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Reiner A, Medina L, Abellan A, Deng Y, Toledo CA, Luksch H, Vega-Zuniga T, Riley NB, Hodos W, Karten HJ. Neurochemistry and circuit organization of the lateral spiriform nucleus of birds: A uniquely nonmammalian direct pathway component of the basal ganglia. J Comp Neurol 2024; 532:e25620. [PMID: 38733146 PMCID: PMC11090467 DOI: 10.1002/cne.25620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 03/24/2024] [Accepted: 04/16/2024] [Indexed: 05/13/2024]
Abstract
We used diverse methods to characterize the role of avian lateral spiriform nucleus (SpL) in basal ganglia motor function. Connectivity analysis showed that SpL receives input from globus pallidus (GP), and the intrapeduncular nucleus (INP) located ventromedial to GP, whose neurons express numerous striatal markers. SpL-projecting GP neurons were large and aspiny, while SpL-projecting INP neurons were medium sized and spiny. Connectivity analysis further showed that SpL receives inputs from subthalamic nucleus (STN) and substantia nigra pars reticulata (SNr), and that the SNr also receives inputs from GP, INP, and STN. Neurochemical analysis showed that SpL neurons express ENK, GAD, and a variety of pallidal neuron markers, and receive GABAergic terminals, some of which also contain DARPP32, consistent with GP pallidal and INP striatal inputs. Connectivity and neurochemical analysis showed that the SpL input to tectum prominently ends on GABAA receptor-enriched tectobulbar neurons. Behavioral studies showed that lesions of SpL impair visuomotor behaviors involving tracking and pecking moving targets. Our results suggest that SpL modulates brainstem-projecting tectobulbar neurons in a manner comparable to the demonstrated influence of GP internus on motor thalamus and of SNr on tectobulbar neurons in mammals. Given published data in amphibians and reptiles, it seems likely the SpL circuit represents a major direct pathway-type circuit by which the basal ganglia exerts its motor influence in nonmammalian tetrapods. The present studies also show that avian striatum is divided into three spatially segregated territories with differing connectivity, a medial striato-nigral territory, a dorsolateral striato-GP territory, and the ventrolateral INP motor territory.
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Affiliation(s)
- Anton Reiner
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163
| | - Loreta Medina
- Department of Experimental Medicine, Universitat de Lleida, Lleida, Spain
- Laboratory of Evolutionary and Developmental Neurobiology, Lleida’s Institute for Biomedical Research-Dr. Pifarré Foundation (IRBLleida), Lleida, Catalonia, Spain
| | - Antonio Abellan
- Department of Experimental Medicine, Universitat de Lleida, Lleida, Spain
- Laboratory of Evolutionary and Developmental Neurobiology, Lleida’s Institute for Biomedical Research-Dr. Pifarré Foundation (IRBLleida), Lleida, Catalonia, Spain
| | - Yunping Deng
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163
| | - Claudio A.B. Toledo
- Neuroscience Research Nucleus, Universidade Cidade de Sao Paulo, Sao Paulo 65057-420, Brazil
| | - Harald Luksch
- School of Life Sciences, Technische Universität München, Freising-Weihenstephan, Germany
| | - Tomas Vega-Zuniga
- School of Life Sciences, Technische Universität München, Freising-Weihenstephan, Germany
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Nell B. Riley
- Department of Psychology, University of Maryland College Park 20742-4411
| | - William Hodos
- Department of Psychology, University of Maryland College Park 20742-4411
| | - Harvey J. Karten
- Department of Neurosciences, University of California San Diego, San Diego, CA 92093-0608
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Genaro K, Yoshimura RF, Doan BP, Johnstone TB, Hogenkamp DJ, Gee KW. Allosteric modulators of the δ GABA A receptor subtype demonstrate a therapeutic effect in morphine-antinociceptive tolerance and withdrawal in mice. Neuropharmacology 2022; 219:109221. [PMID: 36084794 PMCID: PMC11012237 DOI: 10.1016/j.neuropharm.2022.109221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 07/29/2022] [Accepted: 08/09/2022] [Indexed: 11/26/2022]
Abstract
The present study evaluated the effects of compounds targeting extrasynaptic δ subunit-containing γ-aminobutyric acid type A receptors (δ*-GABAARs) to interrogate the role of tonic inhibition in the development of antinociceptive tolerance caused by repeated morphine administration. We investigated the effect of subchronic or acute treatment with non-steroidal positive allosteric modulators (PAMs) of δ*-GABAARs, such as 2-261, on the morphine-antinociceptive tolerance. Mice were treated twice daily with morphine for 9 days and antinociception was measured using the hot water tail immersion test. Co-treatment with 2-261 and morphine prevented morphine-antinociceptive tolerance and acute administration of 2-261 on day 9 was sufficient to reverse the tolerance. Other compounds with activity at δ*-GABAARs also reversed morphine tolerance, whereas an enaminone that lacked activity at δ*-GABAARs did not. Acute administration of 2-261 did not cause an additive or synergistic antinociceptive effect when combined with an acute submaximal dose of morphine. We then used Cre/LoxP recombination to generate GABAA δ-subunit knockout mice to corroborate the pharmacological results. Observations of male δ-knockout mice demonstrated that the δ*-GABAARs was necessary for 2-261 modulation of both analgesic tolerance and somatic withdrawal symptoms produced by subchronic morphine. While female mice still benefited from the positive effects of 2-261, the δ-subunit was not necessary for these effects, highlighting a distinction of the different pathways that could have implications for some of the sex-related differences seen in human opioid-induced outcomes. Consequently, subtype-specific allosteric modulators of GABAARs may warrant further investigation as pharmacological targets to manage tolerance and withdrawal from opioids.
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Affiliation(s)
- K Genaro
- Department of Pharmaceutical Sciences, University of California Irvine, Irvine, CA, 92697-4625, USA; Department of Anesthesiology, School of Medicine, University of California, Irvine, CA, 92697, USA.
| | - R F Yoshimura
- Department of Pharmaceutical Sciences, University of California Irvine, Irvine, CA, 92697-4625, USA.
| | - B P Doan
- Department of Pharmaceutical Sciences, University of California Irvine, Irvine, CA, 92697-4625, USA; Department of Anesthesiology, School of Medicine, University of California, Irvine, CA, 92697, USA
| | - T B Johnstone
- Department of Pharmaceutical Sciences, University of California Irvine, Irvine, CA, 92697-4625, USA
| | - D J Hogenkamp
- Department of Pharmaceutical Sciences, University of California Irvine, Irvine, CA, 92697-4625, USA
| | - K W Gee
- Department of Pharmaceutical Sciences, University of California Irvine, Irvine, CA, 92697-4625, USA
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The Regional and Cellular Distribution of GABAA Receptor Subunits in the Human Amygdala. J Chem Neuroanat 2022; 126:102185. [DOI: 10.1016/j.jchemneu.2022.102185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 09/17/2022] [Accepted: 10/26/2022] [Indexed: 11/06/2022]
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El Khoueiry C, Alba-Delgado C, Antri M, Gutierrez-Mecinas M, Todd AJ, Artola A, Dallel R. GABAA and Glycine Receptor-Mediated Inhibitory Synaptic Transmission onto Adult Rat Lamina IIi PKCγ-Interneurons: Pharmacological but not Anatomical Specialization. Cells 2022; 11:cells11081356. [PMID: 35456035 PMCID: PMC9033052 DOI: 10.3390/cells11081356] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/07/2022] [Accepted: 04/13/2022] [Indexed: 11/16/2022] Open
Abstract
Mechanical allodynia (pain to normally innocuous tactile stimuli) is a widespread symptom of inflammatory and neuropathic pain. Spinal or medullary dorsal horn (SDH or MDH) circuits mediating tactile sensation and pain need to interact in order to evoke mechanical allodynia. PKCγ-expressing (PKCγ+) interneurons and inhibitory controls within SDH/MDH inner lamina II (IIi) are pivotal in connecting touch and pain circuits. However, the relative contribution of GABA and glycine to PKCγ+ interneuron inhibition remains unknown. We characterized inhibitory inputs onto PKCγ+ interneurons by combining electrophysiology to record spontaneous and miniature IPSCs (sIPSCs, mIPSCs) and immunohistochemical detection of GABAARα2 and GlyRα1 subunits in adult rat MDH. While GlyR-only- and GABAAR-only-mediated mIPSCs/sIPSCs are predominantly recorded from PKCγ+ interneurons, immunohistochemistry reveals that ~80% of their inhibitory synapses possess both GABAARα2 and GlyRα1. Moreover, nearly all inhibitory boutons at gephyrin-expressing synapses on these cells contain glutamate decarboxylase and are therefore GABAergic, with around half possessing the neuronal glycine transporter (GlyT2) and therefore being glycinergic. Thus, while GABA and glycine are presumably co-released and GABAARs and GlyRs are present at most inhibitory synapses on PKCγ+ interneurons, these interneurons exhibit almost exclusively GABAAR-only and GlyR-only quantal postsynaptic inhibitory currents, suggesting a pharmacological specialization of their inhibitory synapses.
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Affiliation(s)
- Corinne El Khoueiry
- Neuro-Dol, Inserm, Université Clermont Auvergne, CHU Clermont-Ferrand, F-63000 Clermont-Ferrand, France; (C.E.K.); (C.A.-D.); (M.A.)
| | - Cristina Alba-Delgado
- Neuro-Dol, Inserm, Université Clermont Auvergne, CHU Clermont-Ferrand, F-63000 Clermont-Ferrand, France; (C.E.K.); (C.A.-D.); (M.A.)
| | - Myriam Antri
- Neuro-Dol, Inserm, Université Clermont Auvergne, CHU Clermont-Ferrand, F-63000 Clermont-Ferrand, France; (C.E.K.); (C.A.-D.); (M.A.)
| | - Maria Gutierrez-Mecinas
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, UK; (M.G.-M.); (A.J.T.)
| | - Andrew J. Todd
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, UK; (M.G.-M.); (A.J.T.)
| | - Alain Artola
- Neuro-Dol, Inserm, Université Clermont Auvergne, CHU Clermont-Ferrand, F-63000 Clermont-Ferrand, France; (C.E.K.); (C.A.-D.); (M.A.)
- Correspondence: (A.A.); (R.D.)
| | - Radhouane Dallel
- Neuro-Dol, Inserm, Université Clermont Auvergne, CHU Clermont-Ferrand, F-63000 Clermont-Ferrand, France; (C.E.K.); (C.A.-D.); (M.A.)
- Correspondence: (A.A.); (R.D.)
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Mizutani Y, Adachi S, Nakano S, Hayashi K, Higashi A, Kikuchi K, Maeda T, Murate K, Shima S, Iizuka T, Ueda A, Ito M, Watanabe H. Severe dysautonomia in glycine receptor antibody-positive progressive encephalomyelitis with rigidity and myoclonus (PERM): A case report. Auton Neurosci 2021; 237:102910. [PMID: 34801829 DOI: 10.1016/j.autneu.2021.102910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/29/2021] [Accepted: 11/10/2021] [Indexed: 10/19/2022]
Abstract
Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a severe form of stiff-person spectrum disorder. We report a 59-year-old man who presented with progressive encephalomyelitis causing diplopia, bulbar palsy, severe dysautonomia, followed by stiffness and myoclonic cluster. Laboratory tests showed mild pleocytosis, with markedly elevated plasma levels of norepinephrine, epinephrine, and arginine vasopressin. Glycine-receptor antibodies were identified in both serum and CSF. Despite a poor response to methylprednisolone, immunoglobulins, and plasma exchange, α-blocker stabilized dysautonomia. Dysautonomia is presumed to be due to antibody-mediated disinhibited sympathetic hyperactivity; however, this case suggests that concomitant use of α-blocker with immunotherapy may ameliorate dysautonomia.
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Affiliation(s)
- Yasuaki Mizutani
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Shunsuke Adachi
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Shoko Nakano
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Kazutaka Hayashi
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Atsuhiro Higashi
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Kouichi Kikuchi
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Toshiki Maeda
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Kenichiro Murate
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Sayuri Shima
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Takahiro Iizuka
- Department of Neurology, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Akihiro Ueda
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Mizuki Ito
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Hirohisa Watanabe
- Department of Neurology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan.
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Della Vecchia A, Arone A, Piccinni A, Mucci F, Marazziti D. GABA System in Depression: Impact on Pathophysiology and Psychopharmacology. Curr Med Chem 2021; 29:5710-5730. [PMID: 34781862 DOI: 10.2174/0929867328666211115124149] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/21/2021] [Accepted: 09/30/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND The pathophysiology of major depressive disorder (MDD), one of the major causes of worldwide disability, is still largely unclear, despite the increasing data reporting evidence of multiple alterations of different systems. Recently, there was a renewed interest in the signalling of gamma aminobutyric acid (GABA) - the main inhibitory neurotransmitter. OBJECTIVE The aim of this study was to review and comment on the available literature about the involvement of GABA in MDD, as well as on novel GABAergic compounds possibly useful as antidepressants. METHODS We carried out a narrative review through Pubmed, Google Scholar and Scopus, by using specific keywords. RESULTS The results, derived from various research tools, strongly support the presence of a deficiency of the GABA system in MDD, which appears to be restored by common antidepressant treatments. More recent publications would indicate the complex interactions between GABA and all the other processes involved in MDD, such as monoamine neurotransmission, hypothalamus-pituitary adrenal axis functioning, neurotrophism, and immune response. Taken together, all these findings seem to further support the complexity of the pathophysiology of MDD, possibly reflecting the heterogeneity of the clinical pictures. CONCLUSION Although further data are necessary to support the specificity of GABA deficiency in MDD, the available findings would suggest that novel GABAergic compounds might constitute innovative therapeutic strategies in MDD.
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Affiliation(s)
- Alessandra Della Vecchia
- Department of Clinical and Experimental Medicine, Section of Psychiatry, University of Pisa. Italy
| | - Alessandro Arone
- Department of Clinical and Experimental Medicine, Section of Psychiatry, University of Pisa. Italy
| | - Armando Piccinni
- Saint Camillus International University of Health and Medical Sciences, Rome. Italy
| | - Federico Mucci
- Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena. Italy
| | - Donatella Marazziti
- Department of Clinical and Experimental Medicine, Section of Psychiatry, University of Pisa. Italy
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Cano JC, Huang W, Fénelon K. The amygdala modulates prepulse inhibition of the auditory startle reflex through excitatory inputs to the caudal pontine reticular nucleus. BMC Biol 2021; 19:116. [PMID: 34082731 PMCID: PMC8176709 DOI: 10.1186/s12915-021-01050-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 05/12/2021] [Indexed: 01/20/2023] Open
Abstract
Background Sensorimotor gating is a fundamental pre-attentive process that is defined as the inhibition of a motor response by a sensory event. Sensorimotor gating, commonly measured using the prepulse inhibition (PPI) of the auditory startle reflex task, is impaired in patients suffering from various neurological and psychiatric disorders. PPI deficits are a hallmark of schizophrenia, and they are often associated with attention and other cognitive impairments. Although the reversal of PPI deficits in animal models is widely used in pre-clinical research for antipsychotic drug screening, the neurotransmitter systems and synaptic mechanisms underlying PPI are still not resolved, even under physiological conditions. Recent evidence ruled out the longstanding hypothesis that PPI is mediated by midbrain cholinergic inputs to the caudal pontine reticular nucleus (PnC). Instead, glutamatergic, glycinergic, and GABAergic inhibitory mechanisms are now suggested to be crucial for PPI, at the PnC level. Since amygdalar dysfunctions alter PPI and are common to pathologies displaying sensorimotor gating deficits, the present study was designed to test that direct projections to the PnC originating from the amygdala contribute to PPI. Results Using wild type and transgenic mice expressing eGFP under the control of the glycine transporter type 2 promoter (GlyT2-eGFP mice), we first employed tract-tracing, morphological reconstructions, and immunohistochemical analyses to demonstrate that the central nucleus of the amygdala (CeA) sends glutamatergic inputs lateroventrally to PnC neurons, including GlyT2+ cells. Then, we showed the contribution of the CeA-PnC excitatory synapses to PPI in vivo by demonstrating that optogenetic inhibition of this connection decreases PPI, and optogenetic activation induces partial PPI. Finally, in GlyT2-Cre mice, whole-cell recordings of GlyT2+ PnC neurons in vitro paired with optogenetic stimulation of CeA fibers, as well as photo-inhibition of GlyT2+ PnC neurons in vivo, allowed us to implicate GlyT2+ neurons in the PPI pathway. Conclusions Our results uncover a feedforward inhibitory mechanism within the brainstem startle circuit by which amygdalar glutamatergic inputs and GlyT2+ PnC neurons contribute to PPI. We are providing new insights to the clinically relevant theoretical construct of PPI, which is disrupted in various neuropsychiatric and neurological diseases. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01050-z.
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Affiliation(s)
- Jose Carlos Cano
- Department of Biological Sciences, University of Texas at El Paso, 500 West University Avenue, El Paso, TX, 79912, USA
| | - Wanyun Huang
- Biology Department, University of Massachusetts Amherst, Life Science Laboratories, 240 Thatcher Road, Amherst, MA, 01002, USA
| | - Karine Fénelon
- Biology Department, University of Massachusetts Amherst, Life Science Laboratories, 240 Thatcher Road, Amherst, MA, 01002, USA.
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Kelly L, Seifi M, Ma R, Mitchell SJ, Rudolph U, Viola KL, Klein WL, Lambert JJ, Swinny JD. Identification of intraneuronal amyloid beta oligomers in locus coeruleus neurons of Alzheimer's patients and their potential impact on inhibitory neurotransmitter receptors and neuronal excitability. Neuropathol Appl Neurobiol 2021; 47:488-505. [PMID: 33119191 DOI: 10.1111/nan.12674] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/14/2020] [Accepted: 10/16/2020] [Indexed: 12/22/2022]
Abstract
AIMS Amyloid β-oligomers (AβO) are potent modulators of Alzheimer's pathology, yet their impact on one of the earliest brain regions to exhibit signs of the condition, the locus coeruleus (LC), remains to be determined. Of particular importance is whether AβO impact the spontaneous excitability of LC neurons. This parameter determines brain-wide noradrenaline (NA) release, and thus NA-mediated brain functions, including cognition, emotion and immune function, which are all compromised in Alzheimer's patients. Therefore, the aim of the study was to determine the expression profile of AβO in the LC of Alzheimer's patients and to probe their potential impact on the molecular and functional correlates of LC excitability, using a mouse model of increased Aβ production (APP-PSEN1). METHODS AND RESULTS Immunohistochemistry and confocal microscopy, using AβO-specific antibodies, confirmed LC AβO expression both intraneuronally and extracellularly in both Alzheimer's and APP-PSEN1 samples. Patch clamp electrophysiology recordings revealed that APP-PSEN1 LC neuronal hyperexcitability accompanied this AβO expression profile, arising from a diminished inhibitory effect of GABA due to impaired expression and function of the GABA-A receptor (GABAA R) α3 subunit. This altered LC α3-GABAA R expression profile overlapped with AβO expression in samples from both APP-PSEN1 mice and Alzheimer's patients. Finally, strychnine-sensitive glycine receptors (GlyRs) remained resilient to Aβ-induced changes and their activation reversed LC hyperexcitability. CONCLUSIONS The data suggest a close association between AβO and α3-GABAA Rs in the LC of Alzheimer's patients, and their potential to dysregulate LC activity, thereby contributing to the spectrum of pathology of the LC-NA system in this condition.
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Affiliation(s)
- Louise Kelly
- School of Pharmacy & Biomedical Sciences, University of Portsmouth, Portsmouth, UK
| | - Mohsen Seifi
- School of Pharmacy & Biomedical Sciences, University of Portsmouth, Portsmouth, UK
- Leicester School of Pharmacy, De Montfort University, Leicester, UK
| | - Ruolin Ma
- School of Pharmacy & Biomedical Sciences, University of Portsmouth, Portsmouth, UK
| | - Scott J Mitchell
- Neuroscience, Division of Systems Medicine, Ninewells Hospital & Medical School, Dundee University, Dundee, UK
| | - Uwe Rudolph
- Department of Comparative Biosciences, College of Veterinary Medicine, and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Kirsten L Viola
- Department of Neurobiology and Physiology, Northwestern University, Evanston, IL, USA
| | - William L Klein
- Department of Neurobiology and Physiology, Northwestern University, Evanston, IL, USA
| | - Jeremy J Lambert
- Neuroscience, Division of Systems Medicine, Ninewells Hospital & Medical School, Dundee University, Dundee, UK
| | - Jerome D Swinny
- School of Pharmacy & Biomedical Sciences, University of Portsmouth, Portsmouth, UK
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Lorenzo LE, Godin AG, Ferrini F, Bachand K, Plasencia-Fernandez I, Labrecque S, Girard AA, Boudreau D, Kianicka I, Gagnon M, Doyon N, Ribeiro-da-Silva A, De Koninck Y. Enhancing neuronal chloride extrusion rescues α2/α3 GABA A-mediated analgesia in neuropathic pain. Nat Commun 2020; 11:869. [PMID: 32054836 PMCID: PMC7018745 DOI: 10.1038/s41467-019-14154-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 12/16/2019] [Indexed: 02/06/2023] Open
Abstract
Spinal disinhibition has been hypothesized to underlie pain hypersensitivity in neuropathic pain. Apparently contradictory mechanisms have been reported, raising questions on the best target to produce analgesia. Here, we show that nerve injury is associated with a reduction in the number of inhibitory synapses in the spinal dorsal horn. Paradoxically, this is accompanied by a BDNF-TrkB-mediated upregulation of synaptic GABAARs and by an α1-to-α2GABAAR subunit switch, providing a mechanistic rationale for the analgesic action of the α2,3GABAAR benzodiazepine-site ligand L838,417 after nerve injury. Yet, we demonstrate that impaired Cl- extrusion underlies the failure of L838,417 to induce analgesia at high doses due to a resulting collapse in Cl- gradient, dramatically limiting the benzodiazepine therapeutic window. In turn, enhancing KCC2 activity not only potentiated L838,417-induced analgesia, it rescued its analgesic potential at high doses, revealing a novel strategy for analgesia in pathological pain, by combined targeting of the appropriate GABAAR-subtypes and restoring Cl- homeostasis.
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Affiliation(s)
- Louis-Etienne Lorenzo
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, Canada
| | - Antoine G Godin
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Department of Psychiatry & Neuroscience, Université Laval, Québec, QC, Canada
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada
| | - Francesco Ferrini
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Department of Psychiatry & Neuroscience, Université Laval, Québec, QC, Canada
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada
- Department of Veterinary Sciences, University of Turin, Turin, Italy
| | - Karine Bachand
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
| | - Isabel Plasencia-Fernandez
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada
| | - Simon Labrecque
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
| | - Alexandre A Girard
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Ecole Polytechnique, IP Paris, Palaiseau, France
| | - Dominic Boudreau
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada
| | - Irenej Kianicka
- Chlorion Pharma, Laval, Québec, QC, Canada
- Laurent Pharmaceuticals Inc., Montreal, QC, Canada
| | - Martin Gagnon
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Centre for Innovation, University of Otago, Dunedin, New Zealand
| | - Nicolas Doyon
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Finite Element Interdisciplinary Research Group (GIREF), Université Laval, Québec, QC, Canada
| | - Alfredo Ribeiro-da-Silva
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, Canada
- Department of Anatomy & Cell Biology, McGill University, Montreal, QC, Canada
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
| | - Yves De Koninck
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada.
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, Canada.
- Department of Psychiatry & Neuroscience, Université Laval, Québec, QC, Canada.
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada.
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada.
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Waldvogel H, Biggins F, Singh A, Arasaratnam C, Faull R. Variable colocalisation of GABAA receptor subunits and glycine receptors on neurons in the human hypoglossal nucleus. J Chem Neuroanat 2019; 97:99-111. [DOI: 10.1016/j.jchemneu.2019.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 02/21/2019] [Accepted: 02/21/2019] [Indexed: 11/28/2022]
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12
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Macher S, Zimprich F, De Simoni D, Höftberger R, Rommer PS. Management of Autoimmune Encephalitis: An Observational Monocentric Study of 38 Patients. Front Immunol 2018; 9:2708. [PMID: 30524441 PMCID: PMC6262885 DOI: 10.3389/fimmu.2018.02708] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 11/01/2018] [Indexed: 12/30/2022] Open
Abstract
Over the last years the clinical picture of autoimmune encephalitis has gained importance in neurology. The broad field of symptoms and syndromes poses a great challenge in diagnosis for clinicians. Early diagnosis and the initiation of the appropriate treatment is the most relevant step in the management of the patients. Over the last years advances in neuroimmunology have elucidated pathophysiological basis and improved treatment concepts. In this monocentric study we compare demographics, diagnostics, treatment options and outcomes with knowledge from literature. We present 38 patients suffering from autoimmune encephalitis. Antibodies were detected against NMDAR and LGI1 in seven patients, against GAD in 6 patients) one patient had coexisting antibodies against GABAA and GABAB), against CASPR2, IGLON5, YO, Glycine in 3 patients, against Ma-2 in 2 patients, against CV2 and AMPAR in 1 patient; two patients were diagnosed with hashimoto encephalitis with antibodies against TPO/TG. First, we compare baseline data of patients who were consecutively diagnosed with autoimmune encephalitis from a retrospective view. Further, we discuss when to stop immunosuppressive therapy since how long treatment should be performed after clinical stabilization or an acute relapse is still a matter of debate. Our experiences are comparable with data from literature. However, in contrary to other experts in the field we stop treatment and monitor patients very closely after tumor removal and after rehabilitation from first attack.
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Affiliation(s)
- Stefan Macher
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | | | - Desiree De Simoni
- Institute of Neurology, Medical University of Vienna, Vienna, Austria
| | - Romana Höftberger
- Institute of Neurology, Medical University of Vienna, Vienna, Austria
| | - Paulus S Rommer
- Department of Neurology, Medical University of Vienna, Vienna, Austria
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13
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Ralvenius WT, Neumann E, Pagani M, Acuña MA, Wildner H, Benke D, Fischer N, Rostaher A, Schwager S, Detmar M, Frauenknecht K, Aguzzi A, Hubbs JL, Rudolph U, Favrot C, Zeilhofer HU. Itch suppression in mice and dogs by modulation of spinal α2 and α3GABA A receptors. Nat Commun 2018; 9:3230. [PMID: 30104684 PMCID: PMC6089996 DOI: 10.1038/s41467-018-05709-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 07/20/2018] [Indexed: 11/10/2022] Open
Abstract
Chronic itch is a highly debilitating condition affecting about 10% of the general population. The relay of itch signals is under tight control by inhibitory circuits of the spinal dorsal horn, which may offer a hitherto unexploited therapeutic opportunity. Here, we found that specific pharmacological targeting of inhibitory α2 and α3GABAA receptors reduces acute histaminergic and non-histaminergic itch in mice. Systemic treatment with an α2/α3GABAA receptor selective modulator alleviates also chronic itch in a mouse model of atopic dermatitis and in dogs sensitized to house dust mites, without inducing sedation, motor dysfunction, or loss of antipruritic activity after prolonged treatment. Transsynaptic circuit tracing, immunofluorescence, and electrophysiological experiments identify spinal α2 and α3GABAA receptors as likely molecular targets underlying the antipruritic effect. Our results indicate that drugs targeting α2 and α3GABAA receptors are well-suited to alleviate itch, including non-histaminergic chronic itch for which currently no approved treatment exists.
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Affiliation(s)
- William T Ralvenius
- Institute of Pharmacology and Toxicology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - Elena Neumann
- Institute of Pharmacology and Toxicology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - Martina Pagani
- Institute of Pharmacology and Toxicology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland.,Neuroscience Center Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - Mario A Acuña
- Institute of Pharmacology and Toxicology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - Hendrik Wildner
- Institute of Pharmacology and Toxicology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - Dietmar Benke
- Institute of Pharmacology and Toxicology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland.,Neuroscience Center Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland.,Drug Discovery Network Zürich (DDNZ), Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - Nina Fischer
- Dermatology Department, Clinic for Small Animal Internal Medicine, Vetsuisse Faculty, Winterthurerstrasse 260, CH-8057, Zürich, Switzerland
| | - Ana Rostaher
- Dermatology Department, Clinic for Small Animal Internal Medicine, Vetsuisse Faculty, Winterthurerstrasse 260, CH-8057, Zürich, Switzerland
| | - Simon Schwager
- Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Vladimir-Prelog-Weg 1-5/10, CH-8093, Zürich, Switzerland
| | - Michael Detmar
- Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Vladimir-Prelog-Weg 1-5/10, CH-8093, Zürich, Switzerland
| | - Katrin Frauenknecht
- Institute of Neuropathology, University of Zürich and University Hospital Zürich, Schmelzbergstrasse 12, CH-8091, Zürich, Switzerland
| | - Adriano Aguzzi
- Institute of Neuropathology, University of Zürich and University Hospital Zürich, Schmelzbergstrasse 12, CH-8091, Zürich, Switzerland
| | - Jed Lee Hubbs
- Laboratory of Organic Chemistry, Swiss Federal Institute of Technology (ETH) Zürich, Vladimir-Prelog-Weg 1-5/10, CH-8093, Zürich, Switzerland
| | - Uwe Rudolph
- Laboratory of Genetic Neuropharmacology, McLean Hospital, 115 Mill Street, Belmont, MA, 02478, USA.,Department of Psychiatry, Harvard Medical School, 401 Park Drive, Boston, MA, 02215, USA
| | - Claude Favrot
- Dermatology Department, Clinic for Small Animal Internal Medicine, Vetsuisse Faculty, Winterthurerstrasse 260, CH-8057, Zürich, Switzerland
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland. .,Neuroscience Center Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland. .,Drug Discovery Network Zürich (DDNZ), Winterthurerstrasse 190, CH-8057, Zürich, Switzerland. .,Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Vladimir-Prelog-Weg 1-5/10, CH-8093, Zürich, Switzerland.
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14
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Wu XH, Song JJ, Faull RLM, Waldvogel HJ. GABAAand GABABreceptor subunit localization on neurochemically identified neurons of the human subthalamic nucleus. J Comp Neurol 2017; 526:803-823. [DOI: 10.1002/cne.24368] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 11/12/2017] [Accepted: 11/14/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Xi Hua Wu
- Centre for Brain Research and Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences; The University of Auckland; Auckland New Zealand
| | - Jennifer Junru Song
- Centre for Brain Research and Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences; The University of Auckland; Auckland New Zealand
| | - Richard Lewis Maxwell Faull
- Centre for Brain Research and Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences; The University of Auckland; Auckland New Zealand
| | - Henry John Waldvogel
- Centre for Brain Research and Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences; The University of Auckland; Auckland New Zealand
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15
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Stefanits H, Milenkovic I, Mahr N, Pataraia E, Hainfellner JA, Kovacs GG, Sieghart W, Yilmazer-Hanke D, Czech T. GABAAreceptor subunits in the human amygdala and hippocampus: Immunohistochemical distribution of 7 subunits. J Comp Neurol 2017; 526:324-348. [DOI: 10.1002/cne.24337] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 09/12/2017] [Accepted: 09/19/2017] [Indexed: 12/18/2022]
Affiliation(s)
- Harald Stefanits
- Department of Neurosurgery; Medical University of Vienna; Vienna Austria
- Institute of Neurology, Medical University of Vienna; Vienna Austria
| | - Ivan Milenkovic
- Department of Clinical Neurology; Medical University of Vienna; Vienna Austria
| | - Nina Mahr
- Department of Neurosurgery; Medical University of Vienna; Vienna Austria
| | - Ekaterina Pataraia
- Department of Clinical Neurology; Medical University of Vienna; Vienna Austria
| | | | - Gabor G. Kovacs
- Institute of Neurology, Medical University of Vienna; Vienna Austria
| | - Werner Sieghart
- Center for Brain Research, Department of Molecular Neurosciences; Medical University of Vienna; Vienna Austria
| | - Deniz Yilmazer-Hanke
- Clinical Neuroanatomy, Neurology Department, Medical Faculty; Ulm University; Ulm Germany
| | - Thomas Czech
- Department of Neurosurgery; Medical University of Vienna; Vienna Austria
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16
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Söderpalm B, Lidö HH, Ericson M. The Glycine Receptor-A Functionally Important Primary Brain Target of Ethanol. Alcohol Clin Exp Res 2017; 41:1816-1830. [PMID: 28833225 DOI: 10.1111/acer.13483] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 08/15/2017] [Indexed: 12/27/2022]
Abstract
Identification of ethanol's (EtOH) primary molecular brain targets and determination of their functional role is an ongoing, important quest. Pentameric ligand-gated ion channels, that is, the nicotinic acetylcholine receptor, the γ-aminobutyric acid type A receptor, the 5-hydroxytryptamine3 , and the glycine receptor (GlyR), are such targets. Here, aspects of the structure and function of these receptors and EtOH's interaction with them are briefly reviewed, with special emphasis on the GlyR and the importance of this receptor and its ligands for EtOH pharmacology. It is suggested that GlyRs are involved in (i) the dopamine-activating effect of EtOH, (ii) regulating EtOH intake, and (iii) the relapse preventing effect of acamprosate. Exploration of the GlyR subtypes involved and efforts to develop subtype specific agonists or antagonists may offer new pharmacotherapies for alcohol use disorders.
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Affiliation(s)
- Bo Söderpalm
- Addiction Biology Unit, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Helga H Lidö
- Addiction Biology Unit, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Mia Ericson
- Addiction Biology Unit, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
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17
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Waldvogel H, Munkle M, van Roon-Mom W, Mohler H, Faull R. The immunohistochemical distribution of the GABA A receptor α 1 , α 2 , α 3 , β 2/3 and γ 2 subunits in the human thalamus. J Chem Neuroanat 2017; 82:39-55. [DOI: 10.1016/j.jchemneu.2017.04.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 03/31/2017] [Accepted: 04/19/2017] [Indexed: 11/24/2022]
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18
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Li C, Fitzgerald MEC, Del Mar N, Reiner A. Disinhibition of neurons of the nucleus of solitary tract that project to the superior salivatory nucleus causes choroidal vasodilation: Implications for mechanisms underlying choroidal baroregulation. Neurosci Lett 2016; 633:106-111. [PMID: 27663135 DOI: 10.1016/j.neulet.2016.09.029] [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: 08/09/2016] [Revised: 09/18/2016] [Accepted: 09/19/2016] [Indexed: 02/07/2023]
Abstract
Preganglionic neurons in the superior salivatory nucleus (SSN) that mediate parasympathetic vasodilation of choroidal blood vessels receive a major excitatory input from the baroresponsive part of the nucleus of the solitary tract (NTS). This input appears likely to mediate choroidal vasodilation during systemic hypotension, which prevents decreases in choroidal blood flow (ChBF) due to reduced perfusion pressure. It is uncertain, however, how low blood pressure signals to NTS from the aortic depressor nerve (ADN), which fires at a low rate during systemic hypotension, could yield increased firing in the NTS output to SSN. The simplest hypothesis is that SSN-projecting NTS neurons are under the inhibitory control of ADN-receptive GABAergic NTS neurons. As part of evaluating this hypothesis, we assessed if SSN-projecting NTS neurons, in fact, receive prominent inhibitory input and if blocking GABAergic modulation of them increases ChBF. We found that SSN-projecting NTS neuronal perikarya identified by retrograde labeling are densely coated with GABAergic terminals, but lightly coated with excitatory terminals. We also found that, infusion of the GABA-A receptor antagonist GABAzine into NTS increased ChBF. Our results are consistent with the possibility that low blood pressure signals from the ADN produce vasodilation in choroid by causing diminished activity in ADN-receptive NTS neurons that tonically suppress SSN-projecting NTS neurons.
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Affiliation(s)
- Chunyan Li
- Department of Anatomy and Neurobiology, University of Tennessee, Memphis, TN, 38163, United States.
| | - Malinda E C Fitzgerald
- Department of Anatomy and Neurobiology, University of Tennessee, Memphis, TN, 38163, United States; Department of Ophthalmology, University of Tennessee, Memphis, TN, 38163, United States; Department of Biology, Christian Brothers University, Memphis, TN, United States.
| | - Nobel Del Mar
- Department of Anatomy and Neurobiology, University of Tennessee, Memphis, TN, 38163, United States.
| | - Anton Reiner
- Department of Anatomy and Neurobiology, University of Tennessee, Memphis, TN, 38163, United States; Department of Ophthalmology, University of Tennessee, Memphis, TN, 38163, United States.
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19
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Oh SM, Bhattarai JP, Han SK, Park SJ. Effects of hypotaurine on substantia gelatinosa neurons of the trigeminal subnucleus caudalis in immature mice. Amino Acids 2016; 48:2843-2853. [PMID: 27573934 DOI: 10.1007/s00726-016-2321-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 08/22/2016] [Indexed: 12/18/2022]
Abstract
To understand the action and mechanism of hypotaurine, an immediate precursor of taurine, on orofacial nociceptive processing, we examined the direct effects and receptor types involved in hypotaurine-induced responses using the whole-cell patch clamp technique in the substantia gelatinosa (SG) neurons of the trigeminal subnucleus caudalis (Vc) of immature mice. Under the condition of high-chloride pipette solution, hypotaurine elicited inward currents or upward deflections of membrane potential, which increased in a concentration-dependent manner (30-3000 μM) with the EC50 of 663.8 and 337.6 μM, respectively. The responses to 300 µM hypotaurine were reproducible and recovered upon washout. The 300 µM hypotaurine-induced currents were maintained in the presence of TTX, CNQX, and AP5, indicating direct postsynaptic action of hypotaurine on SG neurons. Responses to both low (300 µM) and high (1 or 3 mM) concentrations of hypotaurine were completely and reversibly blocked by the glycine receptor antagonist strychnine (2 µM), but unaffected by the GABAA receptor antagonist gabazine (3 µM) which blocks synaptic GABAA receptors at low concentration. Furthermore, responses to 300 µM hypotaurine and a maximal concentration of glycine (3 mM) were not additive, indicating that hypotaurine and glycine act on the same receptor. Hypotaurine-induced currents were partially antagonized by picrotoxin (50 µM) which blocks homomeric glycine receptors and by bicuculline (10 µM) which is an antagonist of α2 subunit-containing glycine receptors. These results suggest that hypotaurine-induced responses were mediated by glycine receptor activation in the SG neurons and hypotaurine might be used as an effective therapeutics for orofacial pain.
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Affiliation(s)
- Sun Mi Oh
- Department of Oral Physiology and Institute of Oral Bioscience, School of Dentistry, Chonbuk National University, 664-14, 1 Ga, Deokjin-Dong, Jeonbuk, Jeonju, 561-756, Republic of Korea
| | - Janardhan Prasad Bhattarai
- Department of Oral Physiology and Institute of Oral Bioscience, School of Dentistry, Chonbuk National University, 664-14, 1 Ga, Deokjin-Dong, Jeonbuk, Jeonju, 561-756, Republic of Korea
| | - Seong Kyu Han
- Department of Oral Physiology and Institute of Oral Bioscience, School of Dentistry, Chonbuk National University, 664-14, 1 Ga, Deokjin-Dong, Jeonbuk, Jeonju, 561-756, Republic of Korea
| | - Soo Joung Park
- Department of Oral Physiology and Institute of Oral Bioscience, School of Dentistry, Chonbuk National University, 664-14, 1 Ga, Deokjin-Dong, Jeonbuk, Jeonju, 561-756, Republic of Korea.
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20
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Abstract
Autoantibodies targeting proteins at the neuromuscular junction are known to cause several distinct myasthenic syndromes. Recently, autoantibodies targeting neurotransmitter receptors and associated proteins have also emerged as a cause of severe, but potentially treatable, diseases of the CNS. Here, we review the clinical evidence as well as in vitro and in vivo experimental evidence that autoantibodies account for myasthenic syndromes and autoimmune disorders of the CNS by disrupting the functional or structural integrity of synapses. Studying neurological and psychiatric diseases of autoimmune origin may provide new insights into the cellular and circuit mechanisms underlying a broad range of CNS disorders.
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Affiliation(s)
- Sarah J Crisp
- UCL Institute of Neurology, University College London, Queen Square House, Queen Square, London WC1N 3BG, UK
| | - Dimitri M Kullmann
- UCL Institute of Neurology, University College London, Queen Square House, Queen Square, London WC1N 3BG, UK
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, University of Oxford, Level 6, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, UK
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21
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Stojanovic T, Capo I, Aronica E, Adle-Biassette H, Höger H, Sieghart W, Kovacs GG, Milenkovic I. The α1, α2, α3, and γ2 subunits of GABAA receptors show characteristic spatial and temporal expression patterns in rhombencephalic structures during normal human brain development. J Comp Neurol 2015; 524:1805-24. [PMID: 26518133 DOI: 10.1002/cne.23923] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Revised: 10/24/2015] [Accepted: 10/28/2015] [Indexed: 01/13/2023]
Abstract
γ-Aminobutyric acid (GABA) is the most abundant inhibitory neurotransmitter in adult mammalian brain, mediating its actions chiefly via a pentameric chloride ion channel, the GABAA receptor. Nineteen different subunits (α1-6, β1-3, γ1-3, δ, ε, π, θ, ρ1-3) can give rise to multiple receptor subtypes that are the site of action of many clinically important drugs. In the developing brain, however, GABAA receptors mediate excitatory actions due to an increased chloride concentration within neurons and seem to control cell proliferation, migration, differentiation, synapse maturation, and cell death. Little is known about the distribution of single subunits in the human brain. Here we describe developmental changes in the immunohistochemical distribution of four subunits (α1, α2, α3, and γ2) in the human rhombencephalon. The γ2 was the most abundant subunit in all rhombencephalic structures during development and in adults, whereas α subunits showed a structure- and age-characteristic distribution. The α1 was expressed prenatally in the molecular and Purkinje cell layer, but only postnatally in the granule cell layer and the dentate nucleus. Expression was completely absent in the inferior olivary nucleus. The α2 gradually increased during development, showing some layer specificity in the cerebellar cortex. The α3-immunoreactivity in the cerebellar cortex was relatively weak, but it was abundantly observed in different cell populations in the subcortical cerebellar structures. Structure- and age-characteristic colocalization between subunits during development suggests differences in GABAA receptor composition. Interestingly, subunit expression in several instances differed between human and rodent brain, underlining the importance of immunohistochemical studies in humans.
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Affiliation(s)
- Tamara Stojanovic
- Institute of Neurology, Neurodegeneration Research Group, Medical University of Vienna, Vienna, Austria
| | - Ivan Capo
- Department of Histology and Embryology, Medical Faculty, Vojvodina, Serbia
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, The Netherlands; SEIN - Stichting Epilepsie Instellingen Nederland, Heemstede, The Netherlands; Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, The Netherlands
| | - Homa Adle-Biassette
- Inserm U1141, Paris, France; Univ. Paris Diderot, Sorbonne Paris Cité, UMRS 676, Paris, France, Department of Pathology, Lariboisière Hospital, APHP, Paris, France
| | - Harald Höger
- Division of Laboratory Animal Science and Genetics, Medical University of Vienna, Vienna, Austria
| | - Werner Sieghart
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Gabor G Kovacs
- Institute of Neurology, Neurodegeneration Research Group, Medical University of Vienna, Vienna, Austria
| | - Ivan Milenkovic
- Institute of Neurology, Neurodegeneration Research Group, Medical University of Vienna, Vienna, Austria.,Department of Neurology, Medical University of Vienna, Vienna, Austria
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22
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Joubert B, Honnorat J. Autoimmune channelopathies in paraneoplastic neurological syndromes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2665-76. [PMID: 25883091 DOI: 10.1016/j.bbamem.2015.04.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 03/10/2015] [Accepted: 04/03/2015] [Indexed: 01/17/2023]
Abstract
Paraneoplastic neurological syndromes and autoimmune encephalitides are immune neurological disorders occurring or not in association with a cancer. They are thought to be due to an autoimmune reaction against neuronal antigens ectopically expressed by the underlying tumour or by cross-reaction with an unknown infectious agent. In some instances, paraneoplastic neurological syndromes and autoimmune encephalitides are related to an antibody-induced dysfunction of ion channels, a situation that can be labelled as autoimmune channelopathies. Such functional alterations of ion channels are caused by the specific fixation of an autoantibody upon its target, implying that autoimmune channelopathies are usually highly responsive to immuno-modulatory treatments. Over the recent years, numerous autoantibodies corresponding to various neurological syndromes have been discovered and their mechanisms of action partially deciphered. Autoantibodies in neurological autoimmune channelopathies may target either directly ion channels or proteins associated to ion channels and induce channel dysfunction by various mechanisms generally leading to the reduction of synaptic expression of the considered channel. The discovery of those mechanisms of action has provided insights on the regulation of the synaptic expression of the altered channels as well as the putative roles of some of their functional subdomains. Interestingly, patients' autoantibodies themselves can be used as specific tools in order to study the functions of ion channels. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.
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Affiliation(s)
- Bastien Joubert
- University Lyon 1, University Lyon, Rue Guillaume Paradin, 69372 Lyon Cedex 08, France; INSERM, UMR-S1028, CNRS, UMR-5292, Lyon Neuroscience Research Center, Neuro-Oncology and Neuro-Inflammation Team, 7, Rue Guillaume Paradin, Lyon Cedex 08F-69372, France
| | - Jérôme Honnorat
- University Lyon 1, University Lyon, Rue Guillaume Paradin, 69372 Lyon Cedex 08, France; INSERM, UMR-S1028, CNRS, UMR-5292, Lyon Neuroscience Research Center, Neuro-Oncology and Neuro-Inflammation Team, 7, Rue Guillaume Paradin, Lyon Cedex 08F-69372, France; National Reference Centre for Paraneoplastic Neurological Diseases, hospices civils de Lyon, hôpital neurologique, 69677 Bron, France; Hospices Civils de Lyon, Neuro-oncology, Hôpital Neurologique, F-69677 Bron, France.
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23
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Möhler H. The legacy of the benzodiazepine receptor: from flumazenil to enhancing cognition in Down syndrome and social interaction in autism. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 72:1-36. [PMID: 25600365 DOI: 10.1016/bs.apha.2014.10.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The study of the psychopharmacology of benzodiazepines continues to provide new insights into diverse brain functions related to vigilance, anxiety, mood, epileptiform activity, schizophrenia, cognitive performance, and autism-related social behavior. In this endeavor, the discovery of the benzodiazepine receptor was a key event, as it supplied the primary benzodiazepine drug-target site, provided the molecular link to the allosteric modulation of GABAA receptors and, following the recognition of GABAA receptor subtypes, furnished the platform for future, more selective drug actions. This review has two parts. In a retrospective first part, it acknowledges the contributions to the field made by my collaborators over the years, initially at Hoffmann-La Roche in Basle and later, in academia, at the University and the ETH of Zurich. In the second part, the new frontier of GABA pharmacology, targeting GABAA receptor subtypes, is reviewed with special focus on nonsedative anxiolytics, antidepressants, analgesics, as well as enhancers of cognition in Down syndrome and attenuators of symptoms of autism spectrum disorders. It is encouraging that a clinical trial has been initiated with a partial inverse agonist acting on α5 GABAA receptors in an attempt to alleviate the cognitive deficits in Down syndrome.
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Affiliation(s)
- Hanns Möhler
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland; Department of Chemistry and Applied Biosciences, Federal Institute of Technology (ETH), Zurich, Switzerland.
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24
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Peirs C, Patil S, Bouali-Benazzouz R, Artola A, Landry M, Dallel R. Protein kinase C gamma interneurons in the rat medullary dorsal horn: distribution and synaptic inputs to these neurons, and subcellular localization of the enzyme. J Comp Neurol 2014; 522:393-413. [PMID: 23818225 DOI: 10.1002/cne.23407] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 06/21/2013] [Accepted: 06/21/2013] [Indexed: 12/18/2022]
Abstract
The γ isoform of protein kinase C (PKCγ), which is concentrated in interneurons in the inner part of lamina II (IIi ) of the dorsal horn, has been implicated in the expression of tactile allodynia. Lamina IIi PKCγ interneurons were shown to be activated by tactile inputs and to participate in local circuits through which these inputs can reach lamina I, nociceptive output neurons. That such local circuits are gated by glycinergic inhibition and that A- and C-fibers low threshold mechanoreceptors (LTMRs) terminate in lamina IIi raise the general issue of synaptic inputs to lamina IIi PKCγ interneurons. Combining light and electron microscopic immunochemistry in the rat spinal trigeminal nucleus, we show that PKCγ-immunoreactivity is mostly restricted to interneurons in lamina IIi of the medullary dorsal horn, where they constitute 1/3 of total neurons. The majority of synapses on PKCγ-immunoreactive interneurons are asymmetric (likely excitatory). PKCγ-immunoreactive interneurons appear to receive exclusively myelinated primary afferents in type II synaptic glomeruli. Neither large dense core vesicle terminals nor type I synaptic glomeruli, assumed to be the endings of unmyelinated nociceptive terminals, were found on these interneurons. Moreover, there is no vesicular glutamate transporter 3-immunoreactive bouton, specific to C-LTMRs, on PKCγ-immunoreactive interneurons. PKCγ-immunoreactive interneurons contain GABAA ergic and glycinergic receptors. At the subcellular level, PKCγ-immunoreactivity is mostly concentrated on plasma membranes, close to, but not within, postsynaptic densities. That only myelinated primary afferents were found to contact PKCγ-immunoreactive interneurons suggests that myelinated, but not unmyelinated, LTMRs play a critical role in the expression of mechanical allodynia.
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Affiliation(s)
- Cédric Peirs
- Inserm/UdA U1107, Neuro-Dol: Trigeminal Pain and Migraine, Université d'Auvergne, Faculté de Chirurgie Dentaire, Clermont-Ferrand, 63000, France
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Gephyrin clusters are absent from small diameter primary afferent terminals despite the presence of GABA(A) receptors. J Neurosci 2014; 34:8300-17. [PMID: 24920633 DOI: 10.1523/jneurosci.0159-14.2014] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Whereas both GABA(A) receptors (GABA(A)Rs) and glycine receptors (GlyRs) play a role in control of dorsal horn neuron excitability, their relative contribution to inhibition of small diameter primary afferent terminals remains controversial. To address this, we designed an approach for quantitative analyses of the distribution of GABA(A)R-subunits, GlyR α1-subunit and their anchoring protein, gephyrin, on terminals of rat spinal sensory afferents identified by Calcitonin-Gene-Related-Peptide (CGRP) for peptidergic terminals, and by Isolectin-B4 (IB4) for nonpeptidergic terminals. The approach was designed for light microscopy, which is compatible with the mild fixation conditions necessary for immunodetection of several of these antigens. An algorithm was designed to recognize structures with dimensions similar to those of the microscope resolution. To avoid detecting false colocalization, the latter was considered significant only if the degree of pixel overlap exceeded that expected from randomly overlapping pixels given a hypergeometric distribution. We found that both CGRP(+) and IB4(+) terminals were devoid of GlyR α1-subunit and gephyrin. The α1 GABA(A)R was also absent from these terminals. In contrast, the GABA(A)R α2/α3/α5 and β3 subunits were significantly expressed in both terminal types, as were other GABA(A)R-associated-proteins (α-Dystroglycan/Neuroligin-2/Collybistin-2). Ultrastructural immunocytochemistry confirmed the presence of GABA(A)R β3 subunits in small afferent terminals. Real-time quantitative PCR (qRT-PCR) confirmed the results of light microscopy immunochemical analysis. These results indicate that dorsal horn inhibitory synapses follow different rules of organization at presynaptic versus postsynaptic sites (nociceptive afferent terminals vs inhibitory synapses on dorsal horn neurons). The absence of gephyrin clusters from primary afferent terminals suggests a more diffuse mode of GABA(A)-mediated transmission at presynaptic than at postsynaptic sites.
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Carvajal-González A, Leite MI, Waters P, Woodhall M, Coutinho E, Balint B, Lang B, Pettingill P, Carr A, Sheerin UM, Press R, Press R, Lunn MP, Lim M, Maddison P, Meinck HM, Vandenberghe W, Vincent A. Glycine receptor antibodies in PERM and related syndromes: characteristics, clinical features and outcomes. ACTA ACUST UNITED AC 2014; 137:2178-92. [PMID: 24951641 PMCID: PMC4107739 DOI: 10.1093/brain/awu142] [Citation(s) in RCA: 315] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
See Martinez-Martinez et al. (doi:10.1093/brain/awu153) for a scientific commentary on this article. Carvajal-González et al. describe the first prospective cohort of patients with glycine receptor antibodies. The majority have progressive encephalomyelitis with rigidity and myoclonus. The antibodies bind to extracellular determinants on glycine receptor-α1 and to glycine receptors on spinal cord and brainstem neurons. The patients make a good recovery with immunotherapies. The clinical associations of glycine receptor antibodies have not yet been described fully. We identified prospectively 52 antibody-positive patients and collated their clinical features, investigations and immunotherapy responses. Serum glycine receptor antibody endpoint titres ranged from 1:20 to 1:60 000. In 11 paired samples, serum levels were higher than (n = 10) or equal to (n = 1) cerebrospinal fluid levels; there was intrathecal synthesis of glycine receptor antibodies in each of the six pairs available for detailed study. Four patients also had high glutamic acid decarboxylase antibodies (>1000 U/ml), and one had high voltage-gated potassium channel-complex antibody (2442 pM). Seven patients with very low titres (<1:50) and unknown or alternative diagnoses were excluded from further study. Three of the remaining 45 patients had newly-identified thymomas and one had a lymphoma. Thirty-three patients were classified as progressive encephalomyelitis with rigidity and myoclonus, and two as stiff person syndrome; five had a limbic encephalitis or epileptic encephalopathy, two had brainstem features mainly, two had demyelinating optic neuropathies and one had an unclear diagnosis. Four patients (9%) died during the acute disease, but most showed marked improvement with immunotherapies. At most recent follow-up, (2–7 years, median 3 years, since first antibody detection), the median modified Rankin scale scores (excluding the four deaths) decreased from 5 at maximal severity to 1 (P < 0.0001), but relapses have occurred in five patients and a proportion are on reducing steroids or other maintenance immunotherapies as well as symptomatic treatments. The glycine receptor antibodies activated complement on glycine receptor-transfected human embryonic kidney cells at room temperature, and caused internalization and lysosomal degradation of the glycine receptors at 37°C. Immunoglobulin G antibodies bound to rodent spinal cord and brainstem co-localizing with monoclonal antibodies to glycine receptor-α1. Ten glycine receptor antibody positive samples were also identified in a retrospective cohort of 56 patients with stiff person syndrome and related syndromes. Glycine receptor antibodies are strongly associated with spinal and brainstem disorders, and the majority of patients have progressive encephalomyelitis with rigidity and myoclonus. The antibodies demonstrate in vitro evidence of pathogenicity and the patients respond well to immunotherapies, contrasting with earlier studies of this syndrome, which indicated a poor prognosis. The presence of glycine receptor antibodies should help to identify a disease that responds to immunotherapies, but these treatments may need to be sustained, relapses can occur and maintenance immunosuppression may be required.
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Affiliation(s)
| | - M Isabel Leite
- 1 Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Patrick Waters
- 1 Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Mark Woodhall
- 1 Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Ester Coutinho
- 1 Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Bettina Balint
- 2 Department of Neurology, INF 400, 69120 Heidelberg, Germany
| | - Bethan Lang
- 1 Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Philippa Pettingill
- 1 Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Aisling Carr
- 3 Department of Clinical Neurology, Royal Victoria Hospital, Belfast, Northern Ireland, BT12 6BA
| | - Una-Marie Sheerin
- 4 Department of Clinical Neurosciences, Charing Cross Hospital, Imperial College, London UK
| | | | - Raomand Press
- 5 Clinical Neuroscience, Karolinska Institute, Department of Neurology, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Michael P Lunn
- 6 Centre for Neuromuscular Disease, National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG, UK
| | - Ming Lim
- 1 Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Paul Maddison
- 7 Department of Clinical Neurology, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - H-M Meinck
- 2 Department of Neurology, INF 400, 69120 Heidelberg, Germany
| | - Wim Vandenberghe
- 8 Department of Neurology, University Hospitals Leuven; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Angela Vincent
- 1 Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford OX3 9DU, UK
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Sokolov AY, Lyubashina OA, Amelin AV, Panteleev SS. The role of gamma-aminobutyric acid in migraine pathogenesis. NEUROCHEM J+ 2014. [DOI: 10.1134/s1819712414020093] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Che Ngwa E, Zeeh C, Messoudi A, Büttner-Ennever JA, Horn AKE. Delineation of motoneuron subgroups supplying individual eye muscles in the human oculomotor nucleus. Front Neuroanat 2014; 8:2. [PMID: 24574976 PMCID: PMC3921678 DOI: 10.3389/fnana.2014.00002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Accepted: 01/14/2014] [Indexed: 11/24/2022] Open
Abstract
The oculomotor nucleus (nIII) contains the motoneurons of medial, inferior, and superior recti (MR, IR, and SR), inferior oblique (IO), and levator palpebrae (LP) muscles. The delineation of motoneuron subgroups for each muscle is well-known in monkey, but not in human. We studied the transmitter inputs to human nIII and the trochlear nucleus (nIV), which innervates the superior oblique muscle (SO), to outline individual motoneuron subgroups. Parallel series of sections from human brainstems were immunostained for different markers: choline acetyltransferase combined with glutamate decarboxylase (GAD), calretinin (CR) or glycine receptor. The cytoarchitecture was visualized with cresyl violet, Gallyas staining and expression of non-phosphorylated neurofilaments. Apart from nIV, seven subgroups were delineated in nIII: the central caudal nucleus (CCN), a dorsolateral (DL), dorsomedial (DM), central (CEN), and ventral (VEN) group, the nucleus of Perlia (NP) and the non-preganglionic centrally projecting Edinger–Westphal nucleus (EWcp). DL, VEN, NP, and EWcp were characterized by a strong supply of GAD-positive terminals, in contrast to DM, CEN, and nIV. CR-positive terminals and fibers were confined to CCN, CEN, and NP. Based on location and histochemistry of the motoneuron subgroups in monkey, CEN is considered as the SR and IO motoneurons, DL and VEN as the B- and A-group of MR motoneurons, respectively, and DM as IR motoneurons. A good correlation between monkey and man is seen for the CR input, which labels only motoneurons of eye muscles participating in upgaze (SR, IO, and LP). The CCN contained LP motoneurons, and nIV those of SO. This study provides a map of the individual subgroups of motoneurons in human nIII for the first time, and suggests that NP may contain upgaze motoneurons. Surprisingly, a strong GABAergic input to human MR motoneurons was discovered, which is not seen in monkey and may indicate a functional oculomotor specialization.
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Affiliation(s)
- Emmanuel Che Ngwa
- Oculomotor Group, Institute of Anatomy and Cell Biology, Department I, Ludwig-Maximilians-University of Munich Munich, Germany
| | - Christina Zeeh
- Oculomotor Group, Institute of Anatomy and Cell Biology, Department I, Ludwig-Maximilians-University of Munich Munich, Germany ; German Center for Vertigo and Balance Disorders, Ludwig-Maximilians-University of Munich Munich, Germany
| | - Ahmed Messoudi
- Oculomotor Group, Institute of Anatomy and Cell Biology, Department I, Ludwig-Maximilians-University of Munich Munich, Germany
| | - Jean A Büttner-Ennever
- Oculomotor Group, Institute of Anatomy and Cell Biology, Department I, Ludwig-Maximilians-University of Munich Munich, Germany
| | - Anja K E Horn
- Oculomotor Group, Institute of Anatomy and Cell Biology, Department I, Ludwig-Maximilians-University of Munich Munich, Germany ; German Center for Vertigo and Balance Disorders, Ludwig-Maximilians-University of Munich Munich, Germany
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Nikandrov V, Balashevich T. Glycine receptors in nervous tissue and their functional role. ACTA ACUST UNITED AC 2014; 60:403-15. [DOI: 10.18097/pbmc20146004403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The literature data on glycine metabolism in neural tissue, mitochondrial Gly-cleaving system, Gly-catching system in neural and glial cells are summarized. The peculiarities of localization and distribution of specific glycine receptors and binding-sites in nervous tissue of mammals are described. Four types of glycine-binding receptors are described: own specific glycine receptor (Gly-R), ionotropic receptor, which binds N-methyl-D-aspartate selectively (NMDA-R), and ionotropic receptors of g-aminobutyrate (GABA A -R, GABA С -R). The feutures of glycine effects in neuroglial cultures are discussed
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Avolio E, Facciolo RM, Alò R, Mele M, Carelli A, Canonaco A, Mosciaro L, Talani G, Biggio G, Sanna E, Mahata SK, Canonaco M. Expression variations of chromogranin A and α1,2,4 GABA(A)Rs in discrete limbic and brainstem areas rescue cardiovascular alterations. Neurosci Res 2013; 77:8-15. [PMID: 23916832 DOI: 10.1016/j.neures.2013.07.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 07/08/2013] [Accepted: 07/24/2013] [Indexed: 12/21/2022]
Abstract
Recent interferences of hemodynamic functions via modified brain neuronal mechanisms have proven to be major causes of dementia and sleeping disorders. In this work, cerebral expression differences of the neuroactive vesicular chromogranin A (CgA) and distinct α GABA(A)R subunits were detected in the facultative hibernating hamster. In particular, damaged neuronal fields of hypotensive torpor (TORP) state were correlated to elevated CgA and GABA(A)R α1, α4 mRNA levels in the paraventricular hypothalamic nucleus (PVN), central amygdalar nucleus (CeA) plus solitary tractus nucleus (NTS). Conversely, few neurodegeneration signals of hypertensive arousal (AROU) state, accounted for mostly lower CgA levels in the same areas. This state also provided increased α2-containing sites in amygdala, hippocampal and NTS neurons together with elevated α4-containing receptors in the periventricular hypothalamic nucleus (Pe). Interestingly in our hibernating model, CgA appeared to preferentially feature inhibitory neurosignals as indicated by preliminary perfusion of amygdalar sites with its highly specific antihypertensive derived peptide (catestatin) promoting GABA-dependent sIPSCs. Overall, evident neuronal damages plus altered expression capacities of CgA and α1-, α2-, α4-GABA(A)Rs in CeA, Pe, PVN as well as NTS during both hibernating states corroborate for the first time key molecular switching events guaranteeing useful cardiovascular rescuing abilities of neurodegenerative disorders.
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Affiliation(s)
- Ennio Avolio
- Comparative Neuroanatomy Laboratory, University of Calabria, Ponte P. Bucci 4B, 87030 Arcavacata di Rende, Cosenza, Italy; Health Center srl, via Alimena 6, 87100 Cosenza, Italy; VA San Diego Healthcare System/Department of Medicine, University of California-San Diego, La Jolla, CA 92093-0838, USA
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Loria CJ, Stevens AM, Crummy E, Casadesus G, Jacono FJ, Dick TE, Siegel RE. Respiratory and behavioral dysfunction following loss of the GABAA receptor α4 subunit. Brain Behav 2013; 3:104-13. [PMID: 23533098 PMCID: PMC3607152 DOI: 10.1002/brb3.122] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 12/21/2012] [Accepted: 01/02/2013] [Indexed: 11/10/2022] Open
Abstract
γ-Aminobutyric acid type A (GABAA) receptor plasticity participates in mediating adaptation to environmental change. Previous studies in rats demonstrated that extrasynaptic GABAA receptor subunits and receptors in the pons, a brainstem region involved in respiratory control, are upregulated by exposure to sustained hypobaric hypoxia. In these animals, expression of the mRNA encoding the extrasynaptic α4 subunit rose after 3 days in sustained hypoxia, while those encoding the α6 and δ subunits increased dramatically by 2 weeks. However, the participation of extrasynaptic subunits in maintaining respiration in normoxic conditions remains unknown. To examine the importance of α4 in a normal environment, respiratory function, motor and anxiety-like behaviors, and expression of other GABAA receptor subunit mRNAs were compared in wild-type (WT) and α4 subunit-deficient mice. Loss of the α4 subunit did not impact frequency, but did lead to reduced ventilatory pattern variability. In addition, mice lacking the subunit exhibited increased anxiety-like behavior. Finally, α4 subunit loss resulted in reduced expression of other extrasynaptic (α6 and δ) subunit mRNAs in the pons without altering those encoding the most prominent synaptic subunits. These findings on subunit-deficient mice maintained in normoxia, in conjunction with earlier findings on animals maintained in chronic hypoxia, suggest that the expression and regulation of extrasynaptic GABAA receptor subunits in the pons is interdependent and that their levels influence respiratory control as well as adaptation to stress.
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Affiliation(s)
- C Jean Loria
- Department of Pharmacology, Case Western Reserve University 10900 Euclid Avenue, Cleveland, Ohio, 44106
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Chandley M, Ordway G. Noradrenergic Dysfunction in Depression and Suicide. THE NEUROBIOLOGICAL BASIS OF SUICIDE 2012. [DOI: 10.1201/b12215-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Rakocevic G, Floeter MK. Autoimmune stiff person syndrome and related myelopathies: understanding of electrophysiological and immunological processes. Muscle Nerve 2012; 45:623-34. [PMID: 22499087 DOI: 10.1002/mus.23234] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Stiff person syndrome (SPS) is a disabling autoimmune central nervous system disorder characterized by progressive muscle rigidity and gait impairment with superimposed painful spasms that involve axial and limb musculature, triggered by heightened sensitivity to external stimuli. Impaired synaptic GABAergic inhibition resulting from intrathecal B-cell-mediated clonal synthesis of autoantibodies against various presynaptic and synaptic proteins in the inhibitory neurons of the brain and spinal cord is believed to be an underlying pathogenic mechanism. SPS is most often idiopathic, but it can occur as a paraneoplastic condition. Despite evidence that anti-GAD and related autoantibodies impair GABA synthesis, the exact pathogenic mechanism of SPS is not fully elucidated. The strong association with several MHC-II alleles and improvement of symptoms with immune-modulating therapies support an autoimmune etiology of SPS. In this review, we discuss the clinical spectrum, neurophysiological mechanisms, and therapeutic options, including a rationale for agents that modulate B-cell function in SPS.
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Affiliation(s)
- Goran Rakocevic
- Department of Neurology, Thomas Jefferson University, 900 Walnut Street, Suite 200, Philadelphia, Pennsylvania 19107, USA.
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Abstract
Inhibitory (or strychnine sensitive) glycine receptors (GlyRs) are anion-selective transmitter-gated ion channels of the cys-loop superfamily, which includes among others also the inhibitory γ-aminobutyric acid receptors (GABA(A) receptors). While GABA mediates fast inhibitory neurotransmission throughout the CNS, the action of glycine as a fast inhibitory neurotransmitter is more restricted. This probably explains why GABA(A) receptors constitute a group of extremely successful drug targets in the treatment of a wide variety of CNS diseases, including anxiety, sleep disorders and epilepsy, while drugs specifically targeting GlyRs are virtually lacking. However, the spatially more restricted distribution of glycinergic inhibition may be advantageous in situations when a more localized enhancement of inhibition is sought. Inhibitory GlyRs are particularly relevant for the control of excitability in the mammalian spinal cord, brain stem and a few selected brain areas, such as the cerebellum and the retina. At these sites, GlyRs regulate important physiological functions, including respiratory rhythms, motor control, muscle tone and sensory as well as pain processing. In the hippocampus, RNA-edited high affinity extrasynaptic GlyRs may contribute to the pathology of temporal lobe epilepsy. Although specific modulators have not yet been identified, GlyRs still possess sites for allosteric modulation by a number of structurally diverse molecules, including alcohols, neurosteroids, cannabinoids, tropeines, general anaesthetics, certain neurotransmitters and cations. This review summarizes the present knowledge about this modulation and the molecular bases of the interactions involved.
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Affiliation(s)
- Gonzalo E Yevenes
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
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Zeilhofer HU, Wildner H, Yévenes GE. Fast synaptic inhibition in spinal sensory processing and pain control. Physiol Rev 2012; 92:193-235. [PMID: 22298656 DOI: 10.1152/physrev.00043.2010] [Citation(s) in RCA: 262] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The two amino acids GABA and glycine mediate fast inhibitory neurotransmission in different CNS areas and serve pivotal roles in the spinal sensory processing. Under healthy conditions, they limit the excitability of spinal terminals of primary sensory nerve fibers and of intrinsic dorsal horn neurons through pre- and postsynaptic mechanisms, and thereby facilitate the spatial and temporal discrimination of sensory stimuli. Removal of fast inhibition not only reduces the fidelity of normal sensory processing but also provokes symptoms very much reminiscent of pathological and chronic pain syndromes. This review summarizes our knowledge of the molecular bases of spinal inhibitory neurotransmission and its organization in dorsal horn sensory circuits. Particular emphasis is placed on the role and mechanisms of spinal inhibitory malfunction in inflammatory and neuropathic chronic pain syndromes.
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Chen SH, Tsai YJ, Wang HY, Lin CT, Li SF, Lue JH. Decreases of glycine receptor expression induced by median nerve injury in the rat cuneate nucleus contribute to NPY release and c-Fos expression. Life Sci 2011; 90:278-88. [PMID: 22178676 DOI: 10.1016/j.lfs.2011.11.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 10/07/2011] [Accepted: 11/23/2011] [Indexed: 11/15/2022]
Abstract
AIMS This study aimed to investigate temporal changes in glycine and its receptor expressions in cuneate neurons after median nerve transection (MNT), and the effects of glycine on neuropeptide Y (NPY) release and c-Fos expression in the cuneate nucleus (CN). MAIN METHODS Immunohistochemistry methods were used to appraise changes of glycine- and GlyR-like immunoreactive (LI) neurons in the CN after MNT. The alterations in NPY and c-Fos expressions were used to assess the effects of saline, glycine or strychnine treatment. The CatWalk method was used to assess the efficiency of glycine treatment on the neuropathic signs of rats with MNT. KEY FINDINGS Approximately half of GlyR-LI neurons were fluorogold-labeled cuneothalamic projection neurons in the CN. Following MNT, the number of GlyR-LI neurons significantly decreased in the injured side of CN at 2 and 4 weeks, but the number of glycine-LI neurons remained unchanged. Four weeks after MNT given with electrical stimulation, strychnine significantly decreased the NPY reduction level in the stimulated side CN compared to that of the saline group. However, numbers of c-Fos-LI neurons in the glycine and strychnine groups were both significantly less than that in the saline group. But the paw print width and area in CatWalk analysis showed only a moderate recovery. SIGNIFICANCE We conjecture that glycine increases glycine-mediated postsynaptic inhibition of cuneate neurons, and also blocks GABAergic neurons containing GlyRs which mediate presynaptic inhibition causing temperate NPY release. Consequently, the compromise results showed a weak reduction in c-Fos expression and a slight amelioration of neuropathic behaviors.
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Affiliation(s)
- Seu-Hwa Chen
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, 1-1 Jen Ai Road, Taipei, Taiwan
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Neumann S, Haverkamp S, Auferkorte ON. Intrinsically photosensitive ganglion cells of the primate retina express distinct combinations of inhibitory neurotransmitter receptors. Neuroscience 2011; 199:24-31. [PMID: 22044923 DOI: 10.1016/j.neuroscience.2011.10.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 09/27/2011] [Accepted: 10/17/2011] [Indexed: 10/16/2022]
Abstract
Intrinsically-photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin and function as irradiance detectors, responsible for crucial non-image forming visual functions. In addition to their intrinsic photosensitivity, ipRGCs are also activated by synaptic inputs originating at the classical photoreceptors, rods and cones. Little is known about inhibition through these retinal pathways, despite ipRGCs receiving massive synaptic inputs from inhibitory amacrine interneurons. We performed a wide anatomical screening for neurotransmitter receptors possibly involved in the inhibitory modulation of ipRGCs in the macaque retina. We investigated both subtypes of primate ipRGCs described so far and report that outer-stratifying (M1) cells possess mainly GlyR α2 and GABA(A)R α3 subunits, while inner-stratifying (M2) cells are overall subject to less inhibitory modulation. Our results suggest that M1 and M2 ipRGC subtypes are modulated via distinct inhibitory intraretinal circuits.
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Affiliation(s)
- S Neumann
- Department of Neuroanatomy, Max-Planck-Institute for Brain Research, D-60528 Frankfurt a.M., Germany
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Maturation of the GABAergic transmission in normal and pathologic motoneurons. Neural Plast 2011; 2011:905624. [PMID: 21785735 PMCID: PMC3140191 DOI: 10.1155/2011/905624] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 04/17/2011] [Indexed: 12/14/2022] Open
Abstract
γ-aminobutyric acid (GABA) acting on Cl−-permeable ionotropic type A (GABAA) receptors (GABAAR) is the major inhibitory neurotransmitter in the adult central nervous system of vertebrates. In immature brain structures, GABA exerts depolarizing effects mostly contributing to the expression of spontaneous activities that are instructive for the construction of neural networks but GABA also acts as a potent trophic factor. In the present paper, we concentrate on brainstem and spinal motoneurons that are largely targeted by GABAergic interneurons, and we bring together data on the switch from excitatory to inhibitory effects of GABA, on the maturation of the GABAergic system and GABAAR subunits. We finally discuss the role of GABA and its GABAAR in immature hypoglossal motoneurons of the spastic (SPA) mouse, a model of human hyperekplexic syndrome.
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Geis HR, Schmid S. Glycine inhibits startle-mediating neurons in the caudal pontine reticular formation but is not involved in synaptic depression underlying short-term habituation of startle. Neurosci Res 2011; 71:114-23. [PMID: 21726589 DOI: 10.1016/j.neures.2011.06.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 06/16/2011] [Accepted: 06/17/2011] [Indexed: 01/24/2023]
Abstract
The mammalian startle response is controlled by glycine inhibition in the spinal cord. Evidence for additional glycine inhibition on the level of the brainstem, namely in the caudal pontine reticular nucleus (PnC), is controversial. Startle mediating PnC neurons receive fast input from sensory pathways and project to cranial and spinal motoneurons. Synaptic depression in the sensory synapses in the PnC has been indicated as underlying mechanism of short-term habituation of startle. We here performed patch-clamp recordings of PnC giant neurons in rat brain slices to test the hypothesis that the activation of glycine receptors inhibits PnC neurons and that this inhibition is involved in synaptic depression in the PnC. Glycine strongly inhibited PnC neuron activity and synaptic signalling, indicating that functional glycine receptors mediate a powerful inhibition of PnC neurons over a wide range of glycine concentrations. Strychnine reversed all glycine effects, but had no effect on PnC neurons itself. Thus, we found no evidence for a tonic glycine inhibition or for glycine activation within the primary startle pathway indicating that baseline startle reactions are unlikely to be controlled by glycine in the PnC. Most importantly, synaptic depression underlying short-term habituation was not affected by glycine or strychnine.
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Hellsten KS, Sinkkonen ST, Hyde TM, Kleinman JE, Särkioja T, Maksimow A, Uusi-Oukari M, Korpi ER. Human locus coeruleus neurons express the GABA(A) receptor gamma2 subunit gene and produce benzodiazepine binding. Neurosci Lett 2010; 477:77-81. [PMID: 20417252 DOI: 10.1016/j.neulet.2010.04.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 03/30/2010] [Accepted: 04/19/2010] [Indexed: 01/23/2023]
Abstract
Noradrenergic neurons of the locus coeruleus project throughout the cerebral cortex and multiple subcortical structures. Alterations in the locus coeruleus firing are associated with vigilance states and with fear and anxiety disorders. Brain ionotropic type A receptors for gamma-aminobutyric acid (GABA) serve as targets for anxiolytic and sedative drugs, and play an essential regulatory role in the locus coeruleus. GABA(A) receptors are composed of a variable array of subunits forming heteropentameric chloride channels with different pharmacological properties. The gamma2 subunit is essential for the formation of the binding site for benzodiazepines, allosteric modulators of GABA(A) receptors that are clinically often used as sedatives/hypnotics and anxiolytics. There are contradictory reports in regard to the gamma2 subunit's expression and participation in the functional GABA(A) receptors in the mammalian locus coeruleus. We report here that the gamma2 subunit is transcribed and participates in the assembly of functional GABA(A) receptors in the tyrosine hydroxylase-positive neuromelanin-containing neurons within postmortem human locus coeruleus as demonstrated by in situ hybridization with specific gamma2 subunit oligonucleotides and autoradiographic assay for flumazenil-sensitive [(3)H]Ro 15-4513 binding to benzodiazepine sites. These sites were also sensitive to the alpha1 subunit-preferring agonist zolpidem. Our data suggest a species difference in the expression profiles of the alpha1 and gamma2 subunits in the locus coeruleus, with the sedation-related benzodiazepine sites being more important in man than rodents. This may explain the repeated failures in the transition of novel drugs with a promising neuropharmacological profile in rodents to human clinical usage, due to intolerable sedative effects.
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Affiliation(s)
- Kati S Hellsten
- Institute of Biomedicine, Pharmacology, Biomedicum Helsinki, POB 63 (Haartmaninkatu 8), FI-00014 University of Helsinki, Finland
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Baer K, Waldvogel HJ, Faull RLM, Rees MI. Localization of glycine receptors in the human forebrain, brainstem, and cervical spinal cord: an immunohistochemical review. Front Mol Neurosci 2009; 2:25. [PMID: 19915682 PMCID: PMC2776491 DOI: 10.3389/neuro.02.025.2009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Accepted: 10/15/2009] [Indexed: 11/26/2022] Open
Abstract
Inhibitory neurotransmitter receptors for glycine (GlyR) are heteropentameric chloride ion channels that are comprised of four functional subunits, alpha1–3 and beta and that facilitate fast-response, inhibitory neurotransmission in the mammalian brain and spinal cord. We have investigated the distribution of GlyRs in the human forebrain, brainstem, and cervical spinal cord using immunohistochemistry at light and confocal laser scanning microscopy levels. This review will summarize the present knowledge on the GlyR distribution in the human brain using our established immunohistochemical techniques. The results of our immunohistochemical labeling studies demonstrated GlyR immunoreactivity (IR) throughout the human basal ganglia, substantia nigra, various pontine regions, rostral medulla oblongata and the cervical spinal cord present an intense and abundant punctate IR along the membranes of the neuronal soma and dendrites. This work is part of a systematic study of inhibitory neurotransmitter receptor distribution in the human CNS, and provides a basis for additional detailed physiological and pharmacological studies on the inter-relationship of GlyR, GABAAR and gephyrin in the human brain. This basic mapping exercise, we believe, will provide important baselines for the testing of future pharmacotherapies and drug regimes that modulate neuroinhibitory systems. These findings provide new information for understanding the complexity of glycinergic functions in the human brain, which will translate into the contribution of inhibitory mechanisms in paroxysmal disorders and neurodegenerative diseases such as Epilepsy, Huntington's and Parkinson's Disease and Motor Neuron Disease.
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Affiliation(s)
- Kristin Baer
- Molecular Neuroscience, Institute of Life Science, School of Medicine, Swansea University Swansea, UK
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