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Chadwick W, Angulo-Herrera I, Cogram P, Deacon RJM, Mason DJ, Brown D, Roberts I, O’Donovan DJ, Tranfaglia MR, Guilliams T, Thompson NT. A novel combination treatment for fragile X syndrome predicted using computational methods. Brain Commun 2024; 6:fcad353. [PMID: 38226317 PMCID: PMC10789243 DOI: 10.1093/braincomms/fcad353] [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: 06/12/2023] [Revised: 11/07/2023] [Accepted: 12/21/2023] [Indexed: 01/17/2024] Open
Abstract
Fragile X syndrome is a neurodevelopmental disorder caused by silencing of the fragile X messenger ribonucleotide gene. Patients display a wide spectrum of symptoms ranging from intellectual and learning disabilities to behavioural challenges including autism spectrum disorder. In addition to this, patients also display a diversity of symptoms due to mosaicism. These factors make fragile X syndrome a difficult syndrome to manage and suggest that a single targeted therapeutic approach cannot address all the symptoms. To this end, we utilized Healx's data-driven drug discovery platform to identify a treatment strategy to address the wide range of diverse symptoms among patients. Computational methods identified the combination of ibudilast and gaboxadol as a treatment for several pathophysiological targets that could potentially reverse multiple symptoms associated with fragile X syndrome. Ibudilast is an approved broad-spectrum phosphodiesterase inhibitor, selective against both phosphodiesterase 4 and phosphodiesterase 10, and has demonstrated to have several beneficial effects in the brain. Gaboxadol is a GABAA receptor agonist, selective against the delta subunit, which has previously displayed encouraging results in a fragile X syndrome clinical trial. Alterations in GABA and cyclic adenosine monophosphate metabolism have long since been associated with the pathophysiology of fragile X syndrome; however, targeting both pathways simultaneously has never been investigated. Both drugs have a good safety and tolerability profile in the clinic making them attractive candidates for repurposing. We set out to explore whether the combination of ibudilast and gaboxadol could demonstrate therapeutic efficacy in a fragile X syndrome mouse model. We found that daily treatment with ibudilast significantly enhanced the ability of fragile X syndrome mice to perform a number of different cognitive assays while gaboxadol treatment improved behaviours such as hyperactivity, aggression, stereotypy and anxiety. Importantly, when ibudilast and gaboxadol were co-administered, the cognitive deficits as well as the aforementioned behaviours were rescued. Moreover, this combination treatment showed no evidence of tolerance, and no adverse effects were reported following chronic dosing. This work demonstrates for the first time that by targeting multiple pathways, with a combination treatment, we were able to rescue more phenotypes in a fragile X syndrome mouse model than either ibudilast or gaboxadol could achieve as monotherapies. This combination treatment approach holds promise for addressing the wide spectrum of diverse symptoms in this heterogeneous patient population and may have therapeutic potential for idiopathic autism.
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Affiliation(s)
| | | | - Patricia Cogram
- Department of Genetics, Faculty of Science, Institute of Ecology and Biodiversity (IEB), University of Chile, Santiago 7800024, Chile
- Center for Neural Circuit Mapping, UCI, School of Medicine, University of California, Irvine, CA 92617, USA
| | - Robert J M Deacon
- Department of Genetics, Faculty of Science, Institute of Ecology and Biodiversity (IEB), University of Chile, Santiago 7800024, Chile
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Lorenz-Guertin JM, Povysheva N, Chapman CA, MacDonald ML, Fazzari M, Nigam A, Nuwer JL, Das S, Brady ML, Vajn K, Bambino MJ, Weintraub ST, Johnson JW, Jacob TC. Inhibitory and excitatory synaptic neuroadaptations in the diazepam tolerant brain. Neurobiol Dis 2023; 185:106248. [PMID: 37536384 PMCID: PMC10578451 DOI: 10.1016/j.nbd.2023.106248] [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: 05/12/2023] [Revised: 07/20/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023] Open
Abstract
Benzodiazepine (BZ) drugs treat seizures, anxiety, insomnia, and alcohol withdrawal by potentiating γ2 subunit containing GABA type A receptors (GABAARs). BZ clinical use is hampered by tolerance and withdrawal symptoms including heightened seizure susceptibility, panic, and sleep disturbances. Here, we investigated inhibitory GABAergic and excitatory glutamatergic plasticity in mice tolerant to benzodiazepine sedation. Repeated diazepam (DZP) treatment diminished sedative effects and decreased DZP potentiation of GABAAR synaptic currents without impacting overall synaptic inhibition. While DZP did not alter γ2-GABAAR subunit composition, there was a redistribution of extrasynaptic GABAARs to synapses, resulting in higher levels of synaptic BZ-insensitive α4-containing GABAARs and a concomitant reduction in tonic inhibition. Conversely, excitatory glutamatergic synaptic transmission was increased, and NMDAR subunits were upregulated at synaptic and total protein levels. Quantitative proteomics further revealed cortex neuroadaptations of key pro-excitatory mediators and synaptic plasticity pathways highlighted by Ca2+/calmodulin-dependent protein kinase II (CAMKII), MAPK, and PKC signaling. Thus, reduced inhibitory GABAergic tone and elevated glutamatergic neurotransmission contribute to disrupted excitation/inhibition balance and reduced BZ therapeutic power with benzodiazepine tolerance.
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Affiliation(s)
- Joshua M Lorenz-Guertin
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Nadya Povysheva
- Department of Neuroscience and Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Caitlyn A Chapman
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Matthew L MacDonald
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Marco Fazzari
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Aparna Nigam
- Department of Neuroscience and Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jessica L Nuwer
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sabyasachi Das
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Megan L Brady
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Katarina Vajn
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Matthew J Bambino
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Susan T Weintraub
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antoni, TX, USA
| | - Jon W Johnson
- Department of Neuroscience and Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Tija C Jacob
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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3
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Gómez LCG, Medina NB, Blasco SS, Gravielle MC. Diazepam-Induced Down-Regulation of The Gaba a Receptor α1 Subunit, as Mediated by the Activation of L-Type Voltage-Gated Calcium Channel/Ca 2+/Protein Kinase A Signaling Cascade. Neurosci Lett 2023:137358. [PMID: 37356564 DOI: 10.1016/j.neulet.2023.137358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/12/2023] [Accepted: 06/20/2023] [Indexed: 06/27/2023]
Abstract
Benzodiazepines are among the most prescribed drug class worldwide to treat disorders such as anxiety, insomnia, muscle spasticity, and convulsive disorders, and to induce presurgical sedation. Although benzodiazepines exhibit a high therapeutic index and low toxicity in short-term treatments, prolonged administration induces tolerance to most of their therapeutic actions. The mechanism of this tolerance remains unclear. The central actions of benzodiazepines are mediated by binding to GABAA receptors, which mediate most fast inhibitory transmission in the brain. The majority of GABAA receptors are composed of two α-(1-6), two β-(1-3) and one γ-subunits (1-3). In a previous report, we demonstrated that the prolonged exposure of cerebrocortical neurons to diazepam produces a transcriptional repression of the GABAA receptor α1 subunit gene via a mechanism dependent on the activation of L-type voltage-gated calcium channels (L-VGCCs). The results reported here confirm that the diazepam-induced downregulation of the α1 subunit is contingent upon calcium influx from extracellular space. In addition, this regulatory mechanism involves the activation of protein kinase A (PKA) and is accompanied by the activation of two transcription factors, the cAMP-response element-binding protein (CREB) and the inducible cAMP early repressor (ICER). Together, our results suggest that diazepam's activation of an L-VGCC/Ca2+/PKA/CREB-ICER signaling pathway is responsible for the regulation of GABAA receptors. This elucidation of the intracellular signaling cascade activated by a prolonged benzodiazepine exposure, itself potentially involved in the development of tolerance, may contribute to locating molecular targets for future therapeutic interventions.
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Affiliation(s)
- Leydi Carolina González Gómez
- Instituto de Investigaciones Farmacológicas (ININFA). Facultad de Farmacia y Bioquímica. Universidad de Buenos Aires. CONICET. Buenos Aires, Argentina
| | - Nelsy Beatriz Medina
- Instituto de Investigaciones Farmacológicas (ININFA). Facultad de Farmacia y Bioquímica. Universidad de Buenos Aires. CONICET. Buenos Aires, Argentina
| | - Sara Sanz Blasco
- Instituto de Investigaciones Farmacológicas (ININFA). Facultad de Farmacia y Bioquímica. Universidad de Buenos Aires. CONICET. Buenos Aires, Argentina
| | - María Clara Gravielle
- Instituto de Investigaciones Farmacológicas (ININFA). Facultad de Farmacia y Bioquímica. Universidad de Buenos Aires. CONICET. Buenos Aires, Argentina.
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Novel variants in GABA A receptor subunits: A possible association with benzodiazepine resistance in patients with drug-resistant epilepsy. Epilepsy Res 2023; 189:107056. [PMID: 36469977 DOI: 10.1016/j.eplepsyres.2022.107056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/12/2022] [Accepted: 11/22/2022] [Indexed: 11/24/2022]
Abstract
Benzodiazepines (BDZ) such as diazepam and lorazepam are popular as first-line treatment for acute seizures due to their rapid action and high efficacy. However, long-term usage of BDZ leads to benzodiazepine resistance, a phenomenon whose underlying mechanisms are still being investigated. One of the hypothesised mechanisms contributing to BDZ resistance is the presence of mutations in benzodiazepine-sensitive receptors. While a few genetic variants have been reported previously, knowledge of relevant pathogenic variants is still scarce. We used Sanger Sequencing to detect variants in the ligand-binding domain of BDZ-sensitive GABAA receptor subunits α1-3 and 5 expressed in resected brain tissues of drug-resistant epilepsy (DRE) patients with a history of BDZ resistance and found two previously unreported predicted pathogenic frameshifting variants - NM_000807.4(GABRA2):c.367_368insG and NM_000810.4(GABRA5):c.410del - significantly enriched in these patients. The findings were further explored in resected DRE brain tissues through cellular electrophysiological experiments.
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Miyanishi M, Yaguramaki T, Maehara Y, Nagata O. Three cases of difficulty in achieving definitive loss of consciousness with remimazolam. JA Clin Rep 2022; 8:4. [PMID: 35015166 PMCID: PMC8752651 DOI: 10.1186/s40981-021-00485-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 11/04/2021] [Accepted: 11/08/2021] [Indexed: 11/30/2022] Open
Abstract
Background Remimazolam is a novel, ultra-short-acting benzodiazepine used for general anesthesia. Because remimazolam is an emerging drug, the tolerance to remimazolam in benzodiazepine-taking patients has been unclear. Also, the efficacy of remimazolam in different races is not fully elucidated so far. Case presentation Here we experienced three cases in which high dose of remimazolam was needed for attempting to achieve appropriate anesthetic depth. Two of the three cases were of preoperatively benzodiazepine-taking patients. The other was a case of a Chinese patient. In all three cases, conversion to general anesthesia with propofol was necessitated. Conclusions When signs of inadequate sedative effect of remimazolam are observed in patients of benzodiazepine users or of different races, conversion to another sedative agent such as propofol should be considered.
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Affiliation(s)
- Mao Miyanishi
- Department of Anesthesiology, The University of Tokyo Hospital, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
| | - Toru Yaguramaki
- Department of Orthopaedic Surgery, JR Tokyo General Hospital, 2-1-3, Yoyogi, Shibuya-ku, Tokyo, 151-8528, Japan
| | - Yasuhiro Maehara
- Department of Anesthesiology, Center Hospital of the National Center for Global Health and Medicine, 1-21-1, Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan
| | - Osamu Nagata
- Department of Anesthesiology, Center Hospital of the National Center for Global Health and Medicine, 1-21-1, Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan
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6
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Engin E. GABA A receptor subtypes and benzodiazepine use, misuse, and abuse. Front Psychiatry 2022; 13:1060949. [PMID: 36713896 PMCID: PMC9879605 DOI: 10.3389/fpsyt.2022.1060949] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 12/29/2022] [Indexed: 01/14/2023] Open
Abstract
Benzodiazepines have been in use for over half a century. While they remain highly prescribed, their unfavorable side-effect profile and abuse liability motivated a search for alternatives. Most of these efforts focused on the development of benzodiazepine-like drugs that are selective for specific GABAA receptor subtypes. While there is ample evidence that subtype-selective GABAA receptor ligands have great potential for providing symptom relief without typical benzodiazepine side-effects, it is less clear whether subtype-selective targeting strategies can also reduce misuse and abuse potential. This review focuses on the three benzodiazepine properties that are relevant to the DSM-5-TR criteria for Sedative, Hypnotic, or Anxiolytic Use Disorder, namely, reinforcing properties of benzodiazepines, maladaptive behaviors related to benzodiazepine use, and benzodiazepine tolerance and dependence. We review existing evidence regarding the involvement of different GABAA receptor subtypes in each of these areas. The reviewed studies suggest that α1-containing GABAA receptors play an integral role in benzodiazepine-induced plasticity in reward-related brain areas and might be involved in the development of tolerance and dependence to benzodiazepines. However, a systematic comparison of the contributions of all benzodiazepine-sensitive GABAA receptors to these processes, a mechanistic understanding of how the positive modulation of each receptor subtype might contribute to the brain mechanisms underlying each of these processes, and a definitive answer to the question of whether specific chronic modulation of any given subtype would result in some or all of the benzodiazepine effects are currently lacking from the literature. Moreover, how non-selective benzodiazepines might lead to the maladaptive behaviors listed in DSM and how different GABAA receptor subtypes might be involved in the development of these behaviors remains unexplored. Considering the increasing burden of benzodiazepine abuse, the common practice of benzodiazepine misuse that leads to severe dependence, and the current efforts to generate side-effect free benzodiazepine alternatives, there is an urgent need for systematic, mechanistic research that provides a better understanding of the brain mechanisms of benzodiazepine misuse and abuse, including the involvement of specific GABAA receptor subtypes in these processes, to establish an informed foundation for preclinical and clinical efforts.
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Affiliation(s)
- Elif Engin
- Stress Neurobiology Laboratory, Division of Basic Neuroscience, McLean Hospital, Belmont, MA, United States.,Department of Psychiatry, Harvard Medical School, Boston, MA, United States
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7
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Furukawa T, Nikaido Y, Shimoyama S, Masuyama N, Notoya A, Ueno S. Impaired Cognitive Function and Hippocampal Changes Following Chronic Diazepam Treatment in Middle-Aged Mice. Front Aging Neurosci 2021; 13:777404. [PMID: 34899279 PMCID: PMC8664496 DOI: 10.3389/fnagi.2021.777404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 11/04/2021] [Indexed: 01/07/2023] Open
Abstract
Background: Gamma-aminobutyric acid (GABA) type A receptors are positively allosterically modulated by benzodiazepine binding, leading to a potentiated response to GABA. Diazepam (DZP, a benzodiazepine) is widely prescribed for anxiety, epileptic discharge, and insomnia, and is also used as a muscle relaxant and anti-convulsant. However, some adverse effects - such as tolerance, dependence, withdrawal effects, and impairments in cognition and learning - are elicited by the long-term use of DZP. Clinical studies have reported that chronic DZP treatment increases the risk of dementia in older adults. Furthermore, several studies have reported that chronic DZP administration may affect neuronal activity in the hippocampus, dendritic spine structure, and cognitive performance. However, the effects of chronic DZP administration on cognitive function in aged mice is not yet completely understood. Methods: A behavioral test, immunohistochemical analysis of neurogenic and apoptotic markers, dendritic spine density analysis, and long-term potentiation (LTP) assay of the hippocampal CA1 and CA3 were performed in both young (8 weeks old) and middle-aged (12 months old) mice to investigate the effects of chronic DZP administration on cognitive function. The chronic intraperitoneal administration of DZP was performed by implanting an osmotic minipump. To assess spatial learning and memory ability, the Morris water maze test was performed. Dendritic spines were visualized using Lucifer yellow injection into the soma of hippocampal neurons, and spine density was analyzed. Moreover, the effects of exercise on DZP-induced changes in spine density and LTP in the hippocampus were assessed. Results: Learning performance was impaired by chronic DZP administration in middle-aged mice but not in young mice. LTP was attenuated by DZP administration in the CA1 of young mice and the CA3 of middle-aged mice. The spine density of hippocampal neurons was decreased by chronic DZP administration in the CA1 of both young and middle-aged mice as well as in the CA3 of middle-aged mice. Neither neurogenesis nor apoptosis in the hippocampus was affected by chronic DZP administration. Conclusion: The results of this study suggest that the effects of chronic DZP are different between young and middle-aged mice. The chronic DZP-induced memory retrieval performance impairment in middle-aged mice can likely be attributed to decreased LTP and dendritic spine density in hippocampal neurons in the CA3. Notably, prophylactic exercise suppressed the adverse effects of chronic DZP on LTP and spine maintenance in middle-aged mice.
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Affiliation(s)
- Tomonori Furukawa
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Yoshikazu Nikaido
- Department of Frailty Research and Prevention, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.,Department of Anesthesiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Shuji Shimoyama
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.,Research Center for Child Mental Development, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Nozomu Masuyama
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Ayaka Notoya
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Shinya Ueno
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.,Research Center for Child Mental Development, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
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8
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Tolerance and dependence following chronic alprazolam treatment in rhesus monkeys: Role of GABA A receptor subtypes. Drug Alcohol Depend 2021; 228:108985. [PMID: 34500240 PMCID: PMC8595788 DOI: 10.1016/j.drugalcdep.2021.108985] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/24/2021] [Accepted: 07/26/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND To assess GABAA receptor subtypes involved in benzodiazepine tolerance and dependence, we evaluated the ability of subtype-selective and non-selective ligands to substitute for (i.e., produce "cross-tolerance") or precipitate withdrawal during chronic alprazolam treatment. METHODS Four female rhesus monkeys (Macaca mulatta) were implanted with chronic intravenous catheters and administered alprazolam (1.0 mg/kg every 4 h). Following 14+ days of chronic alprazolam, acute administration of selected doses of non-selective and subtype-selective ligands were substituted for, or administered with, alprazolam, followed by quantitative behavioral observations. The ligands included alprazolam and midazolam (positive modulators, non-selective), zolpidem (positive modulator, preferential affinity for α1-containing GABAA receptors), HZ-166 (positive modulator, preferential efficacy at α2- and α3-containing GABAA receptors), and βCCT (antagonist, preferential affinity for α1-containing GABAA receptors). RESULTS Acutely, alprazolam and midazolam both induced observable ataxia along with a mild form of sedation referred to as "rest/sleep posture" at a lower dose (0.1 mg/kg, i.v.), whereas at a higher dose (1.0 mg/kg, i.v.), induced deep sedation and observable ataxia. With chronic alprazolam treatment, observable ataxia and deep sedation were reduced significantly, whereas rest/sleep posture was unchanged or emerged. Zolpidem showed a similar pattern of effects, whereas no behaviors engendered by HZ-166 were changed by chronic alprazolam. Administration of βCCT, but not HZ-166, resulted in significant withdrawal signs. CONCLUSIONS These results are consistent with a role for α1-containing GABAA receptor subtypes in tolerance and dependence observed with chronic alprazolam, although other receptors may be involved in the withdrawal syndrome.
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Gurrell R, Whitlock M, Wei H, Shen Z, Ogden A. Safety, Tolerability, and Pharmacokinetics of Multiple Repeated Oral Doses of the α2/3/5-Subtype Selective GABA A -Positive Allosteric Modulator PF-06372865 in Healthy Volunteers. Clin Pharmacol Drug Dev 2021; 10:756-764. [PMID: 33465277 PMCID: PMC8359322 DOI: 10.1002/cpdd.912] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 12/21/2020] [Indexed: 01/26/2023]
Abstract
Multiple‐dose pharmacokinetics (PK) and safety were investigated in this phase 1 study of PF‐06372865, a positive allosteric modulator of α2/3/5 subunit‐containing γ‐aminobutyric acid A receptors (NCT03351751). In 2 cohorts (7‐8 PF‐06372865 and 2 placebo in each cohort), healthy adult subjects received twice‐daily oral doses of PF‐06372865 for 21 days, which included titration in the first 7 days, followed by a maintenance dose of 25 mg twice daily (Cohort 1) and 42.5 mg twice daily (Cohort 2) for 14 days. Serial PK samples were collected on days 1 and 21. Nineteen subjects were assigned to study treatments; 18 completed the study. Approximate dose‐proportional increases in maximum plasma concentratin and area under the plasma concentration–time curve over the dosing interval were observed. PF‐06372865 was rapidly absorbed with a median time to maximum concentration of 1 to 2 hours following both single‐ and multiple‐dose administration. Mean terminal elimination half‐life on day 21 was approximately 11 hours in both cohorts. All adverse events were mild; the most frequently reported was dizziness. After titration, there were no reports of somnolence. There were no clinically significant safety findings, including a lack of withdrawal symptoms on discontinuation of treatment. These results demonstrate that PF‐06372865 is safe and well tolerated at doses estimated to achieve high receptor occupancy (>80%), a profile differentiated from nonselective benzodiazepines.
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Affiliation(s)
| | | | - Hua Wei
- Pfizer Inc., Shanghai, China
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10
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Horovitz O, Ardi Z, Ashkenazi SK, Ritov G, Anunu R, Richter-Levin G. Network Neuromodulation of Opioid and GABAergic Receptors Following a Combination of "Juvenile" and "Adult Stress" in Rats. Int J Mol Sci 2020; 21:ijms21155422. [PMID: 32751453 PMCID: PMC7432657 DOI: 10.3390/ijms21155422] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/22/2020] [Accepted: 07/23/2020] [Indexed: 12/18/2022] Open
Abstract
Early life stress is suggested to alter behavioral responses during stressful challenges in adulthood and to exacerbate pathological symptoms that reminisce posttraumatic stress disorder (PTSD). These effects are often associated with changes in γ-Aminobutyric acid type A (GABAA) and κ opioid receptor expression and neuromodulation of the limbic system. Anxiety-like and stress coping behaviors were assessed in rats exposed to stress in adulthood on the background of previous exposure to stress in juvenility. Two weeks following behavioral assessment in adulthood, GABAAR α1 and α2 subunits and κ opioid receptor expression levels were measured in the medial prefrontal cortex (mPFC), nucleus accumbens (NAc), amygdala, and periaqueductal gray (PAG). To illustrate changes at the network level, an integrated expression profile was constructed. We found that exposure to juvenile stress affected rats’ behavior during adult stress. The combination of juvenile and adult stress significantly affected rats’ long term anxious-like behavior. Probabilities predicting model integrating the expression of GABAA α1-α2 and κ opioid receptors in different brain regions yielded highly successful classification rates. This study emphasizes the ability of exposure to stress in juvenility to exacerbate the impact of coping with stress in adulthood. Moreover, the use of integrated receptor expression network profiling was found to effectively characterize the discussed affective styles and their behavioral manifestations.
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Affiliation(s)
- Omer Horovitz
- Psychology Department, Tel-Hai Academic College, Haifa 1220800, Israel;
| | - Ziv Ardi
- Department of Behavioral Sciences, Kinneret Academic College on the Sea of Galilee, Sea of Galilee 15132, Israel
- Correspondence: ; Tel.: +972-46653803
| | - Shiri Karni Ashkenazi
- Sagol Department of Neurobiology, University of Haifa, Mount Carmel 31095, Israel; (S.K.A.); (G.R.-L.)
| | - Gilad Ritov
- The Institute for the Study of Affective Neuroscience (ISAN), Mount Carmel 31095, Israel; (G.R.); (R.A.)
| | - Rachel Anunu
- The Institute for the Study of Affective Neuroscience (ISAN), Mount Carmel 31095, Israel; (G.R.); (R.A.)
| | - Gal Richter-Levin
- Sagol Department of Neurobiology, University of Haifa, Mount Carmel 31095, Israel; (S.K.A.); (G.R.-L.)
- The Institute for the Study of Affective Neuroscience (ISAN), Mount Carmel 31095, Israel; (G.R.); (R.A.)
- Psychology Department, University of Haifa, Mount Carmel 31095, Israel
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11
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Zhang Y, Zhu Y, Cao SX, Sun P, Yang JM, Xia YF, Xie SZ, Yu XD, Fu JY, Shen CJ, He HY, Pan HQ, Chen XJ, Wang H, Li XM. MeCP2 in cholinergic interneurons of nucleus accumbens regulates fear learning. eLife 2020; 9:55342. [PMID: 32420873 PMCID: PMC7259956 DOI: 10.7554/elife.55342] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 05/18/2020] [Indexed: 11/25/2022] Open
Abstract
Methyl-CpG-binding protein 2 (MeCP2) encoded by the MECP2 gene is a transcriptional regulator whose mutations cause Rett syndrome (RTT). Mecp2-deficient mice show fear regulation impairment; however, the cellular and molecular mechanisms underlying this abnormal behavior are largely uncharacterized. Here, we showed that Mecp2 gene deficiency in cholinergic interneurons of the nucleus accumbens (NAc) dramatically impaired fear learning. We further found that spontaneous activity of cholinergic interneurons in Mecp2-deficient mice decreased, mediated by enhanced inhibitory transmission via α2-containing GABAA receptors. With MeCP2 restoration, opto- and chemo-genetic activation, and RNA interference in ChAT-expressing interneurons of the NAc, impaired fear retrieval was rescued. Taken together, these results reveal a previously unknown role of MeCP2 in NAc cholinergic interneurons in fear regulation, suggesting that modulation of neurons in the NAc may ameliorate fear-related disorders.
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Affiliation(s)
- Ying Zhang
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Zhu
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shu-Xia Cao
- Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Peng Sun
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jian-Ming Yang
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yan-Fang Xia
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shi-Ze Xie
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiao-Dan Yu
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jia-Yu Fu
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Chen-Jie Shen
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Hai-Yang He
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Hao-Qi Pan
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiao-Juan Chen
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Hao Wang
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiao-Ming Li
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, Center for Brain Science and Brain-Inspired Intelligence, Guangdong-Hong Kong-Macao Greater Bay Area, Joint Institute for Genetics and Genome Medicine between Zhejiang University and University of Toronto, Toronto, Canada
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12
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Duke AN, Platt DM, Rowlett JK. Tolerance and dependence following chronic alprazolam treatment: quantitative observation studies in female rhesus monkeys. Psychopharmacology (Berl) 2020; 237:1183-1194. [PMID: 31927603 PMCID: PMC7988478 DOI: 10.1007/s00213-019-05447-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 12/27/2019] [Indexed: 11/28/2022]
Abstract
RATIONALE In order to understand mechanisms underlying tolerance and dependence following chronic benzodiazepine treatments, quantitative and reproducible behavioral models of these phenomena are required. OBJECTIVES This research evaluated the ability of chronic treatment with a commonly prescribed benzodiazepine, alprazolam, to induce tolerance to sedative effects and physical dependence using a novel set of behavioral measurements in rhesus monkeys. METHODS Four female rhesus monkeys (Macaca mulatta) were implanted with chronic intravenous catheters and administered i.v. alprazolam (1.0 mg/kg every 4 h, 38 days total). Quantitative observation measures were obtained during the 38 days of treatment. Acute administration of the benzodiazepine receptor antagonist flumazenil (0.1, 0.3 mg/kg, i.v.) was given to assess precipitated withdrawal. On day 39, saline was substituted for alprazolam and withdrawal signs were assessed for 7 days. RESULTS Maximal sedation ("deep sedation") was evident on day 1 but was not significantly different from baseline levels by day 4 and was absent for the remainder of the 38 days of treatment. A milder form of sedation, "rest/sleep posture," emerged by day 3 and did not decline over 38 days. Cessation of alprazolam treatment resulted in significant withdrawal signs (nose rub, vomit, procumbent posture, tremor/jerk, rigid posture) that dissipated by day 3. These signs also were observed with flumazenil (0.3 mg/kg). CONCLUSIONS Chronic alprazolam treatment resulted in rapid tolerance to some behaviors (e.g., deep sedation) but no tolerance to others (e.g., rest/sleep posture). Physical dependence was observed via both spontaneous and precipitated withdrawal. Based on previous research, these phenomena may reflect differential plasticity at GABAA receptor subtypes.
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Affiliation(s)
- Angela N Duke
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
- New England Primate Research Center, Harvard Medical School, One Pine Hill Drive, Southborough, MA, 01772, USA
- Wake Forest Baptist Medical Center, Winston-Salem, NC, USA
| | - Donna M Platt
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
- New England Primate Research Center, Harvard Medical School, One Pine Hill Drive, Southborough, MA, 01772, USA
| | - James K Rowlett
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
- New England Primate Research Center, Harvard Medical School, One Pine Hill Drive, Southborough, MA, 01772, USA.
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13
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Translational Studies in the Complex Role of Neurotransmitter Systems in Anxiety and Anxiety Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1191:121-140. [PMID: 32002926 DOI: 10.1007/978-981-32-9705-0_8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Discovery of innovative anxiolytics is severely hampering. Existing anxiolytics are developed decades ago and are still the therapeutics of choice. Moreover, lack of new drug targets forecasts a severe jeopardy in the future treatment of the huge population of CNS-diseased patients. We simply lack the knowledge on what is wrong in brains of anxious people (normal and diseased). Translational research, based on interacting clinical and preclinical research, is extremely urgent. In this endeavor, genetic and genomic approaches are part of the spectrum of contributing factors. We focus on three druggable targets: serotonin transporter, 5-HT1A, and GABAA receptors. It is still uncertain whether and how these targets are involved in normal and diseased anxiety processes. For serotonergic anxiolytics, the slow onset of action points to indirect effects leading to plasticity changes in brain systems leading to reduced anxiety. For GABAA benzodiazepine drugs, acute anxiolytic effects are found indicating primary mechanisms directly influencing anxiety processes. Close translational collaboration between fundamental academic and discovery research will lead to badly needed breakthroughs in the search for new anxiolytics.
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14
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Self-administration of benzodiazepine and cocaine combinations by male and female rhesus monkeys in a choice procedure: role of α1 subunit-containing GABA A receptors. Psychopharmacology (Berl) 2019; 236:3271-3279. [PMID: 31183518 PMCID: PMC6832789 DOI: 10.1007/s00213-019-05286-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/21/2019] [Accepted: 05/24/2019] [Indexed: 12/19/2022]
Abstract
RATIONALE Compounds lacking efficacy at the α1 subunit-containing GABAA (α1GABAA) receptor appear to have reduced abuse potential compared with those having measurable efficacy at this receptor, though their self-administration in nonhuman primates is dependent upon past drug experience. OBJECTIVES We used a drug vs. drug choice procedure to evaluate the hypothesis that L-838,417, a compound lacking efficacy at αGABAA receptors, would not enhance cocaine choice in monkeys trained to self-administer cocaine. We also hypothesized that zolpidem, a compound with preferential modulation of ⍺1GABAA receptors and midazolam, a nonselective benzodiazepine, would enhance cocaine choice in this procedure. METHODS One female and three male rhesus monkeys chose between cocaine alone (0.1 mg/kg/injection) vs. the same dose of cocaine combined with midazolam (0.003-0.1 mg/kg/injection), zolpidem (0.003-0.3 mg/kg/injection), or L-838-417 (0.01-0.1 mg/kg/injection). In addition, we evaluated choice between saline and L-838,417 at select doses to determine whether L-838,417 would function as a reinforcer on its own. RESULTS Consistent with our hypotheses, midazolam- and zolpidem-cocaine mixtures were chosen over cocaine alone at sufficiently high doses. However, L-838,417-cocaine mixtures also were chosen over cocaine alone in three of four subjects with at least one dose. When available alone vs. saline, L-838,417 did not function as a reinforcer in any subject. CONCLUSION Compounds that lack efficacy at α1GABAA receptors may have low abuse potential compared to classic benzodiazepines, but self-administration of these compounds is context-dependent.
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Haider S, Nawaz A, Batool Z, Tabassum S, Perveen T. Alleviation of diazepam-induced conditioned place preference and its withdrawal-associated neurobehavioral deficits following pre-exposure to enriched environment in rats. Physiol Behav 2019; 208:112564. [PMID: 31145918 DOI: 10.1016/j.physbeh.2019.112564] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 05/24/2019] [Accepted: 05/26/2019] [Indexed: 12/18/2022]
Abstract
Diazepam is one of the widely prescribed sedative drugs for the treatment of anxiety and sleep disorders. However, its continuous use can induce addiction, tolerance, and withdrawal symptoms and, therefore, the pharmacological use of diazepam is restricted. Exposure to enriched environment can reduce the addiction to stimulants including amphetamine, cocaine, and nicotine. However, the protective effect of enriched environment against preference of sedative drugs is not yet investigated. This study, therefore, determined the effects of enriched environment to prevent diazepam-preference using conditioned place preference (CPP) paradigm. Adult rats were reared in social (n = 12) or physically (n = 12) enriched environment for four weeks. Each group was then sub-divided into two groups and were administered either saline (Control; n = 6) or diazepam (1 mg/kg; n = 6) on alternate days for thirteen days. During the administration of diazepam, the CPP was conducted to monitor drug preference on 5th, 9th and 13th day of experiment. It was observed that the diazepam administration significantly (p < .01) induced preference in rats. Neurobehavioral deficits including hypolocomotor activity, depression-like behavior, impaired learning and memory functions were also observed after 24 h of drug abstinence. Exposure to enriched environment significantly reduced diazepam-preference and other neurobehavioral deficits. This study provides preliminary evidence to highlight the importance of enriched environment in the attenuation of diazepam-preference.
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Affiliation(s)
- Saida Haider
- Neurochemistry and Biochemical Neuropharmacology Research Unit, Department of Biochemistry, University of Karachi, Karachi 75270, Pakistan.
| | - Amber Nawaz
- Neurochemistry and Biochemical Neuropharmacology Research Unit, Department of Biochemistry, University of Karachi, Karachi 75270, Pakistan; Department of Biomedical Engineering, Sir Syed University of Engineering and Technology, Karachi 75300, Pakistan
| | - Zehra Batool
- Neurochemistry and Biochemical Neuropharmacology Research Unit, Department of Biochemistry, University of Karachi, Karachi 75270, Pakistan; Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Saiqa Tabassum
- Neurochemistry and Biochemical Neuropharmacology Research Unit, Department of Biochemistry, University of Karachi, Karachi 75270, Pakistan; Department of Biosciences, Shaheed Zulfiqar Ali Bhutto Institute of Science and Technology, Karachi, Pakistan
| | - Tahira Perveen
- Neurochemistry and Biochemical Neuropharmacology Research Unit, Department of Biochemistry, University of Karachi, Karachi 75270, Pakistan
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16
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Mohamad FH, Has ATC. The α5-Containing GABA A Receptors-a Brief Summary. J Mol Neurosci 2019; 67:343-351. [PMID: 30607899 DOI: 10.1007/s12031-018-1246-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Accepted: 12/17/2018] [Indexed: 12/21/2022]
Abstract
GABAA receptors are the major inhibitory neurotransmitter receptor in the human brain. The receptors are assembled from combination of protein subunits in pentameric complex which may consist of α1-6, β1-3, γ1-3, ρ1-3, δ, ε, θ, or π subunits. There are a theoretical > 150,000 possible assemblies and arrangements of GABAA subunits, although only a few combinations have been found in human with the most dominant consists of 2α1, 2β2, and 1γ2 in a counterclockwise arrangement as seen from the synaptic cleft. The receptors also possess binding sites for various unrelated substances including benzodiazepines, barbiturates, and anesthetics. The α5-containing GABAARs only make up ≤ 5% of the entire receptor population, but up to 25% of the receptor subtype is located in the crucial learning and memory-associated area of the brain-the hippocampus, which has ignited myriads of hypotheses and theories in regard to its role. As well as exhibiting synaptic phasic inhibition, the α5-containing receptors are also extrasynaptic and mediate tonic inhibition with continuously occurring smaller amplitude. Studies on negative-allosteric modulators for reducing this tonic inhibition have been shown to enhance learning and memory in neurological disorders such as schizophrenia, Down syndrome, and autism with a possible alternative benzodiazepine binding site. Therefore, a few α5 subunit-specific compounds have been developed to address these pharmacological needs. With its small population, the α5-containing receptors could be the key and also the answer for many untreated cognitive dysfunctions and disorders.
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Affiliation(s)
- Fatin H Mohamad
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kampus Kesihatan, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Ahmad Tarmizi Che Has
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kampus Kesihatan, 16150, Kubang Kerian, Kelantan, Malaysia.
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17
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Duarte FS, Duzzioni M, Prim RL, Cardozo AM, Dos Santos CR, da Silva MG, Shiozawa MBC, Mendes BG, Tizziani T, Brighente IMC, Pizzolatti MG, de Lima TCM. Psychopharmacological effects and safety of styryl-2-pyrones and dihydrostyryl-2-pyrones-rich fraction from Polygala sabulosa: absence of withdrawal syndrome and tolerance to anxiolytic-like and anticonvulsant effects. ACTA ACUST UNITED AC 2018; 70:1272-1286. [PMID: 29956326 PMCID: PMC6099234 DOI: 10.1111/jphp.12960] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 06/04/2018] [Indexed: 02/06/2023]
Abstract
Objectives To investigate whether mice develop tolerance to the anxiolytic‐like and anticonvulsant effects of subchronic treatment with EA (the styryl‐2‐pyrones and dihydrostyryl‐2‐pyrones‐rich fraction of Polygala sabulosa), as well as any withdrawal symptoms after abrupt discontinuation; to compare the effects of EA with those of diazepam (DZP) on withdrawal‐induced anxiety; and to evaluate the toxicity of EA according to OECD guidelines. Methods Male or female mice were acutely or subchronically treated with EA or DZP, and their tolerance to anxiolytic (evaluated in the elevated plus maze, EPM) and anticonvulsant effects (measured against pentylenetetrazole (PTZ)‐induced convulsions) were investigated. Other groups received EA or DZP for 28 days followed by withdrawal, being the anxiety‐like behaviour evaluated in the EPM. Key findings Both acute and subchronic treatments with EA induced an anxiolytic effect in the EPM. The anticonvulsant activity of DZP, but not EA, was reduced by protracted treatment. EA withdrawal retained the anxiolytic profile, while DZP withdrawal induced anxiogenesis. EA counteracted the anxiogenic‐like actions of DZP withdrawal. EA has low toxicity as it did not cause any changes in the biochemical, haematological and histopathological markers. Conclusions EA avoids the development of tolerance to its anxiolytic‐like and anticonvulsant actions, and does not promote withdrawal syndrome. EA does not cause relevant toxic effects in rodents.
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Affiliation(s)
- Filipe Silveira Duarte
- Department of Physiology and Pharmacology, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | - Marcelo Duzzioni
- Institute of Biological Sciences and Health, Federal University of Alagoas, Maceió, Alagoas, Brazil
| | - Rafael Luiz Prim
- Department of Pathology, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Alcíbia Maia Cardozo
- Department of Pathology, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Claudia Regina Dos Santos
- Department of Pathology, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Maria Goretti da Silva
- Department of Pathology, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | | | - Beatriz Garcia Mendes
- Department of Chemistry, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Tiago Tizziani
- Department of Chemistry, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | | | - Moacir Geraldo Pizzolatti
- Department of Chemistry, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
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18
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Kato AS, Witkin JM. Protein complexes as psychiatric and neurological drug targets. Biochem Pharmacol 2018; 151:263-281. [PMID: 29330067 DOI: 10.1016/j.bcp.2018.01.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/05/2018] [Indexed: 12/25/2022]
Abstract
The need for improved medications for psychiatric and neurological disorders is clear. Difficulties in finding such drugs demands that all strategic means be utilized for their invention. The discovery of forebrain specific AMPA receptor antagonists, which selectively block the specific combinations of principal and auxiliary subunits present in forebrain regions but spare targets in the cerebellum, was recently disclosed. This discovery raised the possibility that other auxiliary protein systems could be utilized to help identify new medicines. Discussion of the TARP-dependent AMPA receptor antagonists has been presented elsewhere. Here we review the diversity of protein complexes of neurotransmitter receptors in the nervous system to highlight the broad range of protein/protein drug targets. We briefly outline the structural basis of protein complexes as drug targets for G-protein-coupled receptors, voltage-gated ion channels, and ligand-gated ion channels. This review highlights heterodimers, subunit-specific receptor constructions, multiple signaling pathways, and auxiliary proteins with an emphasis on the later. We conclude that the use of auxiliary proteins in chemical compound screening could enhance the detection of specific, targeted drug searches and lead to novel and improved medicines for psychiatric and neurological disorders.
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Affiliation(s)
- Akihiko S Kato
- Neuroscience Discovery, Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN, USA.
| | - Jeffrey M Witkin
- Neuroscience Discovery, Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN, USA
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19
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Cheng T, Wallace DM, Ponteri B, Tuli M. Valium without dependence? Individual GABA A receptor subtype contribution toward benzodiazepine addiction, tolerance, and therapeutic effects. Neuropsychiatr Dis Treat 2018; 14:1351-1361. [PMID: 29872302 PMCID: PMC5973310 DOI: 10.2147/ndt.s164307] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Benzodiazepines are one of the most prescribed medications as first-line treatment of anxiety, insomnia, and epilepsy around the world. Over the past two decades, advances in the neuropharmacological understanding of gamma aminobutyric acid (GABA)A receptors revealed distinct contributions from each subtype and produced effects. Recent findings have highlighted the importance of α1 containing GABAA receptors in the mechanisms of addiction and tolerance in benzodiazepine treatments. This has shown promise in the development of tranquilizers with minimal side effects such as cognitive impairment, dependence, and tolerance. A valium-like drug without its side effects, as repeatedly demonstrated in animals, is achievable.
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Affiliation(s)
| | | | | | - Mahir Tuli
- University of British Columbia, Vancouver, BC, Canada
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20
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Furukawa T, Shimoyama S, Miki Y, Nikaido Y, Koga K, Nakamura K, Wakabayashi K, Ueno S. Chronic diazepam administration increases the expression of Lcn2 in the CNS. Pharmacol Res Perspect 2017; 5:e00283. [PMID: 28596835 PMCID: PMC5461642 DOI: 10.1002/prp2.283] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 11/03/2016] [Accepted: 11/11/2016] [Indexed: 12/17/2022] Open
Abstract
Benzodiazepines (BZDs), which bind with high affinity to gamma-aminobutyric acid type A receptors (GABAA-Rs) and potentiate the effects of GABA, are widely prescribed for anxiety, insomnia, epileptic discharge, and as anticonvulsants. The long-term use of BZDs is limited due to adverse effects such as tolerance, dependence, withdrawal effects, and impairments in cognition and learning. Additionally, clinical reports have shown that chronic BZD treatment increases the risk of Alzheimer's disease. Unusual GABAA-R subunit expression and GABAA-R phosphorylation are induced by chronic BZD use. However, the gene expression and signaling pathways related to these effects are not completely understood. In this study, we performed a microarray analysis to investigate the mechanisms underlying the effect of chronic BZD administration on gene expression. Diazepam (DZP, a BZD) was chronically administered, and whole transcripts in the brain were analyzed. We found that the mRNA expression levels were significantly affected by chronic DZP administration and that lipocalin 2 (Lcn2) mRNA was the most upregulated gene in the cerebral cortex, hippocampus, and amygdala. Lcn2 is known as an iron homeostasis-associated protein. Immunostained signals of Lcn2 were detected in neuron, astrocyte, microglia, and Lcn2 protein expression levels were consistently upregulated. This upregulation was observed without proinflammatory genes upregulation, and was attenuated by chronic treatment of deferoxamine mesylate (DFO), iron chelator. Our results suggest that chronic DZP administration regulates transcription and upregulates Lcn2 expression levels without an inflammatory response in the mouse brain. Furthermore, the DZP-induced upregulation of Lcn2 expression was influenced by ambient iron.
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Affiliation(s)
- Tomonori Furukawa
- Department of Neurophysiology Hirosaki University Graduate School of Medicine Hirosaki Japan
| | - Shuji Shimoyama
- Research Center for Child Mental Development Hirosaki University Graduate School of Medicine Hirosaki Japan
| | - Yasuo Miki
- Department of Neuropathology Hirosaki University Graduate School of Medicine Hirosaki Japan
| | - Yoshikazu Nikaido
- Department of Neurophysiology Hirosaki University Graduate School of Medicine Hirosaki Japan
| | - Kohei Koga
- Department of Neurophysiology Hirosaki University Graduate School of Medicine Hirosaki Japan
| | - Kazuhiko Nakamura
- Research Center for Child Mental Development Hirosaki University Graduate School of Medicine Hirosaki Japan.,Department of Neuropsychiatry Hirosaki University Graduate School of Medicine Hirosaki Japan
| | - Koichi Wakabayashi
- Department of Neuropathology Hirosaki University Graduate School of Medicine Hirosaki Japan
| | - Shinya Ueno
- Department of Neurophysiology Hirosaki University Graduate School of Medicine Hirosaki Japan.,Research Center for Child Mental Development Hirosaki University Graduate School of Medicine Hirosaki Japan
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21
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Chagraoui A, Skiba M, Thuillez C, Thibaut F. To what extent is it possible to dissociate the anxiolytic and sedative/hypnotic properties of GABAA receptors modulators? Prog Neuropsychopharmacol Biol Psychiatry 2016; 71:189-202. [PMID: 27495357 DOI: 10.1016/j.pnpbp.2016.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/21/2016] [Accepted: 08/01/2016] [Indexed: 01/16/2023]
Abstract
The relatively common view indicates a possible dissociation between the anxiolytic and sedative/hypnotic properties of benzodiazepines (BZs). Indeed, GABAA receptor (GABAAR) subtypes have specific cerebral distribution in distinct neural circuits. Thus, GABAAR subtype-selective drugs may be expected to perform distinct functions. However, standard behavioral test assays provide limited direction towards highlighting new action mechanisms of ligands targeting GABAARs. Automated behavioral tests, lack sensitivity as some behavioral characteristics or subtle behavioral changes of drug effects or that are not considered in the overall analysis (Ohl et al., 2001) and observation-based analyses are not always performed. In addition, despite the use of genetically engineered mice, any possible dissociation between the anxiolytic and sedative properties of BZs remains controversial. Moreover, the involvement the different subtypes of GABAAR subtypes in the anxious behavior and the mechanism of action of anxiolytic agents remains unclear since there has been little success in the pharmacological investigations so far. This raises the question of the involvement of the different subunits in anxiolytic-like and/or sedative effects; and the actual implication of these subunits, particularly, α-subunits in the modulation of sedation and/or anxiety-related disorders. This present review was prompted by several conflicting studies on the degree of involvement of these subunits in anxiolytic-like and/or sedative effects. To this end, we explored the GABAergic system, particularly, the role of different subunits containing synaptic GABAARs. We report herein the targeting gene encoding the different subunits and their contribution in anxiolytic-like and/or sedative actions, as well as, the mechanism underlying tolerance to BZs.
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Affiliation(s)
- A Chagraoui
- Inserm U982, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Institute for Research and Innovation in Biomedecine, Normandy University, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France.
| | - M Skiba
- Inserm U982, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Institute for Research and Innovation in Biomedecine, Normandy University, France
| | - C Thuillez
- Department of Pharmacology, Rouen University Hospital, Rouen, and INSERM U1096, Laboratory of New Pharmacological Targets for Endothelial Protection and Heart Failure, Institute for Research and Innovation in Biomedicine, Normandy University, France
| | - F Thibaut
- Department of Psychiatry, University Hospital Cochin (site Tarnier), University of Paris-Descartes and INSERM U 894 Laboratory of Psychiatry and Neurosciences, Paris, France
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22
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Brodie MJ, Chung S, Wade A, Quelen C, Guiraud-Diawara A, François C, Verpillat P, Shen V, Isojarvi J. Clobazam and clonazepam use in epilepsy: Results from a UK database incident user cohort study. Epilepsy Res 2016; 123:68-74. [PMID: 27135706 DOI: 10.1016/j.eplepsyres.2016.04.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 03/14/2016] [Accepted: 04/08/2016] [Indexed: 01/08/2023]
Abstract
OBJECTIVE To compare patient characteristics and treatment patterns among clobazam (CLB) and clonazepam (CZP)-treated patients with epilepsy in a longitudinal primary care database. METHODS In this pharmacoepidemiological study, real-life usage data from the Clinical Practice Research Database (CPRD) were evaluated. The CPRD collects data from approximately 690 primary care practices throughout the UK. Data included were from patients with ≥1 incident CLB or CZP prescription from 1995 to 2011 and were present in the database for ≥182 days prior to the index date (date patient was first prescribed CLB or CZP within the study period). RESULTS Of 21,099 patients who met inclusion criteria, 18.4% were receiving CLB and 81.6% were receiving CZP. More patients used CLB for epilepsy than CZP (76.1% vs 8.7%). CLB-treated adults (≤18years) were younger than those treated with CZP (41.0 vs 48.2 years; p<0.001), while CLB-treated children (≤18 years) were older than those treated with CZP (8.8 vs 7.3 years, p<0.001). The median CLB dosage did not change from baseline to last follow-up, while median CZP dosage increased 25% in adults and 50% in children. Median treatment duration, as well as retention rate up to 10 years, was similar between CLB and CZP in each age group. CONCLUSIONS Among adult and pediatric patients in the UK, CLB is more often prescribed for epilepsy than CZP. The median CLB dosage used by both adults and children remained stable over the 16-year study period, while the median CZP dosage increased in both adults and children.
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Affiliation(s)
- Martin J Brodie
- Epilepsy Unit West Glasgow, ACH-Yorkhill, Glasgow G3 8SJ, Scotland, UK.
| | - Steve Chung
- Neuroscience Institute, Banner University Medical Center, 1111 McDowell Road, Phoenix, AZ, USA.
| | - Alan Wade
- Patients Direct, 3 Todd Campus, Glasgow G20 OXA, Scotland, UK.
| | - Céline Quelen
- Health Economics and Epidemiology and Global Analytics, Lundbeck SAS, Quai du Président Roosevelt 37-45, 92445 Issy-les-Moulineaux, France.
| | - Alice Guiraud-Diawara
- Health Economics and Epidemiology and Global Analytics, Lundbeck SAS, Quai du Président Roosevelt 37-45, 92445 Issy-les-Moulineaux, France.
| | - Clément François
- Health Economics and Outcomes Research, Lundbeck LLC, 4 Parkway North Suite 200, Deerfield, IL 60015, USA.
| | - Patrice Verpillat
- Health Economics and Epidemiology and Global Analytics, Lundbeck SAS, Quai du Président Roosevelt 37-45, 92445 Issy-les-Moulineaux, France.
| | - Vivienne Shen
- Medical Affairs, Lundbeck LLC, 4 Parkway North Suite 200, Deerfield, IL 60015, USA.
| | - Jouko Isojarvi
- Medical Affairs, Lundbeck LLC, 4 Parkway North Suite 200, Deerfield, IL 60015, USA.
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Hong KB, Park Y, Suh HJ. Sleep-promoting effects of a GABA/5-HTP mixture: Behavioral changes and neuromodulation in an invertebrate model. Life Sci 2016; 150:42-9. [PMID: 26921634 DOI: 10.1016/j.lfs.2016.02.086] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 02/17/2016] [Accepted: 02/23/2016] [Indexed: 11/25/2022]
Abstract
AIMS This study was to investigate the sleep promoting effects of combined γ-aminobutyric acid (GABA) and 5-hydroxytryptophan (5-HTP), by examining neuronal processes governing mRNA level alterations, as well as assessing neuromodulator concentrations, in a fruit fly model. MAIN METHODS Behavioral assays were applied to investigate subjective nighttime activity, sleep episodes, and total duration of subjective nighttime sleep of two amino acids and GABA/5-HTP mixture with caffeine treated flies. Also, real-time PCR and HPLC analysis were applied to analyze the signaling pathway. KEY FINDINGS Subjective nighttime activity and sleep patterns of individual flies significantly decreased with 1% GABA treatment in conjunction with 0.1% 5-HTP treatment (p<0.001). Furthermore, GABA/5-HTP mixture resulted in significant differences between groups related to sleep patterns (40%, p<0.017) and significantly induced subjective nighttime sleep in the awake model (p<0.003). These results related to transcript levels of the GABAB receptor (GABAB-R1) and serotonin receptor (5-HT1A), compared to the control group. In addition, GABA/5-HTP mixture significantly increased GABA levels 1h and 12h following treatment (2.1 fold and 1.2 fold higher than the control, respectively) and also increased 5-HTP levels (0 h: 1.01 μg/protein, 12h: 3.45 μg/protein). SIGNIFICANCE In this regard, we successfully demonstrated that using a GABA/5-HTP mixture modulates subjective nighttime activity, sleep episodes, and total duration of subjective nighttime sleep to a greater extent than single administration of each amino acid, and that this modulation occurs via GABAergic and serotonergic signaling.
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Affiliation(s)
- Ki-Bae Hong
- Department of Public Health Sciences, Korea University, Seoul 136-713, Republic of Korea
| | - Yooheon Park
- Dongguk University Research Institute of Biotechnology, Goyang 10326, Republic of Korea.
| | - Hyung Joo Suh
- Department of Public Health Sciences, Korea University, Seoul 136-713, Republic of Korea.
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Gravielle MC. Activation-induced regulation of GABAA receptors: Is there a link with the molecular basis of benzodiazepine tolerance? Pharmacol Res 2015; 109:92-100. [PMID: 26733466 DOI: 10.1016/j.phrs.2015.12.030] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 12/21/2015] [Accepted: 12/22/2015] [Indexed: 12/01/2022]
Abstract
Benzodiazepines have been used clinically for more than 50 years to treat disorders such as insomnia, anxiety, and epilepsy, as well as to aid muscle relaxation and anesthesia. The therapeutic index for benzodiazepines if very high and the toxicity is low. However, their usefulness is limited by the development of either or both tolerance to most of their pharmacological actions and dependence. Tolerance develops at different rates depending on the pharmacological action, suggesting the existence of distinct mechanisms for each behavioral parameter. Alternatively, multiple mechanisms could coexist depending on the subtype of GABAA receptor expressed and the brain region involved. Because most of the pharmacological actions of benzodiazepines are mediated through GABAA receptor binding, adaptive alterations in the number, structure, and/or functions of these receptors may play an important role in the development of tolerance. This review is focused on the regulation of GABAA receptors induced by long-term benzodiazepine exposure and its relationship with the development of tolerance. Understanding the mechanisms behind benzodiazepine tolerance is critical for designing drugs that could maintain their efficacy during long-term treatments.
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Affiliation(s)
- María Clara Gravielle
- Instituto de Investigaciones Farmacológicas, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Junín 956, C1113AAD Buenos Aires, Argentina.
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Tolerance to the sedative and anxiolytic effects of diazepam is associated with different alterations of GABAA receptors in rat cerebral cortex. Neuroscience 2015; 310:152-62. [DOI: 10.1016/j.neuroscience.2015.09.038] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 09/11/2015] [Accepted: 09/12/2015] [Indexed: 11/18/2022]
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Luscher B, Fuchs T. GABAergic control of depression-related brain states. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2015; 73:97-144. [PMID: 25637439 DOI: 10.1016/bs.apha.2014.11.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The GABAergic deficit hypothesis of major depressive disorders (MDDs) posits that reduced γ-aminobutyric acid (GABA) concentration in brain, impaired function of GABAergic interneurons, altered expression and function of GABA(A) receptors, and changes in GABAergic transmission dictated by altered chloride homeostasis can contribute to the etiology of MDD. Conversely, the hypothesis posits that the efficacy of currently used antidepressants is determined by their ability to enhance GABAergic neurotransmission. We here provide an update for corresponding evidence from studies of patients and preclinical animal models of depression. In addition, we propose an explanation for the continued lack of genetic evidence that explains the considerable heritability of MDD. Lastly, we discuss how alterations in GABAergic transmission are integral to other hypotheses of MDD that emphasize (i) the role of monoaminergic deficits, (ii) stress-based etiologies, (iii) neurotrophic deficits, and (iv) the neurotoxic and neural circuit-impairing consequences of chronic excesses of glutamate. We propose that altered GABAergic transmission serves as a common denominator of MDD that can account for all these other hypotheses and that plays a causal and common role in diverse mechanistic etiologies of depressive brain states and in the mechanism of action of current antidepressant drug therapies.
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Affiliation(s)
- Bernhard Luscher
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Center for Molecular Investigation of Neurological Disorders, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA.
| | - Thomas Fuchs
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Center for Molecular Investigation of Neurological Disorders, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
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27
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Wright BT, Gluszek CF, Heldt SA. The effects of repeated zolpidem treatment on tolerance, withdrawal-like symptoms, and GABAA receptor mRNAs profile expression in mice: comparison with diazepam. Psychopharmacology (Berl) 2014; 231:2967-79. [PMID: 24531568 DOI: 10.1007/s00213-014-3473-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 01/26/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Zolpidem is a short-acting, non-benzodiazepine hypnotic that acts as a full agonist at α1-containing GABAA receptors. Overall, zolpidem purportedly has fewer instances of abuse and dependence than traditionally used benzodiazepines. However, several studies have shown that zolpidem may be more similar to benzodiazepines in terms of behavioral tolerance and withdrawal symptoms. OBJECTIVES In the current study, we examined whether subchronic zolpidem or diazepam administration produced deficits in zolpidem's locomotor-impairing effects, anxiety-like behaviors, and changes in GABAAR subunit messenger RNA (mRNA). METHODS Mice were given subchronic injections of either zolpidem (10 mg/kg), diazepam (20 mg/kg), or vehicle twice daily for 7 days. On day 8, mice were given a challenge dose of zolpidem (2 mg/kg) or vehicle before open field testing. Another set of mice underwent the same injection regimen but were sacrificed on day 8 for qRT-PCR analysis. RESULTS We found that subchronic zolpidem and diazepam administration produced deficits in the acute locomotor-impairing effects of zolpidem and increased anxiety-like behaviors 1 day after drug termination. In addition, we found that subchronic treatment of zolpidem and diazepam induced distinct but overlapping GABAAR subunit mRNA changes in the cortex but few changes in the hippocampus, amygdala, or prefrontal cortex. Levels of mRNA measured in separate mice after a single injection of either zolpidem or diazepam revealed no mRNA changes. CONCLUSIONS In mice, subchronic treatment of zolpidem and diazepam can produce deficits in the locomotor-impairing effects of zolpidem, anxiety-like withdrawal symptoms, and subunit-specific mRNA changes.
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Affiliation(s)
- Brittany T Wright
- The Department of Anatomy and Neurobiology, Neuroscience Institute, University of Tennessee Health Science Center, 855 Monroe Ave, Memphis, TN, 38163, USA
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Han S, Tai C, Jones CJ, Scheuer T, Catterall WA. Enhancement of inhibitory neurotransmission by GABAA receptors having α2,3-subunits ameliorates behavioral deficits in a mouse model of autism. Neuron 2014; 81:1282-1289. [PMID: 24656250 DOI: 10.1016/j.neuron.2014.01.016] [Citation(s) in RCA: 174] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2013] [Indexed: 01/24/2023]
Abstract
Autism spectrum disorder (ASD) may arise from increased ratio of excitatory to inhibitory neurotransmission in the brain. Many pharmacological treatments have been tested in ASD, but only limited success has been achieved. Here we report that BTBR T(+)Itpr3(tf)/J (BTBR) mice, a model of idiopathic autism, have reduced spontaneous GABAergic neurotransmission. Treatment with low nonsedating/nonanxiolytic doses of benzodiazepines, which increase inhibitory neurotransmission through positive allosteric modulation of postsynaptic GABAA receptors, improved deficits in social interaction, repetitive behavior, and spatial learning. Moreover, negative allosteric modulation of GABAA receptors impaired social behavior in C57BL/6J and 129SvJ wild-type mice, suggesting that reduced inhibitory neurotransmission may contribute to social and cognitive deficits. The dramatic behavioral improvement after low-dose benzodiazepine treatment was subunit specific-the α2,3-subunit-selective positive allosteric modulator L-838,417 was effective, but the α1-subunit-selective drug zolpidem exacerbated social deficits. Impaired GABAergic neurotransmission may contribute to ASD, and α2,3-subunit-selective positive GABAA receptor modulation may be an effective treatment.
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Affiliation(s)
- Sung Han
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA
| | - Chao Tai
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA
| | - Christina J Jones
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA
| | - Todd Scheuer
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA
| | - William A Catterall
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA.
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The behavioral pharmacology of zolpidem: evidence for the functional significance of α1-containing GABA(A) receptors. Psychopharmacology (Berl) 2014; 231:1865-96. [PMID: 24563183 DOI: 10.1007/s00213-014-3457-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 01/11/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Zolpidem is a positive allosteric modulator of γ-aminobutyric acid (GABA) with preferential binding affinity and efficacy for α1-subunit containing GABA(A) receptors (α1-GABA(A)Rs). Over the last three decades, a variety of animal models and experimental procedures have been used in an attempt to relate the behavioral profile of zolpidem and classic benzodiazepines (BZs) to their interaction with α1-GABA(A)Rs. OBJECTIVES This paper reviews the results of rodent and non-human primate studies that have evaluated the effects of zolpidem on motor behaviors, anxiety, memory, food and fluid intake, and electroencephalogram (EEG) sleep patterns. Also included are studies that examined zolpidem's discriminative, reinforcing, and anticonvulsant effects as well as behavioral signs of tolerance and withdrawal. RESULTS The literature reviewed indicates that α1-GABA(A)Rs play a principle role in mediating the hypothermic, ataxic-like, locomotor- and memory-impairing effects of zolpidem and BZs. Evidence also suggests that α1-GABA(A)Rs play partial roles in the hypnotic, EEG sleep, anticonvulsant effects, and anxiolytic-like of zolpidem and diazepam. These studies also indicate that α1-GABA(A)Rs play a more prominent role in mediating the discriminative stimulus, reinforcing, hyperphagic, and withdrawal effects of zolpidem and BZs in primates than in rodents. CONCLUSIONS The psychopharmacological data from both rodents and non-human primates suggest that zolpidem has a unique pharmacological profile when compared with classic BZs. The literature reviewed here provides an important framework for studying the role of different GABA(A)R subtypes in the behavioral effects of BZ-type drugs and helps guide the development of new pharmaceutical agents for disorders currently treated with BZ-type drugs.
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Rudolph U, Möhler H. GABAA receptor subtypes: Therapeutic potential in Down syndrome, affective disorders, schizophrenia, and autism. Annu Rev Pharmacol Toxicol 2013; 54:483-507. [PMID: 24160694 DOI: 10.1146/annurev-pharmtox-011613-135947] [Citation(s) in RCA: 231] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The γ-aminobutyric acid (GABA) system plays a pivotal role in orchestrating the synchronicity of local networks and the functional coupling of different brain regions. Here we review the impact of the GABAA receptor subtypes on cognitive and emotional behavior, paying particular attention to five disease states: cognitive dysfunction and Down syndrome, anxiety disorders, depression, schizophrenia, and autism. Through the bidirectional modulation of tonic inhibition, α5-subunit-containing GABAA receptors permit the bidirectional modulation of cognitive processes, and a partial inverse agonist acting at the α5-subunit-containing GABAA receptor is in a clinical trial in individuals with Down syndrome. With regard to anxiety disorders, the viability of nonsedative anxiolytics based on the modulation of α2- and α3-subunit-containing GABAA receptors has been established in clinical proof-of-concept trials. Regarding the remaining three disease states, the GABA hypothesis of depression offers new options for antidepressant drug development; cognitive symptoms in schizophrenia are attributed to a cortical GABAergic deficit, and dysfunctional GABAergic inhibition is increasingly understood to contribute to the pathophysiology of autism spectrum disorders.
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Affiliation(s)
- Uwe Rudolph
- Laboratory of Genetic Neuropharmacology, McLean Hospital and Department of Psychiatry, Harvard Medical School, Belmont, Massachusetts 02478;
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Olivier JDA, Vinkers CH, Olivier B. The role of the serotonergic and GABA system in translational approaches in drug discovery for anxiety disorders. Front Pharmacol 2013; 4:74. [PMID: 23781201 PMCID: PMC3677985 DOI: 10.3389/fphar.2013.00074] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 05/21/2013] [Indexed: 12/13/2022] Open
Abstract
There is ample evidence that genetic factors play an important role in anxiety disorders. In support, human genome-wide association studies have implicated several novel candidate genes. However, illumination of such genetic factors involved in anxiety disorders has not resulted in novel drugs over the past decades. A complicating factor is the heterogeneous classification of anxiety disorders in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) and diverging operationalization of anxiety used in preclinical and clinical studies. Currently, there is an increasing focus on the gene × environment (G × E) interaction in anxiety as genes do not operate in isolation and environmental factors have been found to significantly contribute to the development of anxiety disorders in at-risk individuals. Nevertheless, extensive research on G × E mechanisms in anxiety has not resulted in major breakthroughs in drug discovery. Modification of individual genes in rodent models has enabled the specific study of anxiety in preclinical studies. In this context, two extensively studied neurotransmitters involved in anxiety are the gamma-aminobutyric acid (GABA) and 5-HT (5-hydroxytryptamine) system. In this review, we illustrate the complex interplay between genes and environment in anxiety processes by reviewing preclinical and clinical studies on the serotonin transporter (5-HTT), 5-HT1A receptor, 5-HT2 receptor, and GABAA receptor. Even though targets from the serotonin and GABA system have yielded drugs with known anxiolytic efficacy, the relation between the genetic background of these targets and anxiety symptoms and development of anxiety disorders is largely unknown. The aim of this review is to show the vast complexity of genetic and environmental factors in anxiety disorders. In light of the difficulty with which common genetic variants are identified in anxiety disorders, animal models with translational validity may aid in elucidating the neurobiological background of these genes and their possible role in anxiety. We argue that, in addition to human genetic studies, translational models are essential to map anxiety-related genes and to enhance our understanding of anxiety disorders in order to develop potentially novel treatment strategies.
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Affiliation(s)
- Jocelien D A Olivier
- Department of, Women's and Children's Health, Uppsala University Uppsala, Sweden ; Center for Gender Medicine, Karolinska Institutet Stockholm, Sweden
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de Lange EC. The mastermind approach to CNS drug therapy: translational prediction of human brain distribution, target site kinetics, and therapeutic effects. Fluids Barriers CNS 2013; 10:12. [PMID: 23432852 PMCID: PMC3602026 DOI: 10.1186/2045-8118-10-12] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 02/01/2013] [Indexed: 01/11/2023] Open
Abstract
Despite enormous advances in CNS research, CNS disorders remain the world's leading cause of disability. This accounts for more hospitalizations and prolonged care than almost all other diseases combined, and indicates a high unmet need for good CNS drugs and drug therapies.Following dosing, not only the chemical properties of the drug and blood-brain barrier (BBB) transport, but also many other processes will ultimately determine brain target site kinetics and consequently the CNS effects. The rate and extent of all these processes are regulated dynamically, and thus condition dependent. Therefore, heterogenious conditions such as species, gender, genetic background, tissue, age, diet, disease, drug treatment etc., result in considerable inter-individual and intra-individual variation, often encountered in CNS drug therapy.For effective therapy, drugs should access the CNS "at the right place, at the right time, and at the right concentration". To improve CNS therapies and drug development, details of inter-species and inter-condition variations are needed to enable target site pharmacokinetics and associated CNS effects to be translated between species and between disease states. Specifically, such studies need to include information about unbound drug concentrations which drive the effects. To date the only technique that can obtain unbound drug concentrations in brain is microdialysis. This (minimally) invasive technique cannot be readily applied to humans, and we need to rely on translational approaches to predict human brain distribution, target site kinetics, and therapeutic effects of CNS drugs.In this review the term "Mastermind approach" is introduced, for strategic and systematic CNS drug research using advanced preclinical experimental designs and mathematical modeling. In this way, knowledge can be obtained about the contributions and variability of individual processes on the causal path between drug dosing and CNS effect in animals that can be translated to the human situation. On the basis of a few advanced preclinical microdialysis based investigations it will be shown that the "Mastermind approach" has a high potential for the prediction of human CNS drug effects.
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Affiliation(s)
- Elizabeth Cm de Lange
- Division of Pharmacology, Leiden-Academic Center for Drug Research, Leiden University, Leiden, the Netherlands.
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