1
|
Osse AML, Pandey RS, Wirt RA, Ortiz AA, Salazar A, Kimmich M, Toledano Strom EN, Oblak A, Lamb B, Hyman JM, Carter GW, Kinney J. Reduction in GABAB on glia induce Alzheimer's disease related changes. Brain Behav Immun 2023; 110:260-275. [PMID: 36906075 PMCID: PMC10115139 DOI: 10.1016/j.bbi.2023.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 02/26/2023] [Accepted: 03/01/2023] [Indexed: 03/13/2023] Open
Abstract
Alzheimer's Disease (AD) is a neurodegenerative disorder characterized by beta-amyloid plaques (Aβ), neurofibrillary tangles (NFT), and neuroinflammation. Data have demonstrated that neuroinflammation contributes to Aβ and NFT onset and progression, indicating inflammation and glial signaling is vital to understanding AD. A previous investigation demonstrated a significant decrease of the GABAB receptor (GABABR) in APP/PS1 mice (Salazar et al., 2021). To determine if changes in GABABR restricted to glia serve a role in AD, we developed a mouse model with a reduction of GABABR restricted to macrophages, GAB/CX3ert. This model exhibits changes in gene expression and electrophysiological alterations similar to amyloid mouse models of AD. Crossing the GAB/CX3ert mouse with APP/PS1 resulted in significant increases in Aβ pathology. Our data demonstrates that decreased GABABR on macrophages leads to several changes observed in AD mouse models, as well as exacerbation of AD pathology when crossed with existing models. These data suggest a novel mechanism in AD pathogenesis.
Collapse
Affiliation(s)
- Amanda M Leisgang Osse
- University of Nevada, Las Vegas, Department of Brain Health, 4505 S. Maryland Parkway, Las Vegas, NV 89154, United States.
| | - Ravi S Pandey
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06032, United States
| | - Ryan A Wirt
- University of Nevada, Las Vegas, Department of Psychology, 4505 S. Maryland Parkway, Las Vegas, NV 89154, United States
| | - Andrew A Ortiz
- University of Nevada, Las Vegas, Department of Brain Health, 4505 S. Maryland Parkway, Las Vegas, NV 89154, United States
| | - Arnold Salazar
- University of Nevada, Las Vegas, Department of Brain Health, 4505 S. Maryland Parkway, Las Vegas, NV 89154, United States
| | - Michael Kimmich
- University of Nevada, Las Vegas, Department of Brain Health, 4505 S. Maryland Parkway, Las Vegas, NV 89154, United States
| | - Erin N Toledano Strom
- University of Nevada, Las Vegas, Department of Brain Health, 4505 S. Maryland Parkway, Las Vegas, NV 89154, United States
| | - Adrian Oblak
- Indiana University, School of Medicine, 340 W 10(th) Street, Indianapolis, IN 46202, United States
| | - Bruce Lamb
- Indiana University, School of Medicine, 340 W 10(th) Street, Indianapolis, IN 46202, United States
| | - James M Hyman
- University of Nevada, Las Vegas, Department of Psychology, 4505 S. Maryland Parkway, Las Vegas, NV 89154, United States
| | - Gregory W Carter
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06032, United States
| | - Jefferson Kinney
- University of Nevada, Las Vegas, Department of Brain Health, 4505 S. Maryland Parkway, Las Vegas, NV 89154, United States
| |
Collapse
|
2
|
Luquin E, Paternain B, Zugasti I, Santomá C, Mengual E. Stereological estimations and neurochemical characterization of neurons expressing GABAA and GABAB receptors in the rat pedunculopontine and laterodorsal tegmental nuclei. Brain Struct Funct 2022; 227:89-110. [PMID: 34510281 PMCID: PMC8741722 DOI: 10.1007/s00429-021-02375-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 08/31/2021] [Indexed: 11/29/2022]
Abstract
To better understand GABAergic transmission at two targets of basal ganglia downstream projections, the pedunculopontine (PPN) and laterodorsal (LDT) tegmental nuclei, the anatomical localization of GABAA and GABAB receptors was investigated in both nuclei. Specifically, the total number of neurons expressing the GABAA receptor γ2 subunit (GABAAR γ2) and the GABAB receptor R2 subunit (GABAB R2) in PPN and LDT was estimated using stereological methods, and the neurochemical phenotype of cells expressing each subunit was also determined. The mean number of non-cholinergic cells expressing GABAAR γ2 was 9850 ± 1856 in the PPN and 8285 ± 962 in the LDT, whereas those expressing GABAB R2 were 7310 ± 1970 and 9170 ± 1900 in the PPN and LDT, respectively. In addition, all cholinergic neurons in both nuclei co-expressed GABAAR γ2 and 95-98% of them co-expressed GABAB R2. Triple labeling using in situ hybridization revealed that 77% of GAD67 mRNA-positive cells in the PPT and 49% in the LDT expressed GABAAR γ2, while 90% (PPN) and 65% (LDT) of Vglut2 mRNA-positive cells also expressed GABAAR γ2. In contrast, a similar proportion (~2/3) of glutamatergic and GABAergic cells co-expressed GABAB R2 in both nuclei. The heterogeneous distribution of GABAAR and GABABR among non-cholinergic cells in PPN and LDT may give rise to physiological differences within each neurochemical subpopulation. In addition, the dissimilar proportion of GABAAR γ2-expressing glutamatergic and GABAergic neurons in the PPN and LDT may contribute to some of the functional differences found between the two nuclei.
Collapse
Affiliation(s)
- Esther Luquin
- Department of Pathology, Anatomy, and Physiology, School of Medicine, University of Navarra, Ed. Los Castaños, Irunlarrea 1, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| | - Beatriz Paternain
- Department of Pathology, Anatomy, and Physiology, School of Medicine, University of Navarra, Ed. Los Castaños, Irunlarrea 1, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| | - Inés Zugasti
- Department of Pathology, Anatomy, and Physiology, School of Medicine, University of Navarra, Ed. Los Castaños, Irunlarrea 1, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| | - Carmen Santomá
- Department of Pathology, Anatomy, and Physiology, School of Medicine, University of Navarra, Ed. Los Castaños, Irunlarrea 1, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| | - Elisa Mengual
- Department of Pathology, Anatomy, and Physiology, School of Medicine, University of Navarra, Ed. Los Castaños, Irunlarrea 1, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| |
Collapse
|
3
|
Neff R, Kambara K, Bertrand D. Ligand gated receptor interactions: A key to the power of neuronal networks. Biochem Pharmacol 2021; 190:114653. [PMID: 34129858 DOI: 10.1016/j.bcp.2021.114653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/08/2021] [Accepted: 06/09/2021] [Indexed: 10/21/2022]
Abstract
The discovery of the chemical synapse was a seminal finding in Neurobiology but the large body of microscopic interactions involved in synaptic transmission could hardly have been foreseen at the time of these first discoveries. Characterization of the molecular players at work at synapses and the increased granularity at which we can now analyze electrical and chemical signal processing that occur in even the simplest neuronal system are shining a new light on receptor interactions. The aim of this review is to discuss the complexity of some representative interactions between excitatory and inhibitory ligand-gated ion channels and/or G protein coupled receptors, as well as other key machinery that can impact neurotransmission and to explain how such mechanisms can be an important determinant of nervous system function.
Collapse
Affiliation(s)
- R Neff
- Janssen R&D, LLC, 3210 Merryfield Row, San Diego, CA 92121, USA
| | - K Kambara
- HiQScreen Sàrl, 6 rte de Compois, 1222 Vésenaz, Geneva, Switzerland
| | - D Bertrand
- HiQScreen Sàrl, 6 rte de Compois, 1222 Vésenaz, Geneva, Switzerland.
| |
Collapse
|
4
|
Pagès N, Maurois P, Bac P, Meza-Toledo S, Peralta-Cruz J, Chamorro-Cevallos G, Cristóbal-Luna JM, Vamecq J. Anticonvulsive profile of two GABA B receptor antagonists on acute seizure mice models. Epilepsy Res 2021; 174:106644. [PMID: 33932748 DOI: 10.1016/j.eplepsyres.2021.106644] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 04/04/2021] [Accepted: 04/16/2021] [Indexed: 11/28/2022]
Abstract
INTRODUCTION DL-3-hydroxy-3-phenylpentanamide (HEPP) and DL-3-hydroxy-3-(4'chlorophenyl)-pentanamide (Cl-HEPP) are phenyl-alcohol-amides that are metabotropic GABAB receptor (MGBR) antagonists and protective against absence seizures. This study aims to further characterize the anticonvulsant profile of these drugs. METHODS HEPP and Cl-HEPP were evaluated in various standardized acute seizure and toxic tests in female Swiss-OF1 mice. RESULTS Toxicities of HEPP and Cl-HEPP were limited; doses up to 30 mg/kg did not result in hypothermia, reduced spontaneous locomotor activity, or failure of the rotarod test, with doses >15 mg/kg potentiating pentobarbital-induced sleep. In maximal electroshock-induced seizures, 20 mg/kg Cl-HEPP protected 100 % of mice; lower doses shortened post-ictal recovery. Seizure protection occurred against subcutaneous pentylenetetrazole and picrotoxin, being limited against N-methyl-d-aspartate. In bicuculline test, clonic or fatal tonic seizures were decreased, onset delayed, and recovery improved; ED50 values (dose protecting 50 % of the animals) were 37.5 and 25 mg/kg for HEPP and Cl-HEPP, respectively. In magnesium deficiency-dependent audiogenic seizures (MDDAS), ED50 values were 3 and 8 mg/kg for Cl-HEPP and HEPP, respectively. The components of MDDAS (latency, wild running, seizure, and recovery phases) in unprotected animals were only minimally affected by near ED50 doses of Cl-HEPP and HEPP. DISCUSSION HEPP and, to a greater extent, Cl-HEPP provide anti-seizure protections in several acute seizure tests in mice at nontoxic doses. These results are consistent with the action of these drugs on diverse molecular targets directly resulting from their MGBR antagonistic properties. However, other mechanisms might occur possibly for the protection given in the MES test. Finally, a similarity in the modulation of MDDAS components between the two phenyl alcohol amides and ethosuximide could also be based on the MGBR antagonistic properties of the former, given the recently re-evaluated therapeutic relevant targets of the latter.
Collapse
Affiliation(s)
- Nicole Pagès
- Toxicology Laboratory, Faculty of Pharmacy, 67400 Illkirch, France; Neuropharmacology Laboratory, Faculty of Pharmacy, 92290 Châtenay Malabry, France
| | - Pierre Maurois
- Neuropharmacology Laboratory, Faculty of Pharmacy, 92290 Châtenay Malabry, France
| | - Pierre Bac
- Neuropharmacology Laboratory, Faculty of Pharmacy, 92290 Châtenay Malabry, France
| | - Sergio Meza-Toledo
- Departamento de Bioquímica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional (IPN), Ciudad de México, Mexico
| | - Javier Peralta-Cruz
- Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional (IPN), Ciudad de México, Mexico
| | - Germán Chamorro-Cevallos
- Departamento de Farmacia, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional (IPN), Ciudad de México, Mexico
| | - José Melesio Cristóbal-Luna
- Departamento de Farmacia, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional (IPN), Ciudad de México, Mexico
| | - Joseph Vamecq
- Inserm, Biochemistry and Molecular Biology Laboratory, HMNO, CBP, CHRU Lille & EA 7364 - RADEME, North France University Lille, 2, Bld Prof Jules Leclercq, 59037, Lille, France.
| |
Collapse
|
5
|
Ectopic activation of GABA B receptors inhibits neurogenesis and metamorphosis in the cnidarian Nematostella vectensis. Nat Ecol Evol 2020; 5:111-121. [PMID: 33168995 DOI: 10.1038/s41559-020-01338-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 09/29/2020] [Indexed: 01/22/2023]
Abstract
The metabotropic gamma-aminobutyric acid B receptor (GABABR) is a G protein-coupled receptor that mediates neuronal inhibition by the neurotransmitter GABA. While GABABR-mediated signalling has been suggested to play central roles in neuronal differentiation and proliferation across evolution, it has mostly been studied in the mammalian brain. Here, we demonstrate that ectopic activation of GABABR signalling affects neurogenic functions in the sea anemone Nematostella vectensis. We identified four putative Nematostella GABABR homologues presenting conserved three-dimensional extracellular domains and residues needed for binding GABA and the GABABR agonist baclofen. Moreover, sustained activation of GABABR signalling reversibly arrests the critical metamorphosis transition from planktonic larva to sessile polyp life stage. To understand the processes that underlie the developmental arrest, we combined transcriptomic and spatial analyses of control and baclofen-treated larvae. Our findings reveal that the cnidarian neurogenic programme is arrested following the addition of baclofen to developing larvae. Specifically, neuron development and neurite extension were inhibited, resulting in an underdeveloped and less organized nervous system and downregulation of proneural factors including NvSoxB(2), NvNeuroD1 and NvElav1. Our results thus point to an evolutionarily conserved function of GABABR in neurogenesis regulation and shed light on early cnidarian development.
Collapse
|
6
|
Γ-Aminobutyric acid in adult brain: an update. Behav Brain Res 2019; 376:112224. [DOI: 10.1016/j.bbr.2019.112224] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 09/09/2019] [Accepted: 09/09/2019] [Indexed: 01/21/2023]
|
7
|
Dubovyk V, Manahan-Vaughan D. Distinct Time-Course of Alterations of Groups I and II Metabotropic Glutamate Receptor and GABAergic Receptor Expression Along the Dorsoventral Hippocampal Axis in an Animal Model of Psychosis. Front Behav Neurosci 2019; 13:98. [PMID: 31139061 PMCID: PMC6519509 DOI: 10.3389/fnbeh.2019.00098] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/23/2019] [Indexed: 01/13/2023] Open
Abstract
Psychosis is a clinical state that encompasses a range of abnormal conditions, including distortions in sensory information processing and the resultant delusional thinking, emotional discordance and cognitive impairments. Upon developing this condition, the rate at which cognitive and behavioral deteriorations progress steadily increases suggesting an active contribution of the first psychotic event to the progression of structural and functional abnormalities and disease establishment in diagnosed patients. Changes in GABAergic and glutamatergic function, or expression, in the hippocampus have been proposed as a key factor in the pathophysiology of psychosis. However, little is known as to the time-point of onset of putative changes, to what extent they are progressive, and their relation to disease stabilization. Here, we characterized the expression and distribution patterns of groups I and II metabotropic glutamate (mGlu) receptors and GABA receptors 1 week and 3 months after systemic treatment with an N-methyl-D-aspartate receptor (NMDAR) antagonist (MK801) that is used to model a psychosis-like state in adult rats. We found an early alteration in the expression of mGlu1, mGlu2/3, and GABAB receptors across the hippocampal dorsoventral and transverse axes. This expanded to include an up-regulation of mGlu5 levels across the entire CA1 region and a reduction in GABAB expression, as well as GAD67-positive interneurons particularly in the dorsal hippocampus that appeared 3 months after treatment. Our findings indicate that a reduction of excitability may occur in the hippocampus soon after first-episode psychosis. This changes, over time, into increased excitability. These hippocampus-specific alterations are likely to contribute to the pathophysiology and stabilization of psychosis.
Collapse
Affiliation(s)
- Valentyna Dubovyk
- Department of Neurophysiology, Medical Faculty, Ruhr-University Bochum, Bochum, Germany.,International Graduate School of Neuroscience, Ruhr-University Bochum, Bochum, Germany
| | | |
Collapse
|
8
|
Abstract
Respiratory failure is common during acute exacerbation of chronic obstructive pulmonary disease (AE-COPD). Phrenic nerve conduction (PNC), transcranial magnetic stimulation (TMS), and cervical magnetic stimulation (CMS) are of great value in identifying the feature and site of AE-COPD.PNC, TMS, and CMS were performed in 20 AE-COPD patients with respiratory failure, and re-examined after weaning. Latencies and amplitudes of the diaphragmatic compound muscle action potential (dCMAP), motor evoked potential of the diaphragm (dMEP) evoked by TMS and CMS, and central motor conduction time (CMCT) were measured. Blood gas analysis and serum electrolyte levels were also evaluated. The results were compared with those from 20 healthy subjects.AE-COPD patients showed prolonged CMCT and latencies of dCMAP and dMEP, decreased amplitudes of dCMAP and dMEP evoked by CMS, while CMCT and the latency of dMEP evoked by TMS were shortened after weaning. Significant correlation was identified between arterial blood gas analysis, serum electrolyte levels, disease duration, the duration of mechanical ventilation and the electrophysiological findings in AE-COPD patients prior to weaning.The central and peripheral respiratory pathway is involved in AE-COPD. Central respiratory pathway function is improved after weaning in AE-COPD patients with respiratory failure.
Collapse
Affiliation(s)
- Yu Wang
- Department of Neurology, Third Central Hospital of Tianjin
- Tianjin Institute of Hepatobiliary Disease
- Tianjin Key Laboratory of Artificial Cell
- Artificial Cell Engineering Technology Research Center of Public Health Ministry, Tianjin, China
| | - Na Liu
- Department of Neurology, Third Central Hospital of Tianjin
- Tianjin Institute of Hepatobiliary Disease
- Tianjin Key Laboratory of Artificial Cell
- Artificial Cell Engineering Technology Research Center of Public Health Ministry, Tianjin, China
| | - Zhecheng Zhang
- Department of Neurology, Third Central Hospital of Tianjin
- Tianjin Institute of Hepatobiliary Disease
- Tianjin Key Laboratory of Artificial Cell
- Artificial Cell Engineering Technology Research Center of Public Health Ministry, Tianjin, China
| |
Collapse
|
9
|
Aoki N, Yamaguchi S, Fujita T, Mori C, Fujita E, Matsushima T, Homma KJ. GABA-A and GABA-B Receptors in Filial Imprinting Linked With Opening and Closing of the Sensitive Period in Domestic Chicks ( Gallus gallus domesticus). Front Physiol 2018; 9:1837. [PMID: 30618842 PMCID: PMC6305906 DOI: 10.3389/fphys.2018.01837] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 12/06/2018] [Indexed: 12/31/2022] Open
Abstract
Filial imprinting of domestic chicks has a well-defined sensitive (critical) period lasting in the laboratory from hatching to day 3. It is a typical model to investigate the molecular mechanisms underlying memory formation in early learning. We recently found that thyroid hormone 3,5,3′-triiodothyronine (T3) is a determinant of the sensitive period. Rapid increases in cerebral T3 levels are induced by imprinting training, rendering chicks imprintable. Furthermore, the administration of exogenous T3 makes chicks imprintable on days 4 or 6 even after the sensitive period has ended. However, how T3 affects neural transmission to enable imprinting remains mostly unknown. In this study, we demonstrate opposing roles for gamma-aminobutyric acid (GABA)-A and GABA-B receptors in imprinting downstream of T3. Quantitative reverse transcription polymerase chain reaction and immunoblotting showed that the GABA-A receptor expression increases gradually from days 1 to 5, whereas the GABA-B receptor expression gradually decreases. We examined whether neurons in the intermediate medial mesopallium (IMM), the brain region responsible for imprinting, express both types of GABA receptors. Immunostaining showed that morphologically identified putative projection neurons express both GABA-A and GABA-B receptors, suggesting that those GABA receptors interact with each other in these cells to modulate the IMM outputs. The roles of GABA-A and GABA-B receptors were investigated using various agonists and antagonists. Our results show that GABA-B receptor antagonists suppressed imprinting on day 1, while its agonists made day 4 chicks imprintable without administration of exogenous T3. By contrast, GABA-A receptor agonists suppressed imprinting on day 1, while its antagonists induced imprintability on day 4 without exogenous T3. Furthermore, both GABA-A receptor agonists and GABA-B receptor antagonists suppressed T3-induced imprintability on day 4 after the sensitive period has ended. Our data from these pharmacological experiments indicate that GABA-B receptors facilitate imprinting downstream of T3 by initiating the sensitive period, while the GABA-A receptor contributes to the termination of the sensitive period. In conclusion, we propose that opposing roles of GABA-A and GABA-B receptors in the brain during development determine the induction and termination of the sensitive period.
Collapse
Affiliation(s)
- Naoya Aoki
- Department of Life and Health Sciences, Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan
| | - Shinji Yamaguchi
- Department of Life and Health Sciences, Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan
| | - Toshiyuki Fujita
- Department of Life and Health Sciences, Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan
| | - Chihiro Mori
- Research Fellow of the Japan Society for the Promotion of Science, Tokyo, Japan.,Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Eiko Fujita
- Department of Life and Health Sciences, Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan
| | - Toshiya Matsushima
- Department of Biology, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Koichi J Homma
- Department of Life and Health Sciences, Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan
| |
Collapse
|
10
|
Brewer CL, Baccei ML. Enhanced Postsynaptic GABA B Receptor Signaling in Adult Spinal Projection Neurons after Neonatal Injury. Neuroscience 2018; 384:329-339. [PMID: 29885525 PMCID: PMC6053268 DOI: 10.1016/j.neuroscience.2018.05.046] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 04/28/2018] [Accepted: 05/30/2018] [Indexed: 12/19/2022]
Abstract
Clinical and basic science research have revealed persistent effects of early-life injury on nociceptive processing and resulting pain sensitivity. While recent work has identified clear deficits in fast GABAA- and glycine receptor-mediated inhibition in the adult spinal dorsal horn after neonatal tissue damage, the effects of early injury on slow, metabotropic inhibition within spinal pain circuits are poorly understood. Here we provide evidence that neonatal surgical incision significantly enhances postsynaptic GABAB receptor signaling within the mature superficial dorsal horn (SDH) in a cell type-dependent manner. In vitro patch-clamp recordings were obtained from identified lamina I projection neurons and GABAergic interneurons in the SDH of adult female mice following hindpaw incision at postnatal day (P)3. Early tissue damage increased the density of the outward current evoked by baclofen, a selective GABAB receptor agonist, in projection neurons but not inhibitory interneurons. This could reflect enhanced postsynaptic expression of downstream G protein-coupled inward-rectifying potassium channels (GIRKs), as the response to the GIRK agonist ML297 was greater in projection neurons from neonatally incised mice compared to naive littermate controls. Meanwhile, presynaptic GABAB receptor-mediated reduction of spontaneous neurotransmitter release onto both neuronal populations was unaffected by early-life injury. Collectively, our findings suggest that ascending nociceptive transmission to the adult brain is under stronger control by spinal metabotropic inhibition in the aftermath of neonatal tissue damage.
Collapse
Affiliation(s)
- Chelsie L Brewer
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; Pain Research Center, Department of Anesthesiology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Cincinnati, OH 45267, USA
| | - Mark L Baccei
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; Pain Research Center, Department of Anesthesiology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Cincinnati, OH 45267, USA.
| |
Collapse
|
11
|
Shen W, Nan C, Nelson PT, Ripps H, Slaughter MM. GABA B receptor attenuation of GABA A currents in neurons of the mammalian central nervous system. Physiol Rep 2017; 5:5/6/e13129. [PMID: 28348006 PMCID: PMC5371550 DOI: 10.14814/phy2.13129] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 11/18/2016] [Indexed: 11/24/2022] Open
Abstract
Ionotropic receptors are tightly regulated by second messenger systems and are often present along with their metabotropic counterparts on a neuron's plasma membrane. This leads to the hypothesis that the two receptor subtypes can interact, and indeed this has been observed in excitatory glutamate and inhibitory GABA receptors. In both systems the metabotropic pathway augments the ionotropic receptor response. However, we have found that the metabotropic GABAB receptor can suppress the ionotropic GABAA receptor current, in both the in vitro mouse retina and in human amygdala membrane fractions. Expression of amygdala membrane microdomains in Xenopus oocytes by microtransplantation produced functional ionotropic and metabotropic GABA receptors. Most GABAA receptors had properties of α‐subunit containing receptors, with ~5% having ρ‐subunit properties. Only GABAA receptors with α‐subunit‐like properties were regulated by GABAB receptors. In mouse retinal ganglion cells, where only α‐subunit‐containing GABAA receptors are expressed, GABAB receptors suppressed GABAA receptor currents. This suppression was blocked by GABAB receptor antagonists, G‐protein inhibitors, and GABAB receptor antibodies. Based on the kinetic differences between metabotropic and ionotropic receptors, their interaction would suppress repeated, rapid GABAergic inhibition.
Collapse
Affiliation(s)
- Wen Shen
- Department of Biomedical Science, Charles E. Schmidt College of Medicine Florida Atlantic University, Boca Raton, Florida
| | - Changlong Nan
- Department of Biomedical Science, Charles E. Schmidt College of Medicine Florida Atlantic University, Boca Raton, Florida
| | - Peter T Nelson
- Division of Neuropathology, Department of Pathology, University of Kentucky, Lexington, Kentucky.,Sanders-Brown Centre on Aging, University of Kentucky, Lexington, Kentucky
| | - Harris Ripps
- Department of Ophthalmology and Visual Sciences, University of Illinois College of Medicine, Chicago, Illinois.,Whitman Investigator, Marine Biological Laboratory, Woods Hole, Massachusetts
| | - Malcolm M Slaughter
- Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York
| |
Collapse
|