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Kovaříková V, Špirková A, Šefčíková Z, Pisko J, Kalatová L, Koppel J, Fabian D, Čikoš Š. Gamma-aminobutyric acid (GABA) can affect physiological processes in preimplantation embryos via GABA A and GABA B receptors. Reprod Med Biol 2023; 22:e12528. [PMID: 37476368 PMCID: PMC10354355 DOI: 10.1002/rmb2.12528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 06/08/2023] [Accepted: 07/07/2023] [Indexed: 07/22/2023] Open
Abstract
Purpose Several widely used substances (e.g., some therapeutics or food supplements) can act on gamma-aminobutyric acid (GABA) receptors, and we investigated whether the activation of these receptors could affect the preimplantation embryo. Methods Transcripts of all GABA receptor subunits and selected proteins were examined using quantitative RT-PCR and immunohistochemistry. To analyze the effects of receptor activation, in vitro culture of mouse preimplantation embryos with natural and synthetic GABA receptor ligands was used. Results We detected nine GABA receptor transcripts in mouse blastocysts and 14 GABA receptor transcripts in ovulated oocytes. The results of this study indicate that ionotropic GABAA receptors can be formed from α5, β3, and γ3 (or δ, π) subunits, GABAA-ρ receptors can be formed from ρ2 subunits and metabotropic GABA receptors can be formed from GABAB1b and GABAB2 subunits in mouse blastocysts. Supplementing the culture medium with GABA at concentrations of 2-10 mM or with specific GABAA and GABAB receptor agonists (at concentrations of 10-100 μM) significantly increased the proportion of dead cells in blastocysts. The GABA-induced effects were prevented by pretreatment of embryos with GABAA and GABAB receptor antagonists. Conclusion The results of this study indicate that GABA and synthetic GABA receptor ligands can negatively affect preimplantation embryos via GABAA and GABAB receptors.
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Affiliation(s)
- Veronika Kovaříková
- Institute of Animal PhysiologyCentre of Biosciences of the Slovak Academy of SciencesKošiceSlovakia
| | - Alexandra Špirková
- Institute of Animal PhysiologyCentre of Biosciences of the Slovak Academy of SciencesKošiceSlovakia
| | - Zuzana Šefčíková
- Institute of Animal PhysiologyCentre of Biosciences of the Slovak Academy of SciencesKošiceSlovakia
| | - Jozef Pisko
- Institute of Animal PhysiologyCentre of Biosciences of the Slovak Academy of SciencesKošiceSlovakia
| | - Laura Kalatová
- Institute of Animal PhysiologyCentre of Biosciences of the Slovak Academy of SciencesKošiceSlovakia
| | - Juraj Koppel
- Institute of Animal PhysiologyCentre of Biosciences of the Slovak Academy of SciencesKošiceSlovakia
| | - Dušan Fabian
- Institute of Animal PhysiologyCentre of Biosciences of the Slovak Academy of SciencesKošiceSlovakia
| | - Štefan Čikoš
- Institute of Animal PhysiologyCentre of Biosciences of the Slovak Academy of SciencesKošiceSlovakia
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2
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Abstract
GABAB receptors are implicated in numerous central nervous system-based behaviours and mechanisms, including cognitive processing in preclinical animal models. Homeostatic changes in the expression and function of these receptors across brain structures have been found to affect cognitive processing. Numerous preclinical studies have focused on the role of GABAB receptors in learning, memory and cognition per se with some interesting, although sometimes contradictory, findings. The majority of the existing clinical literature focuses on alterations in GABAB receptor function in conditions and disorders whose main symptomatology includes deficits in cognitive processing. The aim of this chapter is to delineate the role of GABAB receptors in cognitive processes in health and disease of animal models and human clinical populations. More specifically, this review aims to present literature on the role of GABAB receptors in animal models with cognitive deficits, especially those of learning and memory. Further, it aims to capture the progress and advances of research studies on the effects of GABAB receptor compounds in neurodevelopmental and neurodegenerative conditions with cognitive dysfunctions. The neurodevelopmental conditions covered include autism spectrum disorders, fragile X syndrome and Down's syndrome and the neurodegenerative conditions discussed are Alzheimer's disease, epilepsy and autoimmune anti-GABAB encephalitis. Although some findings are contradictory, results indicate a possible therapeutic role of GABAB receptor compounds for the treatment of cognitive dysfunction and learning/memory impairments for some of these conditions, especially in neurodegeneration. Moreover, future research efforts should aim to develop selective GABAB receptor compounds with minimal, if any, side effects.
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Adkins JM, Lynch J, Gray M, Jasnow AM. Presynaptic GABA B receptor inhibition sex dependently enhances fear extinction and attenuates fear renewal. Psychopharmacology (Berl) 2021; 238:2059-2071. [PMID: 33855580 PMCID: PMC8295214 DOI: 10.1007/s00213-021-05831-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 03/22/2021] [Indexed: 12/11/2022]
Abstract
Anxiety and trauma-related disorders are highly prevalent worldwide, and are associated with altered associative fear learning. Despite the effectiveness of exposure therapy, which aims to reduce associative fear responses, relapse rates remain high. This is due, in part, to the context specificity of exposure therapy, which is a form of extinction. Many studies show that fear relapses when mice are tested outside the extinction context, and this is known as fear renewal. Using Pavlovian fear conditioning and extinction, we can study the mechanisms underlying extinction and renewal. The aim of the current experiment was to identify the role of presynaptic GABAB receptors in these two processes. Previous work from our lab showed that genetic deletion or pharmacological inhibition of GABAB(1a) receptors that provide presynaptic inhibition on glutamatergic terminals reduces context specificity and leads to generalization. We therefore hypothesized that inactivation of these presynaptic GABAB receptors could be used to reduce the context specificity associated with fear extinction training and suppress renewal when mice are tested outside of the extinction context. Using CGP 36216, an antagonist specific for presynaptic GABAB receptors, we blocked presynaptic GABAB receptors using intracerebroventricular injections during various time points of extinction learning in male and female mice. Results showed that blocking these receptors pre- and post-extinction training led to enhanced extinction learning in male mice only. We also found that post-extinction infusions of CGP reduced renewal rates in male mice when they were tested outside of the extinction context. In an attempt to localize the function of presynaptic GABAB receptors within regions of the extinction circuit, we infused CGP locally within the basolateral amygdala or dorsal hippocampus. We failed to reduce renewal when CGP was infused directly within these regions, suggesting that presynaptic inhibition within these regions per se may not be necessary for driving context specificity during extinction learning. Together, these results show an important sex-dependent role of presynaptic GABAB receptors in extinction and renewal processes and identify a novel receptor target that may be used to design pharmacotherapies to enhance the effectiveness of exposure therapy.
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Affiliation(s)
- Jordan M Adkins
- Department of Psychological Sciences, Kent State University, Kent, OH, 44242, USA
- Brain Health Research Institute, Kent State University, Kent, OH, 44242, USA
| | - Joseph Lynch
- Department of Psychological Sciences, Kent State University, Kent, OH, 44242, USA
- Brain Health Research Institute, Kent State University, Kent, OH, 44242, USA
| | - Michael Gray
- Department of Psychological Sciences, Kent State University, Kent, OH, 44242, USA
- Brain Health Research Institute, Kent State University, Kent, OH, 44242, USA
| | - Aaron M Jasnow
- Department of Psychological Sciences, Kent State University, Kent, OH, 44242, USA.
- Brain Health Research Institute, Kent State University, Kent, OH, 44242, USA.
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, 6439 Garners Ferry Road, Columbia, SC, 29209, USA.
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Behuet S, Cremer JN, Cremer M, Palomero-Gallagher N, Zilles K, Amunts K. Developmental Changes of Glutamate and GABA Receptor Densities in Wistar Rats. Front Neuroanat 2019; 13:100. [PMID: 31920569 PMCID: PMC6933313 DOI: 10.3389/fnana.2019.00100] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 12/02/2019] [Indexed: 12/02/2022] Open
Abstract
Neurotransmitters and their receptors are key molecules of signal transduction and subject to various changes during pre- and postnatal development. Previous studies addressed ontogeny at the level of neurotransmitters and expression of neurotransmitter receptor subunits. However, developmental changes in receptor densities to this day are not well understood. Here, we analyzed developmental changes in excitatory glutamate and inhibitory γ-aminobutyric acid (GABA) receptors in adjacent sections of the rat brain by means of quantitative in vitro receptor autoradiography. Receptor densities of the ionotropic glutamatergic receptors α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), kainate and N-methyl-D-aspartate (NMDA) as well as of the ionotropic GABAA and metabotropic GABAB receptors were investigated using specific high-affinity ligands. For each receptor binding site, significant density differences were demonstrated in the investigated regions of interest [olfactory bulb, striatum, hippocampus, and cerebellum] and developmental stages [postnatal day (P) 0, 10, 20, 30 and 90]. In particular, we showed that the glutamatergic and GABAergic receptor densities were already present between P0 and P10 in all regions of interest, which may indicate the early relevance of these receptors for brain development. A transient increase of glutamatergic receptor densities in the hippocampus was found, indicating their possible involvement in synaptic plasticity. We demonstrated a decline of NMDA receptor densities in the striatum and hippocampus from P30 to P90, which could be due to synapse elimination, a process that redefines neuronal networks in postnatal brains. Furthermore, the highest increase in GABAA receptor densities from P10 to P20 coincides with the developmental shift from excitatory to inhibitory GABA transmission. Moreover, the increase from P10 to P20 in GABAA receptor densities in the cerebellum corresponds to a point in time when functional GABAergic synapses are formed. Taken together, the present data reveal differential changes in glutamate and GABA receptor densities during postnatal rat brain development, which may contribute to their specific functions during ontogenesis, thus providing a deeper understanding of brain ontogenesis and receptor function.
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Affiliation(s)
- Sabrina Behuet
- Institute of Neuroscience and Medicine (INM-1), Jülich Research Centre, Jülich, Germany
| | | | - Markus Cremer
- Institute of Neuroscience and Medicine (INM-1), Jülich Research Centre, Jülich, Germany
| | - Nicola Palomero-Gallagher
- Institute of Neuroscience and Medicine (INM-1), Jülich Research Centre, Jülich, Germany.,Cécile and Oskar Vogt Institute of Brain Research, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany
| | - Karl Zilles
- Institute of Neuroscience and Medicine (INM-1), Jülich Research Centre, Jülich, Germany
| | - Katrin Amunts
- Institute of Neuroscience and Medicine (INM-1), Jülich Research Centre, Jülich, Germany.,Cécile and Oskar Vogt Institute of Brain Research, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany
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5
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Martínez-Campos Z, Pastor N, Pineda-Urbina K, Gómez-Sandoval Z, Fernández-Zertuche M, Razo-Hernández RS. In silico structure-based design of GABA B receptor agonists using a combination of docking and QSAR. Chem Biol Drug Des 2019; 94:1782-1798. [PMID: 31207116 DOI: 10.1111/cbdd.13580] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/29/2019] [Accepted: 06/02/2019] [Indexed: 12/27/2022]
Abstract
The study of γ-aminobutyric acid B receptor (GABAB ) activation is of great interest for several brain disorders. The search of new GABAB receptor agonists has been carried out by many research groups. As a result, Baclofen has become the prototypical GABAB receptor agonist. However, several attempts have been made to modify its structure to generate derivatives with improved activity. In this work, we carried out a theoretical and computational study for a wide range of GABAB receptor agonists reported in the literature. Molecular docking and QSAR techniques were combined by using the interaction energies of the agonists with the key residues of GABAB receptor, as molecular descriptors for the QSAR construction. The resulting mathematical model suggests that the activity of GABAB receptor agonists is influenced by three factors: their shape and molecular size (PW5 and PJI2), their constitutional features (ELUMO and T(N…O)) and the energy interaction with GABAB receptor (ETRP278 ). This model was validated by the QUIK, REDUNDANCY and OVERFITTING rules, and its predicted ability was tasted by the QLOO , QASYM , R 0 2 and r m 2 rules. Finally, six new compounds are proposed (35-40) with high potential to be used as GABAB receptor agonists.
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Affiliation(s)
- Zuleyma Martínez-Campos
- Instituto de Investigación en Ciencias Básicas y Aplicadas, Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
| | - Nina Pastor
- Instituto de Investigación en Ciencias Básicas y Aplicadas, Centro de Investigación en Dinámica Celular, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
| | | | | | - Mario Fernández-Zertuche
- Instituto de Investigación en Ciencias Básicas y Aplicadas, Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
| | - Rodrigo Said Razo-Hernández
- Instituto de Investigación en Ciencias Básicas y Aplicadas, Centro de Investigación en Dinámica Celular, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
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Bernstein DL, Nayak SU, Oliver CF, Rawls SM, Rom S. Methylenedioxypyrovalerone (MDPV) impairs working memory and alters patterns of dopamine signaling in mesocorticolimbic substrates. Neurosci Res 2019; 155:56-62. [PMID: 31302200 DOI: 10.1016/j.neures.2019.07.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 06/30/2019] [Accepted: 07/10/2019] [Indexed: 02/06/2023]
Abstract
Knowledge remains limited about how chronic cathinone exposure impacts dopamine systems in brain reward circuits. In the present study, a binge-like MDPV exposure that impaired novel object recognition (NOR) dysregulated dopamine markers in mesocorticolimbic substrates of rats, with especially profound effects on D1 and D2 receptor's and VMAT gene expression. Our data suggested that dopamine receptivity was reduced in the NAc but increased in the PFC and dopamine-producing VTA. The MDPV-induced impairment of NOR was prevented by a D1 receptor antagonist, suggesting that chronic MDPV exposure produces site-specific dysregulation of dopamine markers in the mesocorticolimbic circuit and memory deficits in the NOR test that are influenced by D1 receptors.
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Affiliation(s)
- David L Bernstein
- Department of Pathology and Laboratory Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Sunyl U Nayak
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Chicora F Oliver
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Scott M Rawls
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA; Department of Pharmacology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Slava Rom
- Department of Pathology and Laboratory Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA; Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA.
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7
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HOLAJOVA M, FRANEK M. Effect of Short- and Long-Term Administration of Baclofen on Spatial Learning and Memory in Rats. Physiol Res 2018; 67:133-141. [DOI: 10.33549/physiolres.933554] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Baclofen is the only clinically available metabotropic GABAB receptor agonist. In our experiment, we tested the hypothesis that long-term baclofen administration can impair learning and memory in rats. The experiment consisted of three parts. In the first part of the study the drug was administered simultaneously with the beginning of the behavioral tests. In the second and third part of the experiment baclofen was administered daily for 14 days and for one month before the tests. In each part of the experiment, adult rats were randomly divided into four treatment groups. Three groups were given an injection of baclofen at doses of 1 mg/kg, 5 mg/kg, 10 mg/kg, while the fourth group was injected with saline. The injections were given after each session. Spatial learning and memory were tested using the Morris water maze, involving three types of tests: Acquisition, Probe, and Re-acquisition. This work reveals that baclofen did not affect spatial learning at any of the tested doses and regardless of the length of administration. Memory was observed to be affected, but only at the highest dose of baclofen and only temporarily. This conclusion is in line with previously published clinical cases.
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Affiliation(s)
- M. HOLAJOVA
- Department of Normal, Pathological and Clinical Physiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic
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8
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Ebrahimi-Ghiri M, Rostampour M, Jamshidi-Mehr M, Nasehi M, Zarrindast MR. Role of CA1 GABAA and GABAB receptors on learning deficit induced by D-AP5 in passive avoidance step-through task. Brain Res 2018; 1678:164-173. [DOI: 10.1016/j.brainres.2017.10.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 06/24/2017] [Accepted: 10/03/2017] [Indexed: 10/18/2022]
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9
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Melandrii Herba Extract Attenuates H₂O₂-Induced Neurotoxicity in Human Neuroblastoma SH-SY5Y Cells and Scopolamine-Induced Memory Impairment in Mice. Molecules 2017; 22:molecules22101646. [PMID: 28973972 PMCID: PMC6151539 DOI: 10.3390/molecules22101646] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 09/20/2017] [Accepted: 09/26/2017] [Indexed: 12/21/2022] Open
Abstract
Oxidative stress plays a significant role in the etiology of a variety of neurodegenerative diseases. In this study, we found that Melandrii Herba extract (ME) attenuated oxidative-induced damage in cells. Mechanistically, ME exhibited protection from H2O2-induced neurotoxicity via caspase-3 inactivation, Bcl-2 downregulation, Bax upregulation, and MAPK activation (ERK 1/2, JNK 1/2, and p38 MAPK) in vitro. Moreover, our in vivo data showed that ME was able to attenuate scopolamine-induced cognitive impairment. These results provide in vitro and in vivo evidence that ME exhibits neuroprotective properties against oxidative stress, which suggests that ME is worthy of further investigation as a complementary, or even as an alternative, product for preventing and treating neurodegenerative disorders.
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Towards a Better Understanding of GABAergic Remodeling in Alzheimer's Disease. Int J Mol Sci 2017; 18:ijms18081813. [PMID: 28825683 PMCID: PMC5578199 DOI: 10.3390/ijms18081813] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 08/16/2017] [Accepted: 08/17/2017] [Indexed: 12/18/2022] Open
Abstract
γ-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the vertebrate brain. In the past, there has been a major research drive focused on the dysfunction of the glutamatergic and cholinergic neurotransmitter systems in Alzheimer’s disease (AD). However, there is now growing evidence in support of a GABAergic contribution to the pathogenesis of this neurodegenerative disease. Previous studies paint a complex, convoluted and often inconsistent picture of AD-associated GABAergic remodeling. Given the importance of the GABAergic system in neuronal function and homeostasis, in the maintenance of the excitatory/inhibitory balance, and in the processes of learning and memory, such changes in GABAergic function could be an important factor in both early and later stages of AD pathogenesis. Given the limited scope of currently available therapies in modifying the course of the disease, a better understanding of GABAergic remodeling in AD could open up innovative and novel therapeutic opportunities.
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GABA B receptor modulation — to B or not to be B a pro-cognitive medicine? Curr Opin Pharmacol 2017; 35:125-132. [DOI: 10.1016/j.coph.2017.09.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 09/26/2017] [Indexed: 11/20/2022]
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12
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Jacobson LH, Hoyer D, Fehlmann D, Bettler B, Kaupmann K, Cryan JF. Blunted 5-HT 1A receptor-mediated responses and antidepressant-like behavior in mice lacking the GABA B1a but not GABA B1b subunit isoforms. Psychopharmacology (Berl) 2017; 234:1511-1523. [PMID: 28070618 DOI: 10.1007/s00213-016-4521-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Accepted: 12/19/2016] [Indexed: 12/13/2022]
Abstract
RATIONALE There is accumulating evidence for a role of GABAB receptors in depression. GABAB receptors are heterodimers of GABAB1 and GABAB2 receptor subunits. The predominant GABAB1 subunit isoforms are GABAB1a and GABAB1b. GABAB1 isoforms in mice differentially influence cognition, conditioned fear, and susceptibility to stress, yet their influence in tests of antidepressant-like activity has not been fully investigated. OBJECTIVES Given the interactions between GABAB receptors and the serotonergic system and the involvement of 5-HT1A receptors (5-HT1AR) in antidepressant action, we sought to evaluate 5-HT1AR function in GABAB1a-/- and GABAB1b-/- mice. METHODS GABAB1a-/- and GABAB1b-/- mice were assessed in the forced swim test (FST), and body temperature and hypothalamic-pituitary-adrenal (HPA) responses to the 5-HT1AR agonist 8-OH-DPAT were determined. Brain 5-HT1AR expression was assessed by [3H]-MPPF and [3H]-8-OH-DPAT autoradiography and 5-HT1AR G-protein coupling by [35S]GTP-γ-S autoradiography. RESULTS As previously described, GABAB1a-/- mice showed an antidepressant-like profile in the FST. GABAB1a-/- mice also demonstrated profoundly blunted hypothermic and motoric responses to 8-OH-DPAT. Furthermore, 8-OH-DPAT-induced corticosterone and adrenocorticotropic hormone (ACTH) release were both attenuated in GABAB1a-/- mice. Interestingly, [3H]-MPPF and [3H]-8-OH-DPAT binding was largely unaffected by genotype. [35S]GTP-γ-S autoradiography suggested that altered 5-HT1AR G-protein coupling only partially contributes to the functional presynaptic 5-HT1AR desensitization, and not at all to the blunted postsynaptic 5-HT1AR-mediated responses, seen in GABAB1a-/- mice. CONCLUSION These data demonstrate distinct functional links between 5-HT1ARs and the GABAB1a subunit isoform and suggest that the GABAB1a isoform may be implicated in the antidepressant-like effects of GABAB receptor antagonists and in neurobiological mechanisms underlying depression.
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Affiliation(s)
- Laura H Jacobson
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia.
- Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, VIC, 3052, Australia.
| | - Daniel Hoyer
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia
- Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, VIC, 3052, Australia
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Dominique Fehlmann
- Autoimmunity, Transplantation and Inflammation, Novartis Institutes for BioMedical Research, Novartis Pharma AG, CH-4002, Basel, Switzerland
| | - Bernhard Bettler
- Department of Biomedicine, Pharmazentrum, University of Basel, CH-4056, Basel, Switzerland
| | - Klemens Kaupmann
- Autoimmunity, Transplantation and Inflammation, Novartis Institutes for BioMedical Research, Novartis Pharma AG, CH-4002, Basel, Switzerland
| | - John F Cryan
- APC Microbiome Institute, University College Cork, Cork, Ireland.
- Department of Anatomy and Neuroscience, University College Cork, Western Gateway Building, Cork, Ireland.
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13
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Hippocampal GABA B(1a) Receptors Constrain Generalized Contextual Fear. Neuropsychopharmacology 2017; 42:914-924. [PMID: 27834391 PMCID: PMC5312073 DOI: 10.1038/npp.2016.255] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 11/01/2016] [Accepted: 11/04/2016] [Indexed: 12/16/2022]
Abstract
Many anxiety disorders are characterized by generalization of fear responses to neutral or ambiguous stimuli. Therefore, a comprehensive understanding of the mechanisms contributing to generalized fear is essential for formulating successful treatments for anxiety disorders. Previous research shows that GABA-mediated presynaptic inhibition has a critical role in cued fear generalization, as animals with genetically deleted presynaptic GABAB(1a) receptors cannot discriminate between CS+ and CS- tones. Work from our laboratory has further identified that GABAB(1a) receptors are necessary for maintaining contextual memory precision, thereby constraining generalized contextual fear. We previously found that GABAB(1a) KO mice show generalized fear to a neutral context 24 h after training, but not 2 h after training. A similar pattern was observed with object location and recognition, suggesting that this receptor subtype affects consolidation and/or retrieval of precise contextual and spatial memories. Here we sought to specifically examine the involvement of GABAB(1a) receptors in consolidation or retrieval of a precise fear memory. To do so, we infused a selective GABAB(1a) receptor antagonist, CGP 36216, intracerebroventricularly (ICV), or locally into the dorsal hippocampus, ventral hippocampus, or anterior cingulate cortex (ACC), during consolidation and retrieval of context fear training. Blockade of GABAB(1a) receptors through ICV, dorsal hippocampal, or ventral hippocampal infusions 'after' training (consolidation) resulted in fear generalization to the neutral context when mice were tested 24, but not 6 h after training. Post-training infusions of CGP into the ACC, however, did not promote generalized fear. In addition, ICV, dorsal hippocampal, ventral hippocampal, or ACC infusions immediately 'before' testing (retrieval) did not result in context fear generalization. These data suggest that GABA-mediated presynaptic inhibition is not critical for retrieval of precise contextual memory, but rather has an important role in the long-term consolidation of precise contextual memories and constrains generalized fear responses.
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14
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Malaspina P, Roullet JB, Pearl PL, Ainslie GR, Vogel KR, Gibson KM. Succinic semialdehyde dehydrogenase deficiency (SSADHD): Pathophysiological complexity and multifactorial trait associations in a rare monogenic disorder of GABA metabolism. Neurochem Int 2016; 99:72-84. [PMID: 27311541 DOI: 10.1016/j.neuint.2016.06.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 06/09/2016] [Accepted: 06/10/2016] [Indexed: 12/21/2022]
Abstract
Discovered some 35 years ago, succinic semialdehyde dehydrogenase deficiency (SSADHD) represents a rare, autosomal recessively-inherited defect in the second step of the GABA degradative pathway. Some 200 patients have been reported, with broad phenotypic and genotypic heterogeneity. SSADHD represents an unusual neurometabolic disorder in which two neuromodulatory agents, GABA (and the GABA analogue, 4-hydroxybutyrate), accumulate to supraphysiological levels. The unexpected occurrence of epilepsy in several patients is counterintuitive in view of the hyperGABAergic state, in which sedation might be expected. However, the epileptic status of some patients is most likely represented by broader imbalances of GABAergic and glutamatergic neurotransmission. Cumulative research encompassing decades of basic and clinical study of SSADHD reveal a monogenic disease with broad pathophysiological and clinical phenotypes. Numerous metabolic perturbations unmasked in SSADHD include alterations in oxidative stress parameters, dysregulation of autophagy and mitophagy, dysregulation of both inhibitory and excitatory neurotransmitters and gene expression, and unique subsets of SNP alterations of the SSADH gene (so-called ALDH5A1, or aldehyde dehydrogenase 5A1 gene) on the 6p22 chromosomal arm. While seemingly difficult to collate and interpret, these anomalies have continued to open novel pathways for pharmacotherapeutic considerations. Here, we present an update on selected aspects of SSADHD, the ALDH5A1 gene, and future avenues for research on this rare disorder of GABA metabolism.
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Affiliation(s)
- P Malaspina
- Department of Biology, University "Tor Vergata", Rome, Italy
| | - J-B Roullet
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane, WA, USA
| | - P L Pearl
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - G R Ainslie
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane, WA, USA
| | - K R Vogel
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane, WA, USA
| | - K M Gibson
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane, WA, USA.
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Hill AT, Rogasch NC, Fitzgerald PB, Hoy KE. TMS-EEG: A window into the neurophysiological effects of transcranial electrical stimulation in non-motor brain regions. Neurosci Biobehav Rev 2016; 64:175-84. [DOI: 10.1016/j.neubiorev.2016.03.006] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 01/10/2023]
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Jacobson LH, Sweeney FF, Kaupmann K, O’Leary OF, Gassmann M, Bettler B, Cryan JF. Differential roles of GABAB1 subunit isoforms on locomotor responses to acute and repeated administration of cocaine. Behav Brain Res 2016; 298:12-6. [DOI: 10.1016/j.bbr.2015.10.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 10/16/2015] [Accepted: 10/20/2015] [Indexed: 12/23/2022]
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Role of GABA(B) receptors in learning and memory and neurological disorders. Neurosci Biobehav Rev 2016; 63:1-28. [PMID: 26814961 DOI: 10.1016/j.neubiorev.2016.01.007] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 12/31/2015] [Accepted: 01/21/2016] [Indexed: 01/13/2023]
Abstract
Although it is evident from the literature that altered GABAB receptor function does affect behavior, these results often do not correspond well. These differences could be due to the task protocol, animal strain, ligand concentration, or timing of administration utilized. Because several clinical populations exhibit learning and memory deficits in addition to altered markers of GABA and the GABAB receptor, it is important to determine whether altered GABAB receptor function is capable of contributing to the deficits. The aim of this review is to examine the effect of altered GABAB receptor function on synaptic plasticity as demonstrated by in vitro data, as well as the effects on performance in learning and memory tasks. Finally, data regarding altered GABA and GABAB receptor markers within clinical populations will be reviewed. Together, the data agree that proper functioning of GABAB receptors is crucial for numerous learning and memory tasks and that targeting this system via pharmaceuticals may benefit several clinical populations.
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Kasten CR, Boehm SL. Identifying the role of pre-and postsynaptic GABA(B) receptors in behavior. Neurosci Biobehav Rev 2015; 57:70-87. [PMID: 26283074 DOI: 10.1016/j.neubiorev.2015.08.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 06/18/2015] [Accepted: 08/09/2015] [Indexed: 12/15/2022]
Abstract
Although many reviews exist characterizing the molecular differences of GABAB receptor isoforms, there is no current review of the in vivo effects of these isoforms. The current review focuses on whether the GABAB1a and GABAB1b isoforms contribute differentially to behaviors in isoform knockout mice. The roles of these receptors have primarily been characterized in cognitive, anxiety, and depressive phenotypes. Currently, the field supports a role of GABAB1a in memory maintenance and protection against an anhedonic phenotype, whereas GABAB1b appears to be involved in memory formation and a susceptibility to developing an anhedonic phenotype. Although GABAB receptors have been strongly implicated in drug abuse phenotypes, no isoform-specific work has been done in this field. Future directions include developing site-specific isoform knockdown to identify the role of different brain regions in behavior, as well as identifying how these isoforms are involved in development of behavioral phenotypes.
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Affiliation(s)
- Chelsea R Kasten
- Department of Psychology, Indianapolis University Purdue University-Indianapolis, 402N Blackford St LD 124, Indianapolis, IN 46202, United States.
| | - Stephen L Boehm
- Department of Psychology, Indianapolis University Purdue University-Indianapolis, 402N Blackford St LD 124, Indianapolis, IN 46202, United States; Indiana Alcohol Research Center, 545 Barnhill Drive EH 317, Indianapolis, IN, United States.
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Foster JD, Kitchen I, Bettler B, Chen Y. GABAB receptor subtypes differentially modulate synaptic inhibition in the dentate gyrus to enhance granule cell output. Br J Pharmacol 2015. [PMID: 23186302 DOI: 10.1111/bph.12073] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Activation of GABAB receptors in the dentate gyrus (DG) enhances granule cell (GC) activity by reducing synaptic inhibition imposed by hilar interneurons. This disinhibitory action facilitates signal transfer from the perforant path to the hippocampus. However, as the two main molecular subtypes, GABA(B(1a,2)) and GABA(B(1b,2)) receptors, prefer axonal terminal and dendritic compartments, respectively, they may modulate the hilar pathways at different synaptic localizations. We examined their relative expression and functions in the DG. EXPERIMENTAL APPROACH The localization of GABAB subtypes was revealed immunohistochemically using subunit-selective antibodies in GABA(B1a)(-/-) and GABA(B1b)(-/-) mice. Effects of subtype activation by the GABAB receptor agonist, baclofen, were examined on the perforant path-stimulated GC population activities in brain slices. KEY RESULTS GABA(B(1a,2)) receptors were concentrated in the inner molecular layer, the neuropil of the hilus and hilar neurons at the border zone; while GABA(B(1b,2)) receptors dominated the outer molecular layer and hilar neurons in the deep layer, showing their differential localization on GC dendrite and in the hilus. Baclofen enhanced the GC population spike to a larger extent in the GABA(B1b)(-/-) mice, demonstrating exclusively disinhibitory roles of the GABA(B(1a,2)) receptors. Conversely, in the GABA(B1a)(-/-) mice baclofen not only enhanced but also inhibited the population spike during GABAA blockade, revealing both disinhibitory and inhibitory effects of GABA(B(1b,2)) receptors. CONCLUSIONS AND IMPLICATIONS The GABA(B(1a,2)) and GABA(B(1b,2)) receptor subtypes differentially modulate GC outputs via selective axonal terminal and dendritic locations in the hilar pathways. The GABA(B(1a,2)) receptors exclusively mediate disinhibition, thereby playing a greater role in gating signal transfer for hippocampal spatial and pattern learning.
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Affiliation(s)
- Joshua D Foster
- Department of Biochemistry and Physiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
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Vagal pathways for microbiome-brain-gut axis communication. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 817:115-33. [PMID: 24997031 DOI: 10.1007/978-1-4939-0897-4_5] [Citation(s) in RCA: 307] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
There is now strong evidence from animal studies that gut microorganism can activate the vagus nerve and that such activation plays a critical role in mediating effects on the brain and behaviour. The vagus appears to differentiate between non-pathogenic and potentially pathogenic bacteria even in the absence of overt inflammation and vagal pathways mediate signals that can induce both anxiogenic and anxiolytic effects, depending on the nature of the stimulus. Certain vagal signals from the gut can instigate an anti-inflammatory reflex with afferent signals to the brain activating an efferent response, releasing mediators including acetylcholine that, through an interaction with immune cells, attenuates inflammation. This immunomodulatory role of the vagus nerve may also have consequences for modulation of brain function and mood.What is currently lacking are relevant data on the electrophysiology of the system. Certainly, important advances in our understanding of the gut-brain and microbiome- gut-brain axis will come from studies of how distinct microbial and nutritional stimuli activate the vagus and the nature of the signals transmitted to the brain that lead to differential changes in the neurochemistry of the brain and behaviour.Understanding the induction and transmission of signals in the vagus nerve may have important implications for the development of microbial-or nutrition based therapeutic strategies for mood disorders.
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GABAB(1) receptor subunit isoforms differentially regulate stress resilience. Proc Natl Acad Sci U S A 2014; 111:15232-7. [PMID: 25288769 DOI: 10.1073/pnas.1404090111] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Stressful life events increase the susceptibility to developing psychiatric disorders such as depression; however, many individuals are resilient to such negative effects of stress. Determining the neurobiology underlying this resilience is instrumental to the development of novel and more effective treatments for stress-related psychiatric disorders. GABAB receptors are emerging therapeutic targets for the treatment of stress-related disorders such as depression. These receptors are predominantly expressed as heterodimers of a GABAB(2) subunit with either a GABAB(1a) or a GABAB(1b) subunit. Here we show that mice lacking the GABAB(1b) receptor isoform are more resilient to both early-life stress and chronic psychosocial stress in adulthood, whereas mice lacking GABAB(1a) receptors are more susceptible to stress-induced anhedonia and social avoidance compared with wild-type mice. In addition, increased hippocampal expression of the GABAB(1b) receptor subunit is associated with a depression-like phenotype in the helpless H/Rouen genetic mouse model of depression. Stress resilience in GABAB(1b)(-/-) mice is coupled with increased proliferation and survival of newly born cells in the adult ventral hippocampus and increased stress-induced c-Fos activation in the hippocampus following early-life stress. Taken together, the data suggest that GABAB(1) receptor subunit isoforms differentially regulate the deleterious effects of stress and, thus, may be important therapeutic targets for the treatment of depression.
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Cullen PK, Dulka BN, Ortiz S, Riccio DC, Jasnow AM. GABA-mediated presynaptic inhibition is required for precision of long-term memory. Learn Mem 2014; 21:180-4. [PMID: 24634352 PMCID: PMC3966537 DOI: 10.1101/lm.032961.113] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 01/07/2014] [Indexed: 12/29/2022]
Abstract
Though much attention has been given to the neural structures that underlie the long-term consolidation of contextual memories, little is known about the mechanisms responsible for the maintenance of memory precision. Here, we demonstrate a rapid time-dependent decline in memory precision in GABAB(1a) receptor knockout mice. First, we show that GABAB(1a) receptors are required for the maintenance, but not encoding, of a precise fear memory. We then demonstrate that GABAB(1a) receptors are required for the maintenance, but not encoding, of spatial memories. Our findings suggest that GABA-mediated presynaptic inhibition regulates the maintenance of memory precision as a function of memory age.
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Affiliation(s)
| | | | | | | | - Aaron M. Jasnow
- Department of Psychology, Kent State University, Kent, Ohio 44242, USA
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Sweeney FF, O’Leary OF, Cryan JF. GABAB receptor ligands do not modify conditioned fear responses in BALB/c mice. Behav Brain Res 2013; 256:151-6. [DOI: 10.1016/j.bbr.2013.07.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 07/21/2013] [Indexed: 01/15/2023]
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Forsythe P, Kunze WA. Voices from within: gut microbes and the CNS. Cell Mol Life Sci 2013; 70:55-69. [PMID: 22638926 PMCID: PMC11113561 DOI: 10.1007/s00018-012-1028-z] [Citation(s) in RCA: 213] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 05/03/2012] [Accepted: 05/07/2012] [Indexed: 02/07/2023]
Abstract
Recent advances in research have greatly increased our understanding of the importance of the gut microbiota. Bacterial colonization of the intestine is critical to the normal development of many aspects of physiology such as the immune and endocrine systems. It is emerging that the influence of the gut microbiota also extends to modulation of host neural development. Furthermore, the overall balance in composition of the microbiota, together with the influence of pivotal species that induce specific responses, can modulate adult neural function, peripherally and centrally. Effects of commensal gut bacteria in adult animals include protection from the central effects of infection and inflammation as well as modulation of normal behavioral responses. There is now robust evidence that gut bacteria influence the enteric nervous system, an effect that may contribute to afferent signaling to the brain. The vagus nerve has also emerged as an important means of communicating signals from gut bacteria to the CNS. Further understanding of the mechanisms underlying microbiome-gut-brain communication will provide us with new insight into the symbiotic relationship between gut microbiota and their mammalian hosts and help us identify the potential for microbial-based therapeutic strategies to aid in the treatment of mood disorders.
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Affiliation(s)
- Paul Forsythe
- The Brain-Body Institute, St. Joseph's Healthcare, McMaster University, 50 Charlton Avenue East, T3302, Hamilton, ON, L8N 4A6, Canada.
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Abstract
PURPOSE OF REVIEW Interest in the microbiota-gut-brain axis is increasing apace and what was, not so long ago, a hypothetical relationship is emerging as a potentially critical factor in the regulation of intestinal and mental health. Studies are now addressing the neural circuitry and mechanisms underlying the influence of gut bacteria on the central nervous system and behavior. RECENT FINDINGS Gut bacteria influence development of the central nervous systems (CNS) and stress responses. In adult animals, the overall composition of the microbiota or exposure to specific bacterial strains can modulate neural function, peripherally and centrally. Gut bacteria can provide protection from the central effects of infection and inflammation as well as modulate normal behavioral responses. Behavioral effects described to date are largely related to stress and anxiety and an altered hypothalamus-pituitary-adrenal axis response is a common observation in many model systems. The vagus nerve has also emerged as an important means of communicating signals from gut microbes to the CNS. SUMMARY Studies of microbiota-gut-brain communication are providing us with a deeper understanding of the relationship between the gut bacteria and their hosts while also suggesting the potential for microbial-based therapeutic strategies that may aid in the treatment of mood disorders.
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Gassmann M, Bettler B. Regulation of neuronal GABA(B) receptor functions by subunit composition. Nat Rev Neurosci 2012; 13:380-94. [PMID: 22595784 DOI: 10.1038/nrn3249] [Citation(s) in RCA: 248] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
GABA(B) receptors (GABA(B)Rs) are G protein-coupled receptors for GABA, the main inhibitory neurotransmitter in the CNS. In the past 5 years, notable advances have been made in our understanding of the molecular composition of these receptors. GABA(B)Rs are now known to comprise principal and auxiliary subunits that influence receptor properties in distinct ways. The principal subunits regulate the surface expression and the axonal versus dendritic distribution of these receptors, whereas the auxiliary subunits determine agonist potency and the kinetics of the receptor response. This Review summarizes current knowledge on how the subunit composition of GABA(B)Rs affects the distribution of these receptors, neuronal processes and higher brain functions.
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Affiliation(s)
- Martin Gassmann
- Department of Biomedicine, Institute of Physiology, University of Basel, Klingelbergstr. 50-70, 4056 Basel, Switzerland.
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Bravo JA, Forsythe P, Chew MV, Escaravage E, Savignac HM, Dinan TG, Bienenstock J, Cryan JF. Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. Proc Natl Acad Sci U S A 2011; 108:16050-5. [PMID: 21876150 PMCID: PMC3179073 DOI: 10.1073/pnas.1102999108] [Citation(s) in RCA: 2377] [Impact Index Per Article: 182.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
There is increasing, but largely indirect, evidence pointing to an effect of commensal gut microbiota on the central nervous system (CNS). However, it is unknown whether lactic acid bacteria such as Lactobacillus rhamnosus could have a direct effect on neurotransmitter receptors in the CNS in normal, healthy animals. GABA is the main CNS inhibitory neurotransmitter and is significantly involved in regulating many physiological and psychological processes. Alterations in central GABA receptor expression are implicated in the pathogenesis of anxiety and depression, which are highly comorbid with functional bowel disorders. In this work, we show that chronic treatment with L. rhamnosus (JB-1) induced region-dependent alterations in GABA(B1b) mRNA in the brain with increases in cortical regions (cingulate and prelimbic) and concomitant reductions in expression in the hippocampus, amygdala, and locus coeruleus, in comparison with control-fed mice. In addition, L. rhamnosus (JB-1) reduced GABA(Aα2) mRNA expression in the prefrontal cortex and amygdala, but increased GABA(Aα2) in the hippocampus. Importantly, L. rhamnosus (JB-1) reduced stress-induced corticosterone and anxiety- and depression-related behavior. Moreover, the neurochemical and behavioral effects were not found in vagotomized mice, identifying the vagus as a major modulatory constitutive communication pathway between the bacteria exposed to the gut and the brain. Together, these findings highlight the important role of bacteria in the bidirectional communication of the gut-brain axis and suggest that certain organisms may prove to be useful therapeutic adjuncts in stress-related disorders such as anxiety and depression.
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Affiliation(s)
- Javier A. Bravo
- Laboratory of NeuroGastroenterology, Alimentary Pharmabiotic Centre
| | - Paul Forsythe
- The McMaster Brain–Body Institute, St. Joseph's Healthcare, Hamilton, ON, Canada L8N 4A6; and Departments of
- Medicine and
| | - Marianne V. Chew
- The McMaster Brain–Body Institute, St. Joseph's Healthcare, Hamilton, ON, Canada L8N 4A6; and Departments of
| | - Emily Escaravage
- The McMaster Brain–Body Institute, St. Joseph's Healthcare, Hamilton, ON, Canada L8N 4A6; and Departments of
| | - Hélène M. Savignac
- Laboratory of NeuroGastroenterology, Alimentary Pharmabiotic Centre
- School of Pharmacy, and Departments of
| | - Timothy G. Dinan
- Laboratory of NeuroGastroenterology, Alimentary Pharmabiotic Centre
- Psychiatry and
| | - John Bienenstock
- The McMaster Brain–Body Institute, St. Joseph's Healthcare, Hamilton, ON, Canada L8N 4A6; and Departments of
- Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada L8S 4L8
| | - John F. Cryan
- Laboratory of NeuroGastroenterology, Alimentary Pharmabiotic Centre
- School of Pharmacy, and Departments of
- Anatomy, University College Cork, Cork, Ireland
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Papaleo F, Lipska BK, Weinberger DR. Mouse models of genetic effects on cognition: relevance to schizophrenia. Neuropharmacology 2011; 62:1204-20. [PMID: 21557953 DOI: 10.1016/j.neuropharm.2011.04.025] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Revised: 04/08/2011] [Accepted: 04/20/2011] [Indexed: 01/27/2023]
Abstract
Cognitive dysfunction is a core feature of schizophrenia. Growing evidence indicates that a wide variety of genetic mutations and polymorphisms impact cognition and may thus be implicated in various aspects of this mental disorder. Despite differences between human and rodent brain structure and function, genetic mouse models have contributed critical information about brain mechanisms involved in cognitive processes. Here, we summarize discoveries of genetic modifications in mice that impact cognition. Based on functional hypotheses, gene modifications within five model systems are described: 1) dopamine (D1, D2, D3, D4, D5, DAT, COMT, MAO); 2) glutamate (GluR-A, NR1, NR2A, NR2B, GRM2, GRM3, GLAST); 3) GABA (α(5), γ(2), α(4), δGABA(A), GABA(B(1)), GAT1); 4) acetylcholine (nAChRβ2, α7, CHRM1); and 5) calcium (CaMKII-α, neurogranin, CaMKKβ, CaMKIV). We also consider other risk-associated genes for schizophrenia such as dysbindin (DTNBP1), neuregulin (NRG1), disrupted-in-schizophrenia1 (DISC1), reelin and proline dehydrogenase (PRODH). Because of the presumed importance of environmental factors, we further consider genetic modifications within the stress-sensitive systems of corticotropin-releasing factor (CRF), brain-derived neurotrophic factor (BDNF) and the endocannabinoid systems. We highlight the missing information and limitations of cognitive assays in genetically modified mice models relevant to schizophrenia pathology.
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Affiliation(s)
- Francesco Papaleo
- Department of Neuroscience and Brain Technologies, The Italian Institute of Technology, Via Morego 30, 16163 Genova, Italy.
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Savignac HM, Dinan TG, Cryan JF. Resistance to early-life stress in mice: effects of genetic background and stress duration. Front Behav Neurosci 2011; 5:13. [PMID: 21519375 PMCID: PMC3075880 DOI: 10.3389/fnbeh.2011.00013] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 03/03/2011] [Indexed: 12/11/2022] Open
Abstract
Early-life stress can induce marked behavioral and physiological impairments in adulthood including cognitive deficits, depression, anxiety, and gastrointestinal dysfunction. Although robust rat models of early-life stress exist there are few established effective paradigms in the mouse. Genetic background and protocol parameters used are two critical variables in such model development. Thus we investigated the impact of two different early-life stress protocols in two commonly used inbred mouse strains. C57BL/6 and innately anxious BALB/c male mice were maternally deprived 3 h daily, either from postnatal day 1 to 14 (protocol 1) or 6 to 10 (protocol 2). Animals were assessed in adulthood for cognitive performance (spontaneous alternation behavior test), anxiety [open-field, light/dark box (L/DB), and elevated plus maze (EPM) tests], and depression-related behaviors (forced swim test) in addition to stress-sensitive physiological changes. Overall, the results showed that early-life stressed mice from both strains displayed good cognitive ability and no elevations in anxiety. However, paradoxical changes occurred in C57BL/6 mice as the longer protocol (protocol 1) decreased anxiety in the L/DB and increased exploration in the EPM. In BALB/c mice there were also limited effects of maternal separation with both separation protocols inducing reductions in stress-induced defecation and protocol 1 reducing the colon length. These data suggest that, independent of stress duration, mice from both strains were on the whole resilient to the maladaptive effects of early-life stress. Thus maternal separation models of brain–gut axis dysfunction should rely on either different stressor protocols or other strains of mice.
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Affiliation(s)
- Hélène M Savignac
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork Cork, Ireland
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Abstract
The inhibitory neurotransmitter, GABA, is a low-molecular-weight molecule that can achieve many low-energy conformations, which are recognized by GABA receptors and transporters. In this article, we assess the structure–activity relationship profiles of GABA analogs at the ionotropic ρ GABAC receptor. Such studies have significantly contributed to the design and development of potent and selective agonists and antagonists for this subclass of GABA receptors. With these tools in hand, the role of ρ GABAC receptors is slowly being realized. Of particular interest is the development of selective phosphinic acid analogs of GABA and their potential use in sleep disorders, inhibiting the development of myopia, and in improving learning and memory.
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Vlachou S, Paterson NE, Guery S, Kaupmann K, Froestl W, Banerjee D, Finn MG, Markou A. Both GABA(B) receptor activation and blockade exacerbated anhedonic aspects of nicotine withdrawal in rats. Eur J Pharmacol 2011; 655:52-8. [PMID: 21262222 DOI: 10.1016/j.ejphar.2011.01.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 12/07/2010] [Accepted: 01/07/2011] [Indexed: 01/19/2023]
Abstract
Nicotine dependence is maintained by the aversive, depression-like effects of nicotine withdrawal and the rewarding effects of acute nicotine. GABA(B) receptor antagonists exhibit antidepressant-like effects in rodents, whereas GABA(B) receptor agonists attenuate the rewarding effects of nicotine. Recent studies with GABA(B) receptor positive modulators showed that these compounds represent potentially improved medications for the treatment of nicotine dependence because of fewer side-effects than GABA(B) receptor agonists. Thus, GABA(B) receptor agonists and antagonists, and GABA(B) receptor positive modulators may have efficacy as smoking cessation aids by targeting different aspects of nicotine dependence and withdrawal. The present study assessed the effects of the GABA(B) receptor agonist CGP44532, the GABA(B) receptor antagonist CGP56433A, and the GABA(B) receptor positive modulator BHF177 on the anhedonic aspects of nicotine withdrawal. Rats were prepared with stimulating electrodes in the posterior lateral hypothalamus. After establishing stable intracranial self-stimulation (ICSS) thresholds, rats were prepared with subcutaneous osmotic minipumps delivering either nicotine or saline for 7 or 14days. ICSS thresholds were assessed 6h post-pump removal. Thirty hours after pump removal, CGP44532, CGP56433A, and BHF177 were administered 30min prior to ICSS testing. Both GABA(B) receptor activation (CGP44532 and BHF177) and blockade (CGP56433A) elevated ICSS thresholds in all groups, resulting in exacerbated effects of nicotine withdrawal in the nicotine-treated groups. These similar effects of GABA(B) receptor activation and blockade on the anhedonic depression-like aspects of nicotine withdrawal were surprising and perhaps reflect differential efficacy of these compounds at presynaptic hetero- and autoreceptors, as well as postsynaptic, GABA(B) receptors.
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Affiliation(s)
- Styliani Vlachou
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, CA 92093-0603, USA
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Differential effects of GABAB receptor subtypes, {gamma}-hydroxybutyric Acid, and Baclofen on EEG activity and sleep regulation. J Neurosci 2010; 30:14194-204. [PMID: 20962240 DOI: 10.1523/jneurosci.3145-10.2010] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The role of GABA(B) receptors in sleep is still poorly understood. GHB (γ-hydroxybutyric acid) targets these receptors and is the only drug approved to treat the sleep disorder narcolepsy. GABA(B) receptors are obligate dimers comprised of the GABA(B2) subunit and either one of the two GABA(B1) subunit isoforms, GABA(B1a) and GABA(B1b). To better understand the role of GABA(B) receptors in sleep regulation, we performed electroencephalogram (EEG) recordings in mice devoid of functional GABA(B) receptors (1(-/-) and 2(-/-)) or lacking one of the subunit 1 isoforms (1a(-/-) and 1b(-/-)). The distribution of sleep over the day was profoundly altered in 1(-/-) and 2(-/-) mice, suggesting a role for GABA(B) receptors in the circadian organization of sleep. Several other sleep and EEG phenotypes pointed to a more prominent role for GABA(B1a) compared with the GABA(B1b) isoform. Moreover, we found that GABA(B1a) protects against the spontaneous seizure activity observed in 1(-/-) and 2(-/-) mice. We also evaluated the effects of the GHB-prodrug GBL (γ-butyrolactone) and of baclofen (BAC), a high-affinity GABA(B) receptor agonist. Both drugs induced a state distinct from physiological sleep that was not observed in 1(-/-) and 2(-/-) mice. Subsequent sleep was not affected by GBL whereas BAC was followed by a delayed hypersomnia even in 1(-/-) and 2(-/-) mice. The differential effects of GBL and BAC might be attributed to differences in GABA(B)-receptor affinity. These results also indicate that all GBL effects are mediated through GABA(B) receptors, although these receptors do not seem to be involved in mediating the BAC-induced hypersomnia.
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Cryan JF, Slattery DA. GABAB Receptors and Depression: Current Status. GABABRECEPTOR PHARMACOLOGY - A TRIBUTE TO NORMAN BOWERY 2010; 58:427-51. [DOI: 10.1016/s1054-3589(10)58016-5] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Pacey LKK, Heximer SP, Hampson DR. Increased GABAB Receptor-Mediated Signaling Reduces the Susceptibility of Fragile X Knockout Mice to Audiogenic Seizures. Mol Pharmacol 2009; 76:18-24. [DOI: 10.1124/mol.109.056127] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Guetg N, Seddik R, Vigot R, Turecek R, Gassmann M, Vogt KE, Bräuner-Osborne H, Shigemoto R, Kretz O, Frotscher M, Kulik Á, Bettler B. The GABAB1a isoform mediates heterosynaptic depression at hippocampal mossy fiber synapses. J Neurosci 2009; 29:1414-23. [PMID: 19193888 PMCID: PMC6666076 DOI: 10.1523/jneurosci.3697-08.2009] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Revised: 12/02/2008] [Accepted: 12/31/2008] [Indexed: 12/22/2022] Open
Abstract
GABA(B) receptor subtypes are based on the subunit isoforms GABA(B1a) and GABA(B1b), which associate with GABA(B2) subunits to form pharmacologically indistinguishable GABA(B(1a,2)) and GABA(B(1b,2)) receptors. Studies with mice selectively expressing GABA(B1a) or GABA(B1b) subunits revealed that GABA(B(1a,2)) receptors are more abundant than GABA(B(1b,2)) receptors at glutamatergic terminals. Accordingly, it was found that GABA(B(1a,2)) receptors are more efficient than GABA(B(1b,2)) receptors in inhibiting glutamate release when maximally activated by exogenous application of the agonist baclofen. Here, we used a combination of genetic, ultrastructural and electrophysiological approaches to analyze to what extent GABA(B(1a,2)) and GABA(B(1b,2)) receptors inhibit glutamate release in response to physiological activation. We first show that at hippocampal mossy fiber (MF)-CA3 pyramidal neuron synapses more GABA(B1a) than GABA(B1b) protein is present at presynaptic sites, consistent with the findings at other glutamatergic synapses. In the presence of baclofen at concentrations >or=1 microm, both GABA(B(1a,2)) and GABA(B(1b,2)) receptors contribute to presynaptic inhibition of glutamate release. However, at lower concentrations of baclofen, selectively GABA(B(1a,2)) receptors contribute to presynaptic inhibition. Remarkably, exclusively GABA(B(1a,2)) receptors inhibit glutamate release in response to synaptically released GABA. Specifically, we demonstrate that selectively GABA(B(1a,2)) receptors mediate heterosynaptic depression of MF transmission, a physiological phenomenon involving transsynaptic inhibition of glutamate release via presynaptic GABA(B) receptors. Our data demonstrate that the difference in GABA(B1a) and GABA(B1b) protein levels at MF terminals is sufficient to produce a strictly GABA(B1a)-specific effect under physiological conditions. This consolidates that the differential subcellular localization of the GABA(B1a) and GABA(B1b) proteins is of regulatory relevance.
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Affiliation(s)
- Nicole Guetg
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, and
- Institute of Anatomy and Cell Biology, Department of Neuroanatomy, University of Freiburg, 79104 Freiburg, Germany
| | - Riad Seddik
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, and
| | - Réjan Vigot
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, and
| | - Rostislav Turecek
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, and
| | - Martin Gassmann
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, and
| | - Kaspar E. Vogt
- Division of Pharmacology and Neurobiology, Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Hans Bräuner-Osborne
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, and
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Ryuichi Shigemoto
- Division of Cerebral Structure, National Institute for Physiological Sciences, and
- Department of Physiological Sciences, The Graduate University of Advanced Studies (Sokendai), Myodaiji, Okazaki 444-8787, Japan, and
- Solution Oriented Research for Science and Technology, Japan Science and Technology Corporation, Kawaguchi 332-0012, Japan
| | - Oliver Kretz
- Institute of Anatomy and Cell Biology, Department of Neuroanatomy, University of Freiburg, 79104 Freiburg, Germany
| | - Michael Frotscher
- Institute of Anatomy and Cell Biology, Department of Neuroanatomy, University of Freiburg, 79104 Freiburg, Germany
| | - Ákos Kulik
- Institute of Anatomy and Cell Biology, Department of Neuroanatomy, University of Freiburg, 79104 Freiburg, Germany
| | - Bernhard Bettler
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, and
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GABA Effects During Neuronal Differentiation of Stem Cells. Neurochem Res 2008; 33:1546-57. [DOI: 10.1007/s11064-008-9642-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Accepted: 02/21/2008] [Indexed: 12/18/2022]
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Senechal Y, Kelly PH, Dev KK. Amyloid precursor protein knockout mice show age-dependent deficits in passive avoidance learning. Behav Brain Res 2008; 186:126-32. [PMID: 17884188 DOI: 10.1016/j.bbr.2007.08.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Revised: 07/27/2007] [Accepted: 08/02/2007] [Indexed: 11/15/2022]
Abstract
Amyloid precursor protein (APP) is involved in the pathogenesis of Alzheimer's disease (AD), but its role in cognition has been relatively little studied. APP knockout (KO) animals have been described previously and show deficits in grip strength, reduced locomotor activity and impaired learning and memory in a conditioned avoidance test and the Morris water-maze. In order to further investigate the in vivo function of APP and its proteolytic derivatives, we tested APP KO mice and age-matched wild type controls at two different ages, 3 and 8 months, in a range of behavioural tests measuring neuromuscular, locomotor and cognitive functions. These tests included the acquisition of a passive avoidance response as a measure of long-term memory of an aversive experience, and spontaneous alternation in a Y-maze, regarded as a measure of spatial short-term memory. The absence of APP expression in APP KO mice was confirmed at the protein level using hippocampal tissue in Western blotting. APP KO mice displayed deficits in forelimb grip strength and locomotor activity in agreement with previous studies. In the Y-maze test used for spontaneous alternation behaviour, APP KO animals did not exhibit reduced alternation rates. On the other hand, in the passive avoidance test, APP KO mice showed an age-related deficit in retention of memory for an aversive experience. The results suggest that APP and/or its proteolytic derivatives may play a role in long-term memory in adult brain and/or may be required during the development and maintenance of neuronal networks involved in this type of memory.
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Affiliation(s)
- Yann Senechal
- Neuroscience Research, Novartis Institutes for BioMedical Research, Novartis Pharma AG, Lichtstrasse 35, CH-4056 Basel, Switzerland
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