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Kaplan GB, Thompson BL. Neuroplasticity of the extended amygdala in opioid withdrawal and prolonged opioid abstinence. Front Pharmacol 2023; 14:1253736. [PMID: 38044942 PMCID: PMC10690374 DOI: 10.3389/fphar.2023.1253736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 11/02/2023] [Indexed: 12/05/2023] Open
Abstract
Opioid use disorder is characterized by excessive use of opioids, inability to control its use, a withdrawal syndrome upon discontinuation of opioids, and long-term likelihood of relapse. The behavioral stages of opioid addiction correspond with affective experiences that characterize the opponent process view of motivation. In this framework, active involvement is accompanied by positive affective experiences which gives rise to "reward craving," whereas the opponent process, abstinence, is associated with the negative affective experiences that produce "relief craving." Relief craving develops along with a hypersensitization to the negatively reinforcing aspects of withdrawal during abstinence from opioids. These negative affective experiences are hypothesized to stem from neuroadaptations to a network of affective processing called the "extended amygdala." This negative valence network includes the three core structures of the central nucleus of the amygdala (CeA), the bed nucleus of the stria terminalis (BNST), and the nucleus accumbens shell (NAc shell), in addition to major inputs from the basolateral amygdala (BLA). To better understand the major components of this system, we have reviewed their functions, inputs and outputs, along with the associated neural plasticity in animal models of opioid withdrawal. These models demonstrate the somatic, motivational, affective, and learning related models of opioid withdrawal and abstinence. Neuroadaptations in these stress and motivational systems are accompanied by negative affective and aversive experiences that commonly give rise to relapse. CeA neuroplasticity accounts for many of the aversive and fear-related effects of opioid withdrawal via glutamatergic plasticity and changes to corticotrophin-releasing factor (CRF)-containing neurons. Neuroadaptations in BNST pre-and post-synaptic GABA-containing neurons, as well as their noradrenergic modulation, may be responsible for a variety of aversive affective experiences and maladaptive behaviors. Opioid withdrawal yields a hypodopaminergic and amotivational state and results in neuroadaptive increases in excitability of the NAc shell, both of which are associated with increased vulnerability to relapse. Finally, BLA transmission to hippocampal and cortical regions impacts the perception of conditioned aversive effects of opioid withdrawal by higher executive systems. The prevention or reversal of these varied neuroadaptations in the extended amygdala during opioid withdrawal could lead to promising new interventions for this life-threatening condition.
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Affiliation(s)
- Gary B Kaplan
- Mental Health Service, VA Boston Healthcare System, Boston, MA, United States
- Department of Psychiatry, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, United States
- Department of Pharmacology and Experimental Therapeutics, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, United States
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Zhang M, Luo Y, Wang J, Sun Y, Xie B, Zhang L, Cong B, Ma C, Wen D. Roles of nucleus accumbens shell small-conductance calcium-activated potassium channels in the conditioned fear freezing. J Psychiatr Res 2023; 163:180-194. [PMID: 37216772 DOI: 10.1016/j.jpsychires.2023.05.057] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 04/27/2023] [Accepted: 05/15/2023] [Indexed: 05/24/2023]
Abstract
BACKGROUND Posttraumatic stress disorder (PTSD), a psychiatric disorder caused by stressful events, is characterized by long-lasting fear memory. The nucleus accumbens shell (NAcS) is a key brain region that regulates fear-associated behavior. Small-conductance calcium-activated potassium channels (SK channels) play a key role in regulating the excitability of NAcS medium spiny neurons (MSNs) but their mechanisms of action in fear freezing are unclear. METHOD We established an animal model of traumatic memory using conditioned fear freezing paradigm, and investigated the alterations in SK channels of NAc MSNs subsequent to fear conditioning in mice. We then utilized an adeno-associated virus (AAV) transfection system to overexpress the SK3 subunit and explore the function of the NAcS MSNs SK3 channel in conditioned fear freezing. RESULTS Fear conditioning activated NAcS MSNs with enhanced excitability and reduced the SK channel-mediated medium after-hyperpolarization (mAHP) amplitude. The expression of NAcS SK3 were also reduced time-dependently. The overexpression of NAcS SK3 impaired conditioned fear consolidation without affecting conditioned fear expression, and blocked fear conditioning-induced alterations in NAcS MSNs excitability and mAHP amplitude. Additionally, the amplitudes of mEPSC, AMPAR/NMDAR ratio, and membrane surface GluA1/A2 expression in NAcS MSNs was increased by fear conditioning and returned to normal levels upon SK3 overexpression, indicating that fear conditioning-induced decrease of SK3 expression caused postsynaptic excitation by facilitating AMPAR transmission to the membrane. CONCLUSION These findings show that the NAcS MSNs SK3 channel plays a critical role in conditioned fear consolidation and that it may influence PTSD pathogenesis, making it a potential therapeutic target against PTSD.
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Affiliation(s)
- Minglong Zhang
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China
| | - Yixiao Luo
- Hunan Province People's Hospital, The First-Affiliated Hospital of Hunan Normal University, Changsha, 410081, PR China
| | - Jian Wang
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China
| | - Yufei Sun
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China
| | - Bing Xie
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China
| | - Ludi Zhang
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China
| | - Bin Cong
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China
| | - Chunling Ma
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China.
| | - Di Wen
- College of Forensic Medicine, Hebei Medical University, Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, Research Unit of Digestive Tract Microecosystem Pharmacology and Toxicology, Chinese Academy of Medical Sciences, Hebei Province, Shijiazhuang, 050017, PR China.
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Nashed MG, Waye S, Hasan SMN, Nguyen D, Wiseman M, Zhang J, Lau H, Dinesh OC, Raymond R, Greig IR, Bambico FR, Nobrega JN. Antidepressant activity of pharmacological and genetic deactivation of the small-conductance calcium-activated potassium channel subtype-3. Psychopharmacology (Berl) 2022; 239:253-266. [PMID: 34982171 DOI: 10.1007/s00213-021-06045-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 12/13/2021] [Indexed: 11/25/2022]
Abstract
RATIONALE The voltage-insensitive, small-conductance calcium-activated potassium (SK) channel is a key regulator of neuronal depolarization and is implicated in the pathophysiology of depressive disorders. OBJECTIVE We ascertained whether the SK channel is impaired in the chronic unpredictable stress (CUS) model and whether it can serve as a molecular target of antidepressant action. METHODS We assessed the depressive-like behavioral phenotype of CUS-exposed rats and performed post-mortem SK channel binding and activity-dependent zif268 mRNA analyses on their brains. To begin an assessment of SK channel subtypes involved, we examined the effects of genetic and pharmacological inhibition of the SK3 channel using conditional knockout mice and selective SK3 channel negative allosteric modulators (NAMs). RESULTS We found that [125I]apamin binding to SK channels is increased in the prefrontal cortex and decreased in the hippocampus, an effect that was associated with reciprocal levels of zif268 mRNA transcripts indicating abnormal regional cell activity in this model. We found that genetic and pharmacological manipulations significantly decreased immobility in the forced swim test without altering general locomotor activity, a hallmark of antidepressant-like activity. CONCLUSIONS Taken together, these findings link depression-related neural and behavioral pathophysiology with abnormal SK channel functioning and suggest that this can be reversed by the selective inhibition of SK3 channels.
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Affiliation(s)
- Mina G Nashed
- Behavioural Neurobiology Laboratory, Research Imaging Center, Centre for Addiction and Mental Health (CAMH), Toronto, ON, M5T 1R8, Canada
| | - Shannon Waye
- Department of Psychology, Memorial University of Newfoundland, St. John's, Newfoundland & Labrador, A1B 3X9, Canada
| | - S M Nageeb Hasan
- Department of Psychology, Memorial University of Newfoundland, St. John's, Newfoundland & Labrador, A1B 3X9, Canada
| | - Diana Nguyen
- Behavioural Neurobiology Laboratory, Research Imaging Center, Centre for Addiction and Mental Health (CAMH), Toronto, ON, M5T 1R8, Canada
| | - Micaela Wiseman
- Behavioural Neurobiology Laboratory, Research Imaging Center, Centre for Addiction and Mental Health (CAMH), Toronto, ON, M5T 1R8, Canada
| | - Jing Zhang
- Behavioural Neurobiology Laboratory, Research Imaging Center, Centre for Addiction and Mental Health (CAMH), Toronto, ON, M5T 1R8, Canada
| | - Harry Lau
- Behavioural Neurobiology Laboratory, Research Imaging Center, Centre for Addiction and Mental Health (CAMH), Toronto, ON, M5T 1R8, Canada
| | - O Chandani Dinesh
- Department of Psychology, Memorial University of Newfoundland, St. John's, Newfoundland & Labrador, A1B 3X9, Canada
| | - Roger Raymond
- Behavioural Neurobiology Laboratory, Research Imaging Center, Centre for Addiction and Mental Health (CAMH), Toronto, ON, M5T 1R8, Canada
| | - Iain R Greig
- Institute of Medical Sciences, University of Aberdeen, King's College, Aberdeen, AB25 2ZD, Scotland
| | - Francis Rodriguez Bambico
- Behavioural Neurobiology Laboratory, Research Imaging Center, Centre for Addiction and Mental Health (CAMH), Toronto, ON, M5T 1R8, Canada. .,Department of Psychology, Memorial University of Newfoundland, St. John's, Newfoundland & Labrador, A1B 3X9, Canada.
| | - José N Nobrega
- Behavioural Neurobiology Laboratory, Research Imaging Center, Centre for Addiction and Mental Health (CAMH), Toronto, ON, M5T 1R8, Canada
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Abstract
This paper is the forty-second consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2019 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, 65-30 Kissena Blvd., Flushing, NY, 11367, United States.
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McCoy MT, Jayanthi S, Cadet JL. Potassium Channels and Their Potential Roles in Substance Use Disorders. Int J Mol Sci 2021; 22:1249. [PMID: 33513859 PMCID: PMC7865894 DOI: 10.3390/ijms22031249] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 01/12/2023] Open
Abstract
Substance use disorders (SUDs) are ubiquitous throughout the world. However, much remains to be done to develop pharmacotherapies that are very efficacious because the focus has been mostly on using dopaminergic agents or opioid agonists. Herein we discuss the potential of using potassium channel activators in SUD treatment because evidence has accumulated to support a role of these channels in the effects of rewarding drugs. Potassium channels regulate neuronal action potential via effects on threshold, burst firing, and firing frequency. They are located in brain regions identified as important for the behavioral responses to rewarding drugs. In addition, their expression profiles are influenced by administration of rewarding substances. Genetic studies have also implicated variants in genes that encode potassium channels. Importantly, administration of potassium agonists have been shown to reduce alcohol intake and to augment the behavioral effects of opioid drugs. Potassium channel expression is also increased in animals with reduced intake of methamphetamine. Together, these results support the idea of further investing in studies that focus on elucidating the role of potassium channels as targets for therapeutic interventions against SUDs.
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Affiliation(s)
| | | | - Jean Lud Cadet
- Molecular Neuropsychiatry Research Branch, NIDA Intramural Research Program, Baltimore, MD 21224, USA; (M.T.M.); (S.J.)
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Qu L, Wang Y, Li Y, Wang X, Li N, Ge S, Wang J, Wang GJ, Volkow ND, Lang B, Wang P, Wu H, Zeng J, Fu J, Li J, Zhang Y, Wang X. Decreased Neuronal Excitability in Medial Prefrontal Cortex during Morphine Withdrawal is associated with enhanced SK channel activity and upregulation of small GTPase Rac1. Am J Cancer Res 2020; 10:7369-7383. [PMID: 32641997 PMCID: PMC7330845 DOI: 10.7150/thno.44893] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 05/25/2020] [Indexed: 12/13/2022] Open
Abstract
Rationale: Neuroadaptations in the medial prefrontal cortex (mPFC) and Nucleus Accumbens (NAc) play a role in the disruption of control-reward circuits in opioid addiction. Small Conductance Calcium-Activated Potassium (SK) channels in the mPFC have been implicated in neuronal excitability changes during morphine withdrawal. However, the mechanism that modulates SK channels during withdrawal is still unknown. Methods: Rats were exposed for one week to daily morphine injections (10 mg·kg-1 s.c.) followed by conditional place preference (CPP) assessment. One week after withdrawal, electrophysiological, morphological and molecular biological methods were applied to investigate the effects of morphine on SK channels in mPFC, including infralimbic (IL), prelimbic (PrL) cortices and NAc (core and shell). We verified the hypothesis that Rac1, a member of Rho family of small GTPases, implicated in SK channel regulation, modulate SK channel neuroadaptations during opiate withdrawal. Results: One week after morphine withdrawal, the neuronal excitability of layer 5 pyramidal neurons in IL was decreased, but not in PrL. Whereas, the excitability was increased in NAc-shell, but not in NAc-core. In mPFC, the expression of the SK3 subunit was enhanced after one-week of withdrawal compared to controls. In the IL, Rac1 signaling was increased during withdrawal, and the Rac1 inhibitor NSC23766 disrupted SK current, which increased neuronal firing. Suppression of Rac1 inhibited morphine-induced CPP and expression of SK channels in IL. Conclusions: These findings highlight the potential value of SK channels and the upstream molecule Rac1, which may throw light on the therapeutic mechanism of neuromodulation treatment for opioid dependence.
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Jayanthi S, Torres OV, Ladenheim B, Cadet JL. A Single Prior Injection of Methamphetamine Enhances Methamphetamine Self-Administration (SA) and Blocks SA-Induced Changes in DNA Methylation and mRNA Expression of Potassium Channels in the Rat Nucleus Accumbens. Mol Neurobiol 2019; 57:1459-1472. [PMID: 31758400 PMCID: PMC7060962 DOI: 10.1007/s12035-019-01830-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/01/2019] [Indexed: 12/27/2022]
Abstract
The transition from occasional to escalated psychostimulant use is accelerated by prior drug exposure. These behavioral observations may be related to long-lasting transcriptional and/or epigenetic changes induced by the drug pre-exposure. Herein, we investigated if a single methamphetamine (METH) injection would enhance METH self-administration (SA) and impact any METH SA-induced epigenetic or transcriptional alterations. We thus injected a single METH dose (10 mg/kg) or saline to rats before training them to self-administer METH or saline. There were three experimental groups in SA experiments: (1) a single saline injection followed by saline SA (SS); (2) a single saline injection followed by METH SA (SM); and (3) a single METH injection followed by METH SA (MM). METH-pretreated rats escalated METH SA earlier and took more METH than saline-pretreated animals. Both groups showed similar incubation of cue-induced METH craving. Because compulsive METH takers and METH-abstinent rats show differences in potassium (K+) channel mRNA levels in their nucleus accumbens (NAc), we wondered if K+ channel expression might also help to distinguish between SM and MM groups. We found increases in mRNA and protein expression of shaker-related voltage-gated K+ channels (Kv1: Kcna1, Kcna3, and Kcna6) and calcium-activated K+ channels (Kcnn1) in the SM compared to MM rats. SM rats also showed decreased DNA methylation at the CpG-rich sites near the promoter region of Kcna1, Kcna3 and Kcnn1 genes in comparison to MM rats. Together, these results provide additional evidence for potentially using K+ channels as therapeutic targets against METH use disorder.
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Affiliation(s)
- Subramaniam Jayanthi
- Molecular Neuropsychiatry Research Branch, Intramural Research Program, NIDA/NIH/DHHS, 251 Bayview Boulevard, Baltimore, MD, 21224, USA
| | - Oscar V Torres
- Department of Behavioral Sciences, San Diego Mesa College, San Diego, CA, USA
| | - Bruce Ladenheim
- Molecular Neuropsychiatry Research Branch, Intramural Research Program, NIDA/NIH/DHHS, 251 Bayview Boulevard, Baltimore, MD, 21224, USA
| | - Jean Lud Cadet
- Molecular Neuropsychiatry Research Branch, Intramural Research Program, NIDA/NIH/DHHS, 251 Bayview Boulevard, Baltimore, MD, 21224, USA.
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