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Cui Y, Kam K, Sherman D, Janczewski WA, Zheng Y, Feldman JL. Defining preBötzinger Complex Rhythm- and Pattern-Generating Neural Microcircuits In Vivo. Neuron 2016; 91:602-14. [PMID: 27497222 PMCID: PMC4978183 DOI: 10.1016/j.neuron.2016.07.003] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 04/05/2016] [Accepted: 06/23/2016] [Indexed: 11/16/2022]
Abstract
Normal breathing in rodents requires activity of glutamatergic Dbx1-derived (Dbx1(+)) preBötzinger Complex (preBötC) neurons expressing somatostatin (SST). We combined in vivo optogenetic and pharmacological perturbations to elucidate the functional roles of these neurons in breathing. In transgenic adult mice expressing channelrhodopsin (ChR2) in Dbx1(+) neurons, photoresponsive preBötC neurons had preinspiratory or inspiratory firing patterns associated with excitatory effects on burst timing and pattern. In transgenic adult mice expressing ChR2 in SST(+) neurons, photoresponsive preBötC neurons had inspiratory or postinspiratory firing patterns associated with excitatory responses on pattern or inhibitory responses that were largely eliminated by blocking synaptic inhibition within preBötC or by local viral infection limiting ChR2 expression to preBötC SST(+) neurons. We conclude that: (1) preinspiratory preBötC Dbx1(+) neurons are rhythmogenic, (2) inspiratory preBötC Dbx1(+) and SST(+) neurons primarily act to pattern respiratory motor output, and (3) SST(+)-neuron-mediated pathways and postsynaptic inhibition within preBötC modulate breathing pattern.
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Affiliation(s)
- Yan Cui
- Department of Physiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China; Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Kaiwen Kam
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - David Sherman
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Wiktor A Janczewski
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Yu Zheng
- Department of Physiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China
| | - Jack L Feldman
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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Lucas SJ, Armstrong DL. Protein phosphatase modulation of somatostatin receptor signaling in the mouse hippocampus. Neuropharmacology 2015. [PMID: 26196943 DOI: 10.1016/j.neuropharm.2015.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Many inhibitory interneurones in the hippocampus release the neuropeptide somatostatin (SST) which inhibits neuronal excitability through Gi/Go-coupled receptors. To investigate the signaling pathways underlying the SST inhibition of neuronal excitability in the hippocampus, we performed perforated patch-clamp recordings from CA1 pyramidal neurones in acute brain slices from P14-P18 mice. Bath application of 1 μM SST reversibly reduces the frequency of action potential firing in response to depolarising current steps, and is associated with neuronal hyperpolarisation and a reduction in membrane resistance. This effect is mediated by potassium channels with KCNK-like pharmacology. In addition, in slices that have been cultured in vitro for seven days or more, SST also produces a hyperpolarisation independent reduction in action potential firing, which can be also observed in acute slices when the Ser/Thr protein phosphatases PP2A and PP4 are inhibited selectively with fostriecin. This hyperpolarisation independent effect of SST appears to be mediated by G-protein-activated inwardly rectifying K+ (GIRK) channels. Knockdown of protein phosphatase 5, by Cre recombinase mediated deletion of the floxed Ppp5c gene, blocks the hyperpolarisation independent effect of SST, and reduces the hyperpolarisation dependent effect in a manner consistent with increased SST receptor desensitisation. Thus, reversible protein phosphorylation provides a mechanism to enhance or diminish the inhibitory effect of SST, which could allow system level regulation of circuit excitability in the hippocampus.
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Affiliation(s)
- Sarah J Lucas
- Lab. Neurobiology, National Institute of Environmental Health Sciences, NIH, Durham, NC, 27709, USA.
| | - David L Armstrong
- Lab. Neurobiology, National Institute of Environmental Health Sciences, NIH, Durham, NC, 27709, USA
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Abstract
Sleep and wake are fundamental behavioral states whose molecular regulation remains mysterious. Brain states and body functions change dramatically between sleep and wake, are regulated by circadian and homeostatic processes, and depend on the nutritional and emotional condition of the animal. Sleep-wake transitions require the coordination of several brain regions and engage multiple neurochemical systems, including neuropeptides. Neuropeptides serve two main functions in sleep-wake regulation. First, they represent physiological states such as energy level or stress in response to environmental and internal stimuli. Second, neuropeptides excite or inhibit their target neurons to induce, stabilize, or switch between sleep-wake states. Thus, neuropeptides integrate physiological subsystems such as circadian time, previous neuron usage, energy homeostasis, and stress and growth status to generate appropriate sleep-wake behaviors. We review the roles of more than 20 neuropeptides in sleep and wake to lay the foundation for future studies uncovering the mechanisms that underlie the initiation, maintenance, and exit of sleep and wake states.
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Affiliation(s)
- Constance Richter
- Department of Molecular and Cellular Biology, Center for Brain Science, Division of Sleep Biology, Harvard University, Cambridge, Massachusetts 02138; ,
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54
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Somatostatin, neuronal vulnerability and behavioral emotionality. Mol Psychiatry 2015; 20:377-87. [PMID: 25600109 PMCID: PMC4355106 DOI: 10.1038/mp.2014.184] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 10/13/2014] [Accepted: 11/17/2014] [Indexed: 12/16/2022]
Abstract
Somatostatin (SST) deficits are common pathological features in depression and other neurological disorders with mood disturbances, but little is known about the contribution of SST deficits to mood symptoms or causes of these deficits. Here we show that mice lacking SST (Sst(KO)) exhibit elevated behavioral emotionality, high basal plasma corticosterone and reduced gene expression of Bdnf, Cortistatin and Gad67, together recapitulating behavioral, neuroendocrine and molecular features of human depression. Studies in Sst(KO) and heterozygous (Sst(HZ)) mice show that elevated corticosterone is not sufficient to reproduce the behavioral phenotype, suggesting a putative role for Sst cell-specific molecular changes. Using laser capture microdissection, we show that cortical SST-positive interneurons display significantly greater transcriptome deregulations after chronic stress compared with pyramidal neurons. Protein translation through eukaryotic initiation factor 2 (EIF2) signaling, a pathway previously implicated in neurodegenerative diseases, was most affected and suppressed in stress-exposed SST neurons. We then show that activating EIF2 signaling through EIF2 kinase inhibition mitigated stress-induced behavioral emotionality in mice. Taken together, our data suggest that (1) low SST has a causal role in mood-related phenotypes, (2) deregulated EIF2-mediated protein translation may represent a mechanism for vulnerability of SST neurons and (3) that global EIF2 signaling has antidepressant/anxiolytic potential.
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55
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Phillips WA, Clark A, Silverstein SM. On the functions, mechanisms, and malfunctions of intracortical contextual modulation. Neurosci Biobehav Rev 2015; 52:1-20. [PMID: 25721105 DOI: 10.1016/j.neubiorev.2015.02.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 02/02/2015] [Accepted: 02/15/2015] [Indexed: 10/23/2022]
Abstract
A broad neuron-centric conception of contextual modulation is reviewed and re-assessed in the light of recent neurobiological studies of amplification, suppression, and synchronization. Behavioural and computational studies of perceptual and higher cognitive functions that depend on these processes are outlined, and evidence that those functions and their neuronal mechanisms are impaired in schizophrenia is summarized. Finally, we compare and assess the long-term biological functions of contextual modulation at the level of computational theory as formalized by the theories of coherent infomax and free energy reduction. We conclude that those theories, together with the many empirical findings reviewed, show how contextual modulation at the neuronal level enables the cortex to flexibly adapt the use of its knowledge to current circumstances by amplifying and grouping relevant activities and by suppressing irrelevant activities.
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Affiliation(s)
- W A Phillips
- Department of Psychology, University of Stirling, FK9 4LA, Scotland, UK
| | - A Clark
- School of Philosophy, Psychology, and Language Sciences, University of Edinburgh, EH12 5AY, Scotland, UK
| | - S M Silverstein
- Rutgers Biomedical and Health Sciences, Piscataway, NJ, USA.
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56
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Cardoso A, Silva D, Magano S, Pereira PA, Andrade JP. Old-onset caloric restriction effects on neuropeptide Y- and somatostatin-containing neurons and on cholinergic varicosities in the rat hippocampal formation. AGE (DORDRECHT, NETHERLANDS) 2014; 36:9737. [PMID: 25471895 PMCID: PMC4259091 DOI: 10.1007/s11357-014-9737-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 11/25/2014] [Indexed: 06/04/2023]
Abstract
Caloric restriction is able to delay age-related neurodegenerative diseases and cognitive impairment. In this study, we analyzed the effects of old-onset caloric restriction that started at 18 months of age, in the number of neuropeptide Y (NPY)- and somatostatin (SS)-containing neurons of the hippocampal formation. Knowing that these neuropeptidergic systems seem to be dependent of the cholinergic system, we also analyzed the number of cholinergic varicosities. Animals with 6 months of age (adult controls) and with 18 months of age were used. The animals aged 18 months were randomly assigned to controls or to caloric-restricted groups. Adult and old control rats were maintained in the ad libitum regimen during 6 months. Caloric-restricted rats were fed, during 6 months, with 60 % of the amount of food consumed by controls. We found that aging induced a reduction of the total number of NPY- and SS-positive neurons in the hippocampal formation accompanied by a decrease of the cholinergic varicosities. Conversely, the 24-month-old-onset caloric-restricted animals maintained the number of those peptidergic neurons and the density of the cholinergic varicosities similar to the 12-month control rats. These results suggest that the aging-associated reduction of these neuropeptide-expressing neurons is not due to neuronal loss and may be dependent of the cholinergic system. More importantly, caloric restriction has beneficial effects in the NPY- and SS-expressing neurons and in the cholinergic system, even when applied in old age.
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Affiliation(s)
- Armando Cardoso
- Department of Anatomy, Faculty of Medicine, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal,
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Martel G, Simon A, Nocera S, Kalainathan S, Pidoux L, Blum D, Leclère-Turbant S, Diaz J, Geny D, Moyse E, Videau C, Buée L, Epelbaum J, Viollet C. Aging, but not tau pathology, impacts olfactory performances and somatostatin systems in THY-Tau22 mice. Neurobiol Aging 2014; 36:1013-28. [PMID: 25433460 DOI: 10.1016/j.neurobiolaging.2014.10.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 10/01/2014] [Accepted: 10/24/2014] [Indexed: 11/15/2022]
Abstract
Somatostatin (SOM) cortical levels decline in Alzheimer's disease (AD) in correlation with cognitive impairment severity, the latter being closely related to the presence of neurofibrillary tangles. Impaired olfaction is another hallmark of AD tightly related to tau pathology in the olfactory pathways. Recent studies showed that SOM modulates olfactory processing, suggesting that alterations in SOM levels participate to olfactory deficits in AD. Herein, we first observed that human olfactory peduncle and cortex are enriched in SOM cells and fibers, in aged postmortem brains. Then, the possible link between SOM alterations and olfactory deficits was evaluated by exploring the impact of age and tau hyperphosphorylation on olfactory SOM networks and behavioral performances in THY-Tau22 mice, a tauopathy transgenic model. Distinct molecular repertoires of SOM peptide and receptors were associated to sensory or cortical olfactory processing structures. Aging mainly affected SOM neurotransmission in piriform and entorhinal cortex in wild-type mice, although olfactory performances decreased. However, no further olfactory impairment was evidenced in THY-Tau22 mice until 12 months although tau pathology early affected olfactory cortical structures. Thus, tau hyperphosphorylation per se has a limited impact on olfactory performances in THY-Tau22 mice.
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Affiliation(s)
- Guillaume Martel
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Axelle Simon
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Sonia Nocera
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Sahana Kalainathan
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Ludivine Pidoux
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - David Blum
- Inserm, UMR837, Jean-Pierre Aubert Research Centre, IMPRT, F-59000, Lille, France; Université de Lille, UDSL, F-59000, Lille, France
| | | | - Jorge Diaz
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - David Geny
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Emmanuel Moyse
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Catherine Videau
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Luc Buée
- Inserm, UMR837, Jean-Pierre Aubert Research Centre, IMPRT, F-59000, Lille, France; Université de Lille, UDSL, F-59000, Lille, France
| | - Jacques Epelbaum
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Cécile Viollet
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France.
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58
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Seney ML, Tripp A, McCune S, Lewis DA, Sibille E. Laminar and cellular analyses of reduced somatostatin gene expression in the subgenual anterior cingulate cortex in major depression. Neurobiol Dis 2014; 73:213-9. [PMID: 25315685 DOI: 10.1016/j.nbd.2014.10.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 09/08/2014] [Accepted: 10/02/2014] [Indexed: 02/05/2023] Open
Abstract
Somatostatin (SST), a neuropeptide expressed in dendritic-targeting gamma-aminobutyric acid (GABA) neurons, is decreased across corticolimbic areas in major depressive disorder (MDD). SST-positive GABA neurons form heterogeneous subgroups with different laminar distributions and electrophysiological properties, so knowing the anatomical and cellular localization of reduced SST may provide insight into the nature of the pathology in MDD. In cohorts of MDD subjects with known reduction of SST in postmortem sgACC gray matter, we used in situ hybridization to quantify the laminar and cellular patterns of altered SST mRNA expression. SST mRNA levels were lower across all cortical layers in the MDD subjects. Expression levels per cell were also lower, but the density of labeled neurons did not differ between subject groups. Consistent with the previous tissue level analysis, differences were more robust in females. In summary, we report MDD-related reduction in SST expression per cell across cortical layers in sgACC, suggesting a general vulnerability of SST neurons independent of specific cell type.
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Affiliation(s)
- Marianne L Seney
- Department of Psychiatry, University of Pittsburgh Medical School, Pittsburgh, PA, USA; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Adam Tripp
- Department of Psychiatry, University of Pittsburgh Medical School, Pittsburgh, PA, USA
| | - Samuel McCune
- Department of Psychiatry, University of Pittsburgh Medical School, Pittsburgh, PA, USA
| | - David A Lewis
- Department of Psychiatry, University of Pittsburgh Medical School, Pittsburgh, PA, USA; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Etienne Sibille
- Department of Psychiatry, University of Pittsburgh Medical School, Pittsburgh, PA, USA; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA; Campbell Family Research Institute, Centre for Addiction and Mental Health, Departments of Psychiatry, Pharmacology and Toxicology, University of Toronto, Toronto, Canada.
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59
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Ouellet L, de Villers-Sidani E. Trajectory of the main GABAergic interneuron populations from early development to old age in the rat primary auditory cortex. Front Neuroanat 2014; 8:40. [PMID: 24917792 PMCID: PMC4040493 DOI: 10.3389/fnana.2014.00040] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 05/13/2014] [Indexed: 11/13/2022] Open
Abstract
In both humans and rodents, decline in cognitive function is a hallmark of the aging process; the basis for this decrease has yet to be fully characterized. However, using aged rodent models, deficits in auditory processing have been associated with significant decreases in inhibitory signaling attributed to a loss of GABAergic interneurons. Not only are these interneurons crucial for pattern detection and other large-scale population dynamics, but they have also been linked to mechanisms mediating plasticity and learning, making them a prime candidate for study and modeling of modifications to cortical communication pathways in neurodegenerative diseases. Using the rat primary auditory cortex (A1) as a model, we probed the known markers of GABAergic interneurons with immunohistological methods, using antibodies against gamma aminobutyric acid (GABA), parvalbumin (PV), somatostatin (SOM), calretinin (CR), vasoactive intestinal peptide (VIP), choline acetyltransferase (ChAT), neuropeptide Y (NPY), and cholecystokinin (CCK) to document the changes observed in interneuron populations across the rat's lifespan. This analysis provided strong evidence that several but not all GABAergic neurons were affected by the aging process, showing most dramatic changes in expression of parvalbumin (PV) and somatostatin (SOM) expression. With this evidence, we show how understanding these trajectories of cell counts may be factored into a simple model to quantify changes in inhibitory signaling across the course of life, which may be applied as a framework for creating more advanced simulations of interneuronal implication in normal cerebral processing, normal aging, or pathological processes.
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Affiliation(s)
- Lydia Ouellet
- Department of Neurology and Neurosurgery, Montreal Neurological Institute Montreal, QC, Canada
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60
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Borbély E, Scheich B, Helyes Z. Neuropeptides in learning and memory. Neuropeptides 2013; 47:439-50. [PMID: 24210137 DOI: 10.1016/j.npep.2013.10.012] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 10/14/2013] [Accepted: 10/14/2013] [Indexed: 12/14/2022]
Abstract
Dementia conditions and memory deficits of different origins (vascular, metabolic and primary neurodegenerative such as Alzheimer's and Parkinson's diseases) are getting more common and greater clinical problems recently in the aging population. Since the presently available cognitive enhancers have very limited therapeutical applications, there is an emerging need to elucidate the complex pathophysiological mechanisms, identify key mediators and novel targets for future drug development. Neuropeptides are widely distributed in brain regions responsible for learning and memory processes with special emphasis on the hippocampus, amygdala and the basal forebrain. They form networks with each other, and also have complex interactions with the cholinergic, glutamatergic, dopaminergic and GABA-ergic pathways. This review summarizes the extensive experimental data in the well-established rat and mouse models, as well as the few clinical results regarding the expression and the roles of the tachykinin system, somatostatin and the closely related cortistatin, vasoactive intestinal polypeptide (VIP) and pituitary adenylate-cyclase activating polypeptide (PACAP), calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY), opioid peptides and galanin. Furthermore, the main receptorial targets, mechanisms and interactions are described in order to highlight the possible therapeutical potentials. Agents not only symptomatically improving the functional impairments, but also inhibiting the progression of the neurodegenerative processes would be breakthroughs in this area. The most promising mechanisms determined at the level of exploratory investigations in animal models of cognitive disfunctions are somatostatin sst4, NPY Y2, PACAP-VIP VPAC1, tachykinin NK3 and galanin GALR2 receptor agonisms, as well as delta opioid receptor antagonism. Potent and selective non-peptide ligands with good CNS penetration are needed for further characterization of these molecular pathways to complete the preclinical studies and decide if any of the above described targets could be appropriate for clinical investigations.
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Affiliation(s)
- Eva Borbély
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Pécs, Szigeti u. 12, H-7624 Pécs, Hungary; Molecular Pharmacology Research Group, János Szentágothai Research Center, University of Pécs, Ifjúság útja 20, H-7624 Pécs, Hungary
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61
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Lin LC, Sibille E. Reduced brain somatostatin in mood disorders: a common pathophysiological substrate and drug target? Front Pharmacol 2013; 4:110. [PMID: 24058344 PMCID: PMC3766825 DOI: 10.3389/fphar.2013.00110] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Accepted: 08/13/2013] [Indexed: 12/23/2022] Open
Abstract
Our knowledge of the pathophysiology of affect dysregulation has progressively increased, but the pharmacological treatments remain inadequate. Here, we summarize the current literature on deficits in somatostatin, an inhibitory modulatory neuropeptide, in major depression and other neurological disorders that also include mood disturbances. We focus on direct evidence in the human postmortem brain, and review rodent genetic and pharmacological studies probing the role of the somatostatin system in relation to mood. We also briefly go over pharmacological developments targeting the somatostatin system in peripheral organs and discuss the challenges of targeting the brain somatostatin system. Finally, the fact that somatostatin deficits are frequently observed across neurological disorders suggests a selective cellular vulnerability of somatostatin-expressing neurons. Potential cell intrinsic factors mediating those changes are discussed, including nitric oxide induced oxidative stress, mitochondrial dysfunction, high inflammatory response, high demand for neurotrophic environment, and overall aging processes. Together, based on the co-localization of somatostatin with gamma-aminobutyric acid (GABA), its presence in dendritic-targeting GABA neuron subtypes, and its temporal-specific function, we discuss the possibility that deficits in somatostatin play a central role in cortical local inhibitory circuit deficits leading to abnormal corticolimbic network activity and clinical mood symptoms across neurological disorders.
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Affiliation(s)
- Li-Chun Lin
- Department of Psychiatry, Center for Neuroscience, University of Pittsburgh Pittsburgh, PA, USA
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