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A pain-induced tonic hypodopaminergic state augments phasic dopamine release in the nucleus accumbens. Pain 2021; 161:2376-2384. [PMID: 32453137 DOI: 10.1097/j.pain.0000000000001925] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Diseases and disorders such as Parkinson disease, schizophrenia, and chronic pain are characterized by altered mesolimbic dopaminergic neurotransmission. Dopamine release in the nucleus accumbens influences behavior through both tonic and phasic signaling. Tonic dopamine levels are hypothesized to inversely regulate phasic signals through dopamine D2 receptor feedback inhibition. We tested this hypothesis directly in the context of ongoing pain. Tonic and phasic dopamine signals were measured using fast-scan controlled-adsorption voltammetry and fast-scan cyclic voltammetry, respectively, in the nucleus accumbens shell of male rats with standardized levels of anesthesia. Application of capsaicin to the cornea produced a transient decrease in tonic dopamine levels. During the pain-induced hypodopaminergic state, electrically evoked phasic dopamine release was significantly increased when compared to baseline, evoked phasic release. A second application of capsaicin to the same eye had a lessened effect on tonic dopamine suggesting desensitization of TRPV1 channels in that eye. Capsaicin treatment in the alternate cornea, however, again produced coincident decreased dopaminergic tone and increased phasic dopamine release. These findings occurred independently of stimulus lateralization relative to the hemisphere of dopamine measurement. Our data show that (1) the mesolimbic dopamine circuit reliably encodes acute noxious stimuli; (2) ongoing pain produces decreases in dopaminergic tone; and (3) pain-induced decreases in tonic dopamine correspond to augmented evoked phasic dopamine release. Enhanced phasic dopamine neurotransmission resulting from salient stimuli may contribute to increased impulsivity and cognitive deficits often observed in conditions associated with decreased dopaminergic tone, including Parkinson disease and chronic pain.
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Amitifadine, a triple reuptake inhibitor, reduces self-administration of the opiate remifentanil in rats. Psychopharmacology (Berl) 2020; 237:1681-1689. [PMID: 32125484 PMCID: PMC7244379 DOI: 10.1007/s00213-020-05489-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 02/14/2020] [Indexed: 10/24/2022]
Abstract
RATIONALE A variety of neural systems are involved in drug addiction, and some of these systems are shared across different addictive drugs. We have found several different types of drug treatments that successfully reduce nicotine self-administration. OBJECTIVES The current set of studies is the first in a series to determine if drug treatments that have been found to significantly reduce nicotine self-administration would reduce opiate self-administration. METHODS Amitifadine, a triple reuptake inhibitor of dopamine, norepinephrine, and serotonin, was assessed in female Sprague-Dawley rats to determine whether it significantly reduces remifentanil self-administration with either acute or chronic treatment. RESULTS Acutely, amitifadine doses of 5, 10, and 20 mg/kg each significantly reduced remifentanil self-administration. In a chronic study, repeated treatment with 10 mg/kg of amitifadine continued to reduce remifentanil self-administration, even after the cessation of treatment. However, amitifadine was not found to attenuate the rise in remifentanil self-administration with continued access. This study and our earlier one showed that the 10 mg/kg amitifadine dose did not significantly affect food motivated responding. Amitifadine did not attenuate remifentanil-induced antinociception as measured on the hot plate test but extended and maintained antinociceptive effects. CONCLUSIONS These studies show the promise of amitifadine as a treatment for countering opiate self-administration for adjunctive use with opioids for analgesia. Further studies are needed to determine the possible efficacy of amitifadine for combating opiate addiction or preventing it in humans during adjunctive use with opioids for chronic pain.
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Huang ZH, Yin LQ, Guan LP, Li ZH, Tan C. Screening of chalcone analogs with anti-depressant, anti-inflammatory, analgesic, and COX-2-inhibiting effects. Bioorg Med Chem Lett 2020; 30:127173. [PMID: 32278513 DOI: 10.1016/j.bmcl.2020.127173] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 04/01/2020] [Accepted: 04/05/2020] [Indexed: 12/18/2022]
Abstract
A group of 2-methyl-4-phenylquinoline-chalcone analogs (2a-2x) was synthesized and investigated for anti-depressant, anti-inflammatory, and analgesic effects as cyclooxygenase-2 inhibitors. Pharmacological experiments identified 24 analogs that exhibited anti-depressant, anti-inflammatory, and analgesic activities. In particular, compounds 2c, 2k, and 2w markedly shortened immobility times and exhibited the most anti-depressant activity. In addition, the mechanisms of action of the analogs 2c, 2k, and 2w were likely related to increased serotonin levels in the central nervous system. Compounds 2c, 2k, and 2w displayed reasonable cyclooxygenase-2 inhibitory effects (IC50 values from 0.21 to 0.29 µmol/L) similar to celecoxib (IC50: 0.19 µmol/L) in vitro. A molecular docking study of compound 2k also was conducted.
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Affiliation(s)
- Zhe-Hao Huang
- Department of Neurosurgery, China-Japan Union Hospital of Jilin University, Changchun 130033, China
| | - Li-Quan Yin
- Rehabilitation Medicine Department, China-Japan Union Hospital of Jilin University, Changchun 130033, China
| | - Li-Ping Guan
- Food and Pharmacy College, Zhejiang Ocean University, Zhoushan 316022, China
| | - Zhao-Hui Li
- Department of Neurosurgery, China-Japan Union Hospital of Jilin University, Changchun 130033, China.
| | - Cheng Tan
- Department of Neurology, China-Japan Union Hospital of Jilin University, Changchun 130033, China.
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González-Cano R, Montilla-García Á, Ruiz-Cantero MC, Bravo-Caparrós I, Tejada MÁ, Nieto FR, Cobos EJ. The search for translational pain outcomes to refine analgesic development: Where did we come from and where are we going? Neurosci Biobehav Rev 2020; 113:238-261. [PMID: 32147529 DOI: 10.1016/j.neubiorev.2020.03.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 02/06/2020] [Accepted: 03/04/2020] [Indexed: 12/11/2022]
Abstract
Pain measures traditionally used in rodents record mere reflexes evoked by sensory stimuli; the results thus may not fully reflect the human pain phenotype. Alterations in physical and emotional functioning, pain-depressed behaviors and facial pain expressions were recently proposed as additional pain outcomes to provide a more accurate measure of clinical pain in rodents, and hence to potentially enhance analgesic drug development. We aimed to review how preclinical pain assessment has evolved since the development of the tail flick test in 1941, with a particular focus on a critical analysis of some nonstandard pain outcomes, and a consideration of how sex differences may affect the performance of these pain surrogates. We tracked original research articles in Medline for the following periods: 1973-1977, 1983-1987, 1993-1997, 2003-2007, and 2014-2018. We identified 606 research articles about alternative surrogate pain measures, 473 of which were published between 2014 and 2018. This indicates that preclinical pain assessment is moving toward the use of these measures, which may soon become standard procedures in preclinical pain laboratories.
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Affiliation(s)
- Rafael González-Cano
- Department of Pharmacology, Faculty of Medicine, University of Granada, Granada, Spain; Institute of Neuroscience, Biomedical Research Center, University of Granada, Armilla, Granada, Spain.
| | - Ángeles Montilla-García
- Department of Pharmacology, Faculty of Medicine, University of Granada, Granada, Spain; Institute of Neuroscience, Biomedical Research Center, University of Granada, Armilla, Granada, Spain.
| | - M Carmen Ruiz-Cantero
- Department of Pharmacology, Faculty of Medicine, University of Granada, Granada, Spain; Institute of Neuroscience, Biomedical Research Center, University of Granada, Armilla, Granada, Spain.
| | - Inmaculada Bravo-Caparrós
- Department of Pharmacology, Faculty of Medicine, University of Granada, Granada, Spain; Institute of Neuroscience, Biomedical Research Center, University of Granada, Armilla, Granada, Spain.
| | - Miguel Á Tejada
- Department of Pharmacology, Faculty of Medicine, University of Granada, Granada, Spain; Institute of Neuroscience, Biomedical Research Center, University of Granada, Armilla, Granada, Spain; IMBA, Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria.
| | - Francisco R Nieto
- Department of Pharmacology, Faculty of Medicine, University of Granada, Granada, Spain; Institute of Neuroscience, Biomedical Research Center, University of Granada, Armilla, Granada, Spain.
| | - Enrique J Cobos
- Department of Pharmacology, Faculty of Medicine, University of Granada, Granada, Spain; Institute of Neuroscience, Biomedical Research Center, University of Granada, Armilla, Granada, Spain; Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain; Teófilo Hernando Institute for Drug Discovery, Madrid, Spain.
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Attenuated dopamine receptor signaling in nucleus accumbens core in a rat model of chemically-induced neuropathy. Neuropharmacology 2020; 166:107935. [PMID: 31917153 DOI: 10.1016/j.neuropharm.2020.107935] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 12/10/2019] [Accepted: 01/02/2020] [Indexed: 02/06/2023]
Abstract
Neuropathy is major source of chronic pain that can be caused by mechanically or chemically induced nerve injury. Intraplantar formalin injection produces local necrosis over a two-week period and has been used to model neuropathy in rats. To determine whether neuropathy alters dopamine (DA) receptor responsiveness in mesolimbic brain regions, we examined dopamine D1-like and D2-like receptor (D1/2R) signaling and expression in male rats 14 days after bilateral intraplantar formalin injections into both rear paws. D2R-mediated G-protein activation and expression of the D2R long, but not short, isoform were reduced in nucleus accumbens (NAc) core, but not in NAc shell, caudate-putamen or ventral tegmental area of formalin- compared to saline-treated rats. In addition, D1R-stimulated adenylyl cyclase activity was also reduced in NAc core, but not in NAc shell or prefrontal cortex, of formalin-treated rats, whereas D1R expression was unaffected. Other proteins involved in dopamine neurotransmission, including dopamine uptake transporter and tyrosine hydroxylase, were unaffected by formalin treatment. In behavioral tests, the potency of a D2R agonist to suppress intracranial self-stimulation (ICSS) was decreased in formalin-treated rats, whereas D1R agonist effects were not altered. The combination of reduced D2R expression and signaling in NAc core with reduced suppression of ICSS responding by a D2R agonist suggest a reduction in D2 autoreceptor function. Altogether, these results indicate that intraplantar formalin produces attenuation of highly specific DA receptor signaling processes in NAc core of male rats and suggest the development of a neuropathy-induced allostatic state in both pre- and post-synaptic DA receptor function.
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Sarrouilhe D, Mesnil M, Dejean C. Targeting Gap Junctions: New Insights into the Treatment of Major Depressive Disorder. Curr Med Chem 2019; 26:3775-3791. [DOI: 10.2174/0929867325666180327103530] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 12/22/2017] [Accepted: 03/21/2018] [Indexed: 01/05/2023]
Abstract
Background:Major depressive disorder (MDD) is a multifactorial chronic and debilitating mood disease with high lifetime prevalence and associated with excess mortality. Treatments for this disease are not effective in all patients showing the need to find new therapeutic targets.Objective:This review aims to update our knowledge on the involvement of astroglial gap junctions and hemichannels in MDD and to show how they have become potential targets for the treatment of this pathology.Methods:The method applied in this review includes a systematic compilation of the relevant literature.Results and Conclusion:The use of rodent models of depression, gene analysis of hippocampal tissues of MDD patients and post-mortem studies on the brains from MDD patients suggest that astrocytic gap junction dysfunction may be a part of MDD etiologies. Chronic antidepressant treatments of rats, rat cultured cortical astrocytes and human astrocytoma cell lines support the hypothesis that the up-regulation of gap junctional coupling between astrocytes could be an underlying mechanism for the therapeutic effect of antidepressants. However, two recent functional studies suggest that connexin43 hemichannel activity is a part of several antidepressants’ mode of action and that astrocyte gap junctional intercellular communication and hemichannels exert different effects on antidepressant drug response. Even if they emerge as new therapeutic targets for new and more active treatments, further studies are needed to decipher the sophisticated and respective role of astrocytic gap junctions and hemichannels in MDD.
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Affiliation(s)
- Denis Sarrouilhe
- Laboratoire de Physiologie Humaine, Faculte de Medecine et Pharmacie, Universite de Poitiers, 6 rue de la Miletrie, Bat D1, TSA 51115, 86073 Poitiers, Cedex 9, France
| | - Marc Mesnil
- STIM, ERL 7003, CNRS-Universite de Poitiers, Pole Biologie Sante, Bat B36, TSA 51106, 1 rue Georges Bonnet, 86073 Poitiers, Cedex 9, France
| | - Catherine Dejean
- Service Pharmacie, Pavillon Janet, Centre Hospitalier Henri Laborit, 370 avenue Jacques Coeur, 86021 Poitiers Cedex, France
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Abstract
All preclinical procedures for analgesic drug discovery involve two components: 1) a "pain stimulus" (the principal independent variable), which is delivered to an experimental subject with the intention of producing a pain state; and 2) a "pain behavior" (the principal dependent variable), which is measured as evidence of that pain state. Candidate analgesics are then evaluated for their effectiveness to reduce the pain behavior, and results are used to prioritize drugs for advancement to clinical testing. This review describes a taxonomy of preclinical procedures organized into an "antinociception matrix" by reference to their types of pain stimulus (noxious, inflammatory, neuropathic, disease related) and pain behavior (unconditioned, classically conditioned, operant conditioned). Particular emphasis is devoted to pain behaviors and the behavioral principals that govern their expression, pharmacological modulation, and preclinical-to-clinical translation. Strengths and weaknesses are compared and contrasted for procedures using each type of behavioral outcome measure, and the following four recommendations are offered to promote strategic use of these procedures for preclinical-to-clinical analgesic drug testing. First, attend to the degree of homology between preclinical and clinical outcome measures, and use preclinical procedures with behavioral outcome measures homologous to clinically relevant outcomes in humans. Second, use combinations of preclinical procedures with complementary strengths and weaknesses to optimize both sensitivity and selectivity of preclinical testing. Third, take advantage of failed clinical translation to identify drugs that can be back-translated preclinically as active negative controls. Finally, increase precision of procedure labels by indicating both the pain stimulus and the pain behavior in naming preclinical procedures.
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Affiliation(s)
- S Stevens Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
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Effects of repeated treatment with methcathinone, mephedrone, and fenfluramine on intracranial self-stimulation in rats. Psychopharmacology (Berl) 2019; 236:1057-1066. [PMID: 30232529 PMCID: PMC6424659 DOI: 10.1007/s00213-018-5029-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 09/04/2018] [Indexed: 12/29/2022]
Abstract
RATIONALE Synthetic cathinones constitute a class of abused drugs that can act at dopamine, norepinephrine, and serotonin transporters (DAT, NET, and SERT, respectively). Intracranial self-stimulation (ICSS) is a preclinical procedure that can be used to evaluate abuse potential of drugs, and prior studies have indicated that abuse-related ICSS effects of monoamine-transporter substrates, including some synthetic cathinones, are positively correlated with drug selectivity for DAT vs. SERT. Abuse potential of drugs can also be influenced by regimens of repeated drug exposure, but the role of repeated exposure on abuse-related ICSS effects of synthetic cathinones has not been examined. OBJECTIVES This study used ICSS to evaluate effects of repeated treatment with the DAT>SERT substrate methcathinone, the DAT<SERT substrate fenfluramine, and the DAT≈SERT substrate mephedrone. METHODS Male Sprague-Dawley rats were trained in a frequency-rate ICSS procedure, and different groups were used to evaluate effects of methcathinone, mephedrone, and fenfluramine before, during, and after regimens of repeated treatment with the designated drug. RESULTS Before repeated treatment, methcathinone produced dose-dependent and abuse-related ICSS facilitation, fenfluramine produced dose-dependent ICSS depression, and mephedrone produced mixed effects that included both facilitation and depression. Chronic treatment produced no change in effects of methcathinone, but complete tolerance to effects of fenfluramine. For mephedrone, chronic treatment produced partial tolerance to ICSS depression and enhanced expression of ICSS facilitation. CONCLUSIONS Repeated exposure to mixed-action DAT≈SERT substrates such as mephedrone can result in increased abuse potential due to sustained expression of DAT-mediated abuse-related effects and tolerance to SERT-mediated abuse-limiting effects.
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Abstract
A great need exists for the identification of new effective analgesics to treat sustained pain. However, most preclinical nociceptive assays measure behavioral responses evoked by noxious stimuli (ie, pain-stimulated behavior), which presents a challenge to distinguish between motor impairing and antinociceptive effects of drugs. Here, we demonstrate that chronic constriction injury (CCI) of the sciatic nerve elicits common pain-stimulated responses (ie, mechanical allodynia and thermal hyperalgesia) as well as reduces marble burying/digging behaviors that occur during the early stages of the neuropathy and resolve within 1 week. Although drugs representing distinct classes of analgesics (ie, morphine, valdecoxib, and gabapentin) reversed both CCI-induced and CCI-depressed nociceptive measures, diazepam lacked antinociceptive effects in all assays and the kappa-opioid receptor agonist U69593 reversed pain-stimulated, but not pain-depressed behaviors. In addition, we tested drugs targeting distinct components of the endocannabinoid system, including agonists at cannabinoid receptors type 1 (CB1) and type 2 (CB2), as well as inhibitors of the endocannabinoid-regulating enzymes fatty acid amide hydrolase and monoacylglycerol lipase. Each of these drugs reversed all CCI-induced nociceptive measures, with the exception of the fatty acid amide hydrolase inhibitor that reversed pain-stimulated behaviors, only. These findings support the use of the mouse marble-burying assay as a model of pain-depressed behavior within the first week of sciatic nerve injury to examine candidate analgesics. These data also support existing preclinical research that cannabinoid receptor agonists and inhibitors of endocannabinoid-regulating enzymes merit consideration for the treatment of pain.
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Abstract
Pain is a significant public health problem, and assessment of pain-related impairment of behavior is a key clinical indicator and treatment target. Similar to opioids and NSAIDs, dopamine (DA) transporter inhibitors block pain-related depression of intracranial self-stimulation (ICSS) in rats. The primary goal of the present study was to determine if the effects of monoamine uptake inhibitors on pain-related depression of ICSS in rats extend to an assay of pain-related depression of nesting in mice. We hypothesized that the DA transporter-selective uptake inhibitor bupropion would block depression of nesting behavior produced by intraperitoneal injection of lactic acid, whereas selective serotonin transporter-selective citalopram, norepinephrine transporter-selective nisoxetine, and the mixed action selective serotonin transporter/norepinephrine transporter inhibitor milnacipran would be ineffective. Effects of the NSAID ketoprofen were also obtained to facilitate interpretation of the effects of the monoamine uptake inhibitors. Consistent with previous findings, ketoprofen blocked pain-related depression of nesting. In contrast, none of the monoamine uptake inhibitors blocked pain-related depression of nesting, although they all blocked pain-related stimulation of stretching. Unlike findings from studies of pain-related depression of ICSS, these results do not support consideration of DA uptake inhibitors for treatment of pain-related depression of behavior.
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Taylor AM. Corticolimbic circuitry in the modulation of chronic pain and substance abuse. Prog Neuropsychopharmacol Biol Psychiatry 2018; 87:263-268. [PMID: 28501595 PMCID: PMC5681440 DOI: 10.1016/j.pnpbp.2017.05.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 04/14/2017] [Accepted: 05/10/2017] [Indexed: 12/13/2022]
Abstract
The transition from acute to chronic pain is accompanied by increased engagement of emotional and motivational circuits. Adaptations within this corticolimbic circuitry contribute to the cellular and behavioral maladaptations associated with chronic pain. Central regions within the corticolimbic brain include the mesolimbic dopamine system, the amygdala, and the medial prefrontal cortex. The evidence reviewed herein supports the notion that chronic pain induces significant changes within these corticolimbic regions that contribute to the chronicity and intractability of pain. In addition, pain-induced changes in corticolimbic circuitry are poised to impact motivated behavior and reward responsiveness to environmental stimuli, and may modulate the addiction liability of drugs of abuse, such as opioids.
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Affiliation(s)
- Anna M.W. Taylor
- Department of Psychiatry and the Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles
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Xue W, Wang P, Tu G, Yang F, Zheng G, Li X, Li X, Chen Y, Yao X, Zhu F. Computational identification of the binding mechanism of a triple reuptake inhibitor amitifadine for the treatment of major depressive disorder. Phys Chem Chem Phys 2018; 20:6606-6616. [DOI: 10.1039/c7cp07869b] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A shared binding mode involving eleven key residues at the S1 site of MATs for the binding of amitifadine is identified.
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Preclinical Models for Assessment of Antidepressant Abuse Potential. CURRENT SEXUAL HEALTH REPORTS 2017. [DOI: 10.1007/s11930-017-0128-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Pharmacological modulation of neuropathic pain-related depression of behavior: effects of morphine, ketoprofen, bupropion and [INCREMENT]9-tetrahydrocannabinol on formalin-induced depression of intracranial self-stimulation in rats. Behav Pharmacol 2017; 27:364-76. [PMID: 26588213 DOI: 10.1097/fbp.0000000000000207] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Neuropathic pain is often associated with behavioral depression. Intraplantar formalin produces sustained, neuropathy-associated depression of intracranial self-stimulation (ICSS) in rats. This study evaluated pharmacological modulation of formalin-induced ICSS depression. Rats with intracranial electrodes targeting the medial forebrain bundle responded for electrical brain stimulation in an ICSS procedure. Bilateral intraplantar formalin administration depressed ICSS for 14 days. Morphine (0.32-3.2 mg/kg), ketoprofen (0.1-10 mg/kg), bupropion (3.2-32 mg/kg), and [INCREMENT]9-tetrahydrocannabinol (THC; 0.32-3.2 mg/kg) were evaluated for their effectiveness to reverse formalin-induced depression of ICSS. Drug effects on formalin-induced mechanical allodynia were evaluated for comparison. Morphine and bupropion reversed both formalin-induced ICSS depression and mechanical allodynia, and effects on ICSS were sustained during repeated treatment. Ketoprofen failed to reverse either formalin effect. THC blocked mechanical allodynia, but decreased ICSS in control rats and exacerbated formalin-induced depression of ICSS. The failure of ketoprofen to alter formalin effects suggests that formalin effects result from neuropathy rather than inflammation. The effectiveness of morphine and bupropion to reverse formalin effects agrees with other evidence that these drugs block pain-depressed behavior in rats and relieve neuropathic pain in humans. The effects of THC suggest general behavioral suppression and do not support the use of THC to treat neuropathic pain.
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N-Alkylated Analogs of 4-Methylamphetamine (4-MA) Differentially Affect Monoamine Transporters and Abuse Liability. Neuropsychopharmacology 2017; 42:1950-1961. [PMID: 28530234 PMCID: PMC5561352 DOI: 10.1038/npp.2017.98] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 05/04/2017] [Accepted: 05/12/2017] [Indexed: 01/22/2023]
Abstract
Clandestine chemists synthesize novel stimulant drugs by exploiting structural templates known to target monoamine transporters for dopamine, norepinephrine, and serotonin (DAT, NET, and SERT, respectively). 4-Methylamphetamine (4-MA) is an emerging drug of abuse that interacts with transporters, but limited structure-activity data are available for its analogs. Here we employed uptake and release assays in rat brain synaptosomes, voltage-clamp current measurements in cells expressing transporters, and calcium flux assays in cells coexpressing transporters and calcium channels to study the effects of increasing N-alkyl chain length of 4-MA on interactions at DAT, NET, and SERT. In addition, we performed intracranial self-stimulation in rats to understand how the chemical modifications affect abuse liability. All 4-MA analogs inhibited uptake at DAT, NET, and SERT, but lengthening the amine substituent from methyl to ethyl, propyl, and butyl produced a stepwise decrease in potency. N-methyl 4-MA was an efficacious substrate-type releaser at DAT that evoked an inward depolarizing current and calcium influx, whereas other analogs did not exhibit these effects. N-methyl and N-ethyl 4-MA were substrates at NET, whereas N-propyl and N-butyl 4-MA were not. All analogs acted as SERT substrates, though N-butyl 4-MA had very weak effects. Intracranial self-stimulation in rats showed that elongating the N-alkyl chain decreased abuse-related effects in vivo that appeared to parallel reductions in DAT activity. Overall, converging lines of evidence show that lengthening the N-alkyl substituent of 4-MA reduces potency to inhibit transporters, eliminates substrate activity at DAT and NET, and decreases abuse liability of the compounds.
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Assessment of Behavioral Disruption in Rats with Abdominal Inflammation Using Visual Cue Titration and the Five-choice Serial-reaction Time Task. Anesthesiology 2017; 127:372-381. [PMID: 28542002 DOI: 10.1097/aln.0000000000001702] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Both acute and chronic pain result in a number of behavioral symptoms in patients, including cognitive effects such as decreased attention and working memory. Intraperitoneal administration of dilute lactic acid in rodents has been used to induce abdominal inflammation and produce effects in behavioral assays of both sensory-discriminative and affective pain modalities. METHODS Intraperitoneal injection of dilute lactic acid was used to study the impact of abdominal inflammation on an operant task requiring sustained visual attention in rats (N = 7 to 15/group) that adapts dynamically to performance ability. The effects of ketoprofen and morphine on lactic acid-induced impairment were compared with those on the disruptive effects of scopolamine. RESULTS Lactic acid impaired performance in a concentration-dependent manner, increasing the duration of cue presentation required to maintain optimal performance from 0.5 ± 0.2 s (mean ± SD) to 17.2 ± 11.4 s after the administration of 1.8% (v/v) (N = 13). The latency to emit correct responses and to retrieve the food reward were both increased by lactic acid. All effects of lactic acid injection were reversed by both ketoprofen and morphine in a dose-dependent manner. Scopolamine, however, produced dose-dependent, nonpain-related disruption in sustained attention that was not altered by either ketoprofen or morphine. CONCLUSIONS These data demonstrate that abdominal inflammation induced by lactic acid produces robust disruption in a visual attention-based operant task and that this disruption is reversed by analgesics. Future studies will focus on pain-related circuitry and its impact on both limbic forebrain and frontal cortical mechanisms.
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Goody SMG, Cannon KE, Liu M, Kallman MJ, Martinolle JP, Mazelin-Winum L, Giarola A, Ardayfio P, Moyer JA, Teuns G, Hudzik TJ. Considerations on nonclinical approaches to modeling risk factors of suicidal ideation and behavior. Regul Toxicol Pharmacol 2017; 89:288-301. [PMID: 28757322 DOI: 10.1016/j.yrtph.2017.07.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 07/22/2017] [Accepted: 07/26/2017] [Indexed: 12/31/2022]
Abstract
Given the serious nature of suicidal ideation and behavior (SIB) and the possibility of treatment-emergent SIB, pharmaceutical companies are now applying more proactive approaches in clinical trials and are considering the value of nonclinical models to predict SIB. The current review summarizes nonclinical approaches to modeling three common risk factors associated with SIB: aggression, impulsivity, and anhedonia. For each risk factor, a general description, advantages and disadvantages, species considerations, nonclinical to clinical translation, and pharmacological validation with respect to treatments associated with SIB are summarized. From this review, several gaps were identified that need to be addressed before use of these nonclinical models can be considered a viable option to predict the relative risk for SIB. Other future directions that may compliment these nonclinical approaches, including the use of selectively-bred or genetically-modified rodent models, transgenic models, gene expression profiling, and biomarker analysis, are discussed. This article was developed with the support of the DruSafe Leadership Group of the International Consortium for Innovation and Quality in Pharmaceutical Development (IQ, www.iqconsortium.org).
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Affiliation(s)
- S M G Goody
- Pfizer Drug Safety Research & Development, Groton, CT, USA.
| | | | - M Liu
- Drinker, Biddle and IQ Consortium, Washington, DC, USA
| | - M J Kallman
- Kallman Preclinical Consulting, Greenfield, IN, USA
| | | | | | - A Giarola
- GlaxoSmithKline Safety Pharmacology Department, Ware, UK
| | - P Ardayfio
- Eli Lilly and Company, Indianapolis, IN, USA
| | - J A Moyer
- Janssen Research & Development, Titusville, NJ, USA
| | - G Teuns
- Janssen Research & Development, Beerse, Belgium
| | - T J Hudzik
- ALA BioPharm Consulting, Gurnee, IL, USA
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18
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Subbaiah MAM. Triple Reuptake Inhibitors as Potential Therapeutics for Depression and Other Disorders: Design Paradigm and Developmental Challenges. J Med Chem 2017; 61:2133-2165. [DOI: 10.1021/acs.jmedchem.6b01827] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Murugaiah A. M. Subbaiah
- Department of Medicinal Chemistry, Biocon Bristol-Myers Squibb R&D Centre, Biocon Park, Bommasandra Phase IV, Jigani Link Road, Bangalore 560099, India
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Rakesh G, Pae CU, Masand PS. Beyond serotonin: newer antidepressants in the future. Expert Rev Neurother 2017; 17:777-790. [DOI: 10.1080/14737175.2017.1341310] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Gopalkumar Rakesh
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
| | - Chi-Un Pae
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
- Department of Psychiatry, The Catholic University of Korea College of Medicine, Seoul, Republic of Korea
| | - Prakash S. Masand
- Academic Medicine Education Institute, Duke-NUS Medical School, Singapore, Singapore
- Global Medical Education, New York, NY, USA
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20
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Lazenka MF, Freitas KC, Henck S, Negus SS. Relief of Pain-Depressed Behavior in Rats by Activation of D1-Like Dopamine Receptors. J Pharmacol Exp Ther 2017; 362:14-23. [PMID: 28411257 DOI: 10.1124/jpet.117.240796] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 04/13/2017] [Indexed: 12/11/2022] Open
Abstract
Clinically significant pain often includes a decrease in both behavior and mesolimbic dopamine signaling. Indirect and/or direct dopamine receptor agonists may alleviate pain-related behavioral depression. To test this hypothesis, the present study compared effects of indirect and direct dopamine agonists in a preclinical assay of pain-depressed operant responding. Male Sprague-Dawley rats with chronic indwelling microelectrodes in the medial forebrain bundle were trained in an intracranial self-stimulation (ICSS) procedure to press a lever for pulses of electrical brain stimulation. Intraperitoneal injection of dilute lactic acid served as an acute noxious stimulus to depress ICSS. Intraperitoneal lactic acid-induced depression of ICSS was dose-dependently blocked by the dopamine transporter inhibitor methylphenidate and the D1-selective agonist SKF82958, but not by the D2/3-selective agonists quinpirole, pramipexole, or sumanirole. The antinociceptive effects of methylphenidate and SKF82958 were blocked by the D1-selective antagonist SCH39166. Acid-induced stimulation of a stretching response was evaluated in separate groups of rats, but all agonists decreased acid-stimulated stretching, and antagonism experiments were inconclusive due to direct effects of the antagonists when administered alone. Taken together, these results suggest that D1-receptor stimulation is both sufficient to block acid-induced depression of ICSS and necessary for methylphenidate antinociception in this procedure. Conversely, D2/3-receptor stimulation is not sufficient to relieve pain-depressed behavior. These results support the hypothesis that pain-related depression of dopamine D1 receptor signaling contributes to pain-related depression of behavior in rats. Additionally, these results support further consideration of indirect dopamine agonists and direct D1 receptor agonists as candidate treatments for pain-related behavioral depression.
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Affiliation(s)
- Matthew F Lazenka
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Kelen C Freitas
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Sydney Henck
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - S Stevens Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
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21
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Tosh DK, Janowsky A, Eshleman AJ, Warnick E, Gao ZG, Chen Z, Gizewski E, Auchampach JA, Salvemini D, Jacobson KA. Scaffold Repurposing of Nucleosides (Adenosine Receptor Agonists): Enhanced Activity at the Human Dopamine and Norepinephrine Sodium Symporters. J Med Chem 2017; 60:3109-3123. [PMID: 28319392 PMCID: PMC5501184 DOI: 10.1021/acs.jmedchem.7b00141] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We have repurposed (N)-methanocarba adenosine derivatives (A3 adenosine receptor (AR) agonists) to enhance radioligand binding allosterically at the human dopamine (DA) transporter (DAT) and inhibit DA uptake. We extended the structure-activity relationship of this series with small N6-alkyl substitution, 5'-esters, deaza modifications of adenine, and ribose restored in place of methanocarba. C2-(5-Halothien-2-yl)-ethynyl 5'-methyl 9 (MRS7292) and 5'-ethyl 10 (MRS7232) esters enhanced binding at DAT (EC50 ∼ 35 nM) and at the norepinephrine transporter (NET). 9 and 10 were selective for DAT compared to A3AR in the mouse but not in humans. At DAT, the binding of two structurally dissimilar radioligands was enhanced; NET binding of only one radioligand was enhanced; SERT radioligand binding was minimally affected. 10 was more potent than cocaine at inhibiting DA uptake (IC50 = 107 nM). Ribose analogues were weaker in DAT interaction than the corresponding bicyclics. Thus, we enhanced the neurotransmitter transporter activity of rigid nucleosides while reducing A3AR affinity.
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Affiliation(s)
- Dilip K. Tosh
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892 USA
| | - Aaron Janowsky
- VA Portland Health Care System, Research Service (R&D-22), and Departments of Psychiatry and Behavioral Neuroscience, Oregon Health and Science Univ., Portland, Oregon 97239 USA
| | - Amy J. Eshleman
- VA Portland Health Care System, Research Service (R&D-22), and Departments of Psychiatry and Behavioral Neuroscience, Oregon Health and Science Univ., Portland, Oregon 97239 USA
| | - Eugene Warnick
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892 USA
| | - Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892 USA
| | - Zhoumou Chen
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri USA 63104
| | - Elizabeth Gizewski
- Department of Pharmacology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226 USA
| | - John A. Auchampach
- Department of Pharmacology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226 USA
| | - Daniela Salvemini
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri USA 63104
| | - Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892 USA
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22
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Mesolimbic dopamine signaling in acute and chronic pain: implications for motivation, analgesia, and addiction. Pain 2017; 157:1194-1198. [PMID: 26797678 PMCID: PMC4866581 DOI: 10.1097/j.pain.0000000000000494] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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23
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Dissociable effects of the prodrug phendimetrazine and its metabolite phenmetrazine at dopamine transporters. Sci Rep 2016; 6:31385. [PMID: 27514281 PMCID: PMC4981850 DOI: 10.1038/srep31385] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 07/19/2016] [Indexed: 11/28/2022] Open
Abstract
Phendimetrazine (PDM) is a clinically available anorectic and a candidate pharmacotherapy for cocaine addiction. PDM has been hypothesized to function as a prodrug that requires metabolism to the amphetamine-like monoamine transporter substrate phenmetrazine (PM) to produce its pharmacological effects; however, whether PDM functions as an inactive prodrug or has pharmacological activity on its own remains unclear. The study aim was to determine PDM pharmacological mechanisms using electrophysiological, neurochemical, and behavioral procedures. PDM blocked the endogenous basal hDAT (human dopamine transporter) current in voltage-clamped (−60 mV) oocytes consistent with a DAT inhibitor profile, whereas its metabolite PM induced an inward hDAT current consistent with a DAT substrate profile. PDM also attenuated the PM-induced inward current during co-application, providing further evidence that PDM functions as a DAT inhibitor. PDM increased nucleus accumbens dopamine levels and facilitated electrical brain stimulation reinforcement within 10 min in rats, providing in vivo evidence supporting PDM pharmacological activity. These results demonstrate that PDM functions as a DAT inhibitor that may also interact with the pharmacological effects of its metabolite PM. Overall, these results suggest a novel mechanism for PDM therapeutic effects via initial PDM DAT inhibition followed by PM DAT substrate-induced dopamine release.
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Lazenka MF, Legakis LP, Negus SS. Opposing effects of dopamine D1- and D2-like agonists on intracranial self-stimulation in male rats. Exp Clin Psychopharmacol 2016; 24:193-205. [PMID: 26987070 PMCID: PMC4891217 DOI: 10.1037/pha0000067] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Dopamine acts through dopamine Type I receptors (comprising D1 and D5 subtypes) and dopamine Type II receptors (comprising D2, D3, and D4 subtypes). Intracranial self-stimulation (ICSS) is 1 experimental procedure that can be used to evaluate abuse-related effects of drugs targeting dopamine receptors. This study evaluated effects of dopamine receptor ligands on ICSS in rats using experimental procedures that have been used previously to examine abused indirect dopamine agonists such as cocaine and amphetamine. Male Sprague-Dawley rats responded under a fixed-ratio 1 schedule for electrical stimulation of the medial forebrain bundle, and frequency of stimulation varied from 56-158 Hz in 0.05 log increments during each experimental session. Drug potency and time course were determined for the D1 ligands A77636, SKF82958, SKF38393, fenoldopam, and SCH39166 and the D2/3 ligands sumanirole, apomorphine, quinpirole, PD128907, pramipexole, aripiprazole, eticlopride, and PG01037. The high-efficacy D1 agonists A77636 and SKF82958 produced dose-dependent, time-dependent, and abuse-related facilitation of ICSS. Lower efficacy D1 ligands and all D2/3 ligands failed to facilitate ICSS at any dose or pretreatment time. A mixture of SKF82958 and quinpirole produced a mixture of effects produced by each drug alone. Quinpirole also failed to facilitate ICSS after regimens of repeated treatment with either quinpirole or cocaine. These studies provide more evidence for divergent effects of dopamine D1- and D2-family agonists on ICSS procedure in rats and suggest that ICSS may be a useful complement to other approaches for preclinical abuse potential assessment, in part because of the reproducibility of results. (PsycINFO Database Record
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Affiliation(s)
- Matthew F. Lazenka
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA, USA
- Corresponding Author: Matthew F. Lazenka, Dept. of Pharmacology and Toxicology, PO Box 980613, 410 North 12 St., Virginia Commonwealth University School of Medicine Richmond, Virginia 23298-0613, Phone: 804-826-2491, FAX: 804-828-1532,
| | - Luke P. Legakis
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA, USA
| | - S. Stevens Negus
- Department of Pharmacology and Toxicology and Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA, USA
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25
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Hillhouse TM, Negus SS. Effects of the noncompetitive N-methyl-d-aspartate receptor antagonists ketamine and MK-801 on pain-stimulated and pain-depressed behaviour in rats. Eur J Pain 2016; 20:1229-40. [PMID: 26914635 DOI: 10.1002/ejp.847] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/01/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND Pain is a significant public health concern, and current pharmacological treatments have problematic side effects and limited effectiveness. N-methyl-d-aspartate (NMDA) glutamate receptor antagonists have emerged as one class of candidate treatments for pain because of the significant contribution of glutamate signalling in nociceptive processing. METHODS This study compared effects of the NMDA receptor antagonists ketamine and MK-801 in assays of pain-stimulated and pain-depressed behaviour in rats. The nonsteroidal anti-inflammatory drug ketoprofen was examined for comparison as a positive control. Intraperitoneal injection of dilute acid served as an acute visceral noxious stimulus to stimulate a stretching response or depress intracranial self-stimulation (ICSS) in male Sprague-Dawley rats. RESULTS Ketamine (1.0-10.0 mg/kg) blocked acid-stimulated stretching but failed to block acid-induced depression of ICSS, whereas MK-801 (0.01-0.1 mg/kg) blocked both acid-stimulated stretching and acid-induced depression of ICSS. These doses of ketamine and MK-801 did not alter control ICSS in the absence of the noxious stimulus; however, higher doses of ketamine (10 mg/kg) and MK-801 (0.32 mg/kg) depressed all behaviour. Ketoprofen (1.0 mg/kg) blocked both acid-induced stimulation of stretching and depression of ICSS without altering control ICSS. CONCLUSION These results support further consideration of NMDA receptor antagonists as analgesics; however, some NMDA receptor antagonists are more efficacious at attenuating pain-depressed behaviours. WHAT DOES THIS STUDY ADD NMDA receptor antagonists produce dissociable effects on pain-depressed behaviour. Provides evidence that pain-depressed behaviours should be considered and evaluated when determining the antinociceptive effects of NMDA receptor antagonists.
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Affiliation(s)
- T M Hillhouse
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA.,Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
| | - S S Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
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26
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Tracy ME, Banks ML, Shelton KL. Negative allosteric modulation of GABAA receptors inhibits facilitation of brain stimulation reward by drugs of abuse in C57BL6/J mice. Psychopharmacology (Berl) 2016; 233:715-25. [PMID: 26612620 PMCID: PMC4825185 DOI: 10.1007/s00213-015-4155-z] [Citation(s) in RCA: 10] [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: 07/20/2015] [Accepted: 11/04/2015] [Indexed: 10/22/2022]
Abstract
RATIONALE There is an emerging body of evidence that implicates a crucial role of γ-aminobutyric acid subtype A (GABAA) receptors in modulating the rewarding effects of a number of abused drugs. Modulation of GABAA receptors may therefore represent a novel drug-class independent mechanism for the development of abuse treatment pharmacotherapeutics. OBJECTIVES We tested the hypothesis that the GABAA receptor benzodiazepine-site (BDZ) negative modulator Ro15-4513 would reduce the reward-related effects of three pharmacologically dissimilar drugs; toluene vapor, d-methamphetamine, and diazepam using intracranial self-stimulation (ICSS) in mice. We also examined whether Ro15-4513 attenuated dopamine release produced by d-methamphetamine in an in vivo microdialysis procedure. RESULTS Ro15-4513 abolished ICSS reward facilitation produced by all three abused drugs at Ro15-4513 doses which had no effect on ICSS when administered alone. In contrast, the BDZ antagonist flumazenil only attenuated the ICSS-facilitating effects of diazepam. Administration of the same dose of Ro15-4513 which abolished drug-facilitated ICSS produced a 58 % decrease in d-methamphetamine-stimulated dopamine in the nucleus accumbens of mice relative to d-methamphetamine alone. CONCLUSIONS These results demonstrate that negative modulation of GABAA receptors can produce profound reductions in reward-related effects of a diverse group of drugs that activate the mesolimbic reward pathway through different mechanisms. These data suggest that pharmacological modulation of GABAA receptors may represent a viable pathway for the development of drug abuse pharmacotherapies.
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Affiliation(s)
- Matthew E Tracy
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, 410 North 12th Street, Room 746, P.O. Box 980613, Richmond, VA, 23298-0613, USA
| | - Matthew L Banks
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, 410 North 12th Street, Room 746, P.O. Box 980613, Richmond, VA, 23298-0613, USA
| | - Keith L Shelton
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, 410 North 12th Street, Room 746, P.O. Box 980613, Richmond, VA, 23298-0613, USA.
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27
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Freitas KC, Carroll FI, Negus SS. Effects of nicotinic acetylcholine receptor agonists in assays of acute pain-stimulated and pain-depressed behaviors in rats. J Pharmacol Exp Ther 2016; 355:341-50. [PMID: 26359313 DOI: 10.1124/jpet.115.226803] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Agonists at nicotinic acetylcholine receptors (nAChRs) constitute one drug class being evaluated as candidate analgesics. Previous preclinical studies have implicated α4β2 and α7 nAChRs as potential mediators of the antinociceptive effects of (–)-nicotine hydrogen tartrate (nicotine) and other nAChR agonists; however, these studies have relied exclusively on measures of pain-stimulated behavior, which can be defined as behaviors that increase in frequency, rate, or intensity after presentation of a noxious stimulus. Pain is also associated with depression of many behaviors, and drug effects can differ in assays of pain-stimulated versus pain-depressed behavior. Accordingly, this study compared the effects of nicotine, the selective α4/6β2 agonist 5-(123I)iodo-3-[2(S)-2-azetidinylmethoxy]pyridine (5-I-A-85380), and the selective α7 agonist N-(3R)-1-azabicyclo(2.2.2)oct-3-yl-4-chlorobenzamide in assays of pain-stimulated and pain-depressed behavior in male Sprague-Dawley rats. Intraperitoneal injection of dilute lactic acid served as an acute noxious stimulus to either stimulate a stretching response or depress the operant responding, which is maintained by electrical brain stimulation in an intracranial self-stimulation (ICSS) procedure. Nicotine produced a dose-dependent, time-dependent, and mecamylamine-reversible blockade of both acid-stimulated stretching and acid-induced depression of ICSS. 5-I-A-85380 also blocked both acid-stimulated stretching and acid-induced depression of ICSS, whereas N-(3R)-1-azabicyclo(2.2.2)oct-3-yl-4-chlorobenzamide produced no effect in either procedure. Both nicotine and 5-I-A-85380 were ≥10-fold more potent in blocking the acid-induced depression of ICSS than in blocking the acid-induced stimulation of stretching. These results suggest that stimulation of α4β2 and/or α6β2 nAChRs may be especially effective to alleviate the signs of pain-related behavioral depression in rats; however, nonselective behavioral effects may contribute to apparent antinociception.
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Affiliation(s)
- Kelen C Freitas
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
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28
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Warner E, Krivitsky R, Cone K, Atherton P, Pitre T, Lanpher J, Giuvelis D, Bergquist I, King T, Bilsky EJ, Stevenson GW. Evaluation of a Postoperative Pain-Like State on Motivated Behavior in Rats: Effects of Plantar Incision on Progressive-Ratio Food-Maintained Responding. Drug Dev Res 2015; 76:432-41. [PMID: 26494422 PMCID: PMC4715615 DOI: 10.1002/ddr.21284] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 10/03/2015] [Indexed: 01/01/2023]
Abstract
There has been recent interest in characterizing the effects of pain-like states on motivated behaviors in order to quantify how pain modulates goal-directed behavior and the persistence of that behavior. The current set of experiments assessed the effects of an incisional postoperative pain manipulation on food-maintained responding under a progressive-ratio (PR) operant schedule. Independent variables included injury state (plantar incision or anesthesia control) and reinforcer type (grain pellet or sugar pellet); dependent variables were tactile sensory thresholds and response breakpoint. Once responding stabilized on the PR schedule, separate groups of rats received a single ventral hind paw incision or anesthesia (control condition). Incision significantly reduced breakpoints in rats responding for grain, but not sugar. In rats responding for sugar, tactile hypersensitivity recovered within 24 hr, indicating a faster recovery of incision-induced tactile hypersensitivity compared to rats responding for grain, which demonstrated recovery at PD2. The NSAID analgesic, diclofenac (5.6 mg/kg) completely restored incision-depressed PR operant responding and tactile sensitivity at 3 hr following incision. The PR schedule differentiated between sucrose and grain, suggesting that relative reinforcing efficacy may be an important determinant in detecting pain-induced changes in motivated behavior.
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Affiliation(s)
- Emily Warner
- Department of Psychology, University of New England, Biddeford, ME, 04005
| | - Rebecca Krivitsky
- Department of Psychology, University of New England, Biddeford, ME, 04005
| | - Katherine Cone
- Department of Psychology, University of New England, Biddeford, ME, 04005
| | - Phillip Atherton
- Department of Psychology, University of New England, Biddeford, ME, 04005
| | - Travis Pitre
- Department of Psychology, University of New England, Biddeford, ME, 04005
| | - Janell Lanpher
- Department of Psychology, University of New England, Biddeford, ME, 04005
| | - Denise Giuvelis
- Department of Biomedical Sciences, University of New England College of Osteopathic Medicine, Biddeford, ME, 04005
| | - Ivy Bergquist
- Department of Biomedical Sciences, University of New England College of Osteopathic Medicine, Biddeford, ME, 04005
| | - Tamara King
- Department of Biomedical Sciences, University of New England College of Osteopathic Medicine, Biddeford, ME, 04005
- Center for Excellence in the Neurosciences, University of New England, ME, 04005
| | - Edward J. Bilsky
- Department of Biomedical Sciences, University of New England College of Osteopathic Medicine, Biddeford, ME, 04005
- Center for Excellence in the Neurosciences, University of New England, ME, 04005
| | - Glenn W. Stevenson
- Department of Psychology, University of New England, Biddeford, ME, 04005
- Center for Excellence in the Neurosciences, University of New England, ME, 04005
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Suyama JA, Sakloth F, Kolanos R, Glennon RA, Lazenka MF, Negus SS, Banks ML. Abuse-Related Neurochemical Effects of Para-Substituted Methcathinone Analogs in Rats: Microdialysis Studies of Nucleus Accumbens Dopamine and Serotonin. J Pharmacol Exp Ther 2015; 356:182-90. [PMID: 26645638 DOI: 10.1124/jpet.115.229559] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 10/14/2015] [Indexed: 11/22/2022] Open
Abstract
Methcathinone (MCAT) is a monoamine releaser and parent compound to a new class of designer drugs that includes the synthetic cathinones mephedrone and flephedrone. Using MCAT and a series of para-substituted (or 4-substituted) MCAT analogs, it has been previously shown that expression of abuse-related behavioral effects in rats correlates both with the volume of the para substituent and in vitro neurochemical selectivity to promote monoamine release via the dopamine (DA) versus serotonin (5-HT) transporters in rat brain synaptosomes. The present study used in vivo microdialysis to determine the relationship between these previous measures and the in vivo neurochemical selectivity of these compounds to alter nucleus accumbens (NAc) DA and 5-HT levels. Male Sprague-Dawley rats were implanted with bilateral guide cannulae targeting the NAc. MCAT and five para-substituted analogs (4-F, 4-Cl, 4-Br, 4-CH3, and 4-OCH3) produced dose- and time-dependent increases in NAc DA and/or 5-HT levels. Selectivity was determined as the dose required to increase peak 5-HT levels by 250% divided by the dose required to increase peak DA levels by 250%. This measure of in vivo neurochemical selectivity varied across compounds and correlated with 1) in vivo expression of abuse-related behavioral effects (r = 0.89, P = 0.02); 2) in vitro selectivity to promote monoamine release via DA and 5-HT transporters (r = 0.95, P < 0.01); and 3) molecular volume of the para substituent (r = -0.85, P = 0.03). These results support a relationship between these molecular, neurochemical, and behavioral measures and support a role for molecular structure as a determinant of abuse-related neurochemical and behavioral effects of MCAT analogs.
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Affiliation(s)
- Julie A Suyama
- Department of Pharmacology and Toxicology (J.A.S., M.F.L., S.S.N., M.L.B.), Department of Medicinal Chemistry (F.S., R.K., R.A.G.), and Institute on Drug and Alcohol Studies (R.A.G., S.S.N., M.L.B.), Virginia Commonwealth University, Richmond, Virginia
| | - Farhana Sakloth
- Department of Pharmacology and Toxicology (J.A.S., M.F.L., S.S.N., M.L.B.), Department of Medicinal Chemistry (F.S., R.K., R.A.G.), and Institute on Drug and Alcohol Studies (R.A.G., S.S.N., M.L.B.), Virginia Commonwealth University, Richmond, Virginia
| | - Renata Kolanos
- Department of Pharmacology and Toxicology (J.A.S., M.F.L., S.S.N., M.L.B.), Department of Medicinal Chemistry (F.S., R.K., R.A.G.), and Institute on Drug and Alcohol Studies (R.A.G., S.S.N., M.L.B.), Virginia Commonwealth University, Richmond, Virginia
| | - Richard A Glennon
- Department of Pharmacology and Toxicology (J.A.S., M.F.L., S.S.N., M.L.B.), Department of Medicinal Chemistry (F.S., R.K., R.A.G.), and Institute on Drug and Alcohol Studies (R.A.G., S.S.N., M.L.B.), Virginia Commonwealth University, Richmond, Virginia
| | - Matthew F Lazenka
- Department of Pharmacology and Toxicology (J.A.S., M.F.L., S.S.N., M.L.B.), Department of Medicinal Chemistry (F.S., R.K., R.A.G.), and Institute on Drug and Alcohol Studies (R.A.G., S.S.N., M.L.B.), Virginia Commonwealth University, Richmond, Virginia
| | - S Stevens Negus
- Department of Pharmacology and Toxicology (J.A.S., M.F.L., S.S.N., M.L.B.), Department of Medicinal Chemistry (F.S., R.K., R.A.G.), and Institute on Drug and Alcohol Studies (R.A.G., S.S.N., M.L.B.), Virginia Commonwealth University, Richmond, Virginia
| | - Matthew L Banks
- Department of Pharmacology and Toxicology (J.A.S., M.F.L., S.S.N., M.L.B.), Department of Medicinal Chemistry (F.S., R.K., R.A.G.), and Institute on Drug and Alcohol Studies (R.A.G., S.S.N., M.L.B.), Virginia Commonwealth University, Richmond, Virginia
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