim Ozdoğan
- Department of Pharmacology and Clinical Pharmacology, University of Turku, FI-20520 Turku, Finland
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49
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Kaminski RM, Shippenberg TS, Witkin JM, Rocha BA. Genetic deletion of the norepinephrine transporter decreases vulnerability to seizures. Neurosci Lett 2005; 382:51-5. [PMID: 15911120 PMCID: PMC1352306 DOI: 10.1016/j.neulet.2005.02.056] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Revised: 01/28/2005] [Accepted: 02/24/2005] [Indexed: 11/20/2022]
Abstract
Norepinephrine (NE) has been reported to modulate neuronal excitability and act as endogenous anticonvulsant. In the present study we used NE transporter knock-out mice (NET-KO), which are characterized by high levels of extracellular NE, to investigate the role of endogenous NE in seizure susceptibility. Seizure thresholds for cocaine (i.p.), pentylenetetrazol (i.v.) and kainic acid (i.v.) were compared in NET-KO, heterozygous (NET-HT) and wild type (NET-WT) female mice. The dose-response curve for cocaine-induced convulsions was significantly shifted to the right in NET-KO mice, indicating higher seizure thresholds. The threshold doses of pentylenetetrazol that induced clonic and tonic seizures were also significantly higher in NET-KO when compared to NET-WT mice. Similarly, NET-KO mice displayed higher resistance to convulsions engendered by kainic acid. For all drugs tested, the response of NET-HT mice was always intermediate. These data provide further support for a role of endogenous NE in the control of seizure susceptibility.
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50
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Ozdogan UK, Lähdesmäki J, Hakala K, Scheinin M. The involvement of alpha 2A-adrenoceptors in morphine analgesia, tolerance and withdrawal in mice. Eur J Pharmacol 2005; 497:161-71. [PMID: 15306201 DOI: 10.1016/j.ejphar.2004.06.051] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2004] [Revised: 06/24/2004] [Accepted: 06/25/2004] [Indexed: 11/16/2022]
Abstract
Alpha(2)-adrenoceptor agonists potentiate opioid analgesia and alleviate opioid withdrawal. The effects of two alpha(2)-adrenoceptor agonists, clonidine (2 mg/kg) and dexmedetomidine (20 and 100 microg/kg), and the alpha(1)-adrenoceptor antagonist prazosin (0.5 mg/kg) were tested on morphine analgesia, tolerance, and withdrawal in wild-type and alpha(2A)-adrenoceptor knock-out (KO) mice. Analgesia and tolerance were assessed with the tail-flick test. Withdrawal was precipitated with naloxone. Prazosin potentiated morphine analgesia equally in both genotypes. Clonidine and dexmedetomidine had no analgesic effects in alpha(2A)-adrenoceptor KO mice, but morphine analgesia and tolerance were similar in both genotypes. Alpha(2A)-Adrenoceptor KO mice exhibited 70% fewer naloxone-precipitated jumps than wild-type mice; weight loss was similar in both genotypes. The alpha(2)-adrenoceptor agonists reduced opioid withdrawal signs only in wild-type mice. We conclude that alpha(2A)-adrenoceptors are not directly involved in morphine analgesia and tolerance, and not critical for potentiation of morphine analgesia by prazosin, but that alpha(2A)-adrenoceptors modulate the expression of opioid withdrawal signs in mice.
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Affiliation(s)
- Umit Kazim Ozdogan
- Department of Pharmacology and Clinical Pharmacology, University of Turku, Itäinen Pitkäkatu 4, FI-20520 Turku, Finland
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