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Esterlis I, DeBonee S, Cool R, Holmes S, Baldassari SR, Maruff P, Pietrzak RH, Davis MT. Differential Role of mGluR5 in Cognitive Processes in Posttraumatic Stress Disorder and Major Depression. CHRONIC STRESS (THOUSAND OAKS, CALIF.) 2022; 6:24705470221105804. [PMID: 35958037 PMCID: PMC9358555 DOI: 10.1177/24705470221105804] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 05/23/2022] [Indexed: 11/16/2022]
Abstract
Background A robust literature supports the role of the metabotropic glutamate receptor type 5 (mGluR5) in cognitive functioning. mGluR5 is also implicated in the pathophysiology of posttraumatic stress disorder (PTSD) and major depressive disorder (MDD), which are characterized by cognitive alterations. However, the relationship between mGluR5 and cognition in MDD and PTSD has not yet been directly investigated. To address this gap, we examined the relationship between in vivo mGluR5 availability and cognition in PTSD, MDD, and matched healthy adults (HA). Methods Individuals with PTSD (N = 28) and MDD (N = 21), and HA (N = 28) were matched for age, gender, and smoking status. Participants completed 18F-FPEB positron emission tomography (PET) scan, psychiatric and cognitive assessments. Results Across models examining the relationship between mGluR5 availability and different domains of cognition across diagnostic groups, only the interaction of diagnosis*attention was significant (F 4,64 = 3.011, P = .024). Higher mGluR5 availability was associated with poorer attention in PTSD in 4 frontolimbic regions of interests (ROI's: OFC (r = -.441, P = .016), vmPFC (r = -.408, P = .028), dlPFC (r = -.421, P = .023), hippocampus (r = -.422, P = .025). By contrast, mGluR5 availability in the MDD group was positively related to Attention (ATTN) in the OFC (r = .590, P = .006), vmPFC (r = .653, P = .002), and dlPFC (r = .620, P = .004). Findings in the hippocampus for MDD followed the same pattern but did not survive correction for multiple comparisons (r = .480, P = .036). ATTN and mGluR5 availability were not significantly related in the HA group. Of note, in MANOVA analyses group*ATTN interaction results in the OFC did not survive multiple comparisons (P = .046). All other findings survived correction for multiple comparisons and remained significant when covarying for potential confounds (eg, depressed mood). Conclusions We observed a significant relationship between frontolimbic mGluR5 availability and performance on tests of attention in individuals with MDD and PTSD. This finding aligns with animal work showing dysregulation in mGluR5 in cognitive functioning, and differed as a function of diagnosis. Results suggest interventions targeting mGluR5 may help bolster cognitive difficulties, highlighting the importance of employing different mGluR5 directed treatment strategies in MDD and PTSD.
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Affiliation(s)
- Irina Esterlis
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
- Department of Psychology, Yale University, New Haven, CT, USA
- National Center for Posttraumatic Stress Disorder, U.S. Department of Veterans Affairs, West Haven, CT, USA
| | - Sarah DeBonee
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Ryan Cool
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Sophie Holmes
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
- Department of Psychology, Yale University, New Haven, CT, USA
- National Center for Posttraumatic Stress Disorder, U.S. Department of Veterans Affairs, West Haven, CT, USA
| | - Stephen R. Baldassari
- Department of Internal Medicine, Section of Pulmonary, Critical Care, and Sleep Medicine, Yale University School of Medicine, New Haven, CT, USA
- Program in Addiction Medicine, Yale University School of Medicine, New Haven, CT, USA
| | | | - Robert H. Pietrzak
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
- National Center for Posttraumatic Stress Disorder, U.S. Department of Veterans Affairs, West Haven, CT, USA
| | - Margaret T. Davis
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
- Department of Psychology, Yale University, New Haven, CT, USA
- National Center for Posttraumatic Stress Disorder, U.S. Department of Veterans Affairs, West Haven, CT, USA
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2
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Tumanova TS, Кokurina TN, Rybakova GI, Aleksandrov VG. Dexamethasone attenuates the modulatory effect of the insular cortex on the baroreflex in anesthetized rat. Can J Physiol Pharmacol 2021; 100:334-340. [PMID: 34644509 DOI: 10.1139/cjpp-2021-0385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The arterial baroreflex (BR) is an important neural mechanism for the stabilization of arterial pressure (AP). It is known that the insular cortex (IC) and other parts of the central autonomic network (CAN) are able to modulate the BR arc, altering baroreflex sensitivity (BRS). In addition, the sensitivity of the BR changes under the influence of hormones, in particular glucocorticoids (GC). It has been suggested that GC may influence BRS by altering the ability of the IC to modulate the BR. This hypothesis has been tested in experiments on rats anesthetized with urethane. It was found that microelectrostimulation of the visceral area in the left IC causes a short-term drop in AP, which is accompanied by bradycardia, and impairs BRS. The synthetic GC dexamethasone (DEX) did not significantly affect the magnitude of depressor responses but increased BRS and impaired the effect of IC stimulation on the BR. The results obtained confirm the hypothesis put forward and suggest that GC can attenuate the inhibitory effects of the IC on the BR arc, thereby enhancing the sensitivity of the BR.
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Affiliation(s)
- Tatiana Sergeevna Tumanova
- Pavlov Institute of Physiology RAS, 68594, Sankt Peterburg, Russian Federation.,Herzen State Pedagogical University of Russia, 104720, Biology, Sankt-Peterburg, Russian Federation;
| | | | | | - Viacheslav G Aleksandrov
- Pavlov Institute of Physiology RAS, 68594, 6, nab. Makarova, Sankt Peterburg, Russian Federation, 199034;
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3
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Hsu JCN, Sekizawa SI, Tochinai R, Kuwahara M. Chronic stimulation of group II metabotropic glutamate receptors in the medulla oblongata attenuates hypertension development in spontaneously hypertensive rats. PLoS One 2021; 16:e0251495. [PMID: 34010316 PMCID: PMC8133461 DOI: 10.1371/journal.pone.0251495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 04/27/2021] [Indexed: 01/06/2023] Open
Abstract
Baroreflex dysfunction is partly implicated in hypertension and one responsible region is the dorsal medulla oblongata including the nucleus tractus solitarius (NTS). NTS neurons receive and project glutamatergic inputs to subsequently regulate blood pressure, while G-protein-coupled metabotropic glutamate receptors (mGluRs) play a modulatory role for glutamatergic transmission in baroreflex pathways. Stimulating group II mGluR subtype 2 and 3 (mGluR2/3) in the brainstem can decrease blood pressure and sympathetic nervous activity. Here, we hypothesized that the chronic stimulation of mGluR2/3 in the dorsal medulla oblongata can alleviate hypertensive development via the modulation of autonomic nervous activity in young, spontaneously hypertensive rats (SHRs). Compared with that in the sham control group, chronic LY379268 application (mGluR2/3 agonist; 0.40 μg/day) to the dorsal medulla oblongata for 6 weeks reduced the progression of hypertension in 6-week-old SHRs as indicated by the 40 mmHg reduction in systolic blood pressure and promoted their parasympathetic nervous activity as evidenced by the heart rate variability. No differences in blood catecholamine levels or any echocardiographic indices were found between the two groups. The improvement of reflex bradycardia, a baroreflex function, appeared after chronic LY379268 application. The mRNA expression level of mGluR2, but not mGluR3, in the dorsal medulla oblongata was substantially reduced in SHRs compared to that of the control strain. In conclusion, mGluR2/3 signaling might be responsible for hypertension development in SHRs, and modulating mGluR2/3 expression/stimulation in the dorsal brainstem could be a novel therapeutic strategy for hypertension via increasing the parasympathetic activity.
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Affiliation(s)
- Julia Chu-Ning Hsu
- Department of Veterinary Pathophysiology and Animal Health, Graduate School of Agricultural and Sciences, The University of Tokyo, Tokyo, Japan
| | - Shin-ichi Sekizawa
- Department of Veterinary Pathophysiology and Animal Health, Graduate School of Agricultural and Sciences, The University of Tokyo, Tokyo, Japan
| | - Ryota Tochinai
- Department of Veterinary Pathophysiology and Animal Health, Graduate School of Agricultural and Sciences, The University of Tokyo, Tokyo, Japan
| | - Masayoshi Kuwahara
- Department of Veterinary Pathophysiology and Animal Health, Graduate School of Agricultural and Sciences, The University of Tokyo, Tokyo, Japan
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4
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Glutamatergic Receptor Trafficking and Delivery: Role of the Exocyst Complex. Cells 2020; 9:cells9112402. [PMID: 33153008 PMCID: PMC7693776 DOI: 10.3390/cells9112402] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/21/2020] [Accepted: 10/23/2020] [Indexed: 12/29/2022] Open
Abstract
Cells comprise several intracellular membrane compartments that allow them to function properly. One of these functions is cargo movement, typically proteins and membranes within cells. These cargoes ride microtubules through vesicles from Golgi and recycling endosomes to the plasma membrane in order to be delivered and exocytosed. In neurons, synaptic functions employ this cargo trafficking to maintain inter-neuronal communication optimally. One of the complexes that oversee vesicle trafficking and tethering is the exocyst. The exocyst is a protein complex containing eight subunits first identified in yeast and then characterized in multicellular organisms. This complex is related to several cellular processes, including cellular growth, division, migration, and morphogenesis, among others. It has been associated with glutamatergic receptor trafficking and tethering into the synapse, providing the molecular machinery to deliver receptor-containing vesicles into the plasma membrane in a constitutive manner. In this review, we discuss the evidence so far published regarding receptor trafficking and the exocyst complex in both basal and stimulated levels, comparing constitutive trafficking and long-term potentiation-related trafficking.
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5
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Belov Kirdajova D, Kriska J, Tureckova J, Anderova M. Ischemia-Triggered Glutamate Excitotoxicity From the Perspective of Glial Cells. Front Cell Neurosci 2020; 14:51. [PMID: 32265656 PMCID: PMC7098326 DOI: 10.3389/fncel.2020.00051] [Citation(s) in RCA: 185] [Impact Index Per Article: 46.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/21/2020] [Indexed: 12/21/2022] Open
Abstract
A plethora of neurological disorders shares a final common deadly pathway known as excitotoxicity. Among these disorders, ischemic injury is a prominent cause of death and disability worldwide. Brain ischemia stems from cardiac arrest or stroke, both responsible for insufficient blood supply to the brain parenchyma. Glucose and oxygen deficiency disrupts oxidative phosphorylation, which results in energy depletion and ionic imbalance, followed by cell membrane depolarization, calcium (Ca2+) overload, and extracellular accumulation of excitatory amino acid glutamate. If tight physiological regulation fails to clear the surplus of this neurotransmitter, subsequent prolonged activation of glutamate receptors forms a vicious circle between elevated concentrations of intracellular Ca2+ ions and aberrant glutamate release, aggravating the effect of this ischemic pathway. The activation of downstream Ca2+-dependent enzymes has a catastrophic impact on nervous tissue leading to cell death, accompanied by the formation of free radicals, edema, and inflammation. After decades of “neuron-centric” approaches, recent research has also finally shed some light on the role of glial cells in neurological diseases. It is becoming more and more evident that neurons and glia depend on each other. Neuronal cells, astrocytes, microglia, NG2 glia, and oligodendrocytes all have their roles in what is known as glutamate excitotoxicity. However, who is the main contributor to the ischemic pathway, and who is the unsuspecting victim? In this review article, we summarize the so-far-revealed roles of cells in the central nervous system, with particular attention to glial cells in ischemia-induced glutamate excitotoxicity, its origins, and consequences.
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Affiliation(s)
- Denisa Belov Kirdajova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia.,Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Jan Kriska
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia.,Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Jana Tureckova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia
| | - Miroslava Anderova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia.,Second Faculty of Medicine, Charles University, Prague, Czechia
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6
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Najjar SA, Davis BM, Albers KM. Epithelial-Neuronal Communication in the Colon: Implications for Visceral Pain. Trends Neurosci 2020; 43:170-181. [PMID: 31983457 DOI: 10.1016/j.tins.2019.12.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/18/2019] [Accepted: 12/30/2019] [Indexed: 02/07/2023]
Abstract
Visceral hypersensitivity and pain result, at least in part, from increased excitability of primary afferents that innervate the colon. In addition to intrinsic changes in these neurons, emerging evidence indicates that changes in lining epithelial cells may also contribute to increased excitability. Here we review recent studies on how colon epithelial cells communicate directly with colon afferents. Specifically, anatomical studies revealed specialized synaptic connections between epithelial cells and nerve fibers and studies using optogenetic activation of the epithelium showed initiation of pain-like responses. We review the possible mechanisms of epithelial-neuronal communication and provide an overview of the possible neurotransmitters and receptors involved. Understanding the biology of this interface and how it changes in pathological conditions may provide new treatments for visceral pain conditions.
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Affiliation(s)
- Sarah A Najjar
- Center for Neuroscience at the University of Pittsburgh, Pittsburgh Center for Pain Research and Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Brian M Davis
- Center for Neuroscience at the University of Pittsburgh, Pittsburgh Center for Pain Research and Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Kathryn M Albers
- Center for Neuroscience at the University of Pittsburgh, Pittsburgh Center for Pain Research and Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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7
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Seo MK, Hien LT, Park MK, Choi AJ, Seog DH, Kim SH, Park SW, Lee JG. AMPA receptor-mTORC1 signaling activation is required for neuroplastic effects of LY341495 in rat hippocampal neurons. Sci Rep 2020; 10:993. [PMID: 31969673 PMCID: PMC6976560 DOI: 10.1038/s41598-020-58017-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 01/09/2020] [Indexed: 12/14/2022] Open
Abstract
The group II metabotropic glutamate 2/3 (mGlu2/3) receptor antagonist LY341495 produces antidepressant-like effects by acting on mammalian target of rapamycin complex 1 (mTORC1) signaling and α-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors in rodent. We investigated whether LY341495 affects neuroplasticity via these mechanisms in rat primary hippocampal cultures under conditions of dexamethasone (DEX)-induced neurotoxicity. Ketamine was used for comparison. Hippocampal cultures were treated with LY341495 under conditions of DEX-induced toxicity. Changes in mTORC1-mediated proteins were determined by Western blotting analyses. Changes in dendritic outgrowth and spine density were evaluated via immunostaining. LY341495 significantly prevented DEX-induced decreases in the levels of mTORC1, 4E-BP1, and p70S6K phosphorylation as well as the levels of the synaptic proteins. These effects were blocked by pretreatment with the AMPA receptor inhibitor 2,3-dihydroxy-6-nitro-7sulfamoyl-benzo(f)quinoxaline (NBQX) and the mTORC1 inhibitor rapamycin. LY341495 significantly attenuated DEX-induced decreases in dendritic outgrowth and spine density. Pretreatment with rapamycin and NBQX blocked these effects of LY341495. Further analyses indicted that induction of BDNF expression produced by LY341495 was blocked by pretreatment with NBQX and rapamycin. LY341495 has neuroplastic effects by acting on AMPA receptor-mTORC1 signaling under neurotoxic conditions. Therefore, activation of AMPA receptor and mTORC1 signaling, which enhance neuroplasticity, may be novel targets for new antidepressants.
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Affiliation(s)
- Mi Kyoung Seo
- Paik Institute for Clinical Research, Inje University, Busan, 47392, Republic of Korea
| | - Le Thi Hien
- Department of Health Science and Technology, Graduate School, Inje University, Busan, 47392, Republic of Korea
| | - Min Kyung Park
- Departement of Psychiatry, Dong-eui Hospital, Dongeui University, Busan, 47227, Republic of Korea
| | - Ah Jeong Choi
- Paik Institute for Clinical Research, Inje University, Busan, 47392, Republic of Korea
| | - Dae-Hyun Seog
- Department of Biochemistry, College of Medicine, Inje University, Busan, 47392, Republic of Korea
| | - Seong-Ho Kim
- Paik Institute for Clinical Research, Inje University, Busan, 47392, Republic of Korea.,Department of Internal Medicine, College of Medicine, Haeundae Paik Hospital, Inje University, Busan, 48108, Republic of Korea
| | - Sung Woo Park
- Paik Institute for Clinical Research, Inje University, Busan, 47392, Republic of Korea. .,Department of Health Science and Technology, Graduate School, Inje University, Busan, 47392, Republic of Korea. .,Department of Convergence Biomedical Science, College of Medicine, Inje University, Busan, 47392, Republic of Korea.
| | - Jung Goo Lee
- Paik Institute for Clinical Research, Inje University, Busan, 47392, Republic of Korea. .,Department of Health Science and Technology, Graduate School, Inje University, Busan, 47392, Republic of Korea. .,Department of Psychiatry, College of Medicine, Haeundae Paik Hospital, Inje University, Busan, 48108, Republic of Korea.
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8
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Davis MT, Hillmer A, Holmes SE, Pietrzak RH, DellaGioia N, Nabulsi N, Matuskey D, Angarita G, Carson RE, Krystal JH, Esterlis I. In vivo evidence for dysregulation of mGluR5 as a biomarker of suicidal ideation. Proc Natl Acad Sci U S A 2019; 116:11490-11495. [PMID: 31085640 PMCID: PMC6561298 DOI: 10.1073/pnas.1818871116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Recent evidence implicates dysregulation of metabotropic glutamatergic receptor 5 (mGluR5) in pathophysiology of PTSD and suicidality. Using positron emission tomography and [18F]FPEB, we quantified mGluR5 availability in vivo in individuals with PTSD (n = 29) and MDD (n = 29) as a function of suicidal ideation (SI) to compare with that of healthy comparison controls (HC; n = 29). Volume of distribution was computed using a venous input function in the five key frontal and limbic brain regions. We observed significantly higher mGluR5 availability in PTSD compared with HC individuals in all regions of interest (P's = 0.001-0.01) and compared with MDD individuals in three regions (P's = 0.007). mGluR5 availability was not significantly different between MDD and HC individuals (P = 0.17). Importantly, we observed an up-regulation in mGluR5 availability in the PTSD-SI group (P's = 0.001-0.007) compared with PTSD individuals without SI. Findings point to the potential role for mGluR5 as a target for intervention and, potentially, suicide risk management in PTSD.
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Affiliation(s)
- Margaret T Davis
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06511
| | - Ansel Hillmer
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06511
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT 06520
| | - Sophie E Holmes
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06511
| | - Robert H Pietrzak
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06511
- Clinical Neurosciences Division, National Center for PTSD, US Department of Veterans Affairs, West Haven, CT 06516
| | - Nicole DellaGioia
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06511
| | - Nabeel Nabulsi
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT 06520
| | - David Matuskey
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06511
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT 06520
| | - Gustavo Angarita
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06511
| | - Richard E Carson
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT 06520
| | - John H Krystal
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06511
- Clinical Neurosciences Division, National Center for PTSD, US Department of Veterans Affairs, West Haven, CT 06516
| | - Irina Esterlis
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06511;
- Clinical Neurosciences Division, National Center for PTSD, US Department of Veterans Affairs, West Haven, CT 06516
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Dai WL, Yan B, Jiang N, Wu JJ, Liu XF, Liu JH, Yu BY. Simultaneous inhibition of NMDA and mGlu1/5 receptors bylevo-corydalmine in rat spinal cord attenuates bone cancer pain. Int J Cancer 2017; 141:805-815. [DOI: 10.1002/ijc.30780] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 04/10/2017] [Accepted: 04/27/2017] [Indexed: 01/30/2023]
Affiliation(s)
- Wen-Ling Dai
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research; Department of Traditional Chinese Medicine, China Pharmaceutical University; Nanjing Jiangsu China
| | - Bing Yan
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research; Department of Traditional Chinese Medicine, China Pharmaceutical University; Nanjing Jiangsu China
| | - Nan Jiang
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research; Department of Traditional Chinese Medicine, China Pharmaceutical University; Nanjing Jiangsu China
| | - Juan-Juan Wu
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research; Department of Traditional Chinese Medicine, China Pharmaceutical University; Nanjing Jiangsu China
| | - Xiu-Feng Liu
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research; Department of Traditional Chinese Medicine, China Pharmaceutical University; Nanjing Jiangsu China
| | - Ji-Hua Liu
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research; Department of Traditional Chinese Medicine, China Pharmaceutical University; Nanjing Jiangsu China
- State Key Laboratory of Natural Medicines; Department of Traditional Chinese Medicine, China Pharmaceutical University; Nanjing Jiangsu China
| | - Bo-Yang Yu
- State Key Laboratory of Natural Medicines; Department of Traditional Chinese Medicine, China Pharmaceutical University; Nanjing Jiangsu China
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Marinova Z, Chuang DM, Fineberg N. Glutamate-Modulating Drugs as a Potential Therapeutic Strategy in Obsessive-Compulsive Disorder. Curr Neuropharmacol 2017; 15:977-995. [PMID: 28322166 PMCID: PMC5652017 DOI: 10.2174/1570159x15666170320104237] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 12/27/2016] [Accepted: 03/15/2017] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE Obsessive-compulsive disorder (OCD) is a mental disease commonly associated with severe distress and impairment of social functioning. Serotonin reuptake inhibitors and/or cognitive behavioural therapy are the therapy of choice, however up to 40% of patients do not respond to treatment. Glutamatergic signalling has also been implicated in OCD. The aim of the current study was to review the clinical evidence for therapeutic utility of glutamate-modulating drugs as an augmentation or monotherapy in OCD patients. METHODS We conducted a search of the MEDLINE database for clinical studies evaluating the effect of glutamate-modulating drugs in OCD. RESULTS Memantine is the compound most consistently showing a positive effect as an augmentation therapy in OCD. Anti-convulsant drugs (lamotrigine, topiramate) and riluzole may also provide therapeutic benefit to some OCD patients. Finally, ketamine may be of interest due to its potential for a rapid onset of action. CONCLUSION Further randomized placebo-controlled trials in larger study populations are necessary in order to draw definitive conclusions on the utility of glutamate-modulating drugs in OCD. Furthermore, genetic and epigenetic factors, clinical symptoms and subtypes predicting treatment response to glutamate-modulating drugs need to be investigated systematically.
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Affiliation(s)
- Zoya Marinova
- Department of Psychosomatic Medicine, Clinic Barmelweid, Barmelweid, Switzerland
| | - De-Maw Chuang
- National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, United States
| | - Naomi Fineberg
- Hertfordshire Partnership University NHS Foundation Trust and University of Hertfordshire, Welwyn Garden City, AL8 6HG, United Kingdom
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11
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Davidson S, Golden JP, Copits BA, Ray PR, Vogt SK, Valtcheva MV, Schmidt RE, Ghetti A, Price T, Gereau RW. Group II mGluRs suppress hyperexcitability in mouse and human nociceptors. Pain 2016; 157:2081-2088. [PMID: 27218869 PMCID: PMC4988887 DOI: 10.1097/j.pain.0000000000000621] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We introduce a strategy for preclinical research wherein promising targets for analgesia are tested in rodent and subsequently validated in human sensory neurons. We evaluate group II metabotropic glutamate receptors, the activation of which is efficacious in rodent models of pain. Immunohistochemical analysis showed positive immunoreactivity for mGlu2 in rodent dorsal root ganglia (DRG), peripheral fibers in skin, and central labeling in the spinal dorsal horn. We also found mGlu2-positive immunoreactivity in human neonatal and adult DRG. RNA-seq analysis of mouse and human DRG revealed a comparative expression profile between species for group II mGluRs and for opioid receptors. In rodent sensory neurons under basal conditions, activation of group II mGluRs with a selective group II agonist produced no changes to membrane excitability. However, membrane hyperexcitability in sensory neurons exposed to the inflammatory mediator prostaglandin E2 (PGE2) was prevented by (2R,4R)-4-aminopyrrolidine-2,4-dicarboxylate (APDC). In human sensory neurons from donors without a history of chronic pain, we show that PGE2 produced hyperexcitability that was similarly blocked by group II mGluR activation. These results reveal a mechanism for peripheral analgesia likely shared by mice and humans and demonstrate a translational research strategy to improve preclinical validation of novel analgesics using cultured human sensory neurons.
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Affiliation(s)
- Steve Davidson
- Washington University in St. Louis, School of Medicine, Pain Center and Department of Anesthesiology. St. Louis, MO. 63110
| | - Judith P. Golden
- Washington University in St. Louis, School of Medicine, Pain Center and Department of Anesthesiology. St. Louis, MO. 63110
| | - Bryan A. Copits
- Washington University in St. Louis, School of Medicine, Pain Center and Department of Anesthesiology. St. Louis, MO. 63110
| | - Pradipta R. Ray
- School of Brain and Behavioral Sciences, University of Texas at Dallas. 75080
| | - Sherri K. Vogt
- Washington University in St. Louis, School of Medicine, Pain Center and Department of Anesthesiology. St. Louis, MO. 63110
| | - Manouela V. Valtcheva
- Washington University in St. Louis, School of Medicine, Pain Center and Department of Anesthesiology. St. Louis, MO. 63110
| | - Robert E. Schmidt
- Washington University in St. Louis, School of Medicine Department of Neuropathology, St. Louis, MO. 63110
| | | | - Theodore Price
- School of Brain and Behavioral Sciences, University of Texas at Dallas. 75080
| | - Robert W. Gereau
- Washington University in St. Louis, School of Medicine, Pain Center and Department of Anesthesiology. St. Louis, MO. 63110
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12
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Abstract
A large body of research has been dedicated to the effects of gastrointestinal peptides on vagal afferent fibres, yet multiple lines of evidence indicate that gastrointestinal peptides also modulate brainstem vagal neurocircuitry, and that this modulation has a fundamental role in the physiology and pathophysiology of the upper gastrointestinal tract. In fact, brainstem vagovagal neurocircuits comprise highly plastic neurons and synapses connecting afferent vagal fibres, second order neurons of the nucleus tractus solitarius (NTS), and efferent fibres originating in the dorsal motor nucleus of the vagus (DMV). Neuronal communication between the NTS and DMV is regulated by the presence of a variety of inputs, both from within the brainstem itself as well as from higher centres, which utilize an array of neurotransmitters and neuromodulators. Because of the circumventricular nature of these brainstem areas, circulating hormones can also modulate the vagal output to the upper gastrointestinal tract. This Review summarizes the organization and function of vagovagal reflex control of the upper gastrointestinal tract, presents data on the plasticity within these neurocircuits after stress, and discusses the gastrointestinal dysfunctions observed in Parkinson disease as examples of physiological adjustment and maladaptation of these reflexes.
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Huang CH, Yu YJ, Chang CH, Gean PW. Involvement of metabotropic glutamate receptor 5 in the inhibition of methamphetamine-associated contextual memory after prolonged extinction training. J Neurochem 2016; 137:216-25. [PMID: 26748780 DOI: 10.1111/jnc.13525] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 12/15/2015] [Accepted: 12/29/2015] [Indexed: 12/31/2022]
Abstract
Addiction is thought to be a memory process between perception and environmental cues and addicted patients often relapse when they come into contact with the drug-related context once again. Here, we used a conditioned place preference protocol to seek a more effective extinction methodology of methamphetamine (METH) memory and delineate its underlying mechanism. Conditioning METH for 3 days in mice markedly increased the time spent in the METH-paired compartment. Then the mice were conditioned with saline for 6 days, from day 6 to day 11, a procedure termed extinction training. However, METH memory returned after a priming injection of METH. We prolonged extinction duration from 6 to 10 days and found that this extensive extinction (EE) training prevented priming effect. At the molecular level, we discovered that prolonged extinction training reversed the METH-conditioned place preference-induced increase in surface expression of GluA2 and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA)/NMDA ratio in the basolateral amygdala. In addition, we found that extinction with metabotropic glutamate receptor 5 (mGluR5) activation had similar results to EE: reduced relapse after extinction, decreased synaptic AMPA receptors AMPARs and the AMPA/NMDA ratio. On the contrary, EE with mGluR5 inhibition suppressed the results of EE. These data indicate that EE training-elicited inhibition of METH-primed reinstatement is mediated by the mGluR5. Conditioning mice with methamphetamine place preference (METH CPP) increases surface expression of AMPA receptors (AMPARs) in the basolateral amygdala. We found prolongation of extinction duration from 6 to 10 days prevented priming effect. At the molecular level, we discovered that extensive extinction (EE) reversed the METH CPP-induced increase in surface expression of GluA2 and AMPA/NMDA ratio. In addition, we found that extinction with the metabotropic glutamate receptor 5 (mGluR5) activation had similar results to EE: reduced relapse after extinction, decreased synaptic AMPARs and the AMPA/NMDA ratio. On the contrary, EE with mGluR5 inhibition suppressed the results of EE. These data indicate that EE training-elicited inhibition of METH-primed reinstatement is mediated by mGluR5 (PAM: positive allosteric modulator).
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Affiliation(s)
- Chien-Hsuan Huang
- Department of Pharmacology, National Cheng-Kung University, Tainan, Taiwan
| | - Yang-Jung Yu
- Department of Pharmacology, National Cheng-Kung University, Tainan, Taiwan
| | - Chih-Hua Chang
- Department of Pharmacology, National Cheng-Kung University, Tainan, Taiwan
| | - Po-Wu Gean
- Department of Pharmacology, National Cheng-Kung University, Tainan, Taiwan
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Johnson AC, Greenwood-Van Meerveld B. The Pharmacology of Visceral Pain. ADVANCES IN PHARMACOLOGY 2016; 75:273-301. [PMID: 26920016 DOI: 10.1016/bs.apha.2015.11.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Visceral pain describes pain emanating from the internal thoracic, pelvic, or abdominal organs. Unlike somatic pain, visceral pain is generally vague, poorly localized, and characterized by hypersensitivity to a stimulus such as organ distension. While current therapeutics provides some relief from somatic pain, drugs used for treatment of chronic visceral pain are typically less efficacious and limited by multiple adverse side effects. Thus, the treatment of visceral pain represents a major unmet medical need. Further, more basic research into the physiology and pathophysiology of visceral pain is needed to provide novel targets for future drug development. In concert with chronic visceral pain, there is a high comorbidity with stress-related psychiatric disorders including anxiety and depression. The mechanisms linking visceral pain with these overlapping comorbidities remain to be elucidated. However, persistent stress facilitates pain perception and sensitizes pain pathways, leading to a feed-forward cycle promoting chronic visceral pain disorders. We will focus on stress-induced exacerbation of chronic visceral pain and provide supporting evidence that centrally acting drugs targeting the pain and stress-responsive brain regions may represent a valid target for the development of novel and effective therapeutics.
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Affiliation(s)
- Anthony C Johnson
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Beverley Greenwood-Van Meerveld
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA; Veterans Affairs Medical Center, Oklahoma City, Oklahoma, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
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15
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Nohara LL, Stanwood SR, Omilusik KD, Jefferies WA. Tweeters, Woofers and Horns: The Complex Orchestration of Calcium Currents in T Lymphocytes. Front Immunol 2015; 6:234. [PMID: 26052328 PMCID: PMC4440397 DOI: 10.3389/fimmu.2015.00234] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 04/30/2015] [Indexed: 11/28/2022] Open
Abstract
Elevation of intracellular calcium ion (Ca2+) levels is a vital event that regulates T lymphocyte homeostasis, activation, proliferation, differentiation, and apoptosis. The mechanisms that regulate intracellular Ca2+ signaling in lymphocytes involve tightly controlled concinnity of multiple ion channels, membrane receptors, and signaling molecules. T cell receptor (TCR) engagement results in depletion of endoplasmic reticulum (ER) Ca2+ stores and subsequent sustained influx of extracellular Ca2+ through Ca2+ release-activated Ca2+ (CRAC) channels in the plasma membrane. This process termed store-operated Ca2+ entry (SOCE) involves the ER Ca2+ sensing molecule, STIM1, and a pore-forming plasma membrane protein, ORAI1. However, several other important Ca2+ channels that are instrumental in T cell function also exist. In this review, we discuss the role of additional Ca2+ channel families expressed on the plasma membrane of T cells that likely contribute to Ca2+ influx following TCR engagement, which include the TRP channels, the NMDA receptors, the P2X receptors, and the IP3 receptors, with a focus on the voltage-dependent Ca2+ (CaV) channels.
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Affiliation(s)
- Lilian L Nohara
- Michael Smith Laboratories, University of British Columbia , Vancouver, BC , Canada ; Department of Microbiology and Immunology, University of British Columbia , Vancouver, BC , Canada
| | - Shawna R Stanwood
- Michael Smith Laboratories, University of British Columbia , Vancouver, BC , Canada ; Department of Microbiology and Immunology, University of British Columbia , Vancouver, BC , Canada
| | - Kyla D Omilusik
- Michael Smith Laboratories, University of British Columbia , Vancouver, BC , Canada ; Department of Microbiology and Immunology, University of British Columbia , Vancouver, BC , Canada
| | - Wilfred A Jefferies
- Michael Smith Laboratories, University of British Columbia , Vancouver, BC , Canada ; Department of Microbiology and Immunology, University of British Columbia , Vancouver, BC , Canada ; Centre for Blood Research, University of British Columbia , Vancouver, BC , Canada ; The Djavad Mowafaghian Centre for Brain Health, University of British Columbia , Vancouver, BC , Canada ; Department of Medical Genetics, University of British Columbia , Vancouver, BC , Canada ; Department of Zoology, University of British Columbia , Vancouver, BC , Canada
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Moloney RD, Golubeva AV, O'Connor RM, Kalinichev M, Dinan TG, Cryan JF. Negative allosteric modulation of the mGlu7 receptor reduces visceral hypersensitivity in a stress-sensitive rat strain. Neurobiol Stress 2015; 2:28-33. [PMID: 26844237 PMCID: PMC4721404 DOI: 10.1016/j.ynstr.2015.04.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 03/15/2015] [Accepted: 04/03/2015] [Indexed: 11/19/2022] Open
Abstract
Glutamate, the main excitatory neurotransmitter in the central nervous system, exerts its effect through ionotropic and metabotropic receptors. Of these, group III mGlu receptors (mGlu 4, 6, 7, 8) are among the least studied due to a lack of pharmacological tools. mGlu7 receptors, the most highly conserved isoform, are abundantly distributed in the brain, especially in regions, such as the amygdala, known to be crucial for the emotional processing of painful stimuli. Visceral hypersensitivity is a poorly understood phenomenon manifesting as an increased sensitivity to visceral stimuli. Glutamate has long been associated with somatic pain processing leading us to postulate that crossover may exist between these two modalities. Moreover, stress has been shown to exacerbate visceral pain. ADX71743 is a novel, centrally penetrant, negative allosteric modulator of mGlu7 receptors. Thus, we used this tool to explore the possible involvement of this receptor in the mediation of visceral pain in a stress-sensitive model of visceral hypersensitivity, namely the Wistar Kyoto (WKY) rat. ADX71743 reduced visceral hypersensitivity in the WKY rat as exhibited by increased visceral sensitivity threshold with concomitant reductions in total number of pain behaviours. Moreover, AD71743 increased total distance and distance travelled in the inner zone of the open field. These findings show, for what is to our knowledge, the first time, that mGlu7 receptor signalling plays a role in visceral pain processing. Thus, negative modulation of the mGlu7 receptor may be a plausible target for the amelioration of stress-induced visceral pain where there is a large unmet medical need.
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Affiliation(s)
- Rachel D. Moloney
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Ireland
- Department of Psychiatry, University College Cork, Ireland
| | - Anna V. Golubeva
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Ireland
| | | | | | - Timothy G. Dinan
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Ireland
- Department of Psychiatry, University College Cork, Ireland
| | - John F. Cryan
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Ireland
- Department of Anatomy and Neuroscience, University College Cork, Ireland
- Corresponding author. Dept Anatomy & Neuroscience, Room 386, Western Gateway Building, University College Cork, Western Rd., Cork, Ireland.
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McIlwrath SL, Westlund KN. Pharmacological attenuation of chronic alcoholic pancreatitis induced hypersensitivity in rats. World J Gastroenterol 2015; 21:836-53. [PMID: 25624717 PMCID: PMC4299336 DOI: 10.3748/wjg.v21.i3.836] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 08/16/2014] [Accepted: 09/29/2014] [Indexed: 02/06/2023] Open
Abstract
AIM To characterize an alcohol and high fat diet induced chronic pancreatitis rat model that mimics poor human dietary choices. METHODS Experimental rats were fed a modified Lieber-DeCarli alcohol (6%) and high-fat (65%) diet (AHF) for 10 wk while control animals received a regular rodent chow diet. Weekly behavioral tests determined mechanical and heat sensitivity. In week 10 a fasting glucose tolerance test was performed, measuring blood glucose levels before and after a 2 g/kg bodyweight intraperitoneal (i.p.) injection of glucose. Post mortem histological analysis was performed by staining pancreas and liver tissue sections with hematoxylin and eosin. Pancreas sections were also stained with Sirius red and fast green to quantify collagen content. Insulin-expressing cells were identified immunohistochemically in separate sections. Tissue staining density was quantified using Image J software. After mechanical and heat sensitivity became stable (weeks 6-10) in the AHF-fed animals, three different drugs were tested for their efficacy in attenuating pancreatitis associated hypersensitivity: a Group II metabotropic glutamate receptor specific agonist (2R,4R)-4-Aminopyrrolidine-2,4-dicarboxylate (APDC, 3 mg/kg, ip; Tocris, Bristol, United Kingdom), nociceptin (20, 60, 200 nmol/kg, ip; Tocris), and morphine sulfate (3 mg/kg, μ-opioid receptor agonist; Baxter Healthcare, Deerfield, IL, United States). RESULTS Histological analysis of pancreas and liver determined that unlike control rats, AHF fed animals had pancreatic fibrosis, acinar and beta cell atrophy, with steatosis in both organs. Fat vacuolization was significantly increased in AHF fed rats (6.4% ± 1.1% in controls vs 23.8% ± 4.2%, P < 0.05). Rats fed the AHF diet had reduced fasting glucose tolerance in week 10 when peak blood glucose levels reached significantly higher concentrations than controls (127.4 ± 9.2 mg/dL in controls vs 161.0 ± 8.6 mg/dL, P < 0.05). This concurred with a 3.5 fold higher incidence of single and small 2-10 cell insulin-positive cell clusters (P < 0.05). Insulin expressing islet of Langerhans cells appeared hypertrophied while islet number and area measurements were not different from controls. Weekly behavioral tests determined that mechanical and heat sensitivities were significantly increased by 4 wk on AHF diet compared to controls. Hypersensitivity was attenuated with efficacy similar to morphine with single dose treatment of either metabotropic glutamate receptor 2/3 agonist APDC, or nociceptin, the endogenous ligand for opioid-receptor-like 1 receptor. CONCLUSION The AHF diet induces a chronic alcoholic pancreatitis in rats with measurable features resembling clinical patients with chronic pancreatitis and type 3c diabetes mellitus.
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MESH Headings
- Analgesics/pharmacology
- Analgesics, Opioid/pharmacology
- Animals
- Behavior, Animal/drug effects
- Blood Glucose/drug effects
- Blood Glucose/metabolism
- Diabetes Mellitus/etiology
- Diet, High-Fat
- Disease Models, Animal
- Ethanol
- Excitatory Amino Acid Agonists/pharmacology
- Humans
- Hyperalgesia/etiology
- Hyperalgesia/metabolism
- Hyperalgesia/physiopathology
- Hyperalgesia/prevention & control
- Liver/drug effects
- Liver/metabolism
- Liver/pathology
- Male
- Morphine/pharmacology
- Nociception/drug effects
- Opioid Peptides/metabolism
- Pain Threshold/drug effects
- Pancreas/drug effects
- Pancreas/metabolism
- Pancreas/pathology
- Pancreatitis, Alcoholic/drug therapy
- Pancreatitis, Alcoholic/etiology
- Pancreatitis, Alcoholic/metabolism
- Pancreatitis, Alcoholic/physiopathology
- Proline/analogs & derivatives
- Proline/pharmacology
- Rats, Inbred F344
- Receptors, Metabotropic Glutamate/agonists
- Receptors, Metabotropic Glutamate/metabolism
- Time Factors
- Visceral Pain/etiology
- Visceral Pain/metabolism
- Visceral Pain/physiopathology
- Visceral Pain/prevention & control
- Nociceptin
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18
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Moloney RD, O'Mahony SM, Dinan TG, Cryan JF. Stress-induced visceral pain: toward animal models of irritable-bowel syndrome and associated comorbidities. Front Psychiatry 2015; 6:15. [PMID: 25762939 PMCID: PMC4329736 DOI: 10.3389/fpsyt.2015.00015] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/28/2015] [Indexed: 12/12/2022] Open
Abstract
Visceral pain is a global term used to describe pain originating from the internal organs, which is distinct from somatic pain. It is a hallmark of functional gastrointestinal disorders such as irritable-bowel syndrome (IBS). Currently, the treatment strategies targeting visceral pain are unsatisfactory, with development of novel therapeutics hindered by a lack of detailed knowledge of the underlying mechanisms. Stress has long been implicated in the pathophysiology of visceral pain in both preclinical and clinical studies. Here, we discuss the complex etiology of visceral pain reviewing our current understanding in the context of the role of stress, gender, gut microbiota alterations, and immune functioning. Furthermore, we review the role of glutamate, GABA, and epigenetic mechanisms as possible therapeutic strategies for the treatment of visceral pain for which there is an unmet medical need. Moreover, we discuss the most widely described rodent models used to model visceral pain in the preclinical setting. The theory behind, and application of, animal models is key for both the understanding of underlying mechanisms and design of future therapeutic interventions. Taken together, it is apparent that stress-induced visceral pain and its psychiatric comorbidities, as typified by IBS, has a multifaceted etiology. Moreover, treatment strategies still lag far behind when compared to other pain modalities. The development of novel, effective, and specific therapeutics for the treatment of visceral pain has never been more pertinent.
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Affiliation(s)
- Rachel D Moloney
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork , Cork , Ireland
| | - Siobhain M O'Mahony
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork , Cork , Ireland ; Department of Anatomy and Neuroscience, University College Cork , Cork , Ireland
| | - Timothy G Dinan
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork , Cork , Ireland ; Department of Psychiatry, University College Cork , Cork , Ireland
| | - John F Cryan
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork , Cork , Ireland ; Department of Anatomy and Neuroscience, University College Cork , Cork , Ireland
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19
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Jobling P, O'Hara K, Hua S. Female reproductive tract pain: targets, challenges, and outcomes. Front Pharmacol 2014; 5:17. [PMID: 24592238 PMCID: PMC3923189 DOI: 10.3389/fphar.2014.00017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 01/27/2014] [Indexed: 12/26/2022] Open
Abstract
Pain from the female reproductive tract (FRT) is a significant clinical problem for which there are few effective therapies. The complex neuroanatomy of pelvic organs not only makes diagnosis of pelvic pain disorders difficult but represents a challenge to development of targeted therapies. A number of potential therapeutic targets have been identified on sensory neurons supplying the FRT but our knowledge on the basic neurophysiology of these neurons is limited compared with other viscera. Until this is addressed we can only guess if the new experimental therapies proposed for somatic, gastrointestinal, or bladder pain will translate to the FRT. Once suitable therapeutic targets become clear, the next challenge is drug delivery. The FRT represents a promising system for topical drug delivery that could be tailored to act locally or systemically depending on formulation. Development of these therapies and their delivery systems will need to be done in concert with more robust in vivo and in vitro models of FRT pain.
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Affiliation(s)
- Phillip Jobling
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan NSW, Australia
| | - Kate O'Hara
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan NSW, Australia
| | - Susan Hua
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan NSW, Australia
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20
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Babic T, Travagli RA. Role of metabotropic glutamate receptors in the regulation of pancreatic functions. Biochem Pharmacol 2013; 87:535-42. [PMID: 24355565 DOI: 10.1016/j.bcp.2013.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 12/05/2013] [Accepted: 12/05/2013] [Indexed: 01/03/2023]
Abstract
The pancreas consists of two major divisions, the exocrine and the endocrine pancreas. Recent data from our laboratory have shown that the functions of the two divisions are under modulatory regulation by separate neurocircuits that originate in the dorsal motor nucleus of the vagus (DMV). Metabotropic glutamate receptors (mGluRs) are expressed throughout the central nervous system and have been implicated in the modulation of synaptic transmission. mGluRs consist of three groups of receptors, which can be distinguished based on their pharmacological properties and second messenger systems. Group I mGluRs predominantly increase, whereas group II and III mGluRs decrease synaptic transmission. Group II and group III mGluRs are present on excitatory and inhibitory synaptic terminals impinging on pancreas-projecting DMV neurons. We have shown that group II mGluRs regulate both exocrine pancreatic secretions and insulin release, whereas group III mGluRs only regulate insulin release. Several mGluR agonists and antagonists have been shown to have clinical uses for disorders accompanied by abnormal synaptic transmission, including anxiety and Parkinson's disease. Moreover, a negative allosteric modulator of Group I mGluRs is effective in alleviating symptoms of gastro-esophageal reflux disease (GERD). Since the role of the three mGluR groups in mediating different gastrointestinal (GI) functions appears to be highly specific, the use of agonists or antagonists directed at a single receptor group could potentially provide highly selective targets for the treatment of GI disorders including GERD, functional dyspepsia and acute pancreatitis.
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Affiliation(s)
- Tanja Babic
- Neural and Behavioral Sciences Penn State College of Medicine, Department of Neural and Behavioral Sciences, 500 University Drive-MC H109 Hershey, PA 17033-0850, USA.
| | - R Alberto Travagli
- Neural and Behavioral Sciences Penn State College of Medicine, Department of Neural and Behavioral Sciences, 500 University Drive-MC H109 Hershey, PA 17033-0850, USA
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21
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Abstract
The gastrointestinal tract presents the largest and most vulnerable surface to the outside world. Simultaneously, it must be accessible and permeable to nutrients and must defend against pathogens and potentially injurious chemicals. Integrated responses to these challenges require the gut to sense its environment, which it does through a range of detection systems for specific chemical entities, pathogenic organisms and their products (including toxins), as well as physicochemical properties of its contents. Sensory information is then communicated to four major effector systems: the enteroendocrine hormonal signalling system; the innervation of the gut, both intrinsic and extrinsic; the gut immune system; and the local tissue defence system. Extensive endocrine-neuro-immune-organ-defence interactions are demonstrable, but under-investigated. A major challenge is to develop a comprehensive understanding of the integrated responses of the gut to the sensory information it receives. A major therapeutic opportunity exists to develop agents that target the receptors facing the gut lumen.
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Affiliation(s)
- John B Furness
- Department of Anatomy & Neuroscience, University of Melbourne, Grattan Street, Parkville, Vic 3010, Australia
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VGLUTs in Peripheral Neurons and the Spinal Cord: Time for a Review. ISRN NEUROLOGY 2013; 2013:829753. [PMID: 24349795 PMCID: PMC3856137 DOI: 10.1155/2013/829753] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 08/25/2013] [Indexed: 02/07/2023]
Abstract
Vesicular glutamate transporters (VGLUTs) are key molecules for the incorporation of glutamate in synaptic vesicles across the nervous system, and since their discovery in the early 1990s, research on these transporters has been intense and productive. This review will focus on several aspects of VGLUTs research on neurons in the periphery and the spinal cord. Firstly, it will begin with a historical account on the evolution of the morphological analysis of glutamatergic systems and the pivotal role played by the discovery of VGLUTs. Secondly, and in order to provide an appropriate framework, there will be a synthetic description of the neuroanatomy and neurochemistry of peripheral neurons and the spinal cord. This will be followed by a succinct description of the current knowledge on the expression of VGLUTs in peripheral sensory and autonomic neurons and neurons in the spinal cord. Finally, this review will address the modulation of VGLUTs expression after nerve and tissue insult, their physiological relevance in relation to sensation, pain, and neuroprotection, and their potential pharmacological usefulness.
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23
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Zhou Q, Wang J, Zhang X, Zeng L, Wang L, Jiang W. Effect of metabotropic glutamate 5 receptor antagonists on morphine efficacy and tolerance in rats with neuropathic pain. Eur J Pharmacol 2013; 718:17-23. [PMID: 24041921 DOI: 10.1016/j.ejphar.2013.09.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 08/29/2013] [Accepted: 09/04/2013] [Indexed: 11/30/2022]
Abstract
The metabotropic glutamate 5 (mGlu5) receptor is involved in both pain processing and modulation of µ-opioid induced antinociception and antihyperalgesia. Systemic mGlu5 receptor antagonists 2-methyl-6-phenylethynylpyridine (MPEP) or 3-[(2-methyl-1,3-thiazol-4-yl) ethynyl] pyridine (MTEP) provide antihyperalgesic effects in various pain models, but few studies have shown their interaction with morphine in neuropathic pain models. The aim of this study is to compare the effects of systemic and intrathecal MPEP/MTEP on morphine efficacy and tolerance in rats with chronic neuropathic pain. L5-6 spinal nerve ligation (SNL) was used to establish neuropathic pain model in rats. The Von Frey test and the hot water tail flick test were employed as behavior tests. Low, medium and high doses of MPEP/MTEP were tested for their effect on both acute morphine efficacy and chronic morphine tolerance. SNL provides sustained neuropathic pain on the ipsilateral hind paw of rats. Both systemic and intrathecal MPEP/MTEP had antiallodynia effects and boosted morphine's efficacy in a dose-dependent manner in the Von Frey tests but not in the tail flick tests. In fact, high doses of MTEP and MPEP attenuated morphine's antinociceptive effect in the latter test. After intrathecal chronic co-administration with morphine, low-doses of MTEP/MPEP attenuated morphine tolerance in both tests. Systemically, only MTEP attenuated morphine tolerance, and only in the Von Frey tests, not in the tail flick tests, whereas MPEP had no effect on morphine tolerance in either tests. The therapeutic use of mGlu5 receptor antagonists may have distinct effects in different pain models.
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Affiliation(s)
- Quanhong Zhou
- Department of Anesthesiology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiaotong University, Shanghai 200233, China
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Davidenko O, Darcel N, Fromentin G, Tomé D. Control of protein and energy intake - brain mechanisms. Eur J Clin Nutr 2013; 67:455-61. [DOI: 10.1038/ejcn.2013.73] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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25
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Babic T, Browning KN, Kawaguchi Y, Tang X, Travagli RA. Pancreatic insulin and exocrine secretion are under the modulatory control of distinct subpopulations of vagal motoneurones in the rat. J Physiol 2012; 590:3611-22. [PMID: 22711959 DOI: 10.1113/jphysiol.2012.234955] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Brainstem vago-vagal neurocircuits modulate upper gastrointestinal functions. Derangement of these sensory-motor circuits is implicated in several pathophysiological states, such as gastroesophageal reflux disease (GERD), functional dyspepsia and, possibly, pancreatitis. While vagal circuits controlling the stomach have received more attention, the organization of brainstem pancreatic neurocircuits is still largely unknown. We aimed to investigate the in vitro and in vivo modulation of brainstem vagal circuits controlling pancreatic secretion. Using patch clamp techniques on identified vagal pancreas-projecting neurones, we studied the effects of metabotropic glutamate receptor (mGluR) agents in relation to the effects of exendin-4, a glucagon-like peptide 1 analogue, cholecystokinin (CCK) and pancreatic polypeptide (PP). An in vivo anaesthetized rat preparation was used to measure pancreatic exocrine secretion (PES) and plasma insulin following microinjection of metabotropic glutamate receptor (mGluR) agonists and exendin-4 in the brainstem. Group II and III mGluR agonists (2R,4R-4-aminopyrrolidine-2,4-dicarboxylate (APDC) and L(+)-2-amino-4-phosphonobutyric acid (L-AP4), respectively) decreased the frequency of miniature inhibitory and excitatory postsynaptic currents (mIPSCs and mEPSCs, respectively) in the majority of the neurones tested. All neurones responsive to L-AP4 were also responsive to APDC, but not vice versa. Further, in neurones where L-AP4 decreased mIPSC frequency, exendin-4 increased, while PP had no effect upon, mIPSC frequency. Brainstem microinjection of APDC or L-AP4 decreased plasma insulin secretion, whereas only APDC microinjections increased PES. Exendin-4 microinjections increased plasma insulin. Our results indicate a discrete organization of vagal circuits, which opens up promising avenues of research aimed at investigating the physiology of homeostatic autonomic neurocircuits.
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Affiliation(s)
- Tanja Babic
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, 500 University Drive, MC H109, Hershey, PA 17033, USA
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Journel M, Chaumontet C, Darcel N, Fromentin G, Tomé D. Brain responses to high-protein diets. Adv Nutr 2012; 3:322-9. [PMID: 22585905 PMCID: PMC3649463 DOI: 10.3945/an.112.002071] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Proteins are suspected to have a greater satiating effect than the other 2 macronutrients. After protein consumption, peptide hormones released from the gastrointestinal tract (mainly anorexigenic gut peptides such as cholecystokinin, glucagon peptide 1, and peptide YY) communicate information about the energy status to the brain. These hormones and vagal afferents control food intake by acting on brain regions involved in energy homeostasis such as the brainstem and the hypothalamus. In fact, a high-protein diet leads to greater activation than a normal-protein diet in the nucleus tractus solitarius and in the arcuate nucleus. More specifically, neural mechanisms triggered particularly by leucine consumption involve 2 cellular energy sensors: the mammalian target of rapamycin and AMP-activated protein kinase. In addition, reward and motivation aspects of eating behavior, controlled mainly by neurons present in limbic regions, play an important role in the reduced hedonic response of a high-protein diet. This review examines how metabolic signals emanating from the gastrointestinal tract after protein ingestion target the brain to control feeding, energy expenditure, and hormones. Understanding the functional roles of brain areas involved in the satiating effect of proteins and their interactions will demonstrate how homeostasis and reward are integrated with the signals from peripheral organs after protein consumption.
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Affiliation(s)
- Marion Journel
- AgroParisTech and,INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France
| | - Catherine Chaumontet
- INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France
| | | | - Gilles Fromentin
- INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France
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Abstract
Recent advances highlight that nutrient receptors (such as T1R1/T1R3 heterodimer, Ca sensing receptor and GPR93 for amino acids and protein, GPR40, GPR41, GPR43 and GPR120 for fatty acids, T1R2/T1R3 heterodimer for monosaccharides) are expressed in the apical face of the gut and sense nutrients in the lumen. They transduce signals for the regulation of nutrient transporter expressions in the apical face. Interestingly, they are also localised in enteroendocrine cells (EEC) and mainly exert a direct control on the secretion in the lamina propria of gastro-intestinal peptides such as cholecystokinin, glucagon-like peptide-1 and peptide YY in response to energy nutrient transit and absorption in the gut. This informs central nuclei involved in the control of feeding such as the hypothalamus and nucleus of the solitary tract of the availability of these nutrients and thus triggers adaptive responses to maintain energy homoeostasis. These nutrient receptors then have a prominent position since they manage nutrient absorption and are principally the generator of the first signal of satiation mechanisms mainly transmitted to the brain by vagal afferents. Moreover, tastants are also able to elicit gut peptides secretion via chemosensory receptors expressed in EEC. Targeting these nutrient and tastant receptors in EEC may thus be helpful to promote satiation and so to fight overfeeding and its consequences.
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