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Guo W, Fan S, Xiao D, He C, Guan M, Xiong W. A midbrain-reticulotegmental circuit underlies exaggerated startle under fear emotions. Mol Psychiatry 2022; 27:4881-4892. [PMID: 36117214 DOI: 10.1038/s41380-022-01782-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 09/02/2022] [Accepted: 09/05/2022] [Indexed: 01/19/2023]
Abstract
Exaggerated startle has been recognized as a core hyperarousal symptom of multiple fear-related anxiety disorders, such as post-traumatic stress disorder (PTSD) and panic disorder. However, the mechanisms driving this symptom are poorly understood. Here we reveal a neural projection from dorsal raphe nucleus (DRN) to a startle-controlling center reticulotegmental nucleus (RtTg) that mediates enhanced startle response under fear condition. Within RtTg, we identify an inhibitory microcircuit comprising GABAergic neurons in pericentral RtTg (RtTgP) and glutamatergic neurons in central RtTg (RtTgC). Inhibition of this RtTgP-RtTgC microcircuit leads to elevated startle amplitudes. Furthermore, we demonstrate that the conditioned fear-activated DRN 5-HTergic neurons send inhibitory projections to RtTgP GABAergic neurons, which in turn upregulate neuronal activities of RtTgC glutamatergic neurons. Chemogenetic activation of the DRN-RtTgP projections mimics the increased startle response under fear emotions. Moreover, conditional deletion of 5-HT1B receptor from RtTgP GABAergic neurons largely reverses the exaggeration of startle during conditioned fear. Thus, our study establishes the disinhibitory DRN-RtTgP-RtTgC circuit as a critical mechanism underlying exaggerated startle under fear emotions, and provides 5-HT1B receptor as a potential therapeutic target for treating hyperarousal symptom in fear-associated psychiatric disorders.
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Affiliation(s)
- Weiwei Guo
- Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230026, China
| | - Sijia Fan
- Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230026, China
| | - Dan Xiao
- Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230026, China
| | - Chen He
- Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230026, China
| | - Mengyuan Guan
- Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230026, China
| | - Wei Xiong
- Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230026, China. .,Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, 230088, China. .,Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China.
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Löscher W, Kaila K. CNS pharmacology of NKCC1 inhibitors. Neuropharmacology 2021; 205:108910. [PMID: 34883135 DOI: 10.1016/j.neuropharm.2021.108910] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 11/25/2021] [Accepted: 11/26/2021] [Indexed: 12/21/2022]
Abstract
The Na-K-2Cl cotransporter NKCC1 and the neuron-specific K-Cl cotransporter KCC2 are considered attractive CNS drug targets because altered neuronal chloride regulation and consequent effects on GABAergic signaling have been implicated in numerous CNS disorders. While KCC2 modulators are not yet clinically available, the loop diuretic bumetanide has been used off-label in attempts to treat brain disorders and as a tool for NKCC1 inhibition in preclinical models. Bumetanide is known to have anticonvulsant and neuroprotective effects under some pathophysiological conditions. However, as shown in several species from neonates to adults (mice, rats, dogs, and by extrapolation in humans), at the low clinical doses of bumetanide approved for diuresis, this drug has negligible access into the CNS, reaching levels that are much lower than what is needed to inhibit NKCC1 in cells within the brain parenchyma. Several drug discovery strategies have been initiated over the last ∼15 years to develop brain-permeant compounds that, ideally, should be selective for NKCC1 to eliminate the diuresis mediated by inhibition of renal NKCC2. The strategies employed to improve the pharmacokinetic and pharmacodynamic properties of NKCC1 blockers include evaluation of other clinically approved loop diuretics; development of lipophilic prodrugs of bumetanide; development of side-chain derivatives of bumetanide; and unbiased high-throughput screening approaches of drug discovery based on large chemical compound libraries. The main outcomes are that (1), non-acidic loop diuretics such as azosemide and torasemide may have advantages as NKCC1 inhibitors vs. bumetanide; (2), bumetanide prodrugs lead to significantly higher brain levels than the parent drug and have lower diuretic activity; (3), the novel bumetanide side-chain derivatives do not exhibit any functionally relevant improvement of CNS accessibility or NKCC1 selectivity vs. bumetanide; (4) novel compounds discovered by high-throughput screening may resolve some of the inherent problems of bumetanide, but as yet this has not been achieved. Thus, further research is needed to optimize the design of brain-permeant NKCC1 inhibitors. In parallel, a major challenge is to identify the mechanisms whereby various NKCC1-expressing cellular targets of these drugs within (e.g., neurons, oligodendrocytes or astrocytes) and outside the brain parenchyma (e.g., the blood-brain barrier, the choroid plexus, and the endocrine system), as well as molecular off-target effects, might contribute to their reported therapeutic and adverse effects.
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Affiliation(s)
- Wolfgang Löscher
- Dept. of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience Hannover, Germany.
| | - Kai Kaila
- Molecular and Integrative Biosciences and Neuroscience Center (HiLIFE), University of Helsinki, Finland
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Chadman KK, Fernandes S, DiLiberto E, Feingold R. Do animal models hold value in Autism spectrum disorder (ASD) drug discovery? Expert Opin Drug Discov 2019; 14:727-734. [DOI: 10.1080/17460441.2019.1621285] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Kathryn K. Chadman
- Behavioral Pharmacology Laboratory, NYS Office for People With Developmental Disabilities, Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - Stephanie Fernandes
- Behavioral Pharmacology Laboratory, NYS Office for People With Developmental Disabilities, Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
- Center for Developmental Neuroscience and Developmental Disabilities, City University of New York, College of Staten Island, Staten Island, NY, USA
| | - Elizabeth DiLiberto
- Behavioral Pharmacology Laboratory, NYS Office for People With Developmental Disabilities, Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
- Department of Psychology, Macaulay Honors College at City University of New York, College of Staten Island, Staten Island, NY, USA
| | - Robert Feingold
- Behavioral Pharmacology Laboratory, NYS Office for People With Developmental Disabilities, Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
- Center for Developmental Neuroscience and Developmental Disabilities, City University of New York, College of Staten Island, Staten Island, NY, USA
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Ostroumov A, Dani JA. Inhibitory Plasticity of Mesocorticolimbic Circuits in Addiction and Mental Illness. Trends Neurosci 2018; 41:898-910. [PMID: 30149979 PMCID: PMC6252277 DOI: 10.1016/j.tins.2018.07.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 07/12/2018] [Accepted: 07/31/2018] [Indexed: 12/19/2022]
Abstract
Behavioral adaptations occur through remodeling of brain circuits, as arising, for instance, from experience-dependent synaptic plasticity. Drugs of abuse and aversive stimuli, such as stress, act on the mesocorticolimbic system, dysregulating adaptive mechanisms and leading to a variety of aberrant behaviors associated with neuropsychiatric disorders. Until recently, research in the field has commonly focused on experience-dependent synaptic plasticity at excitatory synapses. However, there is growing evidence that synaptic plasticity within inhibitory circuits is an important contributor to maladaptive behaviors. We speculate that restoring normal inhibitory synaptic transmission is a promising therapeutic target for correcting some of the circuit abnormalities underlying neuropsychiatric disorders.
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Affiliation(s)
- Alexey Ostroumov
- Department of Neuroscience, Mahoney Institute for Neurosciences, Perelman School for Medicine, Philadelphia, PA 19104, USA.
| | - John A Dani
- Department of Neuroscience, Mahoney Institute for Neurosciences, Perelman School for Medicine, Philadelphia, PA 19104, USA.
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Ko MC, Lee MC, Tang TH, Amstislavskaya TG, Tikhonova MA, Yang YL, Lu KT. Bumetanide blocks the acquisition of conditioned fear in adult rats. Br J Pharmacol 2018; 175:1580-1589. [PMID: 29235092 PMCID: PMC5913399 DOI: 10.1111/bph.14125] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 09/05/2017] [Accepted: 09/08/2017] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Bumetanide has anxiolytic effects in rat models of conditioned fear. As a loop diuretic, bumetanide blocks cation-chloride co-transport and this property may allow bumetanide to act as an anxiolytic by modulating GABAergic synaptic transmission in the CNS. Its potential for the treatment of anxiety disorders deserves further investigation. In this study, we evaluated the possible involvement of the basolateral nucleus of the amygdala in the anxiolytic effect of bumetanide. EXPERIMENTAL APPROACH Brain slices were prepared from Wistar rats. extracellular recording, stereotaxic surgery, fear-potentiated startle response, locomotor activity monitoring and Western blotting were applied in this study. KEY RESULTS Systemic administration of bumetanide (15.2 mg·kg-1 , i.v.), 30 min prior to fear conditioning, significantly inhibited the acquisition of the fear-potentiated startle response. Phosphorylation of ERK in the basolateral nucleus of amygdala was reduced after bumetanide administration. In addition, suprafusion of bumetanide (5 or 10 μM) attenuated long-term potentiation in the amygdala in a dose-dependent manner. Intra-amygdala infusion of bumetanide, 15 min prior to fear conditioning, also blocked the acquisition of the fear-potentiated startle response. Finally, the possible off-target effect of bumetanide on conditioned fear was excluded by side-by-side control experiments. CONCLUSIONS AND IMPLICATIONS These results suggest the basolateral nucleus of amygdala plays a critical role in the anxiolytic effects of bumetanide.
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Affiliation(s)
- Meng-Chang Ko
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Ming-Chung Lee
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Tso-Hao Tang
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Tamara G Amstislavskaya
- Laboratory of Experimental Models of Neurodegenerative Processes, Federal State Budgetary Scientific Institution "Scientific Research Institute of Physiology and Basic Medicine" (SRIPhBM), Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
| | - Maria A Tikhonova
- Laboratory of Experimental Models of Neurodegenerative Processes, Federal State Budgetary Scientific Institution "Scientific Research Institute of Physiology and Basic Medicine" (SRIPhBM), Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
| | - Yi-Ling Yang
- Department of Biochemical Science and Technology, National Chiayi University, Chiayi, Taiwan
| | - Kwok-Tung Lu
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
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