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Pivonello R, Neggers SJCMM, Imran SA. Psychopathology in Acromegaly-Real and Perceived. J Clin Endocrinol Metab 2023; 108:2470-2474. [PMID: 37139644 DOI: 10.1210/clinem/dgad237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/19/2023] [Accepted: 04/21/2023] [Indexed: 05/05/2023]
Abstract
Acromegaly is a chronic condition caused by the excessive production of growth hormone and is characterized by progressive morphological and systemic complications, as well as increased prevalence of psychopathologies, which markedly affect patients' quality of life. The advancing multimodal therapies, while significantly improving the morbidity and mortality, have limited impact on psychopathologies, which often persist despite disease remission. The most common psychopathologies in acromegaly include depression, anxiety and affective disorders, together with sexual dysfunction, which may be considered as either a consequence or potentially even a contributory factor to these psychopathologies. Approximately one-third of patients with acromegaly manifest depression, whereas two-thirds of patients display anxiety, with both conditions tending to be more prevalent and severe in younger patients with shorter duration of disease. Apparently, a major impact of psychological discomfort in women compared with men appears to be the fact that women tend to internalize whereas men tend to externalize their distress. Personality disorders also commonly associated with acromegaly, especially due to body image suffering, are linked to sexual dysfunction, which seems to affect women more than men. In summary, psychopathology in acromegaly is a major determinant of the quality of life and a complex array of psychological abnormalities are associated with acromegaly.
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Affiliation(s)
- Rosario Pivonello
- Dipartimento di Medicina Clinica e Chirurgia, Sezione di Endocrinologia, Diabetologia, Andrologia e Nutrizione, Università Federico II di Napoli, Naples 80131, Italy
| | - Sebastian J C M M Neggers
- Department of Internal Medicine, Section of Endocrinology, Erasmus University Medical Center Rotterdam, Rotterdam 3015GD, The Netherlands
| | - Syed Ali Imran
- Division of Endocrinology and Metabolism, Dalhousie University, Halifax, NS B3H 2Y9, Canada
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2
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Lower morning levels of cortisol and neuropeptides in blood samples from patients with bipolar disorder. JOURNAL OF AFFECTIVE DISORDERS REPORTS 2022. [DOI: 10.1016/j.jadr.2022.100406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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3
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Fee C, Prevot TD, Misquitta K, Knutson DE, Li G, Mondal P, Cook JM, Banasr M, Sibille E. Behavioral Deficits Induced by Somatostatin-Positive GABA Neuron Silencing Are Rescued by Alpha 5 GABA-A Receptor Potentiation. Int J Neuropsychopharmacol 2021; 24:505-518. [PMID: 33438026 PMCID: PMC8278801 DOI: 10.1093/ijnp/pyab002] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 12/15/2020] [Accepted: 01/11/2021] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION Deficits in somatostatin-positive gamma-aminobutyric acid interneurons (SST+ GABA cells) are commonly reported in human studies of mood and anxiety disorder patients. A causal link between SST+ cell dysfunction and symptom-related behaviors has been proposed based on rodent studies showing that chronic stress, a major risk factor for mood and anxiety disorders, induces a low SST+ GABA cellular phenotype across corticolimbic brain regions; that lowering Sst, SST+ cell, or GABA functions induces depressive-/anxiety-like behaviors (a rodent behavioral construct collectively defined as "behavioral emotionality"); and that disinhibiting SST+ cells has antidepressant-like effects. Recent studies found that compounds preferentially potentiating receptors mediating SST+ cell functions, α5-GABAA receptor positive allosteric modulators (α5-PAMs), achieved antidepressant-like effects. Together, the evidence suggests that SST+ cells regulate mood and cognitive functions that are disrupted in mood disorders and that rescuing SST+ cell function via α5-PAM may represent a targeted therapeutic strategy. METHODS We developed a mouse model allowing chemogenetic manipulation of brain-wide SST+ cells and employed behavioral characterization 30 minutes after repeated acute silencing to identify contributions to symptom-related behaviors. We then assessed whether an α5-PAM, GL-II-73, could rescue behavioral deficits. RESULTS Brain-wide SST+ cell silencing induced features of stress-related illnesses, including elevated neuronal activity and plasma corticosterone levels, increased anxiety- and anhedonia-like behaviors, and impaired short-term memory. GL-II-73 led to antidepressant- and anxiolytic-like improvements among behavioral deficits induced by brain-wide SST+ cell silencing. CONCLUSION Our data validate SST+ cells as regulators of mood and cognitive functions and demonstrate that bypassing low SST+ cell function via α5-PAM represents a targeted therapeutic strategy.
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Affiliation(s)
- Corey Fee
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Thomas D Prevot
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Keith Misquitta
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Daniel E Knutson
- Department of Chemistry and Biochemistry, University of Wisconsin–Milwaukee, Milwaukee, Wisconsin, USA
| | - Guanguan Li
- Department of Chemistry and Biochemistry, University of Wisconsin–Milwaukee, Milwaukee, Wisconsin, USA,Shenzhen Key Laboratory of Small Molecule Drug Discovery and Synthesis, Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen, China
| | - Prithu Mondal
- Department of Chemistry and Biochemistry, University of Wisconsin–Milwaukee, Milwaukee, Wisconsin, USA
| | - James M Cook
- Department of Chemistry and Biochemistry, University of Wisconsin–Milwaukee, Milwaukee, Wisconsin, USA
| | - Mounira Banasr
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Etienne Sibille
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada,Department of Psychiatry, University of Toronto, Toronto, ON, Canada,Correspondence: Etienne Sibille, PhD, CAMH, 250 College Street, Room 134, Toronto, ON M5T 1R8, Canada ()
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Hartley ND, Gaulden AD, Báldi R, Winters ND, Salimando GJ, Rosas-Vidal LE, Jameson A, Winder DG, Patel S. Dynamic remodeling of a basolateral-to-central amygdala glutamatergic circuit across fear states. Nat Neurosci 2019; 22:2000-2012. [PMID: 31712775 PMCID: PMC6884697 DOI: 10.1038/s41593-019-0528-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 10/02/2019] [Indexed: 11/09/2022]
Abstract
Acquisition and extinction of learned fear responses utilize conserved but flexible neural circuits. Here we show that acquisition of conditioned freezing behavior is associated with dynamic remodeling of relative excitatory drive from the basolateral amygdala (BLA) away from corticotropin releasing factor-expressing (CRF+) centrolateral amygdala neurons, and toward non-CRF+ (CRF-) and somatostatin-expressing (SOM+) neurons, while fear extinction training remodels this circuit back toward favoring CRF+ neurons. Importantly, BLA activity is required for this experience-dependent remodeling, while directed inhibition of the BLA-centrolateral amygdala circuit impairs both fear memory acquisition and extinction memory retrieval. Additionally, ectopic excitation of CRF+ neurons impairs fear memory acquisition and facilities extinction, whereas CRF+ neuron inhibition impairs extinction memory retrieval, supporting the notion that CRF+ neurons serve to inhibit learned freezing behavior. These data suggest that afferent-specific dynamic remodeling of relative excitatory drive to functionally distinct subcortical neuronal output populations represents an important mechanism underlying experience-dependent modification of behavioral selection.
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Affiliation(s)
- Nolan D Hartley
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
| | - Andrew D Gaulden
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Rita Báldi
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Nathan D Winters
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Gregory J Salimando
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Luis Eduardo Rosas-Vidal
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alexis Jameson
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
| | - Danny G Winder
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Sachin Patel
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA.
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA.
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA.
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Prefrontal cortex interneurons display dynamic sex-specific stress-induced transcriptomes. Transl Psychiatry 2019; 9:292. [PMID: 31712551 PMCID: PMC6848179 DOI: 10.1038/s41398-019-0642-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 08/01/2019] [Indexed: 12/13/2022] Open
Abstract
γ-aminobutyric acid (GABA) inhibitory interneurons play a key role in efferent and afferent control of principle neuron activity in the prefrontal cortex (PFC), thereby regulating signal integrity of cognitive and behavioral processes. Recent evidence suggests that specific subtypes of interneurons in the PFC mediate stress-induced depressive-like behaviors. Abnormalities of GABA interneurons, particularly the somatostatin (human, SST; mouse, Sst) subtype, have been reported in postmortem brains of depressed subjects and include sex differences that could explain the increased incidence of depression in women. Here, we analyze the transcriptional profiles and the effects of chronic stress in males vs. females on GABA interneuron subtypes in the PFC. Using Sst- and Parvalbumin-fluorescence tagged reporter mice and fluorescence-activated cell sorting (FACS) combined with RNA sequencing, we identify distinct transcriptome profiles for these interneuron subtypes in the medial PFC. Based on evidence that SST interneurons are altered in depression, we then determined the effects of chronic stress on this interneuron subtype. Chronic stress causes significant dysregulation of several key pathways, including sex-specific differences in the Sst interneuron profiles. The transcriptional pathways altered by chronic stress in males overlap with enriched pathways in non-stressed females. These changes occurred predominantly in decreased expression of elongation initiation factor 2 (EIF2) signaling, suggesting that dysfunction of the translational machinery of SST interneurons could be critical to the development of depressive-like behaviors in males. In addition, SST interneurons from females exposed to chronic stress show dysregulation of different, growth factor signaling pathways.
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6
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Duman RS, Sanacora G, Krystal JH. Altered Connectivity in Depression: GABA and Glutamate Neurotransmitter Deficits and Reversal by Novel Treatments. Neuron 2019; 102:75-90. [PMID: 30946828 PMCID: PMC6450409 DOI: 10.1016/j.neuron.2019.03.013] [Citation(s) in RCA: 493] [Impact Index Per Article: 98.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/04/2019] [Accepted: 03/07/2019] [Indexed: 12/12/2022]
Abstract
The mechanisms underlying the pathophysiology and treatment of depression and stress-related disorders remain unclear, but studies in depressed patients and rodent models are beginning to yield promising insights. These studies demonstrate that depression and chronic stress exposure cause atrophy of neurons in cortical and limbic brain regions implicated in depression, and brain imaging studies demonstrate altered connectivity and network function in the brains of depressed patients. Studies of the neurobiological basis of the these alterations have focused on both the principle, excitatory glutamate neurons, as well as inhibitory GABA interneurons. They demonstrate structural, functional, and neurochemical deficits in both major neuronal types that could lead to degradation of signal integrity in cortical and hippocampal regions. The molecular mechanisms underlying these changes have not been identified but are thought to be related to stress induced excitotoxic effects in combination with elevated adrenal glucocorticoids and inflammatory cytokines as well as other environmental factors. Transcriptomic studies are beginning to demonstrate important sex differences and, together with genomic studies, are starting to reveal mechanistic domains of overlap and uniqueness with regards to risk and pathophysiological mechanisms with schizophrenia and bipolar disorder. These studies also implicate GABA and glutamate dysfunction as well as immunologic mechanisms. While current antidepressants have significant time lag and efficacy limitations, new rapid-acting agents that target the glutamate and GABA systems address these issues and offer superior therapeutic interventions for this widespread and debilitating disorder.
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Affiliation(s)
- Ronald S Duman
- Department of Psychiatry, Yale University School of Medicine, 34 Park Street, New Haven, CT 06508, USA.
| | - Gerard Sanacora
- Department of Psychiatry, Yale University School of Medicine, 34 Park Street, New Haven, CT 06508, USA
| | - John H Krystal
- Department of Psychiatry, Yale University School of Medicine, 34 Park Street, New Haven, CT 06508, USA
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7
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Fogaça MV, Duman RS. Cortical GABAergic Dysfunction in Stress and Depression: New Insights for Therapeutic Interventions. Front Cell Neurosci 2019. [PMID: 30914923 DOI: 10.3389/fncel.2019.00087/full] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
Major depressive disorder (MDD) is a debilitating illness characterized by neuroanatomical and functional alterations in limbic structures, notably the prefrontal cortex (PFC), that can be precipitated by exposure to chronic stress. For decades, the monoaminergic deficit hypothesis of depression provided the conceptual framework to understand the pathophysiology of MDD. However, accumulating evidence suggests that MDD and chronic stress are associated with an imbalance of excitation-inhibition (E:I) within the PFC, generated by a deficit of inhibitory synaptic transmission onto principal glutamatergic neurons. MDD patients and chronically stressed animals show a reduction in GABA and GAD67 levels in the brain, decreased expression of GABAergic interneuron markers, and alterations in GABAA and GABAB receptor levels. Moreover, genetically modified animals with deletion of specific GABA receptors subunits or interneuron function show depressive-like behaviors. Here, we provide further evidence supporting the role of cortical GABAergic interneurons, mainly somatostatin- and parvalbumin-expressing cells, required for the optimal E:I balance in the PFC and discuss how the malfunction of these cells can result in depression-related behaviors. Finally, considering the relatively low efficacy of current available medications, we review new fast-acting pharmacological approaches that target the GABAergic system to treat MDD. We conclude that deficits in cortical inhibitory neurotransmission and interneuron function resulting from chronic stress exposure can compromise the integrity of neurocircuits and result in the development of MDD and other stress-related disorders. Drugs that can establish a new E:I balance in the PFC by targeting the glutamatergic and GABAergic systems show promising as fast-acting antidepressants and represent breakthrough strategies for the treatment of depression.
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Affiliation(s)
- Manoela V Fogaça
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States
| | - Ronald S Duman
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States
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8
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Rytova V, Ganella DE, Hawkes D, Bathgate RAD, Ma S, Gundlach AL. Chronic activation of the relaxin-3 receptor on GABA neurons in rat ventral hippocampus promotes anxiety and social avoidance. Hippocampus 2019; 29:905-920. [PMID: 30891856 DOI: 10.1002/hipo.23089] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 02/19/2019] [Accepted: 02/22/2019] [Indexed: 12/24/2022]
Abstract
Anxiety disorders are highly prevalent in modern society and better treatments are required. Key brain areas and signaling systems underlying anxiety include prefrontal cortex, hippocampus, and amygdala, and monoaminergic and peptidergic systems, respectively. Hindbrain GABAergic projection neurons that express the peptide, relaxin-3, broadly innervate the forebrain, particularly the septum and hippocampus, and relaxin-3 acts via a Gi/o -protein-coupled receptor known as the relaxin-family peptide 3 receptor (RXFP3). Thus, relaxin-3/RXFP3 signaling is implicated in modulation of arousal, motivation, mood, memory, and anxiety. Ventral hippocampus (vHip) is central to affective and cognitive processing and displays a high density of relaxin-3-positive nerve fibers and RXFP3 binding sites, but the identity of target neurons and associated effects on behavior are unknown. Therefore, in adult, male rats, we assessed the neurochemical nature of hippocampal RXFP3 mRNA-expressing neurons and anxiety-like and social behavior following chronic RXFP3 activation in vHip by viral vector expression of an RXFP3-selective agonist peptide, R3/I5. RXFP3 mRNA detected by fluorescent in situ hybridization was topographically distributed across the hippocampus in somatostatin- and parvalbumin-mRNA expressing GABA neurons. Chronic RXFP3 activation in vHip increased anxiety-like behavior in the light-dark box and elevated-plus maze, but not the large open-field test, and reduced social interaction with a conspecific stranger. Our data reveal disruptive effects of persistent RXFP3 signaling on hippocampal GABA networks important in anxiety; and identify a potential therapeutic target for anxiety disorders that warrants further investigation in relevant preclinical models.
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Affiliation(s)
- Valeria Rytova
- Discovery Science, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Despina E Ganella
- Discovery Science, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - David Hawkes
- Discovery Science, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Ross A D Bathgate
- Discovery Science, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Sherie Ma
- Discovery Science, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Andrew L Gundlach
- Discovery Science, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia.,Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia
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9
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Fogaça MV, Duman RS. Cortical GABAergic Dysfunction in Stress and Depression: New Insights for Therapeutic Interventions. Front Cell Neurosci 2019; 13:87. [PMID: 30914923 PMCID: PMC6422907 DOI: 10.3389/fncel.2019.00087] [Citation(s) in RCA: 191] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 02/20/2019] [Indexed: 12/14/2022] Open
Abstract
Major depressive disorder (MDD) is a debilitating illness characterized by neuroanatomical and functional alterations in limbic structures, notably the prefrontal cortex (PFC), that can be precipitated by exposure to chronic stress. For decades, the monoaminergic deficit hypothesis of depression provided the conceptual framework to understand the pathophysiology of MDD. However, accumulating evidence suggests that MDD and chronic stress are associated with an imbalance of excitation-inhibition (E:I) within the PFC, generated by a deficit of inhibitory synaptic transmission onto principal glutamatergic neurons. MDD patients and chronically stressed animals show a reduction in GABA and GAD67 levels in the brain, decreased expression of GABAergic interneuron markers, and alterations in GABAA and GABAB receptor levels. Moreover, genetically modified animals with deletion of specific GABA receptors subunits or interneuron function show depressive-like behaviors. Here, we provide further evidence supporting the role of cortical GABAergic interneurons, mainly somatostatin- and parvalbumin-expressing cells, required for the optimal E:I balance in the PFC and discuss how the malfunction of these cells can result in depression-related behaviors. Finally, considering the relatively low efficacy of current available medications, we review new fast-acting pharmacological approaches that target the GABAergic system to treat MDD. We conclude that deficits in cortical inhibitory neurotransmission and interneuron function resulting from chronic stress exposure can compromise the integrity of neurocircuits and result in the development of MDD and other stress-related disorders. Drugs that can establish a new E:I balance in the PFC by targeting the glutamatergic and GABAergic systems show promising as fast-acting antidepressants and represent breakthrough strategies for the treatment of depression.
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Affiliation(s)
- Manoela V Fogaça
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States
| | - Ronald S Duman
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States
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10
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Fee C, Banasr M, Sibille E. Somatostatin-Positive Gamma-Aminobutyric Acid Interneuron Deficits in Depression: Cortical Microcircuit and Therapeutic Perspectives. Biol Psychiatry 2017; 82:549-559. [PMID: 28697889 PMCID: PMC5610074 DOI: 10.1016/j.biopsych.2017.05.024] [Citation(s) in RCA: 188] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 05/11/2017] [Accepted: 05/30/2017] [Indexed: 12/17/2022]
Abstract
The functional integration of external and internal signals forms the basis of information processing and is essential for higher cognitive functions. This occurs in finely tuned cortical microcircuits whose functions are balanced at the cellular level by excitatory glutamatergic pyramidal neurons and inhibitory gamma-aminobutyric acidergic (GABAergic) interneurons. The balance of excitation and inhibition, from cellular processes to neural network activity, is characteristically disrupted in multiple neuropsychiatric disorders, including major depressive disorder (MDD), bipolar disorder, anxiety disorders, and schizophrenia. Specifically, nearly 3 decades of research demonstrate a role for reduced inhibitory GABA level and function across disorders. In MDD, recent evidence from human postmortem and animal studies suggests a selective vulnerability of GABAergic interneurons that coexpress the neuropeptide somatostatin (SST). Advances in cell type-specific molecular genetics have now helped to elucidate several important roles for SST interneurons in cortical processing (regulation of pyramidal cell excitatory input) and behavioral control (mood and cognition). Here, we review evidence for altered inhibitory function arising from GABAergic deficits across disorders and specifically in MDD. We then focus on properties of the cortical microcircuit, where SST-positive GABAergic interneuron deficits may disrupt functioning in several ways. Finally, we discuss the putative origins of SST cell deficits, as informed by recent research, and implications for therapeutic approaches. We conclude that deficits in SST interneurons represent a contributing cellular pathology and therefore a promising target for normalizing altered inhibitory function in MDD and other disorders with reduced SST cell and GABA functions.
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Affiliation(s)
- Corey Fee
- Campbell Family Mental Health Research Institute of Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Mounira Banasr
- Campbell Family Mental Health Research Institute of Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Etienne Sibille
- Campbell Family Mental Health Research Institute of Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
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11
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Berent D, Emilien G, Podgórski M, Kusideł E, Kulczycka-Wojdala D, Szymańska B, Macander M, Pawłowska Z. SSTR4, Childhood Adversity, Self-efficacy and Suicide Risk in Alcoholics. Transl Neurosci 2017; 8:76-86. [PMID: 28924491 PMCID: PMC5597949 DOI: 10.1515/tnsci-2017-0013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 07/16/2017] [Indexed: 12/29/2022] Open
Abstract
Background Patients with alcohol dependence (AD) are known to develop poor social skills, to report a higher number of adverse childhood experiences (ACEs) and to attempt suicide more frequently than the general population. The background for the association between ACEs and a higher risk of suicide still remains understudied. SSTR4 rs2567608 is a functional polymorphism of the gene for somatostatin receptor subtype 4, predominantly found in the CA1 hippocampus area and involved in memory formation. We hypothesize that the functional polymorphism SSTR4 rs2567608, general self-efficacy, and adverse childhood experiences influence the risk of suicide attempt in patients with AD. Methodology 176 patients with AD and 127 healthy controls were interviewed regarding 13 categories of ACEs and assessed with the General Self-Efficacy Scale. Genotyping for the SSTR4 rs2567608 polymorphism was performed according to the manufacturer’s standard PCR protocol. Results Patients with AD and the controls did not differ significantly according to the SSTR4 rs2567608 genotype and allele frequencies. Lower general self-efficacy, higher number of ACEs, and the SSTR4 rs2567608 TT genotype increased the risk of suicide attempt in patients with AD, and it persisted significant only in male patients with AD. Conclusions Our study supports previous findings on ACEs and general self-efficacy association with a risk for suicide. Additionally, we suggest that patients with AD of the SSTR4 rs2567608 TT genotype may be more vulnerable to ACEs and at a higher risk of suicide attempt.
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Affiliation(s)
- Dominika Berent
- Medical University of Warsaw, Department of Psychiatry II, Kondratowicza 8 Str., PL-03-242Warsaw, Poland
| | - Gerard Emilien
- Universite Claude Bernard Lyon 1, Departement de Biologie Humaine, 8 Avenue Rckfeller, 69373LYON Cedex 08, France
| | - Michał Podgórski
- Polish Mother's Memorial Hospital Research Institute, Department of Diagnostic Imaging, Rzgowska 281/289 Str., 93-338Lodz, Poland
| | - Ewa Kusideł
- University of Lodz, Department of Spatial Econometrics, Rewolucji 1905 r. 39 Str., 90-214Lodz, Poland
| | | | - Bożena Szymańska
- Medical University of Lodz, Central Scientific Laboratory, Mazowiecka 6/8 Str., 92-215Lodz, Poland
| | - Marian Macander
- Military Institute of Aviation Medicine, Safety Flight Department, Krasińskiego 54/56 Str., 01-755Warsaw, Poland
| | - Zofia Pawłowska
- Medical University of Lodz, Central Scientific Laboratory, Mazowiecka 6/8 Str., 92-215Lodz, Poland
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12
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Banasr M, Lepack A, Fee C, Duric V, Maldonado-Aviles J, DiLeone R, Sibille E, Duman RS, Sanacora G. Characterization of GABAergic marker expression in the chronic unpredictable stress model of depression. CHRONIC STRESS 2017; 1. [PMID: 28835932 PMCID: PMC5565173 DOI: 10.1177/2470547017720459] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Evidence continues to build suggesting that the GABAergic neurotransmitter system is altered in brains of patients with major depressive disorder. However, there is little information available related to the extent of these changes or the potential mechanisms associated with these alterations. As stress is a well-established precipitant to depressive episodes, we sought to explore the impact of chronic stress on GABAergic interneurons. Using western blot analyses and quantitative real-time PCR (qPCR) we assessed the effects of five-weeks of chronic unpredictable stress (CUS) exposure on the expression of GABA-synthesizing enzymes (GAD65 and GAD67), calcium-binding proteins (calbindin (CB), parvalbumin (PV) and calretinin (CR)), and neuropeptides co-expressed in GABAergic neurons (somatostatin (SST), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP) and cholecystokinin (CCK)) in the prefrontal cortex (PFC) and hippocampus (HPC) of rats. We also investigated the effects of corticosterone (CORT) and dexamethasone (DEX) exposure on these markers in vitro in primary cortical and hippocampal cultures. We found that CUS induced significant reductions of GAD67 protein levels in both the PFC and HPC of CUS-exposed rats, but did not detect changes in GAD65 protein expression. Similar protein expression changes were found in vitro in cortical neurons. In addition, our results provide clear evidence of reduced markers of interneuron population(s), namely SST and NPY, in the PFC, suggesting these cell types may be selectively vulnerable to chronic stress. Together, this work highlights that chronic stress induces regional and cell type-selective effects on GABAergic interneurons in rats. These findings provide additional supporting evidence that stress-induced GABA neuron dysfunction and cell vulnerability play critical roles in the pathophysiology of stress-related illnesses, including major depressive disorder.
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Affiliation(s)
- Mounira Banasr
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT.,Campbell Family Mental Health Research Institute of CAMH, Toronto, Canada.,Department of Psychiatry, and of Pharmacology and Toxicology, University of Toronto, Toronto, Canada
| | - Ashley Lepack
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT
| | - Corey Fee
- Campbell Family Mental Health Research Institute of CAMH, Toronto, Canada
| | - Vanja Duric
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT.,Department of Physiology and Pharmacology, Des Moines University, Des Moines, IA
| | | | - Ralph DiLeone
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT
| | - Etienne Sibille
- Campbell Family Mental Health Research Institute of CAMH, Toronto, Canada.,Department of Psychiatry, and of Pharmacology and Toxicology, University of Toronto, Toronto, Canada
| | - Ronald S Duman
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT
| | - Gerard Sanacora
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT
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Roles of Hippocampal Somatostatin Receptor Subtypes in Stress Response and Emotionality. Neuropsychopharmacology 2017; 42:1647-1656. [PMID: 27986975 PMCID: PMC5518893 DOI: 10.1038/npp.2016.281] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 10/30/2016] [Accepted: 12/02/2016] [Indexed: 01/21/2023]
Abstract
Altered brain somatostatin functions recently appeared as key elements for the pathogenesis of stress-related neuropsychiatric disorders. The hippocampus exerts an inhibitory feedback on stress but the mechanisms involved remain unclear. We investigated herein the role of hippocampal somatostatin receptor subtypes in both stress response and behavioral emotionality using C57BL/6, wild type and sst2 or sst4 knockout mice. Inhibitory effects of hippocampal infusions of somatostatin agonists on stress-induced hypothalamo-pituitary-adrenal axis (HPA) activity were tested by monitoring peripheral blood and local hippocampus corticosterone levels, the latter by using microdialysis. Anxiolytic and antidepressant-like effects were determined in the elevated-plus maze, open field, forced swimming, and stress-sensitive beam walking tests. Hippocampal injections of somatostatin analogs and sst2 or sst4, but not sst1 or sst3 receptor agonists produced rapid and sustained inhibition of HPA axis. sst2 agonists selectively produced anxiolytic-like behaviors whereas both sst2 and sst4 agonists had antidepressant-like effects. Consistent with these findings, high corticosterone levels and anxiety were found in sst2KO mice and depressive-like behaviors observed in both sst2KO and sst4KO strains. Both hippocampal sst2 and sst4 receptors selectively inhibit stress-induced HPA axis activation but mediate anxiolytic and antidepressive effects through distinct mechanisms. Such results are to be accounted for in development of pathway-specific somatostatin receptor agents in the treatment of hypercortisolism (Cushing's disease) and stress-related neuropsychiatric disorders.
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14
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Hu B, Cilz NI, Lei S. Somatostatin depresses the excitability of subicular bursting cells: Roles of inward rectifier K + channels, KCNQ channels and Epac. Hippocampus 2017; 27:971-984. [PMID: 28558129 DOI: 10.1002/hipo.22744] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 05/08/2017] [Accepted: 05/18/2017] [Indexed: 12/17/2022]
Abstract
The hippocampus is a crucial component for cognitive and emotional processing. The subiculum provides much of the output for this structure but the modulation and function of this region is surprisingly under-studied. The neuromodulator somatostatin (SST) interacts with five subtypes of SST receptors (sst1 to sst5 ) and each of these SST receptor subtypes is coupled to Gi proteins resulting in inhibition of adenylyl cyclase (AC) and decreased level of intracellular cAMP. SST modulates many physiological functions including cognition, emotion, autonomic responses and locomotion. Whereas SST has been shown to depress neuronal excitability in the subiculum, the underlying cellular and molecular mechanisms have not yet been determined. Here, we show that SST hyperpolarized two classes of subicular neurons with a calculated EC50 of 0.1 μM. Application of SST (1 μM) induced outward holding currents by primarily activating K+ channels including the G-protein-activated inwardly-rectifying potassium channels (GIRK) and KCNQ (M) channels, although inhibition of cation channels in some cells may also be implicated. SST-elicited hyperpolarization was mediated by activation of sst2 receptors and required the function of G proteins. The SST-induced hyperpolarization resulted from decreased activity of AC and reduced levels of cAMP but did not require the activity of either PKA or PKC. Inhibition of Epac2, a guanine nucleotide exchange factor, partially blocked SST-mediated hyperpolarization of subicular neurons. Furthermore, application of SST resulted in a robust depression of subicular action potential firing and the SST-induced hyperpolarization was responsible for its inhibitory action on LTP at the CA1-subicilum synapses. Our results provide a novel cellular and molecular mechanism that may explain the roles of SST in modulation of subicular function and be relevant to SST-related physiological functions.
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Affiliation(s)
- Binqi Hu
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota 58203
| | - Nicholas I Cilz
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota 58203
| | - Saobo Lei
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota 58203
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15
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Calakos KC, Blackman D, Schulz AM, Bauer EP. Distribution of type I corticotropin-releasing factor (CRF1) receptors on GABAergic neurons within the basolateral amygdala. Synapse 2017; 71:10.1002/syn.21953. [PMID: 27997737 PMCID: PMC7876706 DOI: 10.1002/syn.21953] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 11/21/2016] [Accepted: 12/02/2016] [Indexed: 12/23/2022]
Abstract
The neuropeptide corticotropin-releasing factor (CRF) plays a critical role in mediating anxiety-like responses to stressors, and dysfunction of the CRF system has been linked to the etiology of several psychiatric disorders. Extra-hypothalamic CRF can also modulate learning and memory formation, including amygdala-dependent learning. The basolateral nucleus of the amygdala (BLA) contains dense concentrations of CRF receptors, yet the distribution of these receptors on specific neuronal subtypes within the BLA has not been characterized. Here, we quantified the expression of CRF receptors on three nonoverlapping classes of GABAergic interneurons: those containing the calcium-binding protein parvalbumin (PV), and those expressing the neuropeptides somatostatin (SOM) or cholecystokinin (CCK). While the majority of PV+ neurons and roughly half of CCK+ neurons expressed CRF receptors, they were expressed to a much lesser extent on SOM+ interneurons. Knowledge of the distribution of CRF receptors within the BLA can provide insight into how manipulations of the CRF system modulate fear and anxiety-like behaviors.
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Affiliation(s)
- Katina C Calakos
- Barnard College Columbia University, 3009 Broadway, New York, New York, 10027
| | - Dakota Blackman
- Barnard College Columbia University, 3009 Broadway, New York, New York, 10027
| | - Alexandra M Schulz
- Barnard College Columbia University, 3009 Broadway, New York, New York, 10027
| | - Elizabeth P Bauer
- Barnard College Columbia University, 3009 Broadway, New York, New York, 10027
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16
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Pantazopoulos H, Wiseman JT, Markota M, Ehrenfeld L, Berretta S. Decreased Numbers of Somatostatin-Expressing Neurons in the Amygdala of Subjects With Bipolar Disorder or Schizophrenia: Relationship to Circadian Rhythms. Biol Psychiatry 2017; 81:536-547. [PMID: 27259817 PMCID: PMC5065936 DOI: 10.1016/j.biopsych.2016.04.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 04/05/2016] [Accepted: 04/07/2016] [Indexed: 12/20/2022]
Abstract
BACKGROUND Growing evidence points to a key role for somatostatin (SST) in schizophrenia (SZ) and bipolar disorder (BD). In the amygdala, neurons expressing SST play an important role in the regulation of anxiety, which is often comorbid in these disorders. We tested the hypothesis that SST-immunoreactive (IR) neurons are decreased in the amygdala of subjects with SZ and BD. Evidence for circadian SST expression in the amygdala and disrupted circadian rhythms and rhythmic peaks of anxiety in BD suggest a disruption of rhythmic expression of SST in this disorder. METHODS Amygdala sections from 12 SZ, 15 BD, and 15 control subjects were processed for immunocytochemistry for SST and neuropeptide Y, a neuropeptide partially coexpressed in SST-IR neurons. Total numbers (Nt) of IR neurons were measured. Time of death was used to test associations with circadian rhythms. RESULTS SST-IR neurons were decreased in the lateral amygdala nucleus in BD (Nt, p = .003) and SZ (Nt, p = .02). In normal control subjects, Nt of SST-IR neurons varied according to time of death. This pattern was altered in BD subjects, characterized by decreases of SST-IR neurons selectively in subjects with time of death corresponding to the day (6:00 am to 5:59 pm). Numbers of neuropeptide Y-IR neurons were not affected. CONCLUSIONS Decreased SST-IR neurons in the amygdala of patients with SZ and BD, interpreted here as decreased SST expression, may disrupt responses to fear and anxiety regulation in these individuals. In BD, our findings raise the possibility that morning peaks of anxiety depend on a disruption of circadian regulation of SST expression in the amygdala.
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Affiliation(s)
- Harry Pantazopoulos
- Translational Neuroscience Laboratory, Mclean Hospital, Belmont; Department of Psychiatry, Harvard Medical School, Boston, Massachusetts.
| | - Jason T Wiseman
- Translational Neuroscience Laboratory, Mclean Hospital, Belmont
| | - Matej Markota
- Translational Neuroscience Laboratory, Mclean Hospital, Belmont; Department of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota
| | - Lucy Ehrenfeld
- Translational Neuroscience Laboratory, Mclean Hospital, Belmont
| | - Sabina Berretta
- Translational Neuroscience Laboratory, Mclean Hospital, Belmont; Department of Psychiatry, Harvard Medical School, Boston, Massachusetts; Program in Neuroscience, Harvard Medical School, Boston, Massachusetts
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17
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Scheich B, Csekő K, Borbély É, Ábrahám I, Csernus V, Gaszner B, Helyes Z. Higher susceptibility of somatostatin 4 receptor gene-deleted mice to chronic stress-induced behavioral and neuroendocrine alterations. Neuroscience 2017; 346:320-336. [DOI: 10.1016/j.neuroscience.2017.01.039] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 01/17/2017] [Accepted: 01/24/2017] [Indexed: 01/20/2023]
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18
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Yeung M, Treit D, Dickson CT. Ventral hippocampal histamine increases the frequency of evoked theta rhythm but produces anxiolytic-like effects in the elevated plus maze. Neuropharmacology 2015; 106:146-55. [PMID: 26400409 DOI: 10.1016/j.neuropharm.2015.09.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Revised: 09/13/2015] [Accepted: 09/17/2015] [Indexed: 01/06/2023]
Abstract
The neurobiological underpinnings of anxiety are of paramount importance to the development of effective therapeutic treatments. To date, there is considerable pharmacological evidence suggesting that the suppression of hippocampal theta frequency is a robust and predictive assay of anxiolytic drug action. Recently, this idea has been challenged using histamine (2-(4-imidazolyl)ethanamine), an endogenous neurotransmitter involved in a number of brain and behavioral functions. Here, we systematically evaluate the effects of dorsal and ventral hippocampal histamine infusions on evoked theta frequency and behavioral anxiety. Given the complex pharmacological profile of histamine and its receptors in the hippocampus, we reasoned that local intra-hippocampal infusions would be a powerful test of the theta suppression model. While dorsal hippocampal infusions of histamine produced neither significant changes in anxious-like behavior in the elevated plus maze nor changes of evoked theta, ventral infusions of histamine produced potent behavioral anxiolysis which corresponded to an increase, and not a decrease, in evoked theta frequency. As a positive neurophysiological control, we demonstrated that diazepam, a proven anxiolytic drug, decreased the frequency of hippocampal theta following both dorsal and ventral hippocampal infusions. Our results further challenge the hippocampal theta frequency suppression model as a measure of anxiolytic drug action. This article is part of the Special Issue entitled 'Histamine Receptors'.
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Affiliation(s)
- Michelle Yeung
- Department of Psychology, University of Alberta, P-217 Biological Sciences Building, Edmonton, AB T6G 2E9, Canada
| | - Dallas Treit
- Department of Psychology, University of Alberta, P-217 Biological Sciences Building, Edmonton, AB T6G 2E9, Canada; Neuroscience, 4-4142 Katz Group Centre, University of Alberta, Edmonton, AB T6G 2E1, Canada.
| | - Clayton T Dickson
- Department of Psychology, University of Alberta, P-217 Biological Sciences Building, Edmonton, AB T6G 2E9, Canada; Neuroscience, 4-4142 Katz Group Centre, University of Alberta, Edmonton, AB T6G 2E1, Canada; Department of Physiology, 7-55 Medical Sciences Building, University of Alberta, Edmonton, AB T6G 2H7, Canada
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19
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Somatostatin receptor subtype 4 activation is involved in anxiety and depression-like behavior in mouse models. Neuropharmacology 2015; 101:204-15. [PMID: 26387439 DOI: 10.1016/j.neuropharm.2015.09.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 09/04/2015] [Accepted: 09/15/2015] [Indexed: 01/15/2023]
Abstract
Somatostatin regulates stress-related behavior and its expression is altered in mood disorders. However, little is known about the underlying mechanisms, especially about the importance of its receptors (sst1-sst5) in anxiety and depression-like behavior. Here we analyzed the potential role of sst4 receptor in these processes, since sst4 is present in stress-related brain regions, but there are no data about its functional relevance. Genetic deletion of sst4 (Sstr4(-/-)) and its pharmacological activation with the newly developed selective non-peptide agonist J-2156 were used. Anxiety was examined in the elevated plus maze (EPM) and depression-like behavior in the forced swim (FST) and tail suspension tests (TST). Neuronal activation during the TST was monitored by Fos immunohistochemistry, receptor expression was identified by sst4(LacZ) immunostaining in several brain regions. Sstr4(-/-) mice showed increased anxiety in the EPM and enhanced depression-like behavior in the FST. J-2156 (100 μg/kg i.p.) exhibited anxiolytic effect in the EPM and decreased immobility in the TST. J-2156 alone did not influence Fos immunoreactivity in intact mice, but significantly increased the stress-induced Fos response in the dorsal raphe nucleus, central projecting Edinger-Westphal nucleus, periaqueductal gray matter, the magnocellular, but not the parvocellular part of the hypothalamic paraventricular nucleus, lateral septum, bed nucleus of the stria terminalis and the amygdala. Notably, sst4(LacZ) immunoreactivity occurred in the central and basolateral amygdala. Together, these studies reveal that sst4 mediates anxiolytic and antidepressant-like effects by enhancing the stress-responsiveness of several brain regions with special emphasis on the amygdala.
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20
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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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21
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Injections of the somatostatin receptor type 2 agonist L-054,264 into the amygdala block expression but not acquisition of conditioned fear in rats. Behav Brain Res 2014; 265:49-52. [PMID: 24548855 DOI: 10.1016/j.bbr.2014.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 02/05/2014] [Accepted: 02/07/2014] [Indexed: 01/12/2023]
Abstract
The amygdala is a crucial brain site for acquisition and expression of conditioned fear. Neuropeptides such as somatostatin play a critical role in regulating the activity of the amygdala. In the present study, the specific somatostatin receptor type 2 (SSTR2) agonist L-054,264 was injected into the amygdala of rats either before fear acquisition or before the expression test on conditioned fear measured by fear-potentiated startle. L-054,264 injections strongly attenuated fear expression but did not affect fear acquisition. This suggests that amygdaloid SSTR2 plays an important role in the modulation of fear memory expression.
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22
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Albrecht A, Thiere M, Bergado-Acosta JR, Poranzke J, Müller B, Stork O. Circadian modulation of anxiety: a role for somatostatin in the amygdala. PLoS One 2013; 8:e84668. [PMID: 24376834 PMCID: PMC3869835 DOI: 10.1371/journal.pone.0084668] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 11/18/2013] [Indexed: 12/30/2022] Open
Abstract
Pharmacological evidence suggests that the neuropeptide somatostatin (SST) exerts anxiolytic action via the amygdala, but findings concerning the putative role of endogenous SST in the regulation of emotional responses are contradictory. We hypothesized that an endogenous regulation of SST expression over the course of the day may determine its function and tested both SST gene expression and the behavior of SST knock out (SST-/-) mice in different aversive tests in relation to circadian rhythm. In an open field and a light/dark avoidance test, SST-/- mice showed significant hyperactivity and anxiety-like behavior during the second, but not during the first half of the active phase, failing to show the circadian modulation of behavior that was evident in their wild type littermates. Behavioral differences occurred independently of changes of intrinsically motivated activity in the home cage. A circadian regulation of SST mRNA and protein expression that was evident in the basolateral complex of the amygdala of wild type mice may provide a neuronal substrate for the observed behavior. However, fear memory towards auditory cue or the conditioning context displayed neither a time- nor genotype-dependent modulation. Together this indicates that SST, in a circadian manner and putatively via its regulation of expression in the amygdala, modulates behavior responding to mildly aversive conditions in mice.
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Affiliation(s)
- Anne Albrecht
- Department of Genetics & Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
- * E-mail:
| | - Marlen Thiere
- Department of Genetics & Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Jorge Ricardo Bergado-Acosta
- Department of Genetics & Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Janine Poranzke
- Department of Genetics & Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Bettina Müller
- Department of Genetics & Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
- Center for Behavioural Brain Science, Magdeburg, Germany
| | - Oliver Stork
- Department of Genetics & Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
- Center for Behavioural Brain Science, Magdeburg, Germany
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23
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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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24
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Stengel A, Rivier J, Taché Y. Modulation of the adaptive response to stress by brain activation of selective somatostatin receptor subtypes. Peptides 2013; 42:70-7. [PMID: 23287111 PMCID: PMC3633742 DOI: 10.1016/j.peptides.2012.12.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 12/21/2012] [Accepted: 12/21/2012] [Indexed: 01/06/2023]
Abstract
Somatostatin-14 was discovered in 1973 in the hypothalamus as a peptide inhibiting growth hormone release. Somatostatin interacts with five receptor subtypes (sst(1-5)) which are widely distributed in the brain with a distinct, but overlapping, expression pattern. During the last few years, the development of highly selective peptide agonists and antagonists provided new insight to characterize the role of somatostatin receptor subtypes in the pleiotropic actions of somatostatin. Recent evidence in rodents indicates that the activation of selective somatostatin receptor subtypes in the brain blunts stress-corticotropin-releasing factor (CRF) related ACTH release (sst2/5), sympathetic-adrenal activaton (sst5), stimulation of colonic motility (sst1), delayed gastric emptying (sst5), suppression of food intake (sst2) and the anxiogenic-like (sst2) response. These findings suggest that brain somatostatin signaling pathways may play an important role in dampening CRF-mediated endocrine, sympathetic, behavioral and visceral responses to stress.
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Affiliation(s)
- Andreas Stengel
- CURE: Digestive Diseases Research Center and Center for Neurovisceral Sciences & Women's Health, Digestive Diseases Division, David Geffen School of Medicine at UCLA and VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
- Division of Psychosomatic Medicine & Obesity Center Berlin, Department of Medicine, Charité Medical Center and University, Berlin, Germany
| | - Jean Rivier
- Peptide Biology Laboratories, Salk Institute, La Jolla, California, USA
| | - Yvette Taché
- CURE: Digestive Diseases Research Center and Center for Neurovisceral Sciences & Women's Health, Digestive Diseases Division, David Geffen School of Medicine at UCLA and VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
- Address: CURE: Digestive Diseases Research Center, Building 115, Room 117, VA Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Los Angeles, CA 90073, Phone: 310-312-9275, Fax: 1-310-268-4963,
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25
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Yeung M, Treit D. The anxiolytic effects of somatostatin following intra-septal and intra-amygdalar microinfusions are reversed by the selective sst2 antagonist PRL2903. Pharmacol Biochem Behav 2011; 101:88-92. [PMID: 22210489 DOI: 10.1016/j.pbb.2011.12.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 12/10/2011] [Accepted: 12/14/2011] [Indexed: 11/30/2022]
Abstract
Somatostatin (SST) is a polypeptide with two biological isoforms (SST14, and SST28), and five SST receptor subtypes (sst1-5). Together, they mediate a number of neural and hormonal functions. Recently, we found that intracerebroventricular (ICV), intra-amygdalar, and intra-septal microinfusions of SST14, SST28, and a selective sst2 receptor agonist L-779976 all produced anxiolytic-like effects in the elevated plus-maze, a widely used animal model of anxiety. The receptor specificity of these anxiolytic-like effects, however, has not been conclusively established. Accordingly, the anxiolytic effects of SST in the elevated plus-maze were assessed following intra-septal or intra-amygalar microinfusions of 1) SST (1.5μg per hemisphere), 2) the highly selective sst2 receptor antagonist PRL2903 (1.5μg per hemisphere), or 3) the combination of SST and PRL2903 (each 1.5μg per hemisphere). Antagonism of the anxiolytic effects of SST in the plus-maze by PRL2903 should result in open-arm exploration that is equivalent to that of 4) vehicle-injected control rats. Both intra-septal and intra-amygdalar microinfusions of SST produced anxiolytic effects in the elevated plus-maze, consistent with results found previously after ICV microinfusions (see Engin et al., 2008; Engin and Treit, 2009; Yeung et al., 2011). More importantly, infusion of PRL2903 completely reversed the anxiolytic effects of SST in both the amygdala and the septum. These results show that somatostatin's anxiolytic effects are mediated by sst2 receptors contained in the amygdala and septum of the rat brain.
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Affiliation(s)
- Michelle Yeung
- Department of Psychology, University of Alberta, P-449 Biological, Sciences Building, Edmonton, AB, Canada T6G 2E9
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