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Ji G, Presto P, Kiritoshi T, Chen Y, Navratilova E, Porreca F, Neugebauer V. Chemogenetic Manipulation of Amygdala Kappa Opioid Receptor Neurons Modulates Amygdala Neuronal Activity and Neuropathic Pain Behaviors. Cells 2024; 13:705. [PMID: 38667320 PMCID: PMC11049235 DOI: 10.3390/cells13080705] [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: 03/22/2024] [Revised: 04/12/2024] [Accepted: 04/17/2024] [Indexed: 04/28/2024] Open
Abstract
Neuroplasticity in the central nucleus of the amygdala (CeA) plays a key role in the modulation of pain and its aversive component. The dynorphin/kappa opioid receptor (KOR) system in the amygdala is critical for averse-affective behaviors in pain conditions, but its mechanisms are not well understood. Here, we used chemogenetic manipulations of amygdala KOR-expressing neurons to analyze the behavioral consequences in a chronic neuropathic pain model. For the chemogenetic inhibition or activation of KOR neurons in the CeA, a Cre-inducible viral vector encoding Gi-DREADD (hM4Di) or Gq-DREADD (hM3Dq) was injected stereotaxically into the right CeA of transgenic KOR-Cre mice. The chemogenetic inhibition of KOR neurons expressing hM4Di with a selective DREADD actuator (deschloroclozapine, DCZ) in sham control mice significantly decreased inhibitory transmission, resulting in a shift of inhibition/excitation balance to promote excitation and induced pain behaviors. The chemogenetic activation of KOR neurons expressing hM3Dq with DCZ in neuropathic mice significantly increased inhibitory transmission, decreased excitability, and decreased neuropathic pain behaviors. These data suggest that amygdala KOR neurons modulate pain behaviors by exerting an inhibitory tone on downstream CeA neurons. Therefore, activation of these interneurons or blockade of inhibitory KOR signaling in these neurons could restore control of amygdala output and mitigate pain.
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Affiliation(s)
- Guangchen Ji
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, 3601 4th St., Lubbock, TX 79430, USA
- Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Peyton Presto
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, 3601 4th St., Lubbock, TX 79430, USA
- Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Takaki Kiritoshi
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, 3601 4th St., Lubbock, TX 79430, USA
| | - Yong Chen
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, 3601 4th St., Lubbock, TX 79430, USA
- Garrison Institute on Aging, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Edita Navratilova
- Department of Pharmacology, Arizona Health Sciences Center, University of Arizona, Tucson, AZ 85721, USA
| | - Frank Porreca
- Department of Pharmacology, Arizona Health Sciences Center, University of Arizona, Tucson, AZ 85721, USA
| | - Volker Neugebauer
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, 3601 4th St., Lubbock, TX 79430, USA
- Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Garrison Institute on Aging, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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Akyuz E, Celik BR, Aslan FS, Sahin H, Angelopoulou E. Exploring the Role of Neurotransmitters in Multiple Sclerosis: An Expanded Review. ACS Chem Neurosci 2023; 14:527-553. [PMID: 36724132 DOI: 10.1021/acschemneuro.2c00589] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease of the central nervous system (CNS). Although emerging evidence has shown that changes in neurotransmitter levels in the synaptic gap may contribute to the pathophysiology of MS, their specific role has not been elucidated yet. In this review, we aim to analyze preclinical and clinical evidence on the structural and functional changes in neurotransmitters in MS and critically discuss their potential role in MS pathophysiology. Preclinical studies have demonstrated that alterations in glutamate metabolism may contribute to MS pathophysiology, by causing excitotoxic neuronal damage. Dysregulated interaction between glutamate and GABA results in synaptic loss. The GABAergic system also plays an important role, by regulating the activity and plasticity of neural networks. Targeting GABAergic/glutamatergic transmission may be effective in fatigue and cognitive impairment in MS. Acetylcholine (ACh) and dopamine can also affect the T-mediated inflammatory responses, thereby being implicated in MS-related neuroinflammation. Also, melatonin might affect the frequency of relapses in MS, by regulating the sleep-wake cycle. Increased levels of nitric oxide in inflammatory lesions of MS patients may be also associated with axonal neuronal degeneration. Therefore, neurotransmitter imbalance may be critically implicated in MS pathophysiology, and future studies are needed for our deeper understanding of their role in MS.
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Affiliation(s)
- Enes Akyuz
- Department of Biophysics, International School of Medicine, University of Health Sciences, Istanbul, Turkey, 34668
| | - Betul Rana Celik
- Hamidiye School of Medicine, University of Health Sciences, Istanbul, Turkey, 34668
| | - Feyza Sule Aslan
- Hamidiye International School of Medicine, University of Health Sciences, Istanbul, Turkey, 34668
| | - Humeyra Sahin
- School of Medicine, Bezmialem Vakif University, Istanbul, Turkey, 34093
| | - Efthalia Angelopoulou
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens, Greece, 115 27
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