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Zhou JL, de Guglielmo G, Ho AJ, Kallupi M, Pokhrel N, Li HR, Chitre AS, Munro D, Mohammadi P, Carrette LLG, George O, Palmer AA, McVicker G, Telese F. Single-nucleus genomics in outbred rats with divergent cocaine addiction-like behaviors reveals changes in amygdala GABAergic inhibition. Nat Neurosci 2023; 26:1868-1879. [PMID: 37798411 PMCID: PMC10620093 DOI: 10.1038/s41593-023-01452-y] [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: 09/03/2022] [Accepted: 09/06/2023] [Indexed: 10/07/2023]
Abstract
The amygdala processes positive and negative valence and contributes to addiction, but the cell-type-specific gene regulatory programs involved are unknown. We generated an atlas of single-nucleus gene expression and chromatin accessibility in the amygdala of outbred rats with high and low cocaine addiction-like behaviors following prolonged abstinence. Differentially expressed genes between the high and low groups were enriched for energy metabolism across cell types. Rats with high addiction index (AI) showed increased relapse-like behaviors and GABAergic transmission in the amygdala. Both phenotypes were reversed by pharmacological inhibition of the glyoxalase 1 enzyme, which metabolizes methylglyoxal-a GABAA receptor agonist produced by glycolysis. Differences in chromatin accessibility between high and low AI rats implicated pioneer transcription factors in the basic helix-loop-helix, FOX, SOX and activator protein 1 families. We observed opposite regulation of chromatin accessibility across many cell types. Most notably, excitatory neurons had greater accessibility in high AI rats and inhibitory neurons had greater accessibility in low AI rats.
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Affiliation(s)
- Jessica L Zhou
- Bioinformatics and Systems Biology Program, University of California San Diego, La Jolla, CA, USA
- Integrative Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | | | - Aaron J Ho
- Integrative Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Marsida Kallupi
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Narayan Pokhrel
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Hai-Ri Li
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Apurva S Chitre
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Daniel Munro
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Pejman Mohammadi
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA, USA
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | | | - Olivier George
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Abraham A Palmer
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Graham McVicker
- Bioinformatics and Systems Biology Program, University of California San Diego, La Jolla, CA, USA.
- Integrative Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA.
| | - Francesca Telese
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA.
- Department of Medicine, University of California San Diego, La Jolla, CA, USA.
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Domi E, Xu L, Toivainen S, Wiskerke J, Coppola A, Holm L, Augier E, Petrella M, Heilig M. Activation of GABA B receptors in central amygdala attenuates activity of PKCδ + neurons and suppresses punishment-resistant alcohol self-administration in rats. Neuropsychopharmacology 2023:10.1038/s41386-023-01543-1. [PMID: 36739350 PMCID: PMC10354045 DOI: 10.1038/s41386-023-01543-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 01/13/2023] [Accepted: 01/24/2023] [Indexed: 02/06/2023]
Abstract
Alcohol use despite negative consequences is a core phenomenon of alcohol addiction. We recently used alcohol self-administration that is resistant to footshock punishment as a model of this behavior, and found that activity of PKCδ + GABAergic neurons in the central amygdala (CeA) is a determinant of individual susceptibility for punishment resistance. In the present study, we examined whether activation of GABAB receptors in CeA can attenuate the activity of PKCδ + neurons in this region, and whether this will result in suppression of punishment- resistant alcohol self-administration in the minority of rats that show this behavior. Systemic administration of the clinically approved GABAB agonist baclofen (1 and 3 mg/kg) dose- dependently reduced punishment-resistant alcohol self-administration. Bilateral microinjections of baclofen into CeA (64 ng in 0.3 µl/side) reduced the activity of PKCδ + neurons, as measured by Fos expression. This manipulation also selectively suppressed punished alcohol self-administration in punishment-resistant rats. Expression analysis indicated that virtually all CeA PKCδ + neurons express the GABAB receptor. Using in vitro electrophysiology, we found that baclofen induced hyperpolarization of CeA neurons, reducing their firing rate in response to depolarizing current injections. Together, our findings provide a potential mechanism that contributes to the clinical efficacy of baclofen in alcohol addiction. Therapeutic use of baclofen itself is limited by problems of tolerance and need for dose escalation. Our findings support a mechanistic rationale for developing novel, improved alcohol addiction medications that target GABAB receptors, and that lack these limitations, such as e.g., GABAB positive allosteric modulators (PAM:s).
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Affiliation(s)
- Esi Domi
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, S-581 85, Linköping, Sweden. .,School of Pharmacy, Pharmacology Unit, Center for Neuroscience, University of Camerino, Camerino, 62032, Italy.
| | - Li Xu
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, S-581 85, Linköping, Sweden
| | - Sanne Toivainen
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, S-581 85, Linköping, Sweden
| | - Joost Wiskerke
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, S-581 85, Linköping, Sweden
| | - Andrea Coppola
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, S-581 85, Linköping, Sweden
| | - Lovisa Holm
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, S-581 85, Linköping, Sweden
| | - Eric Augier
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, S-581 85, Linköping, Sweden
| | - Michele Petrella
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, S-581 85, Linköping, Sweden
| | - Markus Heilig
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, S-581 85, Linköping, Sweden
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3
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Möhrle D, Wang W, Whitehead SN, Schmid S. GABA B Receptor Agonist R-Baclofen Reverses Altered Auditory Reactivity and Filtering in the Cntnap2 Knock-Out Rat. Front Integr Neurosci 2021; 15:710593. [PMID: 34489651 PMCID: PMC8417788 DOI: 10.3389/fnint.2021.710593] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 07/27/2021] [Indexed: 12/23/2022] Open
Abstract
Altered sensory information processing, and auditory processing, in particular, is a common impairment in individuals with autism spectrum disorder (ASD). One prominent hypothesis for the etiology of ASD is an imbalance between neuronal excitation and inhibition. The selective GABAB receptor agonist R-Baclofen has been shown previously to improve social deficits and repetitive behaviors in several mouse models for neurodevelopmental disorders including ASD, and its formulation Arbaclofen has been shown to ameliorate social avoidance symptoms in some individuals with ASD. The present study investigated whether R-Baclofen can remediate ASD-related altered sensory processing reliant on excitation/inhibition imbalance in the auditory brainstem. To assess a possible excitation/inhibition imbalance in the startle-mediating brainstem underlying ASD-like auditory-evoked behaviors, we detected and quantified brain amino acid levels in the nucleus reticularis pontis caudalis (PnC) of rats with a homozygous loss-of-function mutation in the ASD-linked gene Contactin-associated protein-like 2 (Cntnap2) and their wildtype (WT) littermates using Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (MALDI MS). Abnormal behavioral read-outs of brainstem auditory signaling in Cntnap2 KO rats were accompanied by increased levels of GABA, glutamate, and glutamine in the PnC. We then compared the effect of R-Baclofen on behavioral read-outs of brainstem auditory signaling in Cntnap2 KO and WT rats. Auditory reactivity, sensory filtering, and sensorimotor gating were tested in form of acoustic startle response input-output functions, short-term habituation, and prepulse inhibition before and after acute administration of R-Baclofen (0.75, 1.5, and 3 mg/kg). Systemic R-Baclofen treatment improved disruptions in sensory filtering in Cntnap2 KO rats and suppressed exaggerated auditory startle responses, in particular to moderately loud sounds. Lower ASR thresholds in Cntnap2 KO rats were increased in a dose-dependent fashion, with the two higher doses bringing thresholds close to controls, whereas shorter ASR peak latencies at the threshold were further exacerbated. Impaired prepulse inhibition increased across various acoustic prepulse conditions after administration of R-Baclofen in Cntnap2 KO rats, whereas R-Baclofen did not affect prepulse inhibition in WT rats. Our findings suggest that GABAB receptor agonists may be useful for pharmacologically targeting multiple aspects of sensory processing disruptions involving neuronal excitation/inhibition imbalances in ASD.
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Affiliation(s)
- Dorit Möhrle
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Wenxuan Wang
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Shawn N Whitehead
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Susanne Schmid
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
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Olsen N, Furlong TM, Carrive P. Behavioural and cardiovascular effects of orexin-A infused into the central amygdala under basal and fear conditions in rats. Behav Brain Res 2021; 415:113515. [PMID: 34371088 DOI: 10.1016/j.bbr.2021.113515] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 07/16/2021] [Accepted: 08/03/2021] [Indexed: 10/20/2022]
Abstract
The neuropeptide orexin-A (OX-A) has diverse functions, including maintaining arousal, autonomic control, motor activity and stress responses. These functions are regulated at different terminal regions where OX-A is released. The current study examined the physiological and behavioural effects of OX-A microinjections into the central amygdala (CeA) under basal and stressed conditions in rats. When OX-A was microinjected into the CeA and the animals returned to the home-cage, heart rate and mean arterial pressure were increased compared to vehicle-injected controls. General activity of the animal was also increased, indicating that OX-A activity in CeA contributes to increased arousal. This outcome is similar to the effects of central intracerebroventricular infusions of OX-A, as well as the cardiovascular effects previously demonstrated at many of OX's efferent hypothalamic and brainstem structures. In a second study, animals were fear-conditioned to a context by delivery of electric footshocks and then animals were re-exposed to the conditioned context at test. When OX-A was microinjected at test, freezing behaviour was reduced and there was a corresponding increase in the animal's activity but no impact on the pressor and cardiac responses (i.e, blood pressure and heart rate were unchanged). This reduction in freezing suggests that OX-A activates amygdala neurons that inhibit freezing, which is similar to the actions of other neuropeptides in the CeA that modulate the appropriate defence response to fearful stimuli. Overall, these data indicate that the CeA is an important site of OX-A modulation of cardiovascular and motor activity, as well as conditioned freezing responses.
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Affiliation(s)
- Nick Olsen
- School of Medical Sciences, The University of New South Wales, Sydney, Australia
| | - Teri M Furlong
- School of Medical Sciences, The University of New South Wales, Sydney, Australia; Neuroscience Research Australia, Randwick, Australia.
| | - Pascal Carrive
- School of Medical Sciences, The University of New South Wales, Sydney, Australia
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K v1.1 channels mediate network excitability and feed-forward inhibition in local amygdala circuits. Sci Rep 2021; 11:15180. [PMID: 34312446 PMCID: PMC8313690 DOI: 10.1038/s41598-021-94633-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 07/14/2021] [Indexed: 01/15/2023] Open
Abstract
Kv1.1 containing potassium channels play crucial roles towards dampening neuronal excitability. Mice lacking Kv1.1 subunits (Kcna1−/−) display recurrent spontaneous seizures and often exhibit sudden unexpected death. Seizures in Kcna1−/− mice resemble those in well-characterized models of temporal lobe epilepsy known to involve limbic brain regions and spontaneous seizures result in enhanced cFos expression and neuronal death in the amygdala. Yet, the functional alterations leading to amygdala hyperexcitability have not been identified. In this study, we used Kcna1−/− mice to examine the contributions of Kv1.1 subunits to excitability in neuronal subtypes from basolateral (BLA) and central lateral (CeL) amygdala known to exhibit distinct firing patterns. We also analyzed synaptic transmission properties in an amygdala local circuit predicted to be involved in epilepsy-related comorbidities. Our data implicate Kv1.1 subunits in controlling spontaneous excitatory synaptic activity in BLA pyramidal neurons. In the CeL, Kv1.1 loss enhances intrinsic excitability and impairs inhibitory synaptic transmission, notably resulting in dysfunction of feed-forward inhibition, a critical mechanism for controlling spike timing. Overall, we find inhibitory control of CeL interneurons is reduced in Kcna1−/− mice suggesting that basal inhibitory network functioning is less able to prevent recurrent hyperexcitation related to seizures.
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Marti‐Prats L, Belin‐Rauscent A, Fouyssac M, Puaud M, Cocker PJ, Everitt BJ, Belin D. Baclofen decreases compulsive alcohol drinking in rats characterized by reduced levels of GAT-3 in the central amygdala. Addict Biol 2021; 26:e13011. [PMID: 33527681 PMCID: PMC8603926 DOI: 10.1111/adb.13011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 01/12/2021] [Accepted: 01/14/2021] [Indexed: 11/29/2022]
Abstract
While most individuals with access to alcohol drink it recreationally, some vulnerable individuals eventually lose control over their intake and progressively develop compulsive alcohol drinking and decreased interest in alternative sources of reinforcement, two key features of addiction. The neural and molecular mechanisms underlying this vulnerability to switch from controlled to compulsive alcohol intake have not been fully elucidated. It has been shown that rats having reduced levels of expression of the gamma-aminobutyric acid (GABA) transporter, GAT-3, in the amygdala tend to persist in seeking and drinking alcohol even when adulterated with quinine, suggesting that pharmacological interventions aimed at restoring GABA homeostasis in these individuals may provide a targeted treatment to limit compulsive alcohol drinking. Here, we tested the hypothesis that the GABAB receptor agonist baclofen, which decreases GABA release, specifically reduces compulsive alcohol drinking in vulnerable individuals. In a large cohort of Sprague-Dawley rats allowed to drink alcohol under an intermittent two-bottle choice procedure, a cluster of individuals was identified that persisted in drinking alcohol despite adulteration with quinine or when an alternative ingestive reinforcer, saccharin, was available. In these rats, which were characterized by decreased GAT-3 mRNA levels in the central amygdala, acute baclofen administration (1.5 mg/kg, intraperitoneal) resulted in a decrease in compulsive drinking. These results indicate that low GAT-3 mRNA levels in the central amygdala may represent an endophenotype of vulnerability to develop a compulsive drinking of alcohol that is shown here to be mitigated by baclofen.
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Affiliation(s)
| | | | - Maxime Fouyssac
- Department of Psychology University of Cambridge Cambridge UK
| | - Mickaël Puaud
- Department of Psychology University of Cambridge Cambridge UK
| | - Paul J Cocker
- Department of Psychology University of Cambridge Cambridge UK
| | - Barry J Everitt
- Department of Psychology University of Cambridge Cambridge UK
| | - David Belin
- Department of Psychology University of Cambridge Cambridge UK
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7
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Morley KC, Logge WB, Fraser I, Morris RW, Baillie AJ, Haber PS. High-dose baclofen attenuates insula activation during anticipatory anxiety in treatment-seeking alcohol dependant individuals: Preliminary findings from a pharmaco-fMRI study. Eur Neuropsychopharmacol 2021; 46:28-36. [PMID: 33735709 DOI: 10.1016/j.euroneuro.2021.02.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/28/2021] [Accepted: 02/17/2021] [Indexed: 02/06/2023]
Abstract
The GABA B agonist, baclofen, has been shown to reduce alcohol consumption in patients with alcohol use disorder and also those with comorbid anxiety. This study aimed to evaluate the effect of baclofen versus placebo on the BOLD response during an anticipatory anxiety fMRI task in treatment seeking alcohol patients. Participants included 28 alcohol dependant individuals who had received daily baclofen 30 mg (n = 10), 75 mg (n = 8) or placebo (n = 10) for at least 2 week on a randomized controlled trial (Morley, Leung et al. 2013, Morley, Baillie et al. 2018). Using functional magnetic resonance imaging (fMRI), we examined threat cue-elicited neural activation during a threat reactivity task 120 min following administration of BAC (30 mg or 75 mg) or placebo. Whole-brain analyses revealed no significant differences between the combined BAC doses versus PL. However, there were significant decreases in anticipatory threat cue-elicited activation observed in BAC 75 mg/day compared to PL participants in the insula. In response to threat cues, high dose (75 mg/day) baclofen administration attenuates activation in the insula and inferior frontal gyrus, relative to placebo. These preliminary findings suggests that modulating emotional regulation and attentional allocation during high threat stimuli may be mediated by GABA B receptors and may be a potential mechanism of action for baclofen's beneficial treatment effects for alcohol use disorder.
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Affiliation(s)
- Kirsten C Morley
- Discipline of Addiction Medicine, Central Clinical School, Faculty of Medicine and Health, University of Sydney, NSW, Australia; Edith Collins Centre (Translational Research in Alcohol, Drugs and Toxicology), Sydney Local Health District, Sydney, NSW, Australia.
| | - Warren B Logge
- Discipline of Addiction Medicine, Central Clinical School, Faculty of Medicine and Health, University of Sydney, NSW, Australia; Drug Health Services, Royal Prince Alfred Hospital, NSW, Australia; Edith Collins Centre (Translational Research in Alcohol, Drugs and Toxicology), Sydney Local Health District, Sydney, NSW, Australia
| | - Isabel Fraser
- Discipline of Addiction Medicine, Central Clinical School, Faculty of Medicine and Health, University of Sydney, NSW, Australia
| | - Richard W Morris
- Psychological Medicine, Central Clinical School, Faculty of Medicine and Health, University of Sydney, NSW, Australia
| | - Andrew J Baillie
- Faculty of Health Sciences, University of Sydney, NSW, Australia
| | - Paul S Haber
- Discipline of Addiction Medicine, Central Clinical School, Faculty of Medicine and Health, University of Sydney, NSW, Australia; Drug Health Services, Royal Prince Alfred Hospital, NSW, Australia; Edith Collins Centre (Translational Research in Alcohol, Drugs and Toxicology), Sydney Local Health District, Sydney, NSW, Australia
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Augier E. Recent Advances in the Potential of Positive Allosteric Modulators of the GABAB Receptor to Treat Alcohol Use Disorder. Alcohol Alcohol 2021; 56:139-148. [PMID: 33561865 PMCID: PMC7906877 DOI: 10.1093/alcalc/agab003] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 12/11/2022] Open
Abstract
Aims The effects of alcohol on gamma-aminobutyric acid (GABA) transmission are key for the development and maintenance of alcohol use disorder (AUD). Previous research consistently indicates that GABAB receptor agonists such as baclofen can attenuate addiction-related behaviors in preclinical models of AUD. More importantly, baclofen has also shown promise in clinical studies, particularly in severely alcohol-dependent patients. However, despite this promise, other clinical studies have not confirmed its efficacy and chiefly, larger clinical trials have not been conducted. Therefore, with the exception of France, baclofen is not approved for the treatment of AUD in any other country. Furthermore, it is also important to keep in mind that some patients treated with baclofen may experience important side-effects, including sedation, drowsiness and sleepiness. Methods This short review will first discuss the history of baclofen for AUD treatment. We will then summarize preclinical behavioral results that have investigated the efficacy of GABAB PAMs for addiction treatment, with a special focus on our recent work that investigated the effects of ADX71441, a novel GABAB PAM, on several alcohol-related behaviors in rats that model important aspects of human AUD. Finally, in light of the recent criticism about the translational value of animal models of addiction, the specific translational potential of our work and of other preclinical studies that have unanimously reported the efficacy of GABAB PAMs to attenuate multiple alcohol-related behaviors will be discussed. Results Positive allosteric modulators (PAMs) of the GABAB receptor offer an attractive alternative approach to baclofen and have the potential to achieve mechanistic and therapeutic effects similar to GABAB agonists, while avoiding the tolerance and toxicity issues associated with baclofen. To date, all preclinical behavioral results have invariably shown the efficacy of GABAB PAMs for addiction treatment. Conclusions Preclinical studies indicate that GABAB PAMs have a higher therapeutic index than orthosteric agonists, at least in terms of mitigating the sedative effects of GABAB agonism. This predicts that GABAB PAMs have a high translational potential in humans and merit being tested clinically, in particular in patients with severe AUD.
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Affiliation(s)
- Eric Augier
- Center for Social and Affective Neuroscience, BKV, Linköping University, Linköping 58183, Sweden
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Sun W, Yuill MB. Role of the GABA a and GABA b receptors of the central nucleus of the amygdala in compulsive cocaine-seeking behavior in male rats. Psychopharmacology (Berl) 2020; 237:3759-3771. [PMID: 32875348 PMCID: PMC7686280 DOI: 10.1007/s00213-020-05653-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 08/24/2020] [Indexed: 01/28/2023]
Abstract
RATIONALE Compulsive cocaine use, defined as the continued use despite the dire consequences, is a hallmark of cocaine addiction. Thus, understanding the brain mechanism regulating the compulsive cocaine-seeking and cocaine-taking behaviors is essential to understand cocaine addiction and the key to identification of the molecular targets for the development of medications against this condition. OBJECTIVE This study aimed to determine how the GABAa and GABAb receptors of the central nucleus of the amygdala (CeA) regulate the compulsive cocaine-seeking behavior. METHODS Male Wistar outbred rats were trained to self-administer intravenous cocaine (0.4 mg/kg/infusion) under a chained schedule. The compulsive cocaine-seeking behavior was measured as the cocaine-seeking behavior in the face of footshock punishment. The role of the GABA receptors of CeA in the regulation of such behavior was determined by measuring the dose-dependent effects of the GABAa agonist muscimol or the GABAb agonist baclofen bilaterally microinjected into the CeA on the punished cocaine-seeking behavior. RESULTS The cocaine-seeking behavior was inhibited by footshock punishment in an intensity-dependent manner. Both muscimol and baclofen dose-dependently increased the punished cocaine-seeking behavior. However, the potency of muscimol but not baclofen was negatively correlated with the effects of punishment. CONCLUSION These data indicate that the CeA GABAa receptors play a key role in the regulation of the compulsive cocaine-seeking behavior and suggest that an increase in the function of the GABAa receptors possibly induced by cocaine or genetic factors may be an important mechanism involved in the development of or vulnerability to the compulsive cocaine use and addiction.
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Affiliation(s)
- WenLin Sun
- Department of Pharmacology, University of Tennessee Health Science Center, 71 S. Manassas, Memphis, TN, 38103, USA.
| | - Matt B Yuill
- Department of Pharmacology, University of Tennessee Health Science Center, 71 S. Manassas, Memphis, TN, 38103, USA
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Gao J, Gao Y, Lin S, Zou X, Zhu Y, Chen X, Wan H, Zhu H. Effects of activating GABAB1 receptor on proliferation, migration, invasion and epithelial-mesenchymal transition of ovarian cancer cells. J Ovarian Res 2020; 13:126. [PMID: 33099319 PMCID: PMC7585685 DOI: 10.1186/s13048-020-00726-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/05/2020] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE This study aimed to explore the effects of activating GABAB1 receptor by baclofen on proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of ovarian cancer cells. RESULTS One hundred μmol/L, 200 μmol/L and 300 μmol/L were selected as low, medium and high baclofen concentrations respectively. Cells were divided into four groups: Control, 100 μmol/L, 200 μmol/L and 300 μmol/L. Compared with the control group, the viability, colony formation, migration and invasion of SKOV3 cells were inhibited, and the apoptosis of SKOV3 cells were enhanced significantly at 200 μmol/L and 300 μmol/L baclofen. Moreover, they changed significantly with the increase of baclofen concentration. Compared with the control group, the expression of E-cadherin and GABAB1 increased and the N-cadherin expression decreased significantly in 200 μmol/L and 300 μmol/L groups. Higher concentration of baclofen induced higher expression of E-cadherin and lower expression of N-cadherin. CONCLUSION Baclofen inhibited the proliferation, cloning, migration, invasion and EMT of ovarian cancer cells by activating GABAB1 receptor. These results might contribute a lot to clarify the role and possible mechanism of GABAB1 receptor in ovarian cancer.
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Affiliation(s)
- Jun Gao
- Department of Obstetrics and Gynecology, the Third Affiliated Hospital of Nanchang University, Xiangshanbei Road 128, Donghu District, Nanchang, 330008, Jiangxi, China
| | - Yao Gao
- Postgraduate Department, Jiangxi Medical College of Nanchang University, Nanchang, 330008, Jiangxi, China
| | - Shixin Lin
- Postgraduate Department, Jiangxi Medical College of Nanchang University, Nanchang, 330008, Jiangxi, China
| | - Xia Zou
- Department of Obstetrics and Gynecology, the Third Affiliated Hospital of Nanchang University, Xiangshanbei Road 128, Donghu District, Nanchang, 330008, Jiangxi, China
| | - Yukai Zhu
- Postgraduate Department, Jiangxi Medical College of Nanchang University, Nanchang, 330008, Jiangxi, China
| | - Xintong Chen
- Postgraduate Department, Jiangxi Medical College of Nanchang University, Nanchang, 330008, Jiangxi, China
| | - Hong Wan
- Department of Obstetrics and Gynecology, the Third Affiliated Hospital of Nanchang University, Xiangshanbei Road 128, Donghu District, Nanchang, 330008, Jiangxi, China.
| | - Hong Zhu
- Department of Obstetrics and Gynecology, the Third Affiliated Hospital of Nanchang University, Xiangshanbei Road 128, Donghu District, Nanchang, 330008, Jiangxi, China.
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Presynaptic inhibition rapidly stabilises recurrent excitation in the face of plasticity. PLoS Comput Biol 2020; 16:e1008118. [PMID: 32764742 PMCID: PMC7439813 DOI: 10.1371/journal.pcbi.1008118] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 08/19/2020] [Accepted: 07/01/2020] [Indexed: 01/23/2023] Open
Abstract
Hebbian plasticity, a mechanism believed to be the substrate of learning and memory, detects and further enhances correlated neural activity. Because this constitutes an unstable positive feedback loop, it requires additional homeostatic control. Computational work suggests that in recurrent networks, the homeostatic mechanisms observed in experiments are too slow to compensate instabilities arising from Hebbian plasticity and need to be complemented by rapid compensatory processes. We suggest presynaptic inhibition as a candidate that rapidly provides stability by compensating recurrent excitation induced by Hebbian changes. Presynaptic inhibition is mediated by presynaptic GABA receptors that effectively and reversibly attenuate transmitter release. Activation of these receptors can be triggered by excess network activity, hence providing a stabilising negative feedback loop that weakens recurrent interactions on sub-second timescales. We study the stabilising effect of presynaptic inhibition in recurrent networks, in which presynaptic inhibition is implemented as a multiplicative reduction of recurrent synaptic weights in response to increasing inhibitory activity. We show that networks with presynaptic inhibition display a gradual increase of firing rates with growing excitatory weights, in contrast to traditional excitatory-inhibitory networks. This alleviates the positive feedback loop between Hebbian plasticity and network activity and thereby allows homeostasis to act on timescales similar to those observed in experiments. Our results generalise to spiking networks with a biophysically more detailed implementation of the presynaptic inhibition mechanism. In conclusion, presynaptic inhibition provides a powerful compensatory mechanism that rapidly reduces effective recurrent interactions and thereby stabilises Hebbian learning. Synapses between neurons change during learning and memory formation, a process termed synaptic plasticity. Established models of plasticity rely on strengthening synapses of co-active neurons. In recurrent networks, mutually connected neurons tend to be co-active. The emerging positive feedback loop is believed to be counteracted by homeostatic mechanisms that aim to keep neural activity at a given set point. However, theoretical work indicates that experimentally observed forms of homeostasis are too slow to maintain stable network activity. In this article, we suggest that presynaptic inhibition can alleviate this problem. Presynaptic inhibition is an inhibitory mechanism that weakens synapses rather than suppressing neural activity. Using mathematical analyses and computer simulations, we show that presynaptic inhibition can compensate the strengthening of recurrent connections and thus stabilises neural networks subject to synaptic plasticity, even if homeostasis acts on biologically plausible timescales.
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Crane JW, Holmes NM, Fam J, Westbrook RF, Delaney AJ. Oxytocin increases inhibitory synaptic transmission and blocks development of long-term potentiation in the lateral amygdala. J Neurophysiol 2020; 123:587-599. [DOI: 10.1152/jn.00571.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Oxytocin (OT) is a neuroactive peptide that influences the processing of fearful stimuli in the amygdala. In the central nucleus of the amygdala, the activation of OT receptors alters neural activity and ultimately suppresses the behavioral response to a fear conditioned stimulus. Receptors for OT are also found in the lateral amygdala (LA), and infusion of OT into the basolateral amygdala complex affects the formation and consolidation of fear memories. Yet, how OT receptor activation alters neurons and neural networks in the LA is unknown. In this study we used whole cell electrophysiological recordings to determine how OT-receptor activation changes synaptic transmission and synaptic plasticity in the LA of Sprague-Dawley rats. Our results demonstrate that OT-receptor activation results in a 200% increase in spontaneous inhibitory transmission in the LA that leads to the activation of presynaptic GABAB receptors. The activation of these receptors inhibits excitatory transmission in the LA, blocking long-term potentiation of cortical inputs onto LA neurons. Hence, this study provides the first demonstration that OT influences synaptic transmission and plasticity in the LA, revealing a mechanism that could explain how OT regulates the formation and consolidation of conditioned fear memories in the amygdala. NEW & NOTEWORTHY This study investigates modulation of synaptic transmission by oxytocin (OT) in the lateral amygdala (LA). We demonstrate that OT induces transient increases in spontaneous GABAergic transmission by activating interneurons in the basolateral amygdala. The resultant increase in GABA release in the LA activates presynaptic GABAB receptors on both inhibitory and excitatory inputs onto LA neurons, reducing release probability at these synapses. We subsequently demonstrate that OT modulates synaptic plasticity at cortical inputs to the LA.
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Affiliation(s)
- J. W. Crane
- School of Biomedical Sciences, Charles Sturt University, Orange, New South Wales, Australia
- School of Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - N. M. Holmes
- School of Psychology, University of New South Wales, Sydney, New South Wales, Australia
| | - J. Fam
- School of Psychology, University of New South Wales, Sydney, New South Wales, Australia
| | - R. F. Westbrook
- School of Psychology, University of New South Wales, Sydney, New South Wales, Australia
| | - A. J. Delaney
- School of Biomedical Sciences, Charles Sturt University, Orange, New South Wales, Australia
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Heilig M, Augier E, Pfarr S, Sommer WH. Developing neuroscience-based treatments for alcohol addiction: A matter of choice? Transl Psychiatry 2019; 9:255. [PMID: 31594920 PMCID: PMC6783461 DOI: 10.1038/s41398-019-0591-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 07/05/2019] [Accepted: 08/08/2019] [Indexed: 12/15/2022] Open
Abstract
Excessive alcohol use is the cause of an ongoing public health crisis, and accounts for ~5% of global disease burden. A minority of people with recreational alcohol use develop alcohol addiction (hereafter equated with "alcohol dependence" or simply "alcoholism"), a condition characterized by a systematically biased choice preference for alcohol at the expense of healthy rewards, and continued use despite adverse consequences ("compulsivity"). Alcoholism is arguably the most pressing area of unmet medical needs in psychiatry, with only a small fraction of patients receiving effective, evidence-based treatments. Medications currently approved for the treatment of alcoholism have small effect sizes, and their clinical uptake is negligible. No mechanistically new medications have been approved since 2004, and promising preclinical results have failed to translate into novel treatments. This has contributed to a reemerging debate whether and to what extent alcohol addiction represents a medical condition, or reflects maladaptive choices without an underlying brain pathology. Here, we review this landscape, and discuss the challenges, lessons learned, and opportunities to retool drug development in this important therapeutic area.
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Affiliation(s)
- Markus Heilig
- Center for Social and Affective Neuroscience, Department of Clinical and Experimental Medicine, Linköping University, S-581 83, Linköping, Sweden.
| | - Eric Augier
- 0000 0001 2162 9922grid.5640.7Center for Social and Affective Neuroscience, Department of Clinical and Experimental Medicine, Linköping University, S-581 83 Linköping, Sweden
| | - Simone Pfarr
- 0000 0004 0477 2235grid.413757.3Institute of Psychopharmacology, Central Institute of Mental Health (CIMH), J 5, 68159 Mannheim, Germany
| | - Wolfgang H. Sommer
- 0000 0004 0477 2235grid.413757.3Institute of Psychopharmacology, Central Institute of Mental Health (CIMH), J 5, 68159 Mannheim, Germany ,0000 0004 0477 2235grid.413757.3Department of Addiction Medicine, Central Institute of Mental Health (CIMH), J 5, 68159 Mannheim, Germany
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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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