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Ozdemir E. Adrenergic receptor system as a pharmacological target in the treatment of epilepsy (Review). MEDICINE INTERNATIONAL 2024; 4:20. [PMID: 38476984 PMCID: PMC10928664 DOI: 10.3892/mi.2024.144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 02/16/2024] [Indexed: 03/14/2024]
Abstract
Epilepsy is a complex and common neurological disorder characterized by spontaneous and recurrent seizures, affecting ~75 million individuals worldwide. Numerous studies have been conducted to develop new pharmacological drugs for the effective treatment of epilepsy. In recent years, numerous experimental and clinical studies have focused on the role of the adrenergic receptor (AR) system in the regulation of epileptogenesis, seizure susceptibility and convulsions. α1-ARs (α1A, α1B and α1D), α2-ARs (α2A, α2B and α2C) and β-ARs (β1, β2 and β3), known to have convulsant or anticonvulsant effects, have been isolated. Norepinephrine (NE), the key endogenous agonist of ARs, is considered to play a crucial role in the pathophysiology of epileptic seizures. However, the effects of NE on different ARs have not been fully elucidated. Although the activation of some AR subtypes produces conflicting results, the activation of α1, α2 and β receptor subtypes, in particular, produces anticonvulsant effects. The present review focuses on NE and ARs involved in epileptic seizure formation and discusses therapeutic approaches.
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Affiliation(s)
- Ercan Ozdemir
- Department of Physiology, Faculty of Medicine, Sivas Cumhuriyet University, 58140 Sivas, Turkey
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2
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Hajisoltani R, Meftahi GH. Epinephrine injected into the basolateral amygdala affects anxiety-like behavior and memory performance in stressed rats. Neurosci Lett 2024; 819:137590. [PMID: 38086522 DOI: 10.1016/j.neulet.2023.137590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 12/03/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023]
Abstract
The amygdala is known to mediate in moderating the impacts of emotional arousal and stress on memory. According to a growing body of research, the basolateral amygdala (BLA) is an important locus for integrating neuromodulator influences coordinating the retrieval of different types of memory and anxiety. This study aimed to investigate how the epinephrine in the BLA affects hippocampal fear memory, anxiety, and plasticity in control and stressed rats. For four days, male Wistar rats were exposed to electrical foot-shock stress. Animals received bilateral micro-injections of either vehicle or epinephrine (1 µg/side) into the BLA over four days (5 min before foot-shock stress). Behavioral characteristics (fear memory and anxiety-like behavior), histological features and electrophysiological parameters were investigated. Epinephrine injection into BLA resulted in a considerable impairment of fear memory in stressed rats. On the other hand, epinephrine effectively affected fear memory in control rats. Under stress conditions, epinephrine in the BLA is thought to increase anxiety-like behaviors. Treatment with epinephrine significantly increases the slope of fEPSP in the CA1 region of the hippocampus in the control and stress rats. In different groups, foot-shock stress had no effect on the apical and basal dendritic length in the CA1 region of the hippocampus. These results indicate that activating adrenergic receptors diminish fear memory and anxiety-like behaviors in the foot-shock stress, which this impact is independent of CA1 long-term potentiation induction.
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Affiliation(s)
- Razieh Hajisoltani
- Physiology Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Gholam Hossein Meftahi
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
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Saito A, Murata H, Niitani K, Nagasaki J, Otoda A, Chujo Y, Yanagida J, Nishitani N, Deyama S, Kaneda K. Social defeat stress enhances the rewarding effects of cocaine through α 1A adrenoceptors in the medial prefrontal cortex of mice. Neuropharmacology 2024; 242:109757. [PMID: 37839511 DOI: 10.1016/j.neuropharm.2023.109757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 10/07/2023] [Accepted: 10/07/2023] [Indexed: 10/17/2023]
Abstract
Various stressors potentiate the rewarding effects of cocaine and contribute to cocaine cravings. However, it remains unclear whether psychosocial stress enhances the rewarding effects of cocaine. Accordingly, this study employed a cocaine-conditioned place preference (CPP) paradigm combined with social defeat (SD) exposure to investigate the effects of acute SD stress on cocaine reward in male mice. We found that SD stress immediately before the posttest significantly increased cocaine CPP, and systemic blockade of α1 adrenoceptors, but not β adrenoceptors, suppressed this increase. Fiber photometry recordings with GRABNE1m sensors revealed increased noradrenaline (NA) levels in the medial prefrontal cortex (mPFC) in test mice in response to attacks by aggressor mice during SD. Moreover, the SD stress-induced enhancement of CPP was effectively suppressed by intra-mPFC infusion of an α1 adrenoceptor antagonist. In vitro whole-cell recordings demonstrated that silodosin, an α1A, but not α1B or α1D, adrenoceptor antagonist, inhibited NA-induced depolarizing currents and facilitation of excitatory synaptic transmissions. Consistently, intra-mPFC silodosin infusion significantly suppressed the SD stress-induced CPP enhancement. Conversely, intra-mPFC infusion of α1A adrenoceptor agonist augmented cocaine CPP in the absence of stress exposure. Additionally, intranasal silodosin administration attenuated the SD stress-induced enhancement of CPP, and chemogenetic inhibition of mPFC excitatory neurons also suppressed the SD stress-induced CPP enhancement. Together, these findings suggest that NA stimulation of α1A adrenoceptors and the subsequent activation of mPFC pyramidal cells may contribute to SD stress-induced amplification of the rewarding effects of cocaine, and intranasal silodosin administration may hold therapeutic potential for mitigating stress-associated cocaine craving.
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Affiliation(s)
- Atsushi Saito
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Haruka Murata
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Kazuhei Niitani
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Junpei Nagasaki
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Atsuki Otoda
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Yusuke Chujo
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Junko Yanagida
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Naoya Nishitani
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Satoshi Deyama
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Katsuyuki Kaneda
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan.
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Niitani K, Ito S, Wada S, Izumi S, Nishitani N, Deyama S, Kaneda K. Noradrenergic stimulation of α 1 adrenoceptors in the medial prefrontal cortex mediates acute stress-induced facilitation of seizures in mice. Sci Rep 2023; 13:8089. [PMID: 37208473 DOI: 10.1038/s41598-023-35242-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 05/15/2023] [Indexed: 05/21/2023] Open
Abstract
Stress is one of the critical facilitators for seizure induction in patients with epilepsy. However, the neural mechanisms underlying this facilitation remain poorly understood. Here, we investigated whether noradrenaline (NA) transmission enhanced by stress exposure facilitates the induction of medial prefrontal cortex (mPFC)-originated seizures. In mPFC slices, whole-cell current-clamp recordings revealed that bath application of picrotoxin induced sporadic epileptiform activities (EAs), which consisted of depolarization with bursts of action potentials in layer 5 pyramidal cells. Addition of NA dramatically shortened the latency and increased the number of EAs. Simultaneous whole-cell and field potential recordings revealed that the EAs are synchronous in the mPFC local circuit. Terazosin, but not atipamezole or timolol, inhibited EA facilitation, indicating the involvement of α1 adrenoceptors. Intra-mPFC picrotoxin infusion induced seizures in mice in vivo. Addition of NA substantially shortened the seizure latency, while co-infusion of terazosin into the mPFC inhibited the effect of NA. Finally, acute restraint stress shortened the latency of intra-mPFC picrotoxin infusion-induced seizures, whereas prior infusion of terazosin reversed this stress-induced shortening of seizure latency. Our findings suggest that stress facilitates the induction of mPFC-originated seizures via NA stimulation of α1 adrenoceptors.
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Affiliation(s)
- Kazuhei Niitani
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Shiho Ito
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Shintaro Wada
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Shoma Izumi
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Naoya Nishitani
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Satoshi Deyama
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Katsuyuki Kaneda
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan.
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Pidoplichko VI, Figueiredo TH, Braga MFM, Pan H, Marini AM. Alpha-linolenic acid enhances the facilitation of GABAergic neurotransmission in the BLA and CA1. Exp Biol Med (Maywood) 2023; 248:596-604. [PMID: 37208920 PMCID: PMC10350796 DOI: 10.1177/15353702231165010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/02/2023] [Indexed: 05/21/2023] Open
Abstract
Hyperexcitability is a major mechanism implicated in several neuropsychiatric disorders, such as organophosphate-induced status epilepticus (SE), primary epilepsy, stroke, spinal cord injury, traumatic brain injury, schizophrenia, and autism spectrum disorders. Underlying mechanisms are diverse, but a functional impairment and loss of GABAergic inhibitory neurons are common features in many of these disorders. While novel therapies abound to correct for the loss of GABAergic inhibitory neurons, it has been difficult at best to improve the activities of daily living for the majority of patients. Alpha-linolenic acid (ALA) is an essential omega-3 polyunsaturated fatty acid found in plants. ALA exerts pleiotropic effects in the brain that attenuate injury in chronic and acute brain disease models. However, the effect of ALA on GABAergic neurotransmission in hyperexcitable brain regions involved in neuropsychiatric disorders, such as the basolateral amygdala (BLA) and CA1 subfield of the hippocampus, is unknown. Administration of a single dose of ALA (1500 nmol/kg) subcutaneously increased the charge transfer of inhibitory postsynaptic potential currents mediated by GABAA receptors in pyramidal neurons by 52% in the BLA and by 92% in the CA1 compared to vehicle animals a day later. Similar results were obtained in pyramidal neurons from the BLA and CA1 when ALA was bath-applied in slices from naïve animals. Importantly, pretreatment with the high-affinity, selective TrkB inhibitor, k252, completely abolished the ALA-induced increase in GABAergic neurotransmission in the BLA and CA1, suggesting a brain-derived neurotrophic factor (BDNF)-mediated mechanism. Addition of mature BDNF (20 ng/mL) significantly increased GABAA receptor inhibitory activity in the BLA and CA1 pyramidal neurons similar to the results obtained with ALA. ALA may be an effective treatment for neuropsychiatric disorders where hyperexcitability is a major feature.
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Affiliation(s)
- Volodymir I Pidoplichko
- Department of Anatomy, Physiology and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Taiza H Figueiredo
- Department of Anatomy, Physiology and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Maria FM Braga
- Department of Anatomy, Physiology and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Hongna Pan
- Department of Neurology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Ann M Marini
- Department of Neurology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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Battaglia S, Di Fazio C, Vicario CM, Avenanti A. Neuropharmacological Modulation of N-methyl-D-aspartate, Noradrenaline and Endocannabinoid Receptors in Fear Extinction Learning: Synaptic Transmission and Plasticity. Int J Mol Sci 2023; 24:ijms24065926. [PMID: 36983000 PMCID: PMC10053024 DOI: 10.3390/ijms24065926] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 03/10/2023] [Accepted: 03/13/2023] [Indexed: 03/30/2023] Open
Abstract
Learning to recognize and respond to potential threats is crucial for survival. Pavlovian threat conditioning represents a key paradigm for investigating the neurobiological mechanisms of fear learning. In this review, we address the role of specific neuropharmacological adjuvants that act on neurochemical synaptic transmission, as well as on brain plasticity processes implicated in fear memory. We focus on novel neuropharmacological manipulations targeting glutamatergic, noradrenergic, and endocannabinoid systems, and address how the modulation of these neurobiological systems affects fear extinction learning in humans. We show that the administration of N-methyl-D-aspartate (NMDA) agonists and modulation of the endocannabinoid system by fatty acid amide hydrolase (FAAH) inhibition can boost extinction learning through the stabilization and regulation of the receptor concentration. On the other hand, elevated noradrenaline levels dynamically modulate fear learning, hindering long-term extinction processes. These pharmacological interventions could provide novel targeted treatments and prevention strategies for fear-based and anxiety-related disorders.
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Affiliation(s)
- Simone Battaglia
- Center for Studies and Research in Cognitive Neuroscience, Department of Psychology "Renzo Canestrari", Cesena Campus, Alma Mater Studiorum Università di Bologna, 47521 Cesena, Italy
- Department of Psychology, University of Turin, 10124 Turin, Italy
| | - Chiara Di Fazio
- Center for Studies and Research in Cognitive Neuroscience, Department of Psychology "Renzo Canestrari", Cesena Campus, Alma Mater Studiorum Università di Bologna, 47521 Cesena, Italy
| | - Carmelo M Vicario
- Dipartimento di Scienze Cognitive, Psicologiche, Pedagogiche e Degli Studi Culturali, Università Degli Studi di Messina, 98122 Messina, Italy
| | - Alessio Avenanti
- Center for Studies and Research in Cognitive Neuroscience, Department of Psychology "Renzo Canestrari", Cesena Campus, Alma Mater Studiorum Università di Bologna, 47521 Cesena, Italy
- Neuropsicology and Cognitive Neuroscience Research Center (CINPSI Neurocog), Universidad Católica del Maule, Talca 3460000, Chile
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7
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Perez DM. α 1-Adrenergic Receptors: Insights into Potential Therapeutic Opportunities for COVID-19, Heart Failure, and Alzheimer's Disease. Int J Mol Sci 2023; 24:4188. [PMID: 36835598 PMCID: PMC9963459 DOI: 10.3390/ijms24044188] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 02/22/2023] Open
Abstract
α1-Adrenergic receptors (ARs) are members of the G-Protein Coupled Receptor superfamily and with other related receptors (β and α2), they are involved in regulating the sympathetic nervous system through binding and activation by norepinephrine and epinephrine. Traditionally, α1-AR antagonists were first used as anti-hypertensives, as α1-AR activation increases vasoconstriction, but they are not a first-line use at present. The current usage of α1-AR antagonists increases urinary flow in benign prostatic hyperplasia. α1-AR agonists are used in septic shock, but the increased blood pressure response limits use for other conditions. However, with the advent of genetic-based animal models of the subtypes, drug design of highly selective ligands, scientists have discovered potentially newer uses for both agonists and antagonists of the α1-AR. In this review, we highlight newer treatment potential for α1A-AR agonists (heart failure, ischemia, and Alzheimer's disease) and non-selective α1-AR antagonists (COVID-19/SARS, Parkinson's disease, and posttraumatic stress disorder). While the studies reviewed here are still preclinical in cell lines and rodent disease models or have undergone initial clinical trials, potential therapeutics discussed here should not be used for non-approved conditions.
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Affiliation(s)
- Dianne M Perez
- The Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195, USA
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8
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Faraji N, Meftahi GH, Shiravi A, Bahari Z. Evaluation of the effects of phenylephrine and prazosin injection into basolateral amygdala on the post-stress experience of memory retrieval in rats. LEARNING AND MOTIVATION 2023. [DOI: 10.1016/j.lmot.2022.101868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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9
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Varodayan FP, Patel RR, Matzeu A, Wolfe SA, Curley DE, Khom S, Gandhi PJ, Rodriguez L, Bajo M, D'Ambrosio S, Sun H, Kerr TM, Gonzales RA, Leggio L, Natividad LA, Haass-Koffler CL, Martin-Fardon R, Roberto M. The Amygdala Noradrenergic System Is Compromised With Alcohol Use Disorder. Biol Psychiatry 2022; 91:1008-1018. [PMID: 35430085 PMCID: PMC9167785 DOI: 10.1016/j.biopsych.2022.02.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 02/01/2022] [Accepted: 02/04/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND Alcohol use disorder (AUD) is a leading preventable cause of death. The central amygdala (CeA) is a hub for stress and AUD, while dysfunction of the noradrenaline stress system is implicated in AUD relapse. METHODS Here, we investigated whether alcohol (ethanol) dependence and protracted withdrawal alter noradrenergic regulation of the amygdala in rodents and humans. Male adult rats were housed under control conditions, subjected to chronic intermittent ethanol vapor exposure to induce dependence, or withdrawn from chronic intermittent ethanol vapor exposure for 2 weeks, and ex vivo electrophysiology, biochemistry (catecholamine quantification by high-performance liquid chromatography), in situ hybridization, and behavioral brain-site specific pharmacology studies were performed. We also used real-time quantitative polymerase chain reaction to assess gene expression of α1B, β1, and β2 adrenergic receptors in human postmortem brain tissue from men diagnosed with AUD and matched control subjects. RESULTS We found that α1 receptors potentiate CeA GABAergic (gamma-aminobutyric acidergic) transmission and drive moderate alcohol intake in control rats. In dependent rats, β receptors disinhibit a subpopulation of CeA neurons, contributing to their excessive drinking. Withdrawal produces CeA functional recovery with no change in local noradrenaline tissue concentrations, although there are some long-lasting differences in the cellular patterns of adrenergic receptor messenger RNA expression. In addition, postmortem brain analyses reveal increased α1B receptor messenger RNA in the amygdala of humans with AUD. CONCLUSIONS CeA adrenergic receptors are key neural substrates of AUD. Identification of these novel mechanisms that drive alcohol drinking, particularly during the alcohol-dependent state, supports ongoing new medication development for AUD.
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Affiliation(s)
- Florence P Varodayan
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California; Developmental Exposure Alcohol Research Center and Behavioral Neuroscience Program, Department of Psychology, Binghamton University, State University of New York, Binghamton, New York
| | - Reesha R Patel
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California; Systems Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, California
| | - Alessandra Matzeu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California
| | - Sarah A Wolfe
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California
| | - Dallece E Curley
- Center for Alcohol and Addiction Studies, Department of Behavioral and Social Sciences, School of Public Health, Brown University, Providence, Rhode Island; Neuroscience Graduate Program, Department of Neuroscience, Brown University, Providence, Rhode Island
| | - Sophia Khom
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California
| | - Pauravi J Gandhi
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California
| | - Larry Rodriguez
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California
| | - Michal Bajo
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California
| | - Shannon D'Ambrosio
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California
| | - Hui Sun
- Clinical Core Laboratory, Office of the Clinical Director, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Tony M Kerr
- College of Pharmacy, Division of Pharmacology and Toxicology, University of Texas at Austin, Austin, Texas
| | - Rueben A Gonzales
- College of Pharmacy, Division of Pharmacology and Toxicology, University of Texas at Austin, Austin, Texas
| | - Lorenzo Leggio
- Center for Alcohol and Addiction Studies, Department of Behavioral and Social Sciences, School of Public Health, Brown University, Providence, Rhode Island; Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland; Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse Intramural Research Program, Baltimore, Maryland; Medication Development Program, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland; Division of Addiction Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland; Department of Neuroscience, Georgetown University Medical Center, Washington, DC
| | - Luis A Natividad
- College of Pharmacy, Division of Pharmacology and Toxicology, University of Texas at Austin, Austin, Texas
| | - Carolina L Haass-Koffler
- Center for Alcohol and Addiction Studies, Department of Behavioral and Social Sciences, School of Public Health, Brown University, Providence, Rhode Island; Department of Psychiatry and Human Behavior, Warren Alpert Medical School, Brown University, Providence, Rhode Island; Carney Institute for Brain Science, Brown University, Providence, Rhode Island; Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland; Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse Intramural Research Program, Baltimore, Maryland
| | - Rémi Martin-Fardon
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California
| | - Marisa Roberto
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California.
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10
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Stacy M, Schulkin J. Suicide: Allostatic regulation and resilience. Psychoneuroendocrinology 2022; 139:105691. [PMID: 35218982 DOI: 10.1016/j.psyneuen.2022.105691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 10/19/2022]
Abstract
Suicide is a complex public health problem that is the result of a number of intertwined biopsychosocial factors. The diathesis-stress model suggests that suicide is the result of an interaction between genetic vulnerability and environmental stressors. Chronic stress and trauma contribute to biologic adaptations, including hypothalamus-pituitary-adrenal axis dysregulation, that contribute to the degradation of regulatory mechanisms and promote wear and tear the body, represented by allostatic load (AL). AL has been associated with a number of negative outcomes, including mental health problems and suicide. Fortunately, there are pharmacological and non-pharmacological interventions that are effective at reducing AL and reversing its effects. Thus, AL may provide a construct for supporting early risk identification, prevention, and treatment of suicide. AL biomarkers that are amenable to measurable change, effective treatments to reduce AL and perhaps help prevent suicide, and how to best tailor them to the individual and societal levels are important avenues of therapeutic inquiry.
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Affiliation(s)
- Meaghan Stacy
- Department of Psychiatry, Yale University School of Medicine, 300 George St., Suite 901, New Haven, CT 06511, USA.
| | - Jay Schulkin
- School of Medicine, University of Washington, 1959 Pacific St NE, Seattle, WA 98105, USA.
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Kuniishi H, Sekiguchi M, Yamada M. [The contribution of orbitofrontal cortex to stress-related psychiatric disorders: stress induced synaptic change in the orbitofrontal-basolateral amygdala pathway]. Nihon Yakurigaku Zasshi 2021; 156:62-65. [PMID: 33642531 DOI: 10.1254/fpj.20085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Exposure to stress induces alterations in synaptic functions, and increases the risk of stress-related psychiatric disorders, such as major depression and PTSD. To develop new treatments for stress-related psychiatric disorders, it is important to understand the effect of stress on the emotional circuits, such as prefrontal cortex (PFC), amygdala and other limbic regions. The orbitofrontal cortex (OFC, ventral subregion of the PFC) has important roles for processing of negative emotion and has recently been highlighted as a critical region in stress-related psychiatric disorders. However, mechanisms how stress affect OFC circuit and induce psychiatric symptoms were less understood. OFC sends dense projection to the amygdala, which is one of the key nodes for processing of negative emotion. Taken together, there is a possibility that stress affects the information processing in the OFC-amygdala pathway, and it underlies stress-induced emotional alteration. In this article, we introduce our research that examined effects of stress on the excitatory synaptic transmission from OFC to the basolateral nucleus of the amygdala (BLA) using optogenetic and whole-cell patch-clamp methods in mice.
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Affiliation(s)
- Hiroshi Kuniishi
- Department of Neuropsychopharmacology, National Institute of Mental Health, National Center of Neurology and Psychiatry
| | - Masayuki Sekiguchi
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry
| | - Mitsuhiko Yamada
- Department of Neuropsychopharmacology, National Institute of Mental Health, National Center of Neurology and Psychiatry
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12
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Wahis J, Holt MG. Astrocytes, Noradrenaline, α1-Adrenoreceptors, and Neuromodulation: Evidence and Unanswered Questions. Front Cell Neurosci 2021; 15:645691. [PMID: 33716677 PMCID: PMC7947346 DOI: 10.3389/fncel.2021.645691] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 02/03/2021] [Indexed: 12/27/2022] Open
Abstract
Noradrenaline is a major neuromodulator in the central nervous system (CNS). It is released from varicosities on neuronal efferents, which originate principally from the main noradrenergic nuclei of the brain - the locus coeruleus - and spread throughout the parenchyma. Noradrenaline is released in response to various stimuli and has complex physiological effects, in large part due to the wide diversity of noradrenergic receptors expressed in the brain, which trigger diverse signaling pathways. In general, however, its main effect on CNS function appears to be to increase arousal state. Although the effects of noradrenaline have been researched extensively, the majority of studies have assumed that noradrenaline exerts its effects by acting directly on neurons. However, neurons are not the only cells in the CNS expressing noradrenaline receptors. Astrocytes are responsive to a range of neuromodulators - including noradrenaline. In fact, noradrenaline evokes robust calcium transients in astrocytes across brain regions, through activation of α1-adrenoreceptors. Crucially, astrocytes ensheath neurons at synapses and are known to modulate synaptic activity. Hence, astrocytes are in a key position to relay, or amplify, the effects of noradrenaline on neurons, most notably by modulating inhibitory transmission. Based on a critical appraisal of the current literature, we use this review to argue that a better understanding of astrocyte-mediated noradrenaline signaling is therefore essential, if we are ever to fully understand CNS function. We discuss the emerging concept of astrocyte heterogeneity and speculate on how this might impact the noradrenergic modulation of neuronal circuits. Finally, we outline possible experimental strategies to clearly delineate the role(s) of astrocytes in noradrenergic signaling, and neuromodulation in general, highlighting the urgent need for more specific and flexible experimental tools.
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Affiliation(s)
- Jérôme Wahis
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Leuven, Belgium
- Leuven Brain Institute, Leuven, Belgium
| | - Matthew G. Holt
- Laboratory of Glia Biology, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Leuven, Belgium
- Leuven Brain Institute, Leuven, Belgium
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13
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Fujita S, Yoshida S, Matsuki T, Jaiswal MK, Seki K. The α1-adrenergic receptors in the amygdala regulate the induction of learned despair through protein kinase C-beta signaling. Behav Pharmacol 2021; 32:73-85. [PMID: 33164996 DOI: 10.1097/fbp.0000000000000605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Hyperactivity of amygdala is observed in patients with major depressive disorder. Although the role of α1-adrenoceptor in amygdala on fear memory has been well studied, the role of α1-adrenoceptor in amygdala on depression-like behaviors remains unclear. Therefore, we investigated the effect of α1A-adrenoreceptor in amygdala on despair behavior, evaluated by the immobility time during tail suspension test (TST), pharmacological intervention, and immunohistological methods. C57BL6/J mice given a bilateral intra-amygdala injection of artificial cerebrospinal fluid exhibited an increased duration of immobility in the latter half of both trials of TST with a 24-h interval, a phenomenon known as learned despair. Intra-amygdala injection of WB4101 (1.7 nmol/0.1 µl), an α1 adrenoreceptor antagonist, but not propranolol (250 pmol/0.1 µl), a β-adrenoreceptor antagonist, blocked the induction of learned despair during TST. Immunostaining experiments revealed that ~61-75% of α1A-adrenoreceptor-positive neurons were colocalized with GAD65/67 in amygdala, implying that the α1-adrenoceptors in amygdala may enormously regulate the GABA release. Protein kinase C-beta (PKCβ) was predominantly expressed in the α1A-adrenoreceptor-positive neurons in the BLA, whereas protein kinase C-epsilon (PKCε) was highly expressed with the α1A-adrenoreceptor in the Central nucleus of amygdala. Intra-amygdala injection of ruboxistaurin (10 pmol/0.1 µl), a PKCβ inhibitor, blocked the induction of learned despair during TST, whereas neither TAT-εV1-2 (500 ng/0.1 μl), a cell-permeant PKCε inhibitory peptide, nor HBDDE (50 pmol/0.1 µl), an inhibitor of PKCα and -γ, affected the duration of immobility during TST. These data suggest that the α1-adrenoreceptor in amygdala regulates the induction of learned despair via PKCβ.
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Affiliation(s)
- Shisui Fujita
- Department of Pharmacology, School of Pharmaceutical Science, Ohu University, Koriyama, Fukushima
| | - Satomi Yoshida
- Department of Pharmacology, School of Pharmaceutical Science, Ohu University, Koriyama, Fukushima
| | - Tohru Matsuki
- Department of Cellular Pathology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Aichi, Japan
| | - Manoj Kumar Jaiswal
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Kenjiro Seki
- Department of Pharmacology, School of Pharmaceutical Science, Ohu University, Koriyama, Fukushima
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Aversive Stress Reduces Mu Opioid Receptor Expression in the Intercalated Nuclei of the Rat Amygdala. Cell Mol Neurobiol 2021; 41:1119-1129. [PMID: 33400082 DOI: 10.1007/s10571-020-01026-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 12/03/2020] [Indexed: 02/07/2023]
Abstract
The amygdala plays an important role in the integration of responses to noxious and fearful stimuli. Sensory information from many systems is integrated in the lateral and basolateral amygdala and transmitted to the central amygdala, the major output nucleus of the amygdala regulating both motor and emotional responses. The network of intercalated cells (ITC) which surrounds the lateral and basolateral amygdala and serves to modulate information flow from the lateral amygdala to the central nucleus, express a very high local concentration of mu-type opioid receptors. Loss of the ITC neurons impairs fear extinction. We demonstrate here that exposure of rats to a severe stress experience resulted in a marked downregulation of the level of expression of mu opioid receptors in the ITC nuclei over a period of at least 24 h after the end of the stress exposure. The endogenous opioid dynorphin is also expressed in the central and ITC nuclei of the amygdala. Following stress exposure, we also observed an increase in the expression in the more lateral regions of the central amygdala of pro-dynorphin mRNA and a peptide product of pro-dynorphin with known affinity for mu opioid receptors. It is possible that the downregulation of mu receptors in ITC neurons after stress may result from sustained activation and internalization of mu receptors following a stress-induced increase in the release of endogenous opioid peptides.
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15
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Enhanced Retrieval of Taste Associative Memory by Chemogenetic Activation of Locus Coeruleus Norepinephrine Neurons. J Neurosci 2020; 40:8367-8385. [PMID: 32994339 DOI: 10.1523/jneurosci.1720-20.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 08/28/2020] [Accepted: 09/21/2020] [Indexed: 01/08/2023] Open
Abstract
The ability of animals to retrieve memories stored in response to the environment is essential for behavioral adaptation. Norepinephrine (NE)-containing neurons in the brain play a key role in the modulation of synaptic plasticity underlying various processes of memory formation. However, the role of the central NE system in memory retrieval remains unclear. Here, we developed a novel chemogenetic activation strategy exploiting insect olfactory ionotropic receptors (IRs), termed "IR-mediated neuronal activation," and used it for selective stimulation of NE neurons in the locus coeruleus (LC). Drosophila melanogaster IR84a and IR8a subunits were expressed in LC NE neurons in transgenic mice. Application of phenylacetic acid (a specific ligand for the IR84a/IR8a complex) at appropriate doses induced excitatory responses of NE neurons expressing the receptors in both slice preparations and in vivo electrophysiological conditions, resulting in a marked increase of NE release in the LC nerve terminal regions (male and female). Ligand-induced activation of LC NE neurons enhanced the retrieval process of conditioned taste aversion without affecting taste sensitivity, general arousal state, and locomotor activity. This enhancing effect on taste memory retrieval was mediated, in part, through α1- and β-adrenergic receptors in the basolateral nucleus of the amygdala (BLA; male). Pharmacological inhibition of LC NE neurons confirmed the facilitative role of these neurons in memory retrieval via adrenergic receptors in the BLA (male). Our findings indicate that the LC NE system, through projections to the BLA, controls the retrieval process of taste associative memory.SIGNIFICANCE STATEMENT Norepinephrine (NE)-containing neurons in the brain play a key role in the modulation of synaptic plasticity underlying various processes of memory formation, but the role of the NE system in memory retrieval remains unclear. We developed a chemogenetic activation system based on insect olfactory ionotropic receptors and used it for selective stimulation of NE neurons in the locus coeruleus (LC) in transgenic mice. Ligand-induced activation of LC NE neurons enhanced the retrieval of conditioned taste aversion, which was mediated, in part, through adrenoceptors in the basolateral amygdala. Pharmacological blockade of LC activity confirmed the facilitative role of these neurons in memory retrieval. Our findings indicate that the LC-amygdala pathway plays an important role in the recall of taste associative memory.
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16
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Perez DM. α 1-Adrenergic Receptors in Neurotransmission, Synaptic Plasticity, and Cognition. Front Pharmacol 2020; 11:581098. [PMID: 33117176 PMCID: PMC7553051 DOI: 10.3389/fphar.2020.581098] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/11/2020] [Indexed: 12/14/2022] Open
Abstract
α1-adrenergic receptors are G-Protein Coupled Receptors that are involved in neurotransmission and regulate the sympathetic nervous system through binding and activating the neurotransmitter, norepinephrine, and the neurohormone, epinephrine. There are three α1-adrenergic receptor subtypes (α1A, α1B, α1D) that are known to play various roles in neurotransmission and cognition. They are related to two other adrenergic receptor families that also bind norepinephrine and epinephrine, the β- and α2-, each with three subtypes (β1, β2, β3, α2A, α2B, α2C). Previous studies assessing the roles of α1-adrenergic receptors in neurotransmission and cognition have been inconsistent. This was due to the use of poorly-selective ligands and many of these studies were published before the characterization of the cloned receptor subtypes and the subsequent development of animal models. With the availability of more-selective ligands and the development of animal models, a clearer picture of their role in cognition and neurotransmission can be assessed. In this review, we highlight the significant role that the α1-adrenergic receptor plays in regulating synaptic efficacy, both short and long-term synaptic plasticity, and its regulation of different types of memory. We will also present evidence that the α1-adrenergic receptors, and particularly the α1A-adrenergic receptor subtype, are a potentially good target to treat a wide variety of neurological conditions with diminished cognition.
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Affiliation(s)
- Dianne M Perez
- The Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH, United States
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17
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Kuniishi H, Yamada D, Wada K, Yamada M, Sekiguchi M. Stress induces insertion of calcium-permeable AMPA receptors in the OFC-BLA synapse and modulates emotional behaviours in mice. Transl Psychiatry 2020; 10:154. [PMID: 32424318 PMCID: PMC7235080 DOI: 10.1038/s41398-020-0837-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 04/28/2020] [Accepted: 05/01/2020] [Indexed: 01/31/2023] Open
Abstract
Stress increases the risk of neuropsychiatric disorders, such as major depression. Exposure to stress has been reported to induce various neuronal changes, such as alterations in synaptic transmission and structure. However, a causal link between stress-induced neural circuit alterations and changes in emotional behaviours is not well understood. In the present study, we focused on a projection pathway from the orbitofrontal cortex (OFC) to the basolateral nucleus of the amygdala (BLA) as a crucial circuit for negative emotions and examined the effect of stress on OFC-BLA excitatory synaptic transmission using optogenetic and whole-cell patch-clamp methods in mice. As a stress-inducing procedure, we used repeated tail-shock, which increased stress-related behaviours. We found greater α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)/N-methyl-D-aspartate current ratios and insertion of calcium-permeable AMPA receptors (AMPARs) in the OFC-BLA synapse after stress. These stress-induced synaptic and behavioural changes were reduced by a blockade of protein kinase A, which plays a principal role in stress-induced targeting of AMPARs into the synaptic membrane. To examine a possible causal relationship between alterations in synaptic transmission in the OFC-BLA pathway and stress-related behaviour, we performed optogenetic activation or chemogenetic inactivation of OFC-BLA transmission in mice. We found that optogenetic activation and chemogenetic inactivation of OFC-BLA transmission increased and decreased stress-related behaviour, respectively. In conclusion, we have demonstrated that stress altered the postsynaptic properties of the OFC-BLA pathway. These synaptic changes might be one of the underlying mechanisms of stress-induced behavioural alterations.
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Affiliation(s)
- Hiroshi Kuniishi
- grid.419280.60000 0004 1763 8916Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo Japan ,grid.419280.60000 0004 1763 8916Department of Neuropsychopharmacology, National Institute of Mental Health, National Center of Neurology and Psychiatry, Kodaira, Tokyo Japan
| | - Daisuke Yamada
- grid.419280.60000 0004 1763 8916Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo Japan
| | - Keiji Wada
- grid.419280.60000 0004 1763 8916Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo Japan
| | - Mitsuhiko Yamada
- Department of Neuropsychopharmacology, National Institute of Mental Health, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan.
| | - Masayuki Sekiguchi
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan.
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18
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Brehl AK, Kohn N, Schene AH, Fernández G. A mechanistic model for individualised treatment of anxiety disorders based on predictive neural biomarkers. Psychol Med 2020; 50:727-736. [PMID: 32204741 PMCID: PMC7168651 DOI: 10.1017/s0033291720000410] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 10/09/2019] [Accepted: 02/09/2020] [Indexed: 12/29/2022]
Abstract
Increased amygdala responsiveness is the hallmark of fear and a characteristic across patients with anxiety disorders. The amygdala is embedded in a complex regulatory circuit. Multiple different mechanisms may elevate amygdala responsiveness and lead to the occurrence of an anxiety disorder. While top-down control by the prefrontal cortex (PFC) downregulates amygdala responses, the locus coeruleus (LC) drives up amygdala activation via noradrenergic projections. This indicates that the same fearful phenotype may result from different neural mechanisms. We propose a mechanistic model that defines three different neural biomarkers causing amygdala hyper-responsiveness in patients with anxiety disorders: (a) inherent amygdala hypersensitivity, (b) low prefrontal control and (c) high LC drive. First-line treatment for anxiety disorders is exposure-based cognitive behavioural therapy, which strengthens PFC recruitment during emotion regulation and thus targets low-prefrontal control. A treatment response rate around 50% (Loerinc et al., 2015, Clinical Psychological Reviews, 42, 72-82) might indicate heterogeneity of underlying neurobiological mechanisms among patients, presumably leading to high variation in treatment benefit. Transforming insights from cognitive neuroscience into applicable clinical heuristics to categorise patients based on their underlying biomarker may support individualised treatment selection in psychiatry. We review literature on the three anxiety-related mechanisms and present a mechanistic model that may serve as a rational for pathology-based diagnostic and biomarker-guided treatment selection in psychiatry.
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Affiliation(s)
- Anne-Kathrin Brehl
- Radboud University, Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands
| | - Nils Kohn
- Radboud University, Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands
| | | | - Guillen Fernández
- Radboud University, Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands
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19
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Nasrin Faraji, Shiravi A, Bahari Z, Shirvani H, Meftahi GH. Basolateral Amygdala α1-Adrenergic Receptor Suppression Attenuates Stress-Induced Anxiety-Like Behavior and Spine Morphology Impairment on Hippocampal CA1 Pyramidal Neurons. NEUROCHEM J+ 2020. [DOI: 10.1134/s1819712420010079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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20
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Meis S, Endres T, Munsch T, Lessmann V. Impact of Chronic BDNF Depletion on GABAergic Synaptic Transmission in the Lateral Amygdala. Int J Mol Sci 2019; 20:ijms20174310. [PMID: 31484392 PMCID: PMC6747405 DOI: 10.3390/ijms20174310] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/30/2019] [Accepted: 09/01/2019] [Indexed: 01/14/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) has previously been shown to play an important role in glutamatergic synaptic plasticity in the amygdala, correlating with cued fear learning. While glutamatergic neurotransmission is facilitated by BDNF signaling in the amygdala, its mechanism of action at inhibitory synapses in this nucleus is far less understood. We therefore analyzed the impact of chronic BDNF depletion on GABAA-mediated synaptic transmission in BDNF heterozygous knockout mice (BDNF+/−). Analysis of miniature and evoked inhibitory postsynaptic currents (IPSCs) in the lateral amygdala (LA) revealed neither pre- nor postsynaptic differences in BDNF+/− mice compared to wild-type littermates. In addition, long-term potentiation (LTP) of IPSCs was similar in both genotypes. In contrast, facilitation of spontaneous IPSCs (sIPSCs) by norepinephrine (NE) was significantly reduced in BDNF+/− mice. These results argue against a generally impaired efficacy and plasticity at GABAergic synapses due to a chronic BDNF deficit. Importantly, the increase in GABAergic tone mediated by NE is reduced in BDNF+/− mice. As release of NE is elevated during aversive behavioral states in the amygdala, effects of a chronic BDNF deficit on GABAergic inhibition may become evident in response to states of high arousal, leading to amygdala hyper-excitability and impaired amygdala function.
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Affiliation(s)
- Susanne Meis
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany.
- Center for Behavioral Brain Sciences, D-39106 Magdeburg, Germany.
| | - Thomas Endres
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany.
| | - Thomas Munsch
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany.
- Center for Behavioral Brain Sciences, D-39106 Magdeburg, Germany.
| | - Volkmar Lessmann
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany.
- Center for Behavioral Brain Sciences, D-39106 Magdeburg, Germany.
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Estrade L, Cassel JC, Parrot S, Duchamp-Viret P, Ferry B. Microdialysis Unveils the Role of the α 2-Adrenergic System in the Basolateral Amygdala during Acquisition of Conditioned Odor Aversion in the Rat. ACS Chem Neurosci 2019; 10:1929-1934. [PMID: 30179513 DOI: 10.1021/acschemneuro.8b00314] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Previous work has shown that β-adrenergic and GABAergic systems in the basolateral amygdala (BLA) are involved in the acquisition of conditioned odor aversion (COA) learning. The involvement of α2-adrenoreceptors, however, is poorly documented. In a first experiment, male Long-Evans rats received infusions of 0.1 μg of the selective α2-antagonist dexefaroxan (Dex) in the BLA before being exposed to COA learning. In a second experiment, levels of norepinephrine (NE) were analyzed following Dex retrodialysis into the BLA. While microdialysis data showed a significant enhancement of NE release in the BLA with Dex, behavioral results showed that pre-CS infusion of Dex impaired, rather than facilitated, the acquisition of COA. Our results show that the NE system in the BLA is involved in the acquisition of COA, including a strong α2-receptor modulation until now unsuspected. Supported by the recent literature, the present data suggest moreover that the processes underlying this learning are probably mediated by the balanced effects of NE excitatory/inhibitory signaling in the BLA, in which interneurons are highly involved.
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Affiliation(s)
- Lucile Estrade
- Centre of Research
in Neuroscience Lyon, UMR CNRS 5292 - INSERM U 1028, Université
Claude Bernard Lyon 1, 50 avenue Tony Garnier, 69366 Lyon, France
| | - Jean-Christophe Cassel
- Laboratoire de
Neurosciences Cognitives et Adaptatives, UMR 7364, Université
de Strasbourg − CNRS, Faculté de Psychologie, 12 rue Goethe 67000 Strasbourg, France
| | - Sandrine Parrot
- Centre of Research
in Neurosciences Lyon, INSERM U1028 − Université Claude
Bernard Lyon 1, NeuroDialyTics UNIT, 7 Rue Guillaume Paradin, F-69372 Lyon Cedex 08, France
| | - Patricia Duchamp-Viret
- Centre of Research
in Neuroscience Lyon, UMR CNRS 5292 - INSERM U 1028, Université
Claude Bernard Lyon 1, 50 avenue Tony Garnier, 69366 Lyon, France
| | - Barbara Ferry
- Centre of Research
in Neuroscience Lyon, UMR CNRS 5292 - INSERM U 1028, Université
Claude Bernard Lyon 1, 50 avenue Tony Garnier, 69366 Lyon, France
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22
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Malikowska-Racia N, Salat K. Recent advances in the neurobiology of posttraumatic stress disorder: A review of possible mechanisms underlying an effective pharmacotherapy. Pharmacol Res 2019; 142:30-49. [PMID: 30742899 DOI: 10.1016/j.phrs.2019.02.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 01/24/2019] [Accepted: 02/01/2019] [Indexed: 12/24/2022]
Abstract
Recent progress in the field of neurobiology supported by clinical evidence gradually reveals the mystery of human brain functioning. So far, many psychiatric disorders have been described in great detail, although there are still plenty of cases that are misunderstood. These include posttraumatic stress disorder (PTSD), which is a unique disease that combines a wide range of neurobiological changes, which involve disturbances of the hypothalamic-pituitary-adrenal gland axis, hyperactivation of the amygdala complex, and attenuation of some hippocampal and cortical functions. Such multiplicity results in differential symptomatology, including elevated anxiety, nightmares, fear retrieval episodes that may trigger delusions and hallucinations, sleep disturbances, and many others that strongly interfere with the quality of the patient's life. Because of widespread neurological changes and the disease manifestation, the pharmacotherapy of PTSD remains unclear and requires a multidimensional approach and involvement of polypharmacotherapy. Hopefully, more and more neuroscientists and clinicians will study PTSD, which will provide us with new information that would possibly accelerate establishment of well-tolerated and effective pharmacotherapy. In this review, we have focused on neurobiological changes regarding PTSD, addressing the most disturbed brain structures and neurotransmissions, as well as discussing in detail the recently taken and novel therapeutic paths.
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Affiliation(s)
- Natalia Malikowska-Racia
- Department of Pharmacodynamics, Chair of Pharmacodynamics, Jagiellonian University Medical College, 9 Medyczna St., 30-688 Krakow, Poland.
| | - Kinga Salat
- Department of Pharmacodynamics, Chair of Pharmacodynamics, Jagiellonian University Medical College, 9 Medyczna St., 30-688 Krakow, Poland
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23
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Lucas EK, Wu WC, Roman-Ortiz C, Clem RL. Prazosin during fear conditioning facilitates subsequent extinction in male C57Bl/6N mice. Psychopharmacology (Berl) 2019; 236:273-279. [PMID: 30112577 PMCID: PMC6374171 DOI: 10.1007/s00213-018-5001-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 08/08/2018] [Indexed: 11/25/2022]
Abstract
RATIONALE Recovery from a traumatic experience requires extinction of cue-based fear responses, a process that is impaired in post-traumatic stress disorder. While studies suggest a link between fear behavioral flexibility and noradrenaline signaling, the role of specific receptors and brain regions in these effects is unclear. OBJECTIVES Here, we examine the role of prazosin, an α1-adrenergic receptor (α1-AR) antagonist, in auditory fear conditioning and extinction. METHODS C57Bl/6N mice were subjected to auditory fear conditioning and extinction in combination with systemic (0.1-2 mg/kg) or local microinjections (3 or 6 mM) of the α1-AR antagonist prazosin into the prelimbic division of medial prefrontal cortex or basolateral amygdala. Conditioned fear and anxiety-like behaviors were compared with vehicle-injected control animals. RESULTS Mice that received systemic prazosin prior to fear conditioning exhibited similar initial levels of cue-elicited freezing compared to vehicle controls on the following day. However, at all doses tested, fear that was acquired during prazosin treatment was more readily extinguished, whereas anxiety-like behavior on the day of extinction was unaffected. A similar pattern of results was observed when prazosin was microinjected into the basolateral amygdala but not the prelimbic cortex. In contrast to pre-conditioning injections, prazosin administration prior to extinction had no effect on freezing. CONCLUSIONS Our results indicate that α1-AR activity during aversive conditioning is dispensable for memory acquisition but renders conditioned fear more impervious to extinction. This suggests that behavioral flexibility is constrained by noradrenaline at the time of initial learning via activation of a specific AR isoform.
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Affiliation(s)
- Elizabeth K Lucas
- Fishberg Department of Neuroscience and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1065, New York, NY, 10029, USA
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC, 27606, USA
| | - Wan-Chen Wu
- Fishberg Department of Neuroscience and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1065, New York, NY, 10029, USA
| | - Ciorana Roman-Ortiz
- Fishberg Department of Neuroscience and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1065, New York, NY, 10029, USA
| | - Roger L Clem
- Fishberg Department of Neuroscience and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1065, New York, NY, 10029, USA.
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
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24
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Ghasemi M, Mehranfard N. Mechanisms underlying anticonvulsant and proconvulsant actions of norepinephrine. Neuropharmacology 2018; 137:297-308. [DOI: 10.1016/j.neuropharm.2018.05.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/09/2018] [Accepted: 05/10/2018] [Indexed: 01/02/2023]
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25
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Meis S, Endres T, Munsch T, Lessmann V. Presynaptic Regulation of Tonic Inhibition by Neuromodulatory Transmitters in the Basal Amygdala. Mol Neurobiol 2018; 55:8509-8521. [PMID: 29560580 DOI: 10.1007/s12035-018-0984-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 02/28/2018] [Indexed: 01/23/2023]
Abstract
Tonic inhibition mediated by ambient levels of GABA that activate extrasynaptic GABAA receptors emerges as an essential factor that tunes neuronal network excitability in vitro and shapes behavioral responses in vivo. To address the role of neuromodulatory transmitter systems on this type of inhibition, we employed patch clamp recordings in mouse amygdala slice preparations. Our results show that the current amplitude of tonic inhibition (Itonic) in projection neurons of the basal amygdala (BA) is increased by preincubation with the neurosteroid THDOC, while the benzodiazepine diazepam is ineffective. This suggests involvement of THDOC sensitive δ subunit containing GABAA receptors in mediating tonic inhibition. Moreover, we provide evidence that the neuromodulatory transmitters NE, 5HT, and ACh strongly enhance spontaneous IPSCs as well as Itonic in the BA. As the increase in frequency, amplitude, and charge of sIPSCs by these neuromodulatory transmitters strongly correlated with the amplitude of Itonic, we conclude that spill-over of synaptic GABA leads to activation of Itonic and thereby to dampening of amygdala excitability. Since local injection of THDOC, as a positive modulator of tonic inhibition, into the BA interfered with the expression of contextual fear memory, our results point to a prominent role of Itonic in fear learning.
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Affiliation(s)
- S Meis
- Institut für Physiologie, Otto-von-Guericke-Universität, Leipziger Str. 44, D-39120, Magdeburg, Germany. .,Center for Behavioral Brain Sciences, Magdeburg, Germany.
| | - T Endres
- Institut für Physiologie, Otto-von-Guericke-Universität, Leipziger Str. 44, D-39120, Magdeburg, Germany
| | - T Munsch
- Institut für Physiologie, Otto-von-Guericke-Universität, Leipziger Str. 44, D-39120, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - V Lessmann
- Institut für Physiologie, Otto-von-Guericke-Universität, Leipziger Str. 44, D-39120, Magdeburg, Germany. .,Center for Behavioral Brain Sciences, Magdeburg, Germany.
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26
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Homan P, Lin Q, Murrough JW, Soleimani L, Bach DR, Clem RL, Schiller D. Prazosin during threat discrimination boosts memory of the safe stimulus. ACTA ACUST UNITED AC 2017; 24:597-601. [PMID: 29038221 PMCID: PMC5647929 DOI: 10.1101/lm.045898.117] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/10/2017] [Indexed: 11/24/2022]
Abstract
The α-1 adrenoreceptor antagonist prazosin has shown promise in the treatment of post-traumatic stress disorder (PTSD) symptoms, but its mechanisms are not well understood. Here we administered prazosin or placebo prior to threat conditioning (day 1) and tested subsequent extinction (day 2) and reextinction (day 3) in healthy human participants. Prazosin did not affect threat conditioning but augmented stimulus discrimination during extinction and reextinction, via lower responding to the safe stimulus. These results suggest that prazosin during threat acquisition may have influenced encoding or consolidation of safety processing in particular, subsequently leading to enhanced discrimination between the safe and threatening stimuli.
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Affiliation(s)
- Philipp Homan
- Department of Psychiatry and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Qi Lin
- Department of Psychiatry and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - James W Murrough
- Department of Psychiatry and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA.,Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Laili Soleimani
- Department of Psychiatry and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Dominik R Bach
- Department of Psychiatry, Psychotherapy, and Psychosomatics, University of Zurich, 8032 Zurich, Switzerland
| | - Roger L Clem
- Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Daniela Schiller
- Department of Psychiatry and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA.,Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
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27
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Changes in Gene Expression in the Locus Coeruleus-Amygdala Circuitry in Inhibitory Avoidance PTSD Model. Cell Mol Neurobiol 2017; 38:273-280. [PMID: 28889197 DOI: 10.1007/s10571-017-0548-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 09/02/2017] [Indexed: 12/28/2022]
Abstract
The locus coeruleus (LC)-amygdala circuit is implicated in playing a key role in responses to emotionally arousing stimuli and in the manifestation of post-traumatic stress disorder (PTSD). Here, we examined changes in gene expression of a number of important mediators of the LC-amygdala circuitry in the inhibition avoidance model of PTSD. After testing for basal acoustic startle response (ASR), rats were exposed to a severe footshock (1.5 mA for 10 s) in the inhibitory avoidance apparatus. They were given contextual situational reminders every 5 day for 25 days. Controls were treated identically but with the footshock inactivated. Animals were re-tested on second ASR and decapitated 1 h later. The shock group had enhanced hyperarousal and several changes in gene expression compared to controls. In the LC, mRNA levels of norepinephrine (NE) biosynthetic enzymes (TH, DBH), NE transporter (NET), NPY receptors (Y1R, Y2R), and CB1 receptor of endocannabinoid system were elevated. In the basolateral amygdala (BLA), there were marked reductions in gene expression for CB1, and especially Y1R, with rise for corticotropin-releasing hormone (CRH) system (CRH, CRH receptor 1), and no significant changes in the central amygdala. Our results suggest a fast forward mechanism in the LC-amygdala circuitry in the shock group.
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28
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Sharp BM. Basolateral amygdala and stress-induced hyperexcitability affect motivated behaviors and addiction. Transl Psychiatry 2017; 7:e1194. [PMID: 28786979 PMCID: PMC5611728 DOI: 10.1038/tp.2017.161] [Citation(s) in RCA: 152] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 05/16/2017] [Accepted: 06/08/2017] [Indexed: 12/11/2022] Open
Abstract
The amygdala integrates and processes incoming information pertinent to reward and to emotions such as fear and anxiety that promote survival by warning of potential danger. Basolateral amygdala (BLA) communicates bi-directionally with brain regions affecting cognition, motivation and stress responses including prefrontal cortex, hippocampus, nucleus accumbens and hindbrain regions that trigger norepinephrine-mediated stress responses. Disruption of intrinsic amygdala and BLA regulatory neurocircuits is often caused by dysfunctional neuroplasticity frequently due to molecular alterations in local GABAergic circuits and principal glutamatergic output neurons. Changes in local regulation of BLA excitability underlie behavioral disturbances characteristic of disorders including post-traumatic stress syndrome (PTSD), autism, attention-deficit hyperactivity disorder (ADHD) and stress-induced relapse to drug use. In this Review, we discuss molecular mechanisms and neural circuits that regulate physiological and stress-induced dysfunction of BLA/amygdala and its principal output neurons. We consider effects of stress on motivated behaviors that depend on BLA; these include drug taking and drug seeking, with emphasis on nicotine-dependent behaviors. Throughout, we take a translational approach by integrating decades of addiction research on animal models and human trials. We show that changes in BLA function identified in animal addiction models illuminate human brain imaging and behavioral studies by more precisely delineating BLA mechanisms. In summary, BLA is required to promote responding for natural reward and respond to second-order drug-conditioned cues; reinstate cue-dependent drug seeking; express stress-enhanced reacquisition of nicotine intake; and drive anxiety and fear. Converging evidence indicates that chronic stress causes BLA principal output neurons to become hyperexcitable.
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Affiliation(s)
- B M Sharp
- Department of Pharmacology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA
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29
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Skelly MJ, Ariwodola OJ, Weiner JL. Fear conditioning selectively disrupts noradrenergic facilitation of GABAergic inhibition in the basolateral amygdala. Neuropharmacology 2016; 113:231-240. [PMID: 27720769 DOI: 10.1016/j.neuropharm.2016.10.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 09/26/2016] [Accepted: 10/03/2016] [Indexed: 10/20/2022]
Abstract
Inappropriate fear memory formation is symptomatic of many psychopathologies, and delineating the neurobiology of non-pathological fear learning may provide critical insight into treating these disorders. Fear memory formation is associated with decreased inhibitory signaling in the basolateral amygdala (BLA), and disrupted noradrenergic signaling may contribute to this decrease. BLA noradrenergic neurotransmission has been implicated in fear memory formation, and distinct adrenoreceptor (AR) subtypes modulate excitatory and inhibitory neurotransmission in this region. For example, α1-ARs promote GABA release from local inhibitory interneurons, while β3-ARs potentiate neurotransmission at lateral paracapsular (LPC) GABAergic synapses. Conversely, β1/2-ARs amplify excitatory signaling at glutamatergic synapses in the BLA. As increased BLA excitability promotes fear memory formation, we hypothesized that fear learning shifts the balanced regional effects of noradrenergic signaling toward excitation. To test this hypothesis, we used the fear-potentiated startle paradigm in combination with whole cell patch clamp electrophysiology to examine the effects of AR activation on BLA synaptic transmission following fear conditioning in male Long-Evans rats. We first demonstrated that inhibitory neurotransmission is decreased at both local and LPC synapses following fear conditioning. We next measured noradrenergic facilitation of BLA inhibitory signaling at local and LPC synapses using α1-and β3-AR agonists (1 μM A61603 and 10 μM BRL37344), and found that the ability of these agents to facilitate inhibitory neurotransmission is disrupted following fear conditioning. Conversely, we found that fear learning does not disrupt noradrenergic modulation of glutamatergic signaling via a β1/2-AR agonist (1 μM isoproterenol). Taken together, these studies suggest that fear learning increases BLA excitability by selectively disrupting the inhibitory effects of noradrenaline.
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Affiliation(s)
- M J Skelly
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA
| | - O J Ariwodola
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA
| | - J L Weiner
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
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30
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Effects of Repeated Stress on Age-Dependent GABAergic Regulation of the Lateral Nucleus of the Amygdala. Neuropsychopharmacology 2016; 41:2309-23. [PMID: 26924679 PMCID: PMC4946062 DOI: 10.1038/npp.2016.33] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 01/25/2016] [Accepted: 02/03/2016] [Indexed: 12/17/2022]
Abstract
The adolescent age is associated with lability of mood and emotion. The onset of depression and anxiety disorders peaks during adolescence and there are differences in symptomology during adolescence. This points to differences in the adolescent neural circuitry that underlies mood and emotion, such as the amygdala. The human adolescent amygdala is more responsive to evocative stimuli, hinting to less local inhibitory regulation of the amygdala, but this has not been explored in adolescents. The amygdala, including the lateral nucleus (LAT) of the basolateral amygdala complex, is sensitive to stress. The amygdala undergoes maturational processes during adolescence, and therefore may be more vulnerable to harmful effects of stress during this time period. However, little is known about the effects of stress on the LAT during adolescence. GABAergic inhibition is a key regulator of LAT activity. Therefore, the purpose of this study was to test whether there are differences in the local GABAergic regulation of the rat adolescent LAT, and differences in its sensitivity to repeated stress. We found that LAT projection neurons are subjected to weaker GABAergic inhibition during adolescence. Repeated stress reduced in vivo endogenous and exogenous GABAergic inhibition of LAT projection neurons in adolescent rats. Furthermore, repeated stress decreased measures of presynaptic GABA function and interneuron activity in adolescent rats. In contrast, repeated stress enhanced glutamatergic drive of LAT projection neurons in adult rats. These results demonstrate age differences in GABAergic regulation of the LAT, and age differences in the mechanism for the effects of repeated stress on LAT neuron activity. These findings provide a substrate for increased mood lability in adolescents, and provide a substrate by which adolescent repeated stress can induce distinct behavioral outcomes and psychiatric symptoms.
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31
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Reyes BAS, Kravets JL, Connelly KL, Unterwald EM, Van Bockstaele EJ. Localization of the delta opioid receptor and corticotropin-releasing factor in the amygdalar complex: role in anxiety. Brain Struct Funct 2016; 222:1007-1026. [PMID: 27376372 DOI: 10.1007/s00429-016-1261-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 06/22/2016] [Indexed: 12/24/2022]
Abstract
It is well established that central nervous system norepinephrine (NE) and corticotropin-releasing factor (CRF) systems are important mediators of behavioral responses to stressors. More recent studies have defined a role for delta opioid receptors (DOPR) in maintaining emotional valence including anxiety. The amygdala plays an important role in processing emotional stimuli, and has been implicated in the development of anxiety disorders. Activation of DOPR or inhibition of CRF in the amygdala reduces baseline and stress-induced anxiety-like responses. It is not known whether CRF- and DOPR-containing amygdalar neurons interact or whether they are regulated by NE afferents. Therefore, this study sought to better define interactions between the CRF, DOPR and NE systems in the basolateral (BLA) and central nucleus of the amygdala (CeA) of the male rat using anatomical and functional approaches. Irrespective of the amygdalar subregion, dual immunofluorescence microscopy showed that DOPR was present in CRF-containing neurons. Immunoelectron microscopy confirmed that DOPR was localized to both dendritic processes and axon terminals in the BLA and CeA. Semi-quantitative dual immunoelectron microscopy analysis of gold-silver labeling for DOPR and immunoperoxidase labeling for CRF revealed that 55 % of the CRF neurons analyzed contained DOPR in the BLA while 67 % of the CRF neurons analyzed contained DOPR in the CeA. Furthermore, approximately 41 % of DOPR-labeled axon terminals targeted BLA neurons that expressed CRF while 29 % of DOPR-labeled axon terminals targeted CeA neurons that expressed CRF. Triple label immunofluorescence microscopy revealed that DOPR and CRF were co-localized in common cellular profiles that were in close proximity to NE-containing fibers in both subregions. These anatomical results indicate significant interactions between DOPR and CRF in this critical limbic region and reveal that NE is poised to regulate these peptidergic systems in the amygdala. Functional studies were performed to determine if activation of DOPR could inhibit the anxiety produced by elevation of NE in the amygdala using the pharmacological stressor yohimbine. Administration of the DOPR agonist, SNC80, significantly attenuated elevated anxiogenic behaviors produced by yohimbine as measured in the rat on the elevated zero maze. Taken together, results from this study demonstrate the convergence of three important systems, NE, CRF, and DOPR, in the amygdala and provide insight into their functional role in modulating stress and anxiety responses.
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Affiliation(s)
- Beverly A S Reyes
- Department of Pharmacology and Physiology, College of Medicine, Drexel University, 245 S. 15th Street, Philadelphia, PA, 19102, USA.
| | - J L Kravets
- Department of Pharmacology and Physiology, College of Medicine, Drexel University, 245 S. 15th Street, Philadelphia, PA, 19102, USA
| | - K L Connelly
- Center for Substance Abuse Research, Department of Pharmacology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, 19140, USA
| | - E M Unterwald
- Center for Substance Abuse Research, Department of Pharmacology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, 19140, USA
| | - E J Van Bockstaele
- Department of Pharmacology and Physiology, College of Medicine, Drexel University, 245 S. 15th Street, Philadelphia, PA, 19102, USA
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32
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Butler TR, Karkhanis AN, Jones SR, Weiner JL. Adolescent Social Isolation as a Model of Heightened Vulnerability to Comorbid Alcoholism and Anxiety Disorders. Alcohol Clin Exp Res 2016; 40:1202-14. [PMID: 27154240 DOI: 10.1111/acer.13075] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 03/24/2016] [Indexed: 01/01/2023]
Abstract
Individuals diagnosed with anxiety-related illnesses are at increased risk of developing alcoholism, exhibit a telescoped progression of this disease and fare worse in recovery, relative to alcoholics that do not suffer from a comorbid anxiety disorder. Similarly, preclinical evidence supports the notion that stress and anxiety represent major risk factors for the development of alcohol use disorder (AUD). Despite the importance of understanding the link between anxiety and alcoholism, much remains unknown about the neurobiological substrates underlying this relationship. One stumbling block has been the lack of animal models that reliably reproduce the spectrum of behaviors associated with increased vulnerability to these diseases. Here, we review the literature that has examined the behavioral and neurobiological outcomes of a simple rodent adolescent social isolation procedure and discuss its validity as a model of vulnerability to comorbid anxiety disorders and alcoholism. Recent studies have provided strong evidence that adolescent social isolation of male rats leads to the expression of a variety of behaviors linked with increased vulnerability to anxiety and/or AUD, including deficits in sensory gating and fear extinction, and increases in anxiety measures and ethanol drinking. Neurobiological studies are beginning to identify mesolimbic adaptations that may contribute to the behavioral phenotype engendered by this model. Some of these changes include increased excitability of ventral tegmental area dopamine neurons and pyramidal cells in the basolateral amygdala and significant alterations in baseline and stimulated catecholamine signaling. A growing body of evidence suggests that adolescent social isolation may represent a reliable rodent model of heightened vulnerability to anxiety disorders and alcoholism in male rats. These studies provide initial support for the face, construct, and predictive validity of this model and highlight its utility in identifying neurobiological adaptations associated with increased risk of developing these disorders.
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Affiliation(s)
- Tracy R Butler
- Department of Psychology , University of Dayton, Dayton, Ohio
| | - Anushree N Karkhanis
- Department of Physiology and Pharmacology , Wake Forest School of Medicine, Winston Salem, North Carolina
| | - Sara R Jones
- Department of Physiology and Pharmacology , Wake Forest School of Medicine, Winston Salem, North Carolina
| | - Jeffrey L Weiner
- Department of Physiology and Pharmacology , Wake Forest School of Medicine, Winston Salem, North Carolina
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33
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Skelly MJ, Chappell AM, Ariwodola OJ, Weiner JL. Behavioral and neurophysiological evidence that lateral paracapsular GABAergic synapses in the basolateral amygdala contribute to the acquisition and extinction of fear learning. Neurobiol Learn Mem 2015; 127:10-6. [PMID: 26593151 DOI: 10.1016/j.nlm.2015.11.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 10/12/2015] [Accepted: 11/10/2015] [Indexed: 11/29/2022]
Abstract
The lateral/basolateral amygdala (BLA) is crucial to the acquisition and extinction of Pavlovian fear conditioning, and synaptic plasticity in this region is considered to be a neural correlate of learned fear. We recently reported that activation of BLA β3-adrenoreceptors (β3-ARs) selectively enhances lateral paracapsular (LPC) feed-forward GABAergic inhibition onto BLA pyramidal neurons, and that intra-BLA infusion of a β3-AR agonist reduces measures of unconditioned anxiety-like behavior. Here, we utilized a combination of behavioral and electrophysiological approaches to characterize the role of BLA LPCs in the acquisition of fear and extinction learning in adult male Long-Evans rats. We report that intra-BLA microinjection of β3-AR agonists (BRL37344 or SR58611A, 1μg/0.5μL/side) prior to training fear conditioning or extinction blocks the expression of these behaviors 24h later. Furthermore,ex vivo low-frequency stimulation of the external capsule (LFS; 1Hz, 15min), which engages LPC synapses, induces LTP of BLA fEPSPs, while application of a β3-AR agonist (SR58611A, 5μM) induces LTD of fEPSPs when combined with LFS. Interestingly, fEPSP LTP is not observed in recordings from fear conditioned animals, suggesting that fear learning may engage the same mechanisms that induce synaptic plasticity at this input. In support of this, we find that LFS produces LTD of inhibitory postsynaptic currents (iLTD) at LPC GABAergic synapses, and that this effect is also absent following fear conditioning. Taken together, these data provide preliminary evidence that modulation of LPC GABAergic synapses can influence the acquisition and extinction of fear learning and related synaptic plasticity in the BLA.
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Affiliation(s)
- M J Skelly
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, United States
| | - A M Chappell
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, United States
| | - O J Ariwodola
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, United States
| | - J L Weiner
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, United States.
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34
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Prager EM, Bergstrom HC, Wynn GH, Braga MFM. The basolateral amygdala γ-aminobutyric acidergic system in health and disease. J Neurosci Res 2015; 94:548-67. [PMID: 26586374 DOI: 10.1002/jnr.23690] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/01/2015] [Accepted: 10/18/2015] [Indexed: 01/13/2023]
Abstract
The brain comprises an excitatory/inhibitory neuronal network that maintains a finely tuned balance of activity critical for normal functioning. Excitatory activity in the basolateral amygdala (BLA), a brain region that plays a central role in emotion and motivational processing, is tightly regulated by a relatively small population of γ-aminobutyric acid (GABA) inhibitory neurons. Disruption in GABAergic inhibition in the BLA can occur when there is a loss of local GABAergic interneurons, an alteration in GABAA receptor activation, or a dysregulation of mechanisms that modulate BLA GABAergic inhibition. Disruptions in GABAergic control of the BLA emerge during development, in aging populations, or after trauma, ultimately resulting in hyperexcitability. BLA hyperexcitability manifests behaviorally as an increase in anxiety, emotional dysregulation, or development of seizure activity. This Review discusses the anatomy, development, and physiology of the GABAergic system in the BLA and circuits that modulate GABAergic inhibition, including the dopaminergic, serotonergic, noradrenergic, and cholinergic systems. We highlight how alterations in various neurotransmitter receptors, including the acid-sensing ion channel 1a, cannabinoid receptor 1, and glutamate receptor subtypes, expressed on BLA interneurons, modulate GABAergic transmission and how defects of these systems affect inhibitory tonus within the BLA. Finally, we discuss alterations in the BLA GABAergic system in neurodevelopmental (autism/fragile X syndrome) and neurodegenerative (Alzheimer's disease) diseases and after the development of epilepsy, anxiety, and traumatic brain injury. A more complete understanding of the intrinsic excitatory/inhibitory circuit balance of the amygdala and how imbalances in inhibitory control contribute to excessive BLA excitability will guide the development of novel therapeutic approaches in neuropsychiatric diseases.
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Affiliation(s)
- Eric M Prager
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services, University of the Health Sciences, Bethesda, Maryland
| | | | - Gary H Wynn
- Center for the Study of Traumatic Stress, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Program in Neuroscience, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Maria F M Braga
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services, University of the Health Sciences, Bethesda, Maryland.,Center for the Study of Traumatic Stress, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Program in Neuroscience, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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35
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Karkhanis AN, Alexander NJ, McCool BA, Weiner JL, Jones SR. Chronic social isolation during adolescence augments catecholamine response to acute ethanol in the basolateral amygdala. Synapse 2015; 69:385-95. [PMID: 25963724 DOI: 10.1002/syn.21826] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 04/07/2015] [Accepted: 04/17/2015] [Indexed: 01/18/2023]
Abstract
Adolescent social isolation (SI) results in numerous behavioral alterations associated with increased risk of alcoholism. Notably, many of these changes involve the basolateral amygdala (BLA), including increased alcohol seeking. The BLA sends a strong glutamatergic projection to the nucleus accumbens and activation of this pathway potentiates reward-seeking behavior. Dopamine (DA) and norepinephrine (NE) exert powerful excitatory and inhibitory effects on BLA activity and chronic stress can disrupt the excitation-inhibition balance maintained by these catecholamines. Notably, the impact of SI on BLA DA and NE neurotransmission is unknown. Thus the aim of this study was to characterize SI-mediated catecholamine alterations in the BLA. Male Long Evans rats were housed in groups of four (GH) or in SI for 6 weeks during adolescence. DA and NE transporter levels were then measured using Western blot hybridization and baseline and ethanol-stimulated DA and NE levels were quantified using microdialysis. DA transporter levels were increased and baseline DA levels were decreased in SI compared to GH rats. SI also increased DA responses to an acute ethanol (2 g kg(-1)) challenge. While no group differences were noted in NE transporter or baseline NE levels, acute ethanol (2 g kg(-1)) only significantly increased NE levels in SI animals. Collectively, these SI-dependent changes in BLA catecholamine signaling may lead to an increase in BLA excitability and a strengthening of the glutamatergic projection between the BLA and NAc. Such changes may promote the elevated ethanol drinking behavior observed in rats subjected to chronic adolescent stress.
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Affiliation(s)
- Anushree N Karkhanis
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina.,Translational Center for the Neurobehavioral Study of Alcohol, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Nancy J Alexander
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Brian A McCool
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina.,Translational Center for the Neurobehavioral Study of Alcohol, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Jeffrey L Weiner
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina.,Translational Center for the Neurobehavioral Study of Alcohol, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Sara R Jones
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina.,Translational Center for the Neurobehavioral Study of Alcohol, Wake Forest School of Medicine, Winston-Salem, North Carolina
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36
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Padival MA, Blume SR, Vantrease JE, Rosenkranz JA. Qualitatively different effect of repeated stress during adolescence on principal neuron morphology across lateral and basal nuclei of the rat amygdala. Neuroscience 2015; 291:128-45. [PMID: 25701125 DOI: 10.1016/j.neuroscience.2015.02.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 01/21/2015] [Accepted: 02/07/2015] [Indexed: 01/04/2023]
Abstract
Repeated stress can elicit symptoms of depression and anxiety. The amygdala is a significant contributor to the expression of emotion and the basolateral amygdala (BLA) is a major target for the effects of stress on emotion. The adolescent time period may be particularly susceptible to the effects of stress on emotion. While repeated stress has been demonstrated to modify the morphology of BLA neurons in adult rats, little is known about its effects on BLA neurons during adolescence. This study tests the effects of repeated stress during adolescence on BLA neuronal morphology, and whether these are similar to the effects of stress during adulthood. The BLA includes the basal (BA) and lateral (LAT) nuclei, which are differentially responsive to stress in adults. Therefore, effects of stress during adolescence were compared between the BA and LAT nuclei. Morphological features of reconstructed BLA neurons were examined using Golgi-Cox-stained tissue from control or repeated restraint stress-exposed rats. We found subtle dendritic growth coupled with loss of spines after repeated stress during adolescence. The magnitude and dendritic location of these differences varied between the BA and LAT nuclei in strong contrast to the stress-induced increases in spine number seen in adults. These results demonstrate that repeated stress during adolescence has markedly different effects on BLA neuronal morphology, and the extent of these changes is BLA nucleus-dependent. Moreover, altered neuroanatomy was associated with age-dependent effects of repeated stress on generalization of fear, and may point to the necessity for different approaches to target stress-induced changes in adolescents.
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Affiliation(s)
- M A Padival
- Department of Cellular and Molecular Pharmacology, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, United States
| | - S R Blume
- Department of Cellular and Molecular Pharmacology, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, United States
| | - J E Vantrease
- Department of Cellular and Molecular Pharmacology, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, United States
| | - J A Rosenkranz
- Department of Cellular and Molecular Pharmacology, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, United States.
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Chronic stress impairs α1-adrenoceptor-induced endocannabinoid-dependent synaptic plasticity in the dorsal raphe nucleus. J Neurosci 2015; 34:14560-70. [PMID: 25355210 DOI: 10.1523/jneurosci.1310-14.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alpha 1-adrenergic receptors (α1-ARs) control the activity of dorsal raphe nucleus (DRn) serotonin (5-HT) neurons and play crucial role in the regulation of arousal and stress homoeostasis. However, the precise role of these receptors in regulating glutamate synapses of rat DRn 5-HT neurons and whether chronic stress exposure alters such regulation remain unknown. In the present study, we examined the impact of chronic restraint stress on α1-AR-mediated regulation of glutamate synapses onto DRn 5-HT neurons. We found that, in the control condition, activation of α1-ARs induced an inward current and long-term depression (LTD) of glutamate synapses of DRn 5-HT neurons. The α1-AR LTD was initiated by postsynaptic α1-ARs but mediated by a decrease in glutamate release. The presynaptic expression of the α1-AR LTD was signaled by retrograde endocannabinoids (eCBs). Importantly, we found that chronic exposure to restraint stress profoundly reduced the magnitude of α1-AR LTD but had no effect on the amplitude of α1-AR-induced inward current. Chronic restraint stress also reduced the CB1 receptor-mediated inhibition of EPSC and the eCB-mediated depolarization-induced suppression of excitation. Collectively, these results indicate that chronic restraint stress impairs the α1-AR LTD by reducing the function of presynaptic CB1 receptors and reveal a novel mechanism by which noradrenaline controls synaptic strength and plasticity in the DRn. They also provide evidence that chronic stress impairs eCB signaling in the DRn, which may contribute, at least in part, to the dysregulation of the stress homeostasis.
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Jia M, Smerin SE, Zhang L, Xing G, Li X, Benedek D, Ursano R, Li H. Corticosterone mitigates the stress response in an animal model of PTSD. J Psychiatr Res 2015; 60:29-39. [PMID: 25307716 DOI: 10.1016/j.jpsychires.2014.09.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 09/16/2014] [Accepted: 09/18/2014] [Indexed: 12/18/2022]
Abstract
Activation of glucocorticoid receptor signaling in the stress response to traumatic events has been implicated in the pathogenesis of stress-associated psychiatric disorders such as post-traumatic stress disorder (PTSD). Elevated startle response and hyperarousal are hallmarks of PTSD, and are generally considered to evince fear (DSM V). To further examine the efficacy of corticosterone in treating hyperarousal and elevated fear, the present study utilized a learned helplessness stress model in which rats are restrained and subjected to tail shock for three days. These stressed rats develop a delayed long-lasting exaggeration of the acoustic startle response (ASR) and retarded body weight growth, similar to symptoms of PTSD patients (Myers et al., 2005; Speed et al., 1989). We demonstrate that both pre-stress and post-stress administration of corticosterone (3 mg/kg/day) mitigates a subsequent exaggeration of the ASR measured 14 days after cessation of the stress protocol. Furthermore, the mitigating efficacy of pre-stress administration of corticosterone (3 mg/kg/day for three days) appeared to last significantly longer, up to 21 days after the cessation of the stress protocol, in comparison to that of post-stress administration of corticosterone. However, pre-stress administration of corticosterone at 0.3 mg/kg/day for three days did not mitigate stress-induced exaggeration of the ASR measured at both 14 and 21 days after the cessation of the stress protocol. In addition, pre-stress administration of corticosterone (3 mg/kg/day for three days) mitigates the retardation of body weight growth otherwise resulting from the stress protocol. Congruently, co-administration of the corticosterone antagonist RU486 (40 mg/kg/day for three days) with corticosterone (3 mg/kg/day) prior to stress diminished the mitigating efficacy of the exogenous corticosterone on exaggerated ASR and stress-retarded body weight. The relative efficacy of pre versus post administration of corticosterone and high versus low dose of corticosterone on stress-induced exaggeration of innate fear response and stress-retarded body weight growth indicate that exogenous corticosterone administration within an appropriate time window and dosage are efficacious in diminishing traumatic stress induced pathophysiological processes. Clinical implications associated with the efficacy of prophylactic and therapeutic corticosterone therapy for mitigating symptoms of PTSD are discussed, particularly in relation to diminishing hyperarousal and exaggerated innate fear response.
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Affiliation(s)
- Min Jia
- Department of Psychiatry, Center for the Study of Traumatic Stress, Uniformed Service University of Health Sciences (USUHS), 4301 Jones Bridge Rd., Bethesda, MD 20814, USA
| | - Stanley E Smerin
- Department of Psychiatry, Center for the Study of Traumatic Stress, Uniformed Service University of Health Sciences (USUHS), 4301 Jones Bridge Rd., Bethesda, MD 20814, USA
| | - Lei Zhang
- Department of Psychiatry, Center for the Study of Traumatic Stress, Uniformed Service University of Health Sciences (USUHS), 4301 Jones Bridge Rd., Bethesda, MD 20814, USA
| | - Guoqiang Xing
- Department of Psychiatry, Center for the Study of Traumatic Stress, Uniformed Service University of Health Sciences (USUHS), 4301 Jones Bridge Rd., Bethesda, MD 20814, USA
| | - Xiaoxia Li
- Department of Psychiatry, Center for the Study of Traumatic Stress, Uniformed Service University of Health Sciences (USUHS), 4301 Jones Bridge Rd., Bethesda, MD 20814, USA
| | - David Benedek
- Department of Psychiatry, Center for the Study of Traumatic Stress, Uniformed Service University of Health Sciences (USUHS), 4301 Jones Bridge Rd., Bethesda, MD 20814, USA
| | - Robert Ursano
- Department of Psychiatry, Center for the Study of Traumatic Stress, Uniformed Service University of Health Sciences (USUHS), 4301 Jones Bridge Rd., Bethesda, MD 20814, USA
| | - He Li
- Department of Psychiatry, Center for the Study of Traumatic Stress, Uniformed Service University of Health Sciences (USUHS), 4301 Jones Bridge Rd., Bethesda, MD 20814, USA.
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Spiros A, Roberts P, Geerts H. A computer-based quantitative systems pharmacology model of negative symptoms in schizophrenia: exploring glycine modulation of excitation-inhibition balance. Front Pharmacol 2014; 5:229. [PMID: 25374541 PMCID: PMC4204440 DOI: 10.3389/fphar.2014.00229] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/23/2014] [Indexed: 02/04/2023] Open
Abstract
Although many antipsychotics can reasonably control positive symptoms in schizophrenia, patients' return to society is often hindered by negative symptoms and cognitive deficits. As an alternative to animal rodent models that are often not very predictive for the clinical situation, we developed a new computer-based mechanistic modeling approach. This Quantitative Systems Pharmacology approach combines preclinical basic neurophysiology of a biophysically realistic neuronal ventromedial cortical-ventral striatal network identified from human imaging studies that are associated with negative symptoms. Calibration of a few biological coupling parameters using a retrospective clinical database of 34 drug-dose combinations resulted in correlation coefficients greater than 0.60, while a robust quantitative prediction of a number of independent trials was observed. We then simulated the effect of glycine modulation on the anticipated clinical outcomes. The quantitative biochemistry of glycine interaction with the different NMDA-NR2 subunits, neurodevelopmental trajectory of the NMDA-NR2B in the human schizophrenia pathology, their specific localization on excitatory vs. inhibitory interneurons and the electrogenic nature of the glycine transporter resulted in an inverse U-shape dose-response with an optimum in the low micromolar glycine concentration. Quantitative systems pharmacology based computer modeling of complex humanized brain circuits is a powerful alternative approach to explain the non-monotonic dose-response observed in past clinical trial outcomes with sarcosine, D-cycloserine, glycine, or D-serine or with glycine transporter inhibitors. In general it can be helpful to better understand the human neurophysiology of negative symptoms, especially with targets that show non-monotonic dose-responses.
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Affiliation(s)
- Athan Spiros
- Computational Neuropharmacology, In Silico Biosciences, Inc. Berwyn, PA, USA
| | - Patrick Roberts
- Computational Neuropharmacology, In Silico Biosciences, Inc. Berwyn, PA, USA ; Department of Biomedical Engineering, Oregon Health and Science University Portland, OR, USA
| | - Hugo Geerts
- Computational Neuropharmacology, In Silico Biosciences, Inc. Berwyn, PA, USA ; Department of Laboratory Pathology, Perelman School of Medicine, University of Pennsylvania Philadelphia, PA, USA
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Velásquez-Martínez MC, Vázquez-Torres R, Rojas LV, Sanabria P, Jiménez-Rivera CA. Alpha-1 adrenoreceptors modulate GABA release onto ventral tegmental area dopamine neurons. Neuropharmacology 2014; 88:110-21. [PMID: 25261018 DOI: 10.1016/j.neuropharm.2014.09.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 08/29/2014] [Accepted: 09/01/2014] [Indexed: 01/08/2023]
Abstract
The ventral tegmental area (VTA) plays an important role in reward and motivational processes involved in drug addiction. Previous studies have shown that alpha1-adrenoreceptors (α1-AR) are primarily found pre-synaptically at this area. We hypothesized that GABA released onto VTA-dopamine (DA) cells is modulated by pre-synaptic α1-AR. Recordings were obtained from putative VTA-DA cells of male Sprague-Dawley rats (28-50 days postnatal) using whole-cell voltage clamp technique. Phenylephrine (10 μM; α1-AR agonist) decreased the amplitude of GABAA receptor-mediated inhibitory postsynaptic currents (IPSCs) evoked by electrical stimulation of afferent fibers (n = 7; p < 0.05). Prazosin (1 μM, α1-AR antagonist), blocked this effect. Paired-pulse ratios were increased by phenylephrine application (n = 13; p < 0.05) indicating a presynaptic site of action. Spontaneous IPSCs frequency but not amplitude, were decreased in the presence of phenylephrine (n = 7; p < 0.05). However, frequency or amplitude of miniature IPSCs were not changed (n = 9; p > 0.05). Phenylephrine in low Ca(2+) (1 mM) medium decreased IPSC amplitude (n = 7; p < 0.05). Chelerythrine (a protein kinase C inhibitor) blocked the α1-AR action on IPSC amplitude (n = 6; p < 0.05). Phenylephrine failed to decrease IPSCs amplitude in the presence of paxilline, a BK channel blocker (n = 7; p < 0.05). Taken together, these results demonstrate that α1-ARs at presynaptic terminals can modulate GABA release onto VTA-DA cells. Drug-induced changes in α1-AR could contribute to the modifications occurring in the VTA during the addiction process.
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Affiliation(s)
- Maria C Velásquez-Martínez
- Department of Physiology, Medical Sciences Campus, University of Puerto Rico, San Juan, PR, USA; Laboratorio de Neurociencias y Comportamiento, Departamento de Ciencias Básicas, Facultad de Salud, Universidad Industrial de Santander, Bucaramanga, Colombia
| | - Rafael Vázquez-Torres
- Department of Physiology, Medical Sciences Campus, University of Puerto Rico, San Juan, PR, USA
| | - Legier V Rojas
- Department of Physiology, Universidad Central del Caribe, Bayamón, PR, USA
| | - Priscila Sanabria
- Department of Physiology, Universidad Central del Caribe, Bayamón, PR, USA
| | - Carlos A Jiménez-Rivera
- Department of Physiology, Medical Sciences Campus, University of Puerto Rico, San Juan, PR, USA.
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Pinna G, Rasmusson AM. Ganaxolone improves behavioral deficits in a mouse model of post-traumatic stress disorder. Front Cell Neurosci 2014; 8:256. [PMID: 25309317 PMCID: PMC4161165 DOI: 10.3389/fncel.2014.00256] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 08/11/2014] [Indexed: 12/14/2022] Open
Abstract
Allopregnanolone and its equipotent stereoisomer, pregnanolone (together termed ALLO), are neuroactive steroids that positively and allosterically modulate the action of gamma-amino-butyric acid (GABA) at GABAA receptors. Levels of ALLO are reduced in the cerebrospinal fluid of female premenopausal patients with post-traumatic stress disorder (PTSD), a severe, neuropsychiatric condition that affects millions, yet is without a consistently effective therapy. This suggests that restoring downregulated brain ALLO levels in PTSD may be beneficial. ALLO biosynthesis is also decreased in association with the emergence of PTSD-like behaviors in socially isolated (SI) mice. Similar to PTSD patients, SI mice also exhibit changes in the frontocortical and hippocampal expression of GABAA receptor subunits, resulting in resistance to benzodiazepine-mediated sedation and anxiolysis. ALLO acts at a larger spectrum of GABAA receptor subunits than benzodiazepines, and increasing corticolimbic ALLO levels in SI mice by injecting ALLO or stimulating ALLO biosynthesis with a selective brain steroidogenic stimulant, such as S-norfluoxetine, at doses far below those that block serotonin reuptake, reduces PTSD-like behavior in these mice. This suggests that synthetic analogs of ALLO, such as ganaxolone, may also improve anxiety, aggression, and other PTSD-like behaviors in the SI mouse model. Consistent with this hypothesis, ganaxolone (3.75–30 mg/kg, s.c.) injected 60 min before testing of SI mice, induced a dose-dependent reduction in aggression toward a same-sex intruder and anxiety-like behavior in an elevated plus maze. The EC50 dose of ganaxolone used in these tests also normalized exaggerated contextual fear conditioning and, remarkably, enhanced fear extinction retention in SI mice. At these doses, ganaxolone failed to change locomotion in an open field test. Therefore, unlike benzodiazepines, ganaxolone at non-sedating concentrations appears to improve dysfunctional emotional behavior associated with deficits in ALLO in mice and may provide an alternative treatment for PTSD patients with deficits in the synthesis of ALLO. Selective serotonin reuptake inhibitors (SSRIs) are the only medications currently approved by the FDA for treatment of PTSD, although they are ineffective in a substantial proportion of PTSD patients. Hence, an ALLO analog such as ganaxolone may offer a therapeutic GABAergic alternative to SSRIs for the treatment of PTSD or other disorders in which ALLO biosynthesis may be impaired.
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Affiliation(s)
- Graziano Pinna
- The Psychiatric Institute, College of Medicine, University of Illinois at Chicago Chicago, IL, USA
| | - Ann M Rasmusson
- VA Boston Healthcare System, Women's Health Science Division of the VA National Center for PTSD, and Boston University School of Medicine Boston, MA, USA
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Distinct effects of repeated restraint stress on basolateral amygdala neuronal membrane properties in resilient adolescent and adult rats. Neuropsychopharmacology 2014; 39:2114-30. [PMID: 24619244 PMCID: PMC4104329 DOI: 10.1038/npp.2014.60] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 02/24/2014] [Accepted: 02/27/2014] [Indexed: 12/30/2022]
Abstract
Severe and repeated stress has damaging effects on health, including initiation of depression and anxiety. Stress that occurs during development has long-lasting and particularly damaging effects on emotion. The basolateral amygdala (BLA) plays a key role in many affective behaviors, and repeated stress causes different forms of BLA hyperactivity in adolescent and adult rats. However, the mechanism is not known. Furthermore, not every individual is susceptible to the negative consequences of stress. Differences in the effects of stress on the BLA might contribute to determine whether an individual will be vulnerable or resilient to the effects of stress on emotion. The purpose of this study is to test the cellular underpinnings for age dependency of BLA hyperactivity after stress, and whether protective changes occur in resilient individuals. To test this, the effects of repeated stress on membrane excitability and other membrane properties of BLA principal neurons were compared between adult and adolescent rats, and between vulnerable and resilient rats, using in vitro whole-cell recordings. Vulnerability was defined by adrenal gland weight, and verified by body weight gain after repeated restraint stress, and fecal pellet production during repeated restraint sessions. We found that repeated stress increased the excitability of BLA neurons, but in a manner that depended on age and BLA subnucleus. Furthermore, stress resilience was associated with an opposite pattern of change, with increased slow afterhyperpolarization (AHP) potential, whereas vulnerability was associated with decreased medium AHP. The opposite outcomes in these two populations were further distinguished by differences of anxiety-like behavior in the elevated plus maze that were correlated with BLA neuronal excitability and AHP. These results demonstrate a substrate for BLA hyperactivity after repeated stress, with distinct membrane properties to target, as well as age-dependent factors that contribute to resilience to the effects of stress.
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Liu ZP, Song C, Wang M, He Y, Xu XB, Pan HQ, Chen WB, Peng WJ, Pan BX. Chronic stress impairs GABAergic control of amygdala through suppressing the tonic GABAA receptor currents. Mol Brain 2014; 7:32. [PMID: 24758222 PMCID: PMC4012764 DOI: 10.1186/1756-6606-7-32] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 04/19/2014] [Indexed: 12/29/2022] Open
Abstract
Background Chronic stress is generally known to exacerbate the development of numerous neuropsychiatric diseases such as fear and anxiety disorders, which is at least partially due to the disinhibition of amygdala subsequent to the prolonged stress exposure. GABA receptor A (GABAAR) mediates the primary component of inhibition in brain and its activation produces two forms of inhibition: the phasic and tonic inhibition. While both of them are critically engaged in limiting the activity of amygdala, their roles in the amygdala disinhibition subsequent to chronic stress exposure are largely unknown. Results We investigated the possible alterations of phasic and tonic GABAAR currents and their roles in the amygdala disinhibition subsequent to chronic stress. We found that both chronic immobilization and unpredictable stress led to long lasting loss of tonic GABAAR currents in the projection neurons of lateral amygdala. By contrast, the phasic GABAAR currents, as measured by the spontaneous inhibitory postsynaptic currents, were virtually unaltered. The loss of tonic inhibition varied with the duration of daily stress and the total days of stress exposure. It was prevented by pretreatment with metyrapone to block corticosterone synthesis or RU 38486, a glucocorticoid receptor antagonist, suggesting the critical involvement of glucocorticoid receptor activation. Moreover, chronic treatment with corticosterone mimicked the effect of chronic stress and reduced the tonic inhibition in lateral amygdala of control mice. The loss of tonic inhibition resulted in the impaired GABAergic gating on neuronal excitability in amygdala, which was prevented by metyrapone pretreatment. Conclusions Our study suggests that enduring loss of tonic but not phasic GABAAR currents critically contributes to the prolonged amygdala disinhibition subsequent to chronic stress. We propose that the preferential loss of tonic inhibition may account for the development of stress-related neuropsychiatric diseases.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Bing-Xing Pan
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China.
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Abstract
The discovery that even small changes in extracellular acidity can alter the excitability of neuronal networks via activation of acid-sensing ion channels (ASICs) could have therapeutic application in a host of neurological and psychiatric illnesses. Recent evidence suggests that activation of ASIC1a, a subtype of ASICs that is widely distributed in the brain, is necessary for the expression of fear and anxiety. Antagonists of ASIC1a, therefore, have been proposed as a potential treatment for anxiety. The basolateral amygdala (BLA) is central to fear generation, and anxiety disorders are characterized by BLA hyperexcitability. To better understand the role of ASIC1a in anxiety, we attempted to provide a direct assessment of whether ASIC1a activation increases BLA excitability. In rat BLA slices, activation of ASIC1a by low pH or ammonium elicited inward currents in both interneurons and principal neurons, and increased spontaneous IPSCs recorded from principal cells significantly more than spontaneous EPSCs. Epileptiform activity induced by high potassium and low magnesium was suppressed by ammonium. Antagonism of ASIC1a decreased spontaneous IPSCs more than EPSCs, and increased the excitability of the BLA network, as reflected by the pronounced increase of evoked field potentials, suggesting that ASIC1a channels are active in the basal state. In vivo activation or blockade of ASIC1a in the BLA suppressed or increased, respectively, anxiety-like behavior. Thus, in the rat BLA, ASIC1a has an inhibitory and anxiolytic function. The discovery of positive ASIC1a modulators may hold promise for the treatment of anxiety disorders.
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The GABA-synthetic enzyme GAD65 controls circadian activation of conditioned fear pathways. Behav Brain Res 2014; 260:92-100. [DOI: 10.1016/j.bbr.2013.11.042] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Revised: 11/19/2013] [Accepted: 11/25/2013] [Indexed: 11/21/2022]
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Diaz MR, Jotty K, Locke JL, Jones SR, Valenzuela CF. Moderate Alcohol Exposure during the Rat Equivalent to the Third Trimester of Human Pregnancy Alters Regulation of GABAA Receptor-Mediated Synaptic Transmission by Dopamine in the Basolateral Amygdala. Front Pediatr 2014; 2:46. [PMID: 24904907 PMCID: PMC4035091 DOI: 10.3389/fped.2014.00046] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 05/10/2014] [Indexed: 01/22/2023] Open
Abstract
Fetal ethanol (EtOH) exposure leads to a range of neurobehavioral alterations, including deficits in emotional processing. The basolateral amygdala (BLA) plays a critical role in modulating emotional processing, in part, via dopamine (DA) regulation of GABA transmission. This BLA modulatory system is acquired during the first 2 weeks of postnatal life in rodents (equivalent to the third trimester of human pregnancy) and we hypothesized that it could be altered by EtOH exposure during this period. We found that exposure of rats to moderate levels of EtOH vapor during the third trimester-equivalent [postnatal days (P) 2-12] alters DA modulation of GABAergic transmission in BLA pyramidal neurons during periadolescence. Specifically, D1R-mediated potentiation of spontaneous inhibitory postsynaptic currents (IPSCs) was significantly attenuated in EtOH-exposed animals. However, this was associated with a compensatory decrease in D3R-mediated suppression of miniature IPSCs. Western blot analysis revealed that these effects were not a result of altered D1R or D3R levels. BLA samples from EtOH-exposed animals also had significantly lower levels of the DA precursor (L-3,4-dihydroxyphenylalanine) but DA levels were not affected. This is likely a consequence of reduced catabolism of DA, as indicated by reduced levels of 3,4-dihydroxyphenylacetic acid and homovanillic acid in the BLA samples. Anxiety-like behavior was not altered in EtOH-exposed animals. This is the first study to demonstrate that the modulatory actions of DA in the BLA are altered by developmental EtOH exposure. Although compensatory adaptations were engaged in our moderate EtOH exposure paradigm, it is possible that these are not able to restore homeostasis and correct anxiety-like behaviors under conditions of heavier EtOH exposure. Therefore, future studies should investigate the potential role of alterations in the modulatory actions of DA in the pathophysiology of fetal alcohol spectrum disorders.
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Affiliation(s)
- Marvin Rafael Diaz
- Department of Neurosciences, University of New Mexico Health Sciences Center , Albuquerque, NM , USA
| | - Karick Jotty
- Department of Neurosciences, University of New Mexico Health Sciences Center , Albuquerque, NM , USA
| | - Jason L Locke
- Department of Physiology and Pharmacology, Wake Forest School of Medicine , Winston-Salem, NC , USA
| | - Sara R Jones
- Department of Physiology and Pharmacology, Wake Forest School of Medicine , Winston-Salem, NC , USA
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Sears RM, Schiff HC, LeDoux JE. Molecular Mechanisms of Threat Learning in the Lateral Nucleus of the Amygdala. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 122:263-304. [DOI: 10.1016/b978-0-12-420170-5.00010-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Kravets JL, Reyes BAS, Unterwald EM, Van Bockstaele EJ. Direct targeting of peptidergic amygdalar neurons by noradrenergic afferents: linking stress-integrative circuitry. Brain Struct Funct 2013; 220:541-58. [PMID: 24271021 DOI: 10.1007/s00429-013-0674-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 11/07/2013] [Indexed: 12/12/2022]
Abstract
Amygdalar norepinephrine (NE) plays a key role in regulating neural responses to emotionally arousing stimuli and is involved in memory consolidation of emotionally charged events. Corticotropin-releasing factor (CRF) and dynorphin (DYN), two neuropeptides that mediate the physiological and behavioral responses to stress, are abundant in the central nucleus of the amygdala (CeA), and directly innervate brainstem noradrenergic locus coeruleus (LC) neurons. Whether the CRF- and DYN-containing amygdalar neurons receive direct noradrenergic innervation has not yet been elucidated. The present study sought to define cellular substrates underlying noradrenergic modulation of CRF- and DYN-containing neurons in the CeA using immunohistochemistry and electron microscopy. Ultrastructural analysis revealed that NE-labeled axon terminals form synapses with CRF- and DYN-containing neurons in the CeA. Semi-quantitative analysis showed that approximately 31 % of NET-labeled axon terminals targeted CeA neurons that co-expressed DYN and CRF. As a major source of CRF innervation to the LC, it is also not known whether CRF-containing CeA neurons are directly targeted by noradrenergic afferents. To test this, retrograde tract tracing using FluoroGold from the LC was combined with immunocytochemical detection of CRF and NET in the CeA. Our results revealed a population of LC-projecting CRF-containing CeA neurons that are directly innervated by NE afferents. Analysis showed that approximately 34 % of NET-labeled axon terminals targeted LC-projecting CeA neurons that contain CRF. Taken together, these results indicate significant interactions between NE, CRF and DYN in this critical limbic region and reveal direct synaptic interactions of NE with amygdalar CRF that influence the LC-NE arousal system.
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Affiliation(s)
- J L Kravets
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 S. 15th Street, Philadelphia, PA, 19102, USA
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Pidoplichko VI, Prager EM, Aroniadou-Anderjaska V, Braga MFM. α7-Containing nicotinic acetylcholine receptors on interneurons of the basolateral amygdala and their role in the regulation of the network excitability. J Neurophysiol 2013; 110:2358-69. [PMID: 24004528 DOI: 10.1152/jn.01030.2012] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The basolateral amygdala (BLA) plays a key role in fear-related learning and memory, in the modulation of cognitive functions, and in the overall regulation of emotional behavior. Pathophysiological alterations involving hyperexcitability in this brain region underlie anxiety and other emotional disorders as well as some forms of epilepsy. GABAergic interneurons exert a tight inhibitory control over the BLA network; understanding the mechanisms that regulate their activity is necessary for understanding physiological and disordered BLA functions. The BLA receives dense cholinergic input from the basal forebrain, affecting both normal functions and dysfunctions of the amygdala, but the mechanisms involved in the cholinergic regulation of inhibitory activity in the BLA are unclear. Using whole cell recordings in rat amygdala slices, here we demonstrate that the α(7)-containing nicotinic acetylcholine receptors (α(7)-nAChRs) are present on somatic or somatodendritic regions of BLA interneurons. These receptors are active in the basal state enhancing GABAergic inhibition, and their further, exogenous activation produces a transient but dramatic increase of spontaneous inhibitory postsynaptic currents in principal BLA neurons. In the absence of AMPA/kainate receptor antagonists, activation of α(7)-nAChRs in the BLA network increases both GABAergic and glutamatergic spontaneous currents in BLA principal cells, but the inhibitory currents are enhanced significantly more than the excitatory currents, reducing overall excitability. The anxiolytic effects of nicotine as well as the role of the α(7)-nAChRs in seizure activity involving the amygdala and in mental illnesses, such as schizophrenia and Alzheimer's disease, may be better understood in light of the present findings.
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Affiliation(s)
- Volodymyr I Pidoplichko
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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Padival M, Quinette D, Rosenkranz JA. Effects of repeated stress on excitatory drive of basal amygdala neurons in vivo. Neuropsychopharmacology 2013; 38:1748-62. [PMID: 23535779 PMCID: PMC3717551 DOI: 10.1038/npp.2013.74] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 03/12/2013] [Accepted: 03/21/2013] [Indexed: 02/07/2023]
Abstract
Chronic stress leads to heightened affective behaviors, and can precipitate the emergence of depression and anxiety. These disorders are associated with increased amygdala activity. In animal models, chronic stress leads to increased amygdala-dependent behaviors, as well as hyperactivity of amygdala neurons. However, it is not known whether increased excitatory synaptic drive after chronic stress contributes to hyperactivity of basolateral amygdala (BLA; comprised of basal, lateral, and accessory basal nuclei) neurons. This study tested whether repeated stress causes an increase in excitatory drive of basal amygdala (BA) neurons in vivo, and whether this is correlated with an increase in the number of dendritic spines and a shift in dendritic distribution. Using in vivo intracellular recordings, this study found that repeated restraint stress caused an increase in the frequency of spontaneous excitatory synaptic events in vivo, which correlated with the number of dendritic spines in reconstructed neurons. Furthermore, parallel changes in the kinetics of the synaptic events and the distribution of spines indicated a more prominent functional contribution of synaptic inputs from across the dendritic tree. The shift in spine distribution across the dendritic tree was further confirmed with the examination of Golgi-stained tissue. This abnormal physiological drive of BA neurons after repeated stress may contribute to heightened affective responses after chronic stress. A reduction in the impact of excitatory drive in the BA may therefore be a potential treatment for the harmful effects of chronic stress in psychiatric disorders.
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Affiliation(s)
- Mallika Padival
- Department of Cellular and Molecular Pharmacology, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - Danielle Quinette
- Department of Cellular and Molecular Pharmacology, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - J Amiel Rosenkranz
- Department of Cellular and Molecular Pharmacology, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA,Department of Cellular and Molecular Pharmacology, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, USA, Tel: +1 847 578 8680, E-mail:
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