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Welch N, Singh SS, Musich R, Mansuri MS, Bellar A, Mishra S, Chelluboyina AK, Sekar J, Attaway AH, Li L, Willard B, Hornberger TA, Dasarathy S. Shared and unique phosphoproteomics responses in skeletal muscle from exercise models and in hyperammonemic myotubes. iScience 2022; 25:105325. [PMID: 36345342 PMCID: PMC9636548 DOI: 10.1016/j.isci.2022.105325] [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: 04/18/2022] [Revised: 08/22/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022] Open
Abstract
Skeletal muscle generation of ammonia, an endogenous cytotoxin, is increased during exercise. Perturbations in ammonia metabolism consistently occur in chronic diseases, and may blunt beneficial skeletal muscle molecular responses and protein homeostasis with exercise. Phosphorylation of skeletal muscle proteins mediates cellular signaling responses to hyperammonemia and exercise. Comparative bioinformatics and machine learning-based analyses of published and experimentally derived phosphoproteomics data identified differentially expressed phosphoproteins that were unique and shared between hyperammonemic murine myotubes and skeletal muscle from exercise models. Enriched processes identified in both hyperammonemic myotubes and muscle from exercise models with selected experimental validation included protein kinase A (PKA), calcium signaling, mitogen-activated protein kinase (MAPK) signaling, and protein homeostasis. Our approach of feature extraction from comparative untargeted "omics" data allows for selection of preclinical models that recapitulate specific human exercise responses and potentially optimize functional capacity and skeletal muscle protein homeostasis with exercise in chronic diseases.
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Affiliation(s)
- Nicole Welch
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH 44195, USA
- Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Shashi Shekhar Singh
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Ryan Musich
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH 44195, USA
| | - M. Shahid Mansuri
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Annette Bellar
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Saurabh Mishra
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH 44195, USA
| | | | - Jinendiran Sekar
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Amy H. Attaway
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Ling Li
- Proteomics Core, Cleveland Clinic, Cleveland, OH 44195, USA
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA
| | - Belinda Willard
- Proteomics Core, Cleveland Clinic, Cleveland, OH 44195, USA
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA
| | - Troy A. Hornberger
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA
| | - Srinivasan Dasarathy
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, OH 44195, USA
- Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH 44195, USA
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2
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Mirabella F, Desiato G, Mancinelli S, Fossati G, Rasile M, Morini R, Markicevic M, Grimm C, Amegandjin C, Termanini A, Peano C, Kunderfranco P, di Cristo G, Zerbi V, Menna E, Lodato S, Matteoli M, Pozzi D. Prenatal interleukin 6 elevation increases glutamatergic synapse density and disrupts hippocampal connectivity in offspring. Immunity 2021; 54:2611-2631.e8. [PMID: 34758338 PMCID: PMC8585508 DOI: 10.1016/j.immuni.2021.10.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/24/2021] [Accepted: 10/07/2021] [Indexed: 02/07/2023]
Abstract
Early prenatal inflammatory conditions are thought to be a risk factor for different neurodevelopmental disorders. Maternal interleukin-6 (IL-6) elevation during pregnancy causes abnormal behavior in offspring, but whether these defects result from altered synaptic developmental trajectories remains unclear. Here we showed that transient IL-6 elevation via injection into pregnant mice or developing embryos enhanced glutamatergic synapses and led to overall brain hyperconnectivity in offspring into adulthood. IL-6 activated synaptogenesis gene programs in glutamatergic neurons and required the transcription factor STAT3 and expression of the RGS4 gene. The STAT3-RGS4 pathway was also activated in neonatal brains during poly(I:C)-induced maternal immune activation, which mimics viral infection during pregnancy. These findings indicate that IL-6 elevation at early developmental stages is sufficient to exert a long-lasting effect on glutamatergic synaptogenesis and brain connectivity, providing a mechanistic framework for the association between prenatal inflammatory events and brain neurodevelopmental disorders.
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Affiliation(s)
- Filippo Mirabella
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Milan, Italy; IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Genni Desiato
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy; Institute of Neuroscience - National Research Council, 20139 Milan, Italy
| | - Sara Mancinelli
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Giuliana Fossati
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Marco Rasile
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Milan, Italy
| | - Raffaella Morini
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Marija Markicevic
- Neuroscience Center Zürich, ETH Zürich and University of Zürich, Zürich 8057, Switzerland
| | - Christina Grimm
- Neuroscience Center Zürich, ETH Zürich and University of Zürich, Zürich 8057, Switzerland
| | - Clara Amegandjin
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada; CHU Sainte-Justine Research Center, Montréal, QC, Canada
| | - Alberto Termanini
- Bioinformatic Unit, Humanitas Clinical and Research Center, 20089 Rozzano, Milan, Italy
| | - Clelia Peano
- Institute of Genetic and Biomedical Research, UoS Milan, National Research Council, 20089 Rozzano, Milan, Italy; Genomic Unit, Humanitas Clinical and Research Center, 20089 Rozzano, Milan, Italy
| | - Paolo Kunderfranco
- Bioinformatic Unit, Humanitas Clinical and Research Center, 20089 Rozzano, Milan, Italy
| | - Graziella di Cristo
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada; CHU Sainte-Justine Research Center, Montréal, QC, Canada
| | - Valerio Zerbi
- Neuroscience Center Zürich, ETH Zürich and University of Zürich, Zürich 8057, Switzerland; Neural Control of Movement Lab, Department of Health Sciences and Technology, ETH Zürich, Zürich 8057, Switzerland
| | - Elisabetta Menna
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy; Institute of Neuroscience - National Research Council, 20139 Milan, Italy
| | - Simona Lodato
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Milan, Italy; IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Michela Matteoli
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy; Institute of Neuroscience - National Research Council, 20139 Milan, Italy.
| | - Davide Pozzi
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Milan, Italy; IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy.
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3
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Neurotrophic factors and target-specific retrograde signaling interactions define the specificity of classical and neuropeptide cotransmitter release at identified Lymnaea synapses. Sci Rep 2020; 10:13526. [PMID: 32782285 PMCID: PMC7419297 DOI: 10.1038/s41598-020-70322-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 07/22/2020] [Indexed: 12/26/2022] Open
Abstract
Many neurons concurrently and/or differentially release multiple neurotransmitter substances to selectively modulate the activity of distinct postsynaptic targets within a network. However, the molecular mechanisms that produce synaptic heterogeneity by regulating the cotransmitter release characteristics of individual presynaptic terminals remain poorly defined. In particular, we know little about the regulation of neuropeptide corelease, despite the fact that they mediate synaptic transmission, plasticity and neuromodulation. Here, we report that an identified Lymnaea neuron selectively releases its classical small molecule and peptide neurotransmitters, acetylcholine and FMRFamide-derived neuropeptides, to differentially influence the activity of distinct postsynaptic targets that coordinate cardiorespiratory behaviour. Using a combination of electrophysiological, molecular, and pharmacological approaches, we found that neuropeptide cotransmitter release was regulated by cross-talk between extrinsic neurotrophic factor signaling and target-specific retrograde arachidonic acid signaling, which converged on modulation of glycogen synthase kinase 3. In this context, we identified a novel role for the Lymnaea synaptophysin homologue as a specific and synapse-delimited inhibitory regulator of peptide neurotransmitter release. This study is among the first to define the cellular and molecular mechanisms underlying the differential release of cotransmitter substances from individual presynaptic terminals, which allow for context-dependent tuning and plasticity of the synaptic networks underlying patterned motor behaviour.
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Getz AM, Wijdenes P, Riaz S, Syed NI. Uncovering the Cellular and Molecular Mechanisms of Synapse Formation and Functional Specificity Using Central Neurons of Lymnaea stagnalis. ACS Chem Neurosci 2018. [PMID: 29528213 DOI: 10.1021/acschemneuro.7b00448] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
All functions of the nervous system are contingent upon the precise organization of neuronal connections that are initially patterned during development, and then continually modified throughout life. Determining the mechanisms that specify the formation and functional modulation of synaptic circuitry are critical to advancing both our fundamental understanding of the nervous system as well as the various neurodevelopmental, neurological, neuropsychiatric, and neurodegenerative disorders that are met in clinical practice when these processes go awry. Defining the cellular and molecular mechanisms underlying nervous system development, function, and pathology has proven challenging, due mainly to the complexity of the vertebrate brain. Simple model system approaches with invertebrate preparations, on the other hand, have played pivotal roles in elucidating the fundamental mechanisms underlying the formation and plasticity of individual synapses, and the contributions of individual neurons and their synaptic connections that underlie a variety of behaviors, and learning and memory. In this Review, we discuss the experimental utility of the invertebrate mollusc Lymnaea stagnalis, with a particular emphasis on in vitro cell culture, semi-intact and in vivo preparations, which enable molecular and electrophysiological identification of the cellular and molecular mechanisms governing the formation, plasticity, and specificity of individual synapses at a single-neuron or single-synapse resolution.
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Affiliation(s)
- Angela M. Getz
- Department of Cell Biology & Anatomy, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 1N4, Canada
- Department of Neuroscience, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Pierre Wijdenes
- Department of Cell Biology & Anatomy, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 1N4, Canada
- Biomedical Engineering Graduate Program, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Saba Riaz
- Department of Cell Biology & Anatomy, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Naweed I. Syed
- Department of Cell Biology & Anatomy, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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5
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cAMP-Inhibits Cytoplasmic Phospholipase A₂ and Protects Neurons against Amyloid-β-Induced Synapse Damage. BIOLOGY 2015; 4:591-606. [PMID: 26389963 PMCID: PMC4588152 DOI: 10.3390/biology4030591] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 08/26/2015] [Accepted: 09/07/2015] [Indexed: 11/25/2022]
Abstract
A key event in Alzheimer’s disease (AD) is the production of amyloid-β (Aβ) peptides and the loss of synapses. In cultured neurons Aβ triggered synapse damage as measured by the loss of synaptic proteins. α-synuclein (αSN), aggregates of which accumulate in Parkinson’s disease, also caused synapse damage. Synapse damage was associated with activation of cytoplasmic phospholipase A2 (cPLA2), an enzyme that regulates synapse function and structure, and the production of prostaglandin (PG) E2. In synaptosomes PGE2 increased concentrations of cyclic adenosine monophosphate (cAMP) which suppressed the activation of cPLA2 demonstrating an inhibitory feedback system. Thus, Aβ/αSN-induced activated cPLA2 produces PGE2 which increases cAMP which in turn suppresses cPLA2 and, hence, its own production. Neurons pre-treated with pentoxifylline and caffeine (broad spectrum phosphodiesterase (PDE) inhibitors) or the PDE4 specific inhibitor rolipram significantly increased the Aβ/αSN-induced increase in cAMP and consequently protected neurons against synapse damage. The addition of cAMP analogues also inhibited cPLA2 and protected neurons against synapse damage. These results suggest that drugs that inhibit Aβ-induced activation of cPLA2 and cross the blood–brain barrier may reduce synapse damage in AD.
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6
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Lidocaine treatment during synapse reformation periods permanently inhibits NGF-induced excitation in an identified reconstructed synapse of Lymnaea stagnalis. J Anesth 2011; 26:45-53. [DOI: 10.1007/s00540-011-1257-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 09/22/2011] [Indexed: 10/15/2022]
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High-fidelity patch-clamp recordings from neurons cultured on a polymer microchip. Biomed Microdevices 2010; 12:977-85. [DOI: 10.1007/s10544-010-9452-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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8
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Itziou A, Dimitriadis VK. The potential role of cAMP as a pollution biomarker of terrestrial environments using the land snail Eobania vermiculata: correlation with lysosomal membrane stability. CHEMOSPHERE 2009; 76:1315-1322. [PMID: 19631962 DOI: 10.1016/j.chemosphere.2009.06.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 06/03/2009] [Accepted: 06/15/2009] [Indexed: 05/28/2023]
Abstract
The present study investigates the role of the signal transduction molecule cAMP, and the lysosomal membrane stability (LMS), as biomarkers of terrestrial environmental pollution using the land snail Eobania vermiculata. Snails were exposed to different concentrations of heavy metals (Cd, Pb and Cu) and organic pollutants (chlorpyrifos, parathion-methyl and PAHs) in laboratory conditions for 25 days. In addition, snails were collected from various sites located at different distances away from two polluted areas in northern Greece (the road Agiou Dimitriou in Thessaloniki city and a lignite power station in the district of Kozani). The results of the current investigation showed significantly increased levels of cAMP in the digestive gland of snails, as well as decreased LMS values in all experimental groups compared to control animals. In support of our data, cAMP levels were significantly negatively correlated with the conventional biomarker LMS, thus encouraging the use of cAMP as a new potential stress index in terrestrial pollution biomonitoring studies.
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Affiliation(s)
- A Itziou
- Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece.
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9
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Dunn T, McCamphill P, Syed N. Activity-induced large amplitude postsynaptic mPSPs at soma-soma synapses between Lymnaea neurons. Synapse 2008; 63:117-25. [DOI: 10.1002/syn.20589] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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10
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Involvement of the cAMP-dependent pathway in the reduction of epileptiform bursting caused by somatostatin in the mouse hippocampus. Naunyn Schmiedebergs Arch Pharmacol 2008; 378:563-77. [PMID: 18665350 DOI: 10.1007/s00210-008-0338-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Accepted: 07/10/2008] [Indexed: 11/27/2022]
Abstract
The cyclic AMP pathway is major signal transduction system involved in hippocampal neurotransmission. Recently, the peptide somatostatin-14 (SRIF) has emerged as a key signal that, by activating its receptors, inhibits epileptiform bursting in the mouse hippocampus. Little is known on transduction mechanisms, which may mediate SRIF function in native cell/tissues. Using a well-established model of epileptiform activity induced by Mg(2+)-free medium with 4-aminopyridine [0 Mg(2+)/4-aminopyridine (4-AP)] in mouse hippocampal slices, we demonstrated that protein kinase A (PKA)-related signaling is upregulated by hippocampal bursting and that treatment with SRIF normalizes this upregulation. We also demonstrated that the SRIF-induced inhibition of PKA impairs phosphorylation of the NMDA receptor subunit NR1. Extracellular recordings of the 0 Mg(2+)/4-AP-induced hippocampal discharge from the CA3 region demonstrated that treating slices with compounds, which interfere with PKA activity, prevent SRIF inhibition of epileptiform bursting. Our results suggest that SRIF modulation of hippocampal activity may involve PKA-related signaling.
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11
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Kajana S, Goshgarian HG. Spinal activation of the cAMP-PKA pathway induces respiratory motor recovery following high cervical spinal cord injury. Brain Res 2008; 1232:206-13. [PMID: 18656458 DOI: 10.1016/j.brainres.2008.07.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 07/02/2008] [Accepted: 07/02/2008] [Indexed: 11/18/2022]
Abstract
The present study investigated the involvement of the adenosine 3'5'-cyclic monophosphate-dependent protein kinase A (cAMP-PKA) pathway in the activation of the crossed-phrenic pathways after left C2 spinal cord hemisection. Experiments were conducted on left C2 spinal cord hemisected, anesthetized, vagotomized, pancuronium paralyzed, and artificially ventilated male Sprague-Dawley rats. One week post-injury, the ipsilateral phrenic nerve exhibited no respiratory-related activity indicating a functionally complete hemisection. Intrathecal spinal cord administration of the cAMP analog, 8-Br-cAMP at the level of the phrenic nucleus resulted in an enhancement of contralateral phrenic nerve output and a restoration of respiratory-related activity in the phrenic nerve ipsilateral to the hemisection. Furthermore, pre-treatment with Rp-8-Br-cAMP, a PKA inhibitor, abolished the effects of 8-Br-cAMP. These results suggest that PKA activation is necessary for the cAMP-mediated respiratory recovery following high cervical spinal cord injury and that activation of intracellular signaling cascades may represent an important strategy for improving respiratory function after spinal cord injury.
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Affiliation(s)
- S Kajana
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, 540 East Canfield, Detroit, MI 48201, USA
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12
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McCamphill PK, Dunn TW, Syed NI. Serotonin modulates transmitter release at central Lymnaea synapses through a G-protein-coupled and cAMP-mediated pathway. Eur J Neurosci 2008; 27:2033-42. [PMID: 18412624 DOI: 10.1111/j.1460-9568.2008.06180.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Neuromodulation is central to all nervous system function, although the precise mechanisms by which neurotransmitters affect synaptic efficacy between central neurons remain to be fully elucidated. In this study, we examined the neuromodulatory action of serotonin [5-hydroxytryptamine (5-HT)] at central synapses between identified neurons from the pond snail Lymnaea stagnalis. Using whole-cell voltage-clamp and sharp electrode recording, we show that 5-HT strongly depresses synaptic strength between cultured, cholinergic neuron visceral dorsal 4 (VD4 - presynaptic) and its serotonergic target left pedal dorsal 1 (LPeD1 - postsynaptic). This inhibition was accompanied by a reduction in synaptic depression, but had no effect on postsynaptic input resistance, indicating a presynaptic origin. In addition, serotonin inhibited the presynaptic calcium current (I(Ca)) on a similar time course as the change in synaptic transmission. Introduction of a non-condensable GDP analog, GDP-beta-S, through the presynaptic pipette inhibited the serotonin-mediated effect on I(Ca.) Similar results were obtained with a membrane-impermeable inactive cAMP analog, 8OH-cAMP. Furthermore, stimulation of the serotonergic postsynaptic cell also inhibited presynaptic currents, indicating the presence of a negative feedback loop between LPeD1 and VD4. Taken together, this study provides direct evidence for a negative feedback mechanism, whereby the activity of a presynaptic respiratory central pattern-generating neuron is regulated by its postsynaptic target cell. We demonstrate that either serotonin or LPeD1 activity-induced depression of presynaptic transmitter release from VD4 involves voltage-gated calcium channels and is mediated through a G-protein-coupled and cAMP-mediated system.
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Affiliation(s)
- P K McCamphill
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
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13
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Sampaio LDFS. Melatonin inhibitory effect on cAMP accumulation in the chick retina development. Int J Dev Neurosci 2008; 26:277-82. [PMID: 18343081 DOI: 10.1016/j.ijdevneu.2008.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Revised: 01/31/2008] [Accepted: 02/01/2008] [Indexed: 10/22/2022] Open
Abstract
During vertebrate neurodevelopment, neuritogenesis and synaptogenesis are modulated by intracellular cAMP rises. Melatonin, which is implicated in neuronal differentiation, mainly inhibits this pathway. Here, an investigation about the profile of this effect during the vertebrate neurodevelopment is reported. In the embryonic chick retinas at days 8, 12, 14, 16 and at 2 days post-hatched (E8, E12, E14, E16 and PH), those control embryonic retinas incubated only with the phosphodiesterase inhibitor at days corresponding to commencement of neuronal differentiation (E8, E12) and PH, presented cAMP levels inhibited by melatonin. While the cAMP accumulation stimulated by forskolin was inhibited in the embryonic retinas at all testing days. Neither the unselective antagonist N-acetyl-2-benziltryptamine (luzindole) nor the selective Mel(1b) antagonist 4-phenyl-2-propionamidotetralin (4-P-PDOT) blocked the melatonin concentration-dependent inhibitory effect on cAMP accumulation in the retinas initiating differentiation (E7-E9), suggesting a tight binding between melatonin and their receptors. However, 4-P-PDOT competitively reverted the melatonin effect on cAMP stimulated by forskolin during synaptogenesis stages. Together, the melatonin effect on cAMP levels in chick retina, which is mainly through melatonin receptors, is depending on the developmental period observed, probably taking part in the mechanisms surrounding the melatonin action on neuronal differentiation.
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Affiliation(s)
- Lucia de Fatima Sobral Sampaio
- Laboratório de Bioquímica do Desenvolvimento do Sistema Nervoso, Instituto de Ciências Biológicas, Universidade Federal do Pará, 1 Belém, PA, Brazil.
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14
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Dunn TW, Syed NI. Ryanodine receptor-transmitter release site coupling increases quantal size in a synapse-specific manner. Eur J Neurosci 2007; 24:1591-605. [PMID: 17004923 DOI: 10.1111/j.1460-9568.2006.05028.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The mechanisms by which presynaptic neurones differentially regulate synaptic transmission with multiple postsynaptic targets in the brain are not fully understood. Using intracellular sharp electrode and whole-cell voltage-clamp recordings of soma-soma synapses between identified Lymnaea neurones, we provide direct evidence that quantal size is regulated presynaptically through the coupling of multiple release sites. This coupling effectively multiplies quantal size, thereby providing significant influence over parameters of synaptic transmission that are influenced by quantal size, such as the variance in transmitter release at stationary release probabilities. Variation in the degree of coupling is dependent on the identity of the postsynaptic cell, even though the variation in quantal size is of presynaptic origin. We have therefore demonstrated the presence of a novel mechanism by which presynaptic neurones may differentially regulate quantal size at select synaptic connections, in turn providing them with a means of regulating synaptic transmission with multiple postsynaptic cells.
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Affiliation(s)
- Tyler W Dunn
- Hotchkiss Brain Institute, Department of Cell Biology and Anatomy, Faculty of Medicine, University of Calgary, 3330 Hospital Drive, NW, Calgary, Alberta T2N4N1, Canada
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15
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Munno DW, Syed NI. Synaptogenesis in the CNS: an odyssey from wiring together to firing together. J Physiol 2003; 552:1-11. [PMID: 12897180 PMCID: PMC2343306 DOI: 10.1113/jphysiol.2003.045062] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2003] [Accepted: 08/01/2003] [Indexed: 12/31/2022] Open
Abstract
To acquire a better comprehension of nervous system function, it is imperative to understand how synapses are assembled during development and subsequently altered throughout life. Despite recent advances in the fields of neurodevelopment and synaptic plasticity, relatively little is known about the mechanisms that guide synapse formation in the central nervous system (CNS). Although many structural components of the synaptic machinery are pre-assembled prior to the arrival of growth cones at the site of their potential targets, innumerable changes, central to the proper wiring of the brain, must subsequently take place through contact-mediated cell-cell communications. Identification of such signalling molecules and a characterization of various events underlying synaptogenesis are pivotal to our understanding of how a brain cell completes its odyssey from "wiring together to firing together". Here we attempt to provide a comprehensive overview that pertains directly to the cellular and molecular mechanisms of selection, formation and refinement of synapses during the development of the CNS in both vertebrates and invertebrates.
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Affiliation(s)
- David W Munno
- Neuroscience and Respiratory Research Groups, Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada T2N 4N1
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