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Xu C, Zhou Y, Liu Y, Lin L, Liu P, Wang X, Xu Z, Pin JP, Rondard P, Liu J. Specific pharmacological and G i/o protein responses of some native GPCRs in neurons. Nat Commun 2024; 15:1990. [PMID: 38443355 PMCID: PMC10914727 DOI: 10.1038/s41467-024-46177-z] [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: 08/08/2022] [Accepted: 02/15/2024] [Indexed: 03/07/2024] Open
Abstract
G protein-coupled receptors (GPCRs) constitute the largest family of membrane proteins and are important drug targets. The discovery of drugs targeting these receptors and their G protein signaling properties are based on assays mainly performed with modified receptors expressed in heterologous cells. However, GPCR responses may differ in their native environment. Here, by using highly sensitive Gi/o sensors, we reveal specific properties of Gi/o protein-mediated responses triggered by GABAB, α2 adrenergic and cannabinoid CB1 receptors in primary neurons, different from those in heterologous cells. These include different profiles in the Gi/o protein subtypes-mediated responses, and differences in the potencies of some ligands even at similar receptor expression levels. Altogether, our results show the importance of using biosensors compatible with primary cells for evaluating the activities of endogenous GPCRs in their native environment.
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Affiliation(s)
- Chanjuan Xu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, 510005, Guangzhou, China
| | - Yiwei Zhou
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Kindstar Global Precision Medicine Institute, Wuhan, China
| | - Yuxuan Liu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Li Lin
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Peng Liu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xiaomei Wang
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zhengyuan Xu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, 34094, Montpellier, France.
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, 34094, Montpellier, France.
| | - Jianfeng Liu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China.
- Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, 510005, Guangzhou, China.
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Ching-Ju Huang, Zayabaatar E, Wang SM, Keshari S, Peng WH, Kung HN, Lee YH. Bacillus amyloliquefaciens-Inoculated GABA-Rich Rice Upregulate Neuropeptide Y to Relieve Psychological Stress through Mediations of GABAB Receptor and Vagus Nerves. BIOL BULL+ 2023. [DOI: 10.1134/s1062359022700054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
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3
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Kamel AS, Wahid A, Abdelkader NF, Ibrahim WW. Boosting amygdaloid GABAergic and neurotrophic machinery via dapagliflozin-enhanced LKB1/AMPK signaling in anxious demented rats. Life Sci 2022; 310:121002. [PMID: 36191679 DOI: 10.1016/j.lfs.2022.121002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/19/2022] [Accepted: 09/22/2022] [Indexed: 11/18/2022]
Abstract
Anxiety is a neuropsychiatric disturbance that is commonly manifested in various dementia forms involving Alzheimer's disease (AD). The mechanisms underlying AD-associated anxiety haven't clearly recognized the role of energy metabolism in anxiety represented by the amygdala's autophagic sensors; liver kinase B1 (LKB1)/adenosine monophosphate kinase (AMPK). Dapagliflozin (DAPA), a SGLT2 inhibitor, acts as an autophagic activator through LKB1 activation in several diseases including AD. Herein, the propitious yet undetected anxiolytic potential of DAPA as an autophagic enhancer was investigated in AD animal model with emphasis on amygdala's GABAergic neurotransmission and brain-derived neurotrophic factor (BDNF). Alzheimer's disease was induced by ovariectomy (OVX) along with seventy-days-D-galactose (D-Gal) administration (150 mg/kg/day, i.p). On the 43rd day of D-Gal injection, OVX/D-Gal-subjected rats received DAPA (1 mg/kg/day, p.o) alone or with dorsomorphin the AMPK inhibitor (DORSO, 25 μg/rat, i.v.). In the amygdala, LKB1/AMPK were activated by DAPA inducing GABAB2 receptor stimulation; an effect that was abrogated by DORSO. Dapagliflozin also replenished the amygdala GABA, NE, and 5-HT levels along with glutamate suppression. Moreover, DAPA triggered BDNF production with consequent activation of its receptor, TrkB through activating GABAB2-related downstream phospholipase C/diacylglycerol/protein kinase C (PLC/DAG/PKC) signaling. This may promote GABAA expression, verifying the crosstalk between GABAA and GABAB2. The DAPA's anxiolytic effect was visualized by improved behavioral traits in elevated plus maze together with amendment of amygdala' histopathological abnormalities. Thus, the present study highlighted DAPA's anxiolytic effect which was attributed to GABAB2 activation and its function to induce BDNF/TrkB and GABAA expression through PLC/DAG/PKC pathway in AMPK-dependent manner.
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Affiliation(s)
- Ahmed S Kamel
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Egypt
| | - Ahmed Wahid
- Department of Pharmaceutical Biochemistry, Faculty of Pharmacy, Alexandria University, Egypt
| | - Noha F Abdelkader
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Egypt.
| | - Weam W Ibrahim
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Egypt
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Eller OC, Willits AB, Young EE, Baumbauer KM. Pharmacological and non-pharmacological therapeutic interventions for the treatment of spinal cord injury-induced pain. FRONTIERS IN PAIN RESEARCH 2022; 3:991736. [PMID: 36093389 PMCID: PMC9448954 DOI: 10.3389/fpain.2022.991736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/05/2022] [Indexed: 11/29/2022] Open
Abstract
Spinal cord injury (SCI) is a complex neurophysiological disorder, which can result in many long-term complications including changes in mobility, bowel and bladder function, cardiovascular function, and metabolism. In addition, most individuals with SCI experience some form of chronic pain, with one-third of these individuals rating their pain as severe and unrelenting. SCI-induced chronic pain is considered to be "high impact" and broadly affects a number of outcome measures, including daily activity, physical and cognitive function, mood, sleep, and overall quality of life. The majority of SCI pain patients suffer from pain that emanates from regions located below the level of injury. This pain is often rated as the most severe and the underlying mechanisms involve injury-induced plasticity along the entire neuraxis and within the peripheral nervous system. Unfortunately, current therapies for SCI-induced chronic pain lack universal efficacy. Pharmacological treatments, such as opioids, anticonvulsants, and antidepressants, have been shown to have limited success in promoting pain relief. In addition, these treatments are accompanied by many adverse events and safety issues that compound existing functional deficits in the spinally injured, such as gastrointestinal motility and respiration. Non-pharmacological treatments are safer alternatives that can be specifically tailored to the individual and used in tandem with pharmacological therapies if needed. This review describes existing non-pharmacological therapies that have been used to treat SCI-induced pain in both preclinical models and clinical populations. These include physical (i.e., exercise, acupuncture, and hyper- or hypothermia treatments), psychological (i.e., meditation and cognitive behavioral therapy), and dietary interventions (i.e., ketogenic and anti-inflammatory diet). Findings on the effectiveness of these interventions in reducing SCI-induced pain and improving quality of life are discussed. Overall, although studies suggest non-pharmacological treatments could be beneficial in reducing SCI-induced chronic pain, further research is needed. Additionally, because chronic pain, including SCI pain, is complex and has both emotional and physiological components, treatment should be multidisciplinary in nature and ideally tailored specifically to the patient.
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Affiliation(s)
- Olivia C. Eller
- Department of Cell Biology and Physiology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Adam B. Willits
- Department of Anesthesiology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Erin E. Young
- Department of Cell Biology and Physiology, University of Kansas Medical Center, Kansas City, KS, United States
- Department of Anesthesiology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Kyle M. Baumbauer
- Department of Cell Biology and Physiology, University of Kansas Medical Center, Kansas City, KS, United States
- Department of Anesthesiology, University of Kansas Medical Center, Kansas City, KS, United States
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Ito M, Spence A, Blauwet MB, Heo N, Goldwater R, Maruff P, Marek GJ. A phase 1 study to assess potential interaction between ASP8062 and alcohol in healthy adult subjects. J Psychopharmacol 2022; 36:756-767. [PMID: 34994232 DOI: 10.1177/02698811211058967] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND ASP8062 is a novel orally active GABAB receptor positive allosteric modulator in clinical development for the treatment of alcohol use disorder (AUD) and opioid use disorder (OUD). AIMS This study assessed the potential pharmacokinetic/pharmacodynamic interaction between ASP8062 and alcohol under single-dose conditions in healthy adults. METHODS A double-blind, placebo-controlled, crossover phase 1 study was conducted in which 20 subjects were randomly assigned to four treatment sequences (ASP8062 + alcohol; ASP8062 + placebo alcohol; placebo + alcohol; placebo + placebo alcohol) each consisting of four treatment periods, separated by washout periods of at least 14 days. An analysis of variance was used to assess pharmacokinetic interaction and a mixed-effects analysis of covariance was used to assess pharmacodynamic interaction. RESULTS/OUTCOMES After administration of alcohol, a mild to minimal increase in plasma exposure (AUCinf and Cmax) of ASP8062 was observed, but tmax and t½ for ASP8062 remained unchanged after administration of alcohol. In contrast, ASP8062 did not affect the AUClast and Cmax of ethanol. No clinically relevant differences in cognition measurements were observed with ASP8062 compared with placebo, but there were expected impairments in psychomotor and executive function with alcohol alone. ASP8062 in combination with alcohol resulted in worse scores in cognition measurements than alcohol alone, but this potentiation was not consistent. ASP8062 administered alone was safe and well-tolerated and safety findings in subjects administered alcohol alone were not augmented when ASP8062 was administered in combination with alcohol. CONCLUSION/INTERPRETATION The data support further clinical studies investigating ASP8062 in patients with AUD.
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Affiliation(s)
- Mototsugu Ito
- Astellas Pharma Global Development, Inc., Northbrook, IL, USA
| | - Anna Spence
- Astellas Pharma Global Development, Inc., Northbrook, IL, USA
| | | | - Nakyo Heo
- Astellas Pharma Global Development, Inc., Northbrook, IL, USA
| | | | | | - Gerard J Marek
- Astellas Pharma Global Development, Inc., Northbrook, IL, USA
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6
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Janz P, Nicolas MJ, Redondo RL, Valencia M.
GABA
B
R
activation partially normalizes acute
NMDAR
hypofunction oscillatory abnormalities but fails to rescue sensory processing deficits. J Neurochem 2022; 161:417-434. [DOI: 10.1111/jnc.15602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/21/2022] [Accepted: 02/12/2022] [Indexed: 12/01/2022]
Affiliation(s)
- Philipp Janz
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases, Roche Innovation Center Basel, F. Hoffmann‐La Roche Ltd, Grenzacherstrasse 124, 4070 Basel Switzerland
| | - Maria Jesus Nicolas
- Universidad de Navarra, CIMA, Program of Neuroscience, 31080 Pamplona Spain
- IdiSNA Navarra Institute for Health Research, 31080 Pamplona Spain
| | - Roger L. Redondo
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases, Roche Innovation Center Basel, F. Hoffmann‐La Roche Ltd, Grenzacherstrasse 124, 4070 Basel Switzerland
| | - Miguel Valencia
- Universidad de Navarra, CIMA, Program of Neuroscience, 31080 Pamplona Spain
- IdiSNA Navarra Institute for Health Research, 31080 Pamplona Spain
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7
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Liu L, Fan Z, Rovira X, Xue L, Roux S, Brabet I, Xin M, Pin JP, Rondard P, Liu J. Allosteric ligands control the activation of a class C GPCR heterodimer by acting at the transmembrane interface. eLife 2021; 10:70188. [PMID: 34866572 PMCID: PMC8700296 DOI: 10.7554/elife.70188] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 12/02/2021] [Indexed: 01/02/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are among the most promising drug targets. They often form homo- and heterodimers with allosteric cross-talk between receptor entities, which contributes to fine-tuning of transmembrane signaling. Specifically controlling the activity of GPCR dimers with ligands is a good approach to clarify their physiological roles and validate them as drug targets. Here, we examined the mode of action of positive allosteric modulators (PAMs) that bind at the interface of the transmembrane domains of the heterodimeric GABAB receptor. Our site-directed mutagenesis results show that mutations of this interface impact the function of the three PAMs tested. The data support the inference that they act at the active interface between both transmembrane domains, the binding site involving residues of the TM6s of the GABAB1 and the GABAB2 subunit. Importantly, the agonist activity of these PAMs involves a key region in the central core of the GABAB2 transmembrane domain, which also controls the constitutive activity of the GABAB receptor. This region corresponds to the sodium ion binding site in class A GPCRs that controls the basal state of the receptors. Overall, these data reveal the possibility of developing allosteric compounds able to specifically modulate the activity of GPCR homo- and heterodimers by acting at their transmembrane interface.
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Affiliation(s)
- Lei Liu
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.,Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Zhiran Fan
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Xavier Rovira
- MCS, Laboratory of Medicinal Chemistry, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Barcelona, Spain
| | - Li Xue
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.,Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Salomé Roux
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Isabelle Brabet
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Mingxia Xin
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Jianfeng Liu
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
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Shaye H, Stauch B, Gati C, Cherezov V. Molecular mechanisms of metabotropic GABA B receptor function. SCIENCE ADVANCES 2021; 7:7/22/eabg3362. [PMID: 34049877 PMCID: PMC8163086 DOI: 10.1126/sciadv.abg3362] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 04/14/2021] [Indexed: 05/06/2023]
Abstract
Metabotropic γ-aminobutyric acid G protein-coupled receptors (GABAB) represent one of the two main types of inhibitory neurotransmitter receptors in the brain. These receptors act both pre- and postsynaptically by modulating the transmission of neuronal signals and are involved in a range of neurological diseases, from alcohol addiction to epilepsy. A series of recent cryo-EM studies revealed critical details of the activation mechanism of GABAB Structures are now available for the receptor bound to ligands with different modes of action, including antagonists, agonists, and positive allosteric modulators, and captured in different conformational states from the inactive apo to the fully active state bound to a G protein. These discoveries provide comprehensive insights into the activation of the GABAB receptor, which not only broaden our understanding of its structure, pharmacology, and physiological effects but also will ultimately facilitate the discovery of new therapeutic drugs and neuromodulators.
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Affiliation(s)
- Hamidreza Shaye
- Department of Chemistry, University of Southern California, Los Angeles, CA, USA
- Bridge Institute, Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA, USA
| | - Benjamin Stauch
- Department of Chemistry, University of Southern California, Los Angeles, CA, USA
- Bridge Institute, Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA, USA
| | - Cornelius Gati
- Bridge Institute, Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA, USA
- Biosciences Division, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Vadim Cherezov
- Department of Chemistry, University of Southern California, Los Angeles, CA, USA.
- Bridge Institute, Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA, USA
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
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Porcu A, Mostallino R, Serra V, Melis M, Sogos V, Beggiato S, Ferraro L, Manetti F, Gianibbi B, Bettler B, Corelli F, Mugnaini C, Castelli MP. COR758, a negative allosteric modulator of GABA B receptors. Neuropharmacology 2021; 189:108537. [PMID: 33798546 DOI: 10.1016/j.neuropharm.2021.108537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 03/20/2021] [Accepted: 03/22/2021] [Indexed: 10/21/2022]
Abstract
Allosteric modulators of G protein coupled receptors (GPCRs), including GABABRs (GABABRs), are promising therapeutic candidates. While several positive allosteric modulators (PAM) of GABABRs have been characterized, only recently the first negative allosteric modulator (NAM) has been described. In the present study, we report the characterization of COR758, which acts as GABABR NAM in rat cortical membranes and CHO cells stably expressing GABABRs (CHO-GABAB). COR758 failed to displace the antagonist [3H]CGP54626 from the orthosteric binding site of GABABRs showing that it acts through an allosteric binding site. Docking studies revealed a possible new allosteric binding site for COR758 in the intrahelical pocket of the GABAB1 monomer. COR758 inhibited basal and GABABR-stimulated O-(3-[35Sthio)-triphosphate ([35S]GTPγS) binding in brain membranes and blocked the enhancement of GABABR-stimulated [35S]GTPγS binding by the PAM GS39783. Bioluminescent resonance energy transfer (BRET) measurements in CHO-GABAB cells showed that COR758 inhibited G protein activation by GABA and altered GABABR subunit rearrangements. Additionally, the compound altered GABABR-mediated signaling such as baclofen-induced inhibition of cAMP production in transfected HEK293 cells, agonist-induced Ca2+ mobilization as well as baclofen and the ago-PAM CGP7930 induced phosphorylation of extracellular signal-regulated kinases (ERK1/2) in CHO-GABAB cells. COR758 also prevented baclofen-induced outward currents recorded from rat dopamine neurons, substantiating its property as a NAM for GABABRs. Altogether, these data indicate that COR758 inhibits G protein signaling by GABABRs, likely by interacting with an allosteric binding-site. Therefore, COR758 might serve as a scaffold to develop additional NAMs for therapeutic intervention.
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Affiliation(s)
- Alessandra Porcu
- Department of Biomedical Sciences, University of Cagliari, 09042, Monserrato, Italy; Department of Biomedicine, University of Basel, Klingelbergstrasse 50-70, CH-4056, Basel, Switzerland
| | - Rafaela Mostallino
- Department of Biomedical Sciences, University of Cagliari, 09042, Monserrato, Italy
| | - Valeria Serra
- Department of Biomedical Sciences, University of Cagliari, 09042, Monserrato, Italy
| | - Miriam Melis
- Department of Biomedical Sciences, University of Cagliari, 09042, Monserrato, Italy
| | - Valeria Sogos
- Department of Biomedical Sciences, University of Cagliari, 09042, Monserrato, Italy
| | - Sarah Beggiato
- Department of Life Sciences and Biotechnology, Section of Medicinal and Health Products, and LTTA Center, University of Ferrara, Ferrara, Italy; Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, 66100, Chieti, Italy
| | - Luca Ferraro
- Department of Life Sciences and Biotechnology, Section of Medicinal and Health Products, and LTTA Center, University of Ferrara, Ferrara, Italy
| | - Fabrizio Manetti
- Department of Biotechnology, Chemistry, and Pharmacy, University of Siena, I-53100, Siena, SI, Italy
| | - Beatrice Gianibbi
- Department of Biotechnology, Chemistry, and Pharmacy, University of Siena, I-53100, Siena, SI, Italy
| | - Bernhard Bettler
- Department of Biomedicine, University of Basel, Klingelbergstrasse 50-70, CH-4056, Basel, Switzerland
| | - Federico Corelli
- Department of Biotechnology, Chemistry, and Pharmacy, University of Siena, I-53100, Siena, SI, Italy
| | - Claudia Mugnaini
- Department of Biotechnology, Chemistry, and Pharmacy, University of Siena, I-53100, Siena, SI, Italy
| | - M Paola Castelli
- Department of Biomedical Sciences, University of Cagliari, 09042, Monserrato, Italy; Guy Everett Laboratory, University of Cagliari, 09042, Monserrato, Italy; Center of Excellence "Neurobiology of Addiction", University of Cagliari, 09042, Monserrato, Italy.
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10
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A randomized phase 1 single-dose polysomnography study of ASP8062, a GABA B receptor positive allosteric modulator. Psychopharmacology (Berl) 2021; 238:867-876. [PMID: 33433644 PMCID: PMC7914186 DOI: 10.1007/s00213-020-05738-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 12/01/2020] [Indexed: 12/29/2022]
Abstract
RATIONALE Previous research suggests that sleep polysomnography and EEG endpoints can be used to assess GABAergic activity; however, the impact of GABAB receptor positive allosteric modulators on sleep endpoints remains unclear. OBJECTIVES This phase 1 study compared a single dose of ASP8062 (35 mg or 70 mg), a GABAB receptor positive allosteric modulator, with placebo and paroxetine (40 mg). METHODS Healthy adult volunteers were randomized to four treatments (35 mg ASP8062, 70 mg ASP8062, paroxetine 40 mg, or matching placebo), each separated by a 14-day washout. Primary endpoints obtained by polysomnography were time in stage N3 or SWS and time in rapid eye movement (REM) sleep. Secondary endpoints included impact on sleep stages and electroencephalography parameters, pharmacokinetics, nighttime growth hormone (GH), and safety/tolerability. RESULTS In 20 randomized volunteers, ASP8062 led to a significant and seemingly dose-dependent increase in SWS over the entire night; this increase was mainly observed during the first third of the night. ASP8062 did not impact time in REM sleep. Paroxetine had no effect on SWS but produced a significant reduction in time spent in REM sleep. A dose-dependent trend in increased GH release was also observed with ASP8062. Headache and nausea were the most commonly reported treatment-emergent adverse events (TEAEs) for ASP8062; most TEAEs were mild in severity. CONCLUSIONS Single-dose ASP8062 (35 and 70 mg) appeared to result in CNS penetration and enhanced GABAergic activity as measured by increases in slow-wave sleep and growth hormone release.
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11
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Matsumoto R, Yamada K, Nakazawa M, Mori S, Kitajima S. Structure–Activity Relationship Study of T1R2/T1R3 Positive Allosteric Modulators and Evaluation of Their Enhancing Effect on Various Sweeteners. ChemistrySelect 2020. [DOI: 10.1002/slct.202002159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Ryo Matsumoto
- Ajinomoto Co., Inc., 1–1, Suzuki-Cho Kawasaki-Ku Kawasaki-Shi 210-8681 Japan
| | - Kei Yamada
- Ajinomoto Co., Inc., 1–1, Suzuki-Cho Kawasaki-Ku Kawasaki-Shi 210-8681 Japan
| | - Masakazu Nakazawa
- Ajinomoto Co., Inc., 1–1, Suzuki-Cho Kawasaki-Ku Kawasaki-Shi 210-8681 Japan
| | - Suguru Mori
- Ajinomoto Co., Inc., 1–1, Suzuki-Cho Kawasaki-Ku Kawasaki-Shi 210-8681 Japan
| | - Seiji Kitajima
- Ajinomoto Co., Inc., 1–1, Suzuki-Cho Kawasaki-Ku Kawasaki-Shi 210-8681 Japan
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12
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Evenseth LSM, Gabrielsen M, Sylte I. The GABA B Receptor-Structure, Ligand Binding and Drug Development. Molecules 2020; 25:molecules25133093. [PMID: 32646032 PMCID: PMC7411975 DOI: 10.3390/molecules25133093] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/02/2020] [Accepted: 07/06/2020] [Indexed: 11/17/2022] Open
Abstract
The γ-aminobutyric acid (GABA) type B receptor (GABAB-R) belongs to class C of the G-protein coupled receptors (GPCRs). Together with the GABAA receptor, the receptor mediates the neurotransmission of GABA, the main inhibitory neurotransmitter in the central nervous system (CNS). In recent decades, the receptor has been extensively studied with the intention being to understand pathophysiological roles, structural mechanisms and develop drugs. The dysfunction of the receptor is linked to a broad variety of disorders, including anxiety, depression, alcohol addiction, memory and cancer. Despite extensive efforts, few compounds are known to target the receptor, and only the agonist baclofen is approved for clinical use. The receptor is a mandatory heterodimer of the GABAB1 and GABAB2 subunits, and each subunit is composed of an extracellular Venus Flytrap domain (VFT) and a transmembrane domain of seven α-helices (7TM domain). In this review, we briefly present the existing knowledge about the receptor structure, activation and compounds targeting the receptor, emphasizing the role of the receptor in previous and future drug design and discovery efforts.
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Affiliation(s)
- Linn Samira Mari Evenseth
- Molecular Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Mari Gabrielsen
- Molecular Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Ingebrigt Sylte
- Molecular Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
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Walzer M, Marek GJ, Wu R, Nagata M, Han D. Single- and Multiple-Dose Safety, Tolerability, and Pharmacokinetic Profiles of ASP8062: Results From 2 Phase 1 Studies. Clin Pharmacol Drug Dev 2020; 9:297-306. [PMID: 31926000 DOI: 10.1002/cpdd.766] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 11/19/2019] [Indexed: 12/29/2022]
Abstract
ASP8062 is an orally active γ-amino-butyric acid type B (GABAB ) receptor positive allosteric modulator currently in phase 2 development. Safety and pharmacokinetic (PK) profiles of ASP8062 were evaluated in 2 studies in healthy subjects. The first study (a first-in-human study) evaluated single ascending doses (SAD) of ASP8062. The second study was composed of 2 parts: part 1 evaluated multiple ascending doses (MAD) of ASP8062 for 14 days, and part 2 was a single-dose arm to assess the PK of ASP8062 in cerebrospinal fluid (CSF). Fifty-six men (SAD) and 56 subjects (24 women and 32 men; MAD) were enrolled. Across the SAD dosing range, area under the concentration-time curve was dose proportional; increases in maximum plasma concentration appeared linear but were slightly less than dose proportional. Time to maximal concentration and half-life were 1-4 hours and ∼40-50 hours, respectively; no food effect was observed. ASP8062 PK properties at steady state were similar to those following a single dose. Steady state was achieved by ∼day 9 with ∼2-fold accumulation, and ASP8062 was detected in CSF. ASP8062 was well tolerated; no clear evidence of ASP8062's effects on safety, cognition, drug withdrawal, or suicidal ideation/behavior was observed. These data support the development of ASP8062 in indications where the GABAB receptor is a target.
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Affiliation(s)
- Mark Walzer
- Astellas Pharma Global Development, Northbrook, Illinois, USA
| | - Gerard J Marek
- Astellas Pharma Global Development, Northbrook, Illinois, USA
| | - Ruishan Wu
- Astellas Pharma Global Development, Northbrook, Illinois, USA
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Blum K, Lott L, Baron D, Smith DE, Badgaiyan RD, Gold MS. Improving naltrexone compliance and outcomes with putative pro- dopamine regulator KB220, compared to treatment as usual. ACTA ACUST UNITED AC 2020; 7. [PMID: 32934823 PMCID: PMC7489288 DOI: 10.15761/jsin.1000229] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A recent analysis from Stanford University suggested that without any changes in currently available treatment, prevention, and public health approaches, we should expect to have 510,000 deaths from prescription opioids and street heroin from 2016 to 2025 in the US. In a recent review, Mayo Clinic Proceedings (October 2019), Gold and colleagues at Mayo Clinic reviewed the available medications used in opioid use disorders and concluded that in private and community practice adherence is more important as a limiting factor to retention, relapse, and repeat overdose. It is agreed that the primary utilization of known opioid agonists like methadone, buprenorphine and naloxone combinations, while useful as a way of reducing societal harm, is limited by 50% of more discontinuing treatment within 6 months, their diversion, and addiction liability. Opioid agonists may have other unintended consequences, like continuing the down regulation of dopamine systems. While naltrexone would be expected to have opposite effects, adherence is also low even after detoxification and long acting naltrexone injections. Recent studies have shown Naltrexone is beneficial by attenuation of craving via “psychological extinction” and reducing relapse. Buprenorphine is the MAT of choice currently but injectable Naltrexone plus an agent to improve dopaminergic function and tone may renew interest amongst addiction physicians and patients. Understanding this dilemma there is increasing movement to opt for the non-addicting narcotic antagonist Naltrexone. Even with extended injectable option there is still poor compliance. As such, we describe an open label investigation in humans showing improvement of naltrexone compliance and outcomes with dopamine augmentation with the pro- dopamine regulator KB220 (262 days) compared to naltrexone alone (37days). This well studied complex consists of amino-acid neurotransmitter precursors and enkephalinase inhibitor therapy compared to treatment as usual. Consideration of this novel paradigm shift may assist in not only addressing the current opioid epidemic but the broader question of reward deficiency in general.
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Affiliation(s)
- Kenneth Blum
- Western University Health Sciences, Graduate College, Pomona, CA, USA
| | - Lisa Lott
- Division of Behavioral Precision Management, Geneus Health, LLC, San Antonio, TX, USA
| | - David Baron
- Western University Health Sciences, Graduate College, Pomona, CA, USA
| | - David E Smith
- Department of Pharmacology, University of California San Francisco School of Medicine, San Francisco, CA, USA
| | - Rajendra D Badgaiyan
- Department of Psychiatry, Icahn School of Medicine Mt Sinai, New York, NY, USA and Department of Psychiatry, South Texas Veteran Health Care System, Audie L. Murphy Memorial VA Hospital, San Antonio, TX, Long School of Medicine, University of Texas Medical Center, San Antonio, TX, USA
| | - Mark S Gold
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Mo, USA
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Murai N, Kondo Y, Akuzawa S, Mihara T, Shiraishi N, Kakimoto S, Matsumoto M. A novel GABAB receptor positive allosteric modulator, ASP8062, exerts analgesic effects in a rat model of fibromyalgia. Eur J Pharmacol 2019; 865:172750. [DOI: 10.1016/j.ejphar.2019.172750] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 10/11/2019] [Accepted: 10/18/2019] [Indexed: 11/24/2022]
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16
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Downs BW, Blum K, Baron D, Bowirrat A, Lott L, Brewer R, Boyett B, Siwicki D, Roy AK, Podesta A, Badgaiyan S, Hajela R, Fried L, Badgaiyan RD. Death by Opioids: Are there non-addictive scientific solutions? ACTA ACUST UNITED AC 2019; 5. [PMID: 31824737 DOI: 10.15761/jsin.1000211] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In the face of the current Opioid crisis in America killing close to 800,000 people since 2004, we are proposing a novel approach to assist in at least attenuating these unwanted premature deaths. While we applaud the wonderful efforts of our governmental institutes and professional societies (NIDA, NIAAA, ASAM, ABAM ) in their extraordinary efforts in combating this continued dilemma, the current approach is failing, and other alternative approaches should at least be tested. These truths present a serious ethical dilemma to scientists, clinicians and counselors in the Reward Deficiency Syndrome (RDS) treatment community. It is important to realize that the current DSM-5 does not actually accurately display the natural brain reward process. The human brain has not been designed to carve out specific drugs like opioids, alcohol, nicotine, cocaine, benzodiazepines or cannabis and process addictions such as gambling as distinct endophenotypes. This is true in spite of natural ligands for cannabinoids, endorphins, or even benzodiazepines. The most accurate endophenotype is indeed reward dysfunction (e.g hypodopaminergic or hyperdopaminergic). With this mind, we are hereby proposing that the current Medication Assisted Treatment (i.e. 'MAT') expands to needed individuals as an initial "Band-Aid" to reduce harm avoidance, with the long-term goal of prophylaxis. So, to be clear, there may be other promising modalities other than MAT such as repetitive transcranial magnetic stimulation (rTMS), exercise and even new medications with positive allosteric modulators of GABA-A receptors, as well as the highly researched Genetic Addiction Risk Score (GARS) coupled with precision KB220Z. This will induce "dopamine homeostasis" to effectively rebalance and restore healthier brain function by promoting the cross talk between various brain regions (e.g. Nucleus accumbens, cingulate gyrus, hippocampus etc.) resulting in dopamine homeostasis. Our laudable goal is to not only save lives, but to redeem joy and improve the quality of life in the recovery community through scientifically sound natural non-addicting alternatives.
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Affiliation(s)
- B William Downs
- Department of Nutrigenomic Research, Victory Nutrition International, Inc., Lederach, PA, USA
| | - Kenneth Blum
- Department of Nutrigenomic Research, Victory Nutrition International, Inc., Lederach, PA, USA.,Western University, Health Sciences, Graduate School of Biomedical Sciences, Pomona, CA, USA.,Division of Neuroscience and Addiction Research, Pathway Healthcare, Birmingham, AL, USA.,Eotvos Loránd University, Institute of Psychology, Budapest, Hungary.,Department of Psychiatry, Wright State University Boonshoft School of Medicine and Dayton VA Medical Center, Dayton, OH, USA.,Division of Precision Nutrigenomics, Geneus Health, LLC., San Antonio, TX, USA
| | - David Baron
- Western University, Health Sciences, Graduate School of Biomedical Sciences, Pomona, CA, USA
| | - Abdalla Bowirrat
- Department of Neuroscience and Genetics, Interdisciplinary Center Herzliya, Israel
| | - Lisa Lott
- Division of Precision Nutrigenomics, Geneus Health, LLC., San Antonio, TX, USA
| | - Raymond Brewer
- Division of Precision Nutrigenomics, Geneus Health, LLC., San Antonio, TX, USA
| | - Brent Boyett
- Division of Neuroscience and Addiction Research, Pathway Healthcare, Birmingham, AL, USA
| | - David Siwicki
- Division of Precision Nutrigenomics, Geneus Health, LLC., San Antonio, TX, USA
| | - A Kenison Roy
- Department of Psychiatry, Tulane University School of Medicine, New Orleans, LA, USA
| | - Arwen Podesta
- Department of Psychiatry, Tulane University School of Medicine, New Orleans, LA, USA
| | - Sampada Badgaiyan
- Division of Precision Nutrigenomics, Geneus Health, LLC., San Antonio, TX, USA
| | - Raju Hajela
- Department of Family Medicine, Cumming School of Medicine, University of Calgary, AB, Canada
| | - Lyle Fried
- Transformations Treatment Center, Delray Beach, FL, USA
| | - Rajendra D Badgaiyan
- Department of Psychiatry, South Texas Veteran Health Care System, Audie L. Murphy Memorial VA Hospital, San Antonio, TX, Long School of Medicine, University of Texas Medical Center, San Antonio, TX, USA
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17
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Evenseth LM, Warszycki D, Bojarski AJ, Gabrielsen M, Sylte I. In Silico Methods for the Discovery of Orthosteric GABA B Receptor Compounds. Molecules 2019; 24:E935. [PMID: 30866507 PMCID: PMC6429233 DOI: 10.3390/molecules24050935] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 02/20/2019] [Accepted: 03/01/2019] [Indexed: 12/27/2022] Open
Abstract
The GABAB receptor (GABAB-R) is a heterodimeric class C G protein-coupled receptor comprised of the GABAB1a/b and GABAB2 subunits. The endogenous orthosteric agonist γ-amino-butyric acid (GABA) binds within the extracellular Venus flytrap (VFT) domain of the GABAB1a/b subunit. The receptor is associated with numerous neurological and neuropsychiatric disorders including learning and memory deficits, depression and anxiety, addiction and epilepsy, and is an interesting target for new drug development. Ligand- and structure-based virtual screening (VS) are used to identify hits in preclinical drug discovery. In the present study, we have evaluated classical ligand-based in silico methods, fingerprinting and pharmacophore mapping and structure-based in silico methods, structure-based pharmacophores, docking and scoring, and linear interaction approximation (LIA) for their aptitude to identify orthosteric GABAB-R compounds. Our results show that the limited number of active compounds and their high structural similarity complicate the use of ligand-based methods. However, by combining ligand-based methods with different structure-based methods active compounds were identified in front of DUDE-E decoys and the number of false positives was reduced, indicating that novel orthosteric GABAB-R compounds may be identified by a combination of ligand-based and structure-based in silico methods.
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Affiliation(s)
- Linn M Evenseth
- Molecular Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, NO-9037 Tromsø, Norway.
| | - Dawid Warszycki
- Department of Medicinal Chemistry, Institute of Pharmacology, Polish Academy of Science, Smetna 12, 31-343 Kraków, Poland.
| | - Andrzej J Bojarski
- Department of Medicinal Chemistry, Institute of Pharmacology, Polish Academy of Science, Smetna 12, 31-343 Kraków, Poland.
| | - Mari Gabrielsen
- Molecular Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, NO-9037 Tromsø, Norway.
| | - Ingebrigt Sylte
- Molecular Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, NO-9037 Tromsø, Norway.
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Sengmany K, Hellyer SD, Albold S, Wang T, Conn PJ, May LT, Christopoulos A, Leach K, Gregory KJ. Kinetic and system bias as drivers of metabotropic glutamate receptor 5 allosteric modulator pharmacology. Neuropharmacology 2019; 149:83-96. [PMID: 30763654 DOI: 10.1016/j.neuropharm.2019.02.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 01/18/2019] [Accepted: 02/04/2019] [Indexed: 12/17/2022]
Abstract
Allosteric modulators of the metabotropic glutamate receptor subtype 5 (mGlu5) have been proposed as potential therapies for various CNS disorders. These ligands bind to sites distinct from the orthosteric (or endogenous) ligand, often with improved subtype selectivity and spatio-temporal control over receptor responses. We recently revealed that mGlu5 allosteric agonists and positive allosteric modulators exhibit biased agonism and/or modulation. To establish whether negative allosteric modulators (NAMs) engender similar bias, we rigorously characterized the pharmacology of eight diverse mGlu5 NAMs. Radioligand inhibition binding studies revealed novel modes of interaction with mGlu5 for select NAMs, with biphasic or incomplete inhibition of the radiolabeled NAM, [3H]methoxy-PEPy. We assessed mGlu5-mediated intracellular Ca2+ (iCa2+) mobilization and inositol phosphate (IP1) accumulation in HEK293A cells stably expressing low levels of mGlu5 (HEK293A-rat mGlu5-low) and mouse embryonic cortical neurons. The apparent affinity of acetylenic NAMs, MPEP, MTEP and dipraglurant, was dependent on the signaling pathway measured, agonist used, and cell type (HEK293A-rat mGlu5-low versus mouse cortical neurons). In contrast, the acetylenic partial NAM, M-5MPEP, and structurally distinct NAMs (VU0366248, VU0366058, fenobam), had similar affinity estimates irrespective of the assay or cellular background. Biased modulation was evident for VU0366248 in mouse cortical neurons where it was a NAM for DHPG-mediated iCa2+ mobilization, but neutral with DHPG in IP1 accumulation assays. Overall, this study highlights the inherent complexity in mGlu5 NAM pharmacology that we hypothesize may influence interpretation when translating into preclinical models and beyond in the design and development of novel therapeutics for neuropsychiatric and neurological disorders.
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Affiliation(s)
- Kathy Sengmany
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - Shane D Hellyer
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - Sabine Albold
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - Taide Wang
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - P Jeffrey Conn
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Lauren T May
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - Katie Leach
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - Karen J Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia.
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Frangaj A, Fan QR. Structural biology of GABA B receptor. Neuropharmacology 2018; 136:68-79. [PMID: 29031577 PMCID: PMC5897222 DOI: 10.1016/j.neuropharm.2017.10.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 10/09/2017] [Accepted: 10/11/2017] [Indexed: 11/17/2022]
Abstract
Metabotropic GABAB receptor is a G protein-coupled receptor (GPCR) that mediates slow and prolonged inhibitory neurotransmission in the brain. It functions as a constitutive heterodimer composed of the GABAB1 and GABAB2 subunits. Each subunit contains three domains; the extracellular Venus flytrap module, seven-helix transmembrane region and cytoplasmic tail. In recent years, the three-dimensional structures of GABAB receptor extracellular and intracellular domains have been elucidated. These structures reveal the molecular basis of ligand recognition, receptor heterodimerization and receptor activation. Here we provide a brief review of the GABAB receptor structures, with an emphasis on describing the different ligand-bound states of the receptor. We will also compare these with the known structures of related GPCRs to shed light on the molecular mechanisms of activation and regulation in the GABAB system, as well as GPCR dimers in general. This article is part of the "Special Issue Dedicated to Norman G. Bowery".
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Affiliation(s)
- Aurel Frangaj
- Department of Pharmacology, Columbia University, New York, NY 10032, USA
| | - Qing R Fan
- Department of Pharmacology, Columbia University, New York, NY 10032, USA; Department of Pathology & Cell Biology, Columbia University, New York, NY 10032, USA.
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Borroto-Escuela DO, Tarakanov AO, Brito I, Fuxe K. Glutamate heteroreceptor complexes in the brain. Pharmacol Rep 2018; 70:936-950. [PMID: 32002960 DOI: 10.1016/j.pharep.2018.04.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 03/26/2018] [Accepted: 04/09/2018] [Indexed: 10/17/2022]
Abstract
The existence of mGluR, NMDAR, AMPAR and putative KAR heteroreceptor complexes in synaptic and extrasynaptic regions of brain glutamate synapses represents a major integrative mechanism. Our aim in the current article is to analyze if the formation of the different types glutamate hetereceptor complexes involves the contribution of triplet amino acid homologies (protriplets) in a postulated receptor interface based on the triplet puzzle theory. Seven main sets (lists) of receptor pairs in databases were used containing various sets (lists) of human receptor heteromers and nonheteromers obtained from the available scientific publications including the publically available GPCR-hetnet database. Brain mGluR1-mGluR5 and mGluR2-mGluR4 isoreceptor complexes were demonstrated with a predominant extrasynaptic localization at a post- and prejunctional localization. The existence of putative mGluR4-mGluR7 heteroreceptor complexes in the basal ganglia is proposed. Metabotropic glutamate receptor subtypes also participated in the formation of a large number of heteroreceptor complexes like mGluR1-A1R, mGluR5-A2AR, mGluR5-D2R and D2R-A2AR-mGluR5, located in relation to glutamate synapses, especially in the basal ganglia. A putative mGluR1-GABAB1/2 heterocomplex may also exist. NMDAR heteroreceptor complexes were also demonstrated as a fundamental integrative mechanism in the glutamate synapse and its extrasynaptic membranes. It represented fundamental work on inter alia NMDAR-mGluR5, NMDAR-D1R and NMDAR-D2R heteroreceptor complexes involving both antagonistic and facilitatory allosteric receptor-receptor interactions. As to AMPA receptors, a heterocomplex was found for the interaction between IFNgR1 and the AMPAR mediated via the subunit GluA1 which may be of relevance for neuroinflammation. AMPAR-D2R heteroreceptor complexes were also demonstrated. Besides glutamate heteroreceptor complexes and their allosteric receptor-receptor interactions, a significant mechanism for the functional crosstalk can also be phosphorylation and/or reorganization of adapter proteins with dynamic binding to the two receptors modulating the allosteric receptor mechanism.
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Affiliation(s)
- Dasiel O Borroto-Escuela
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Department of Biomolecular Science, Section of Physiology, University of Urbino, Campus Scientifico Enrico Mattei, Urbino, Italy.,Grupo Bohío-Estudio, Observatorio Cubano de Neurociencias, Yaguajay, Cuba
| | - Alexander O Tarakanov
- St. Petersburg Institute for Informatics and Automation, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Ismel Brito
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Grupo Bohío-Estudio, Observatorio Cubano de Neurociencias, Yaguajay, Cuba
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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TERUNUMA M. Diversity of structure and function of GABA B receptors: a complexity of GABA B-mediated signaling. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2018; 94:390-411. [PMID: 30541966 PMCID: PMC6374141 DOI: 10.2183/pjab.94.026] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 10/09/2018] [Indexed: 05/24/2023]
Abstract
γ-aminobutyric acid type B (GABAB) receptors are broadly expressed in the nervous system and play an important role in neuronal excitability. GABAB receptors are G protein-coupled receptors that mediate slow and prolonged inhibitory action, via activation of Gαi/o-type proteins. GABAB receptors mediate their inhibitory action through activating inwardly rectifying K+ channels, inactivating voltage-gated Ca2+ channels, and inhibiting adenylate cyclase. Functional GABAB receptors are obligate heterodimers formed by the co-assembly of R1 and R2 subunits. It is well established that GABAB receptors interact not only with G proteins and effectors but also with various proteins. This review summarizes the structure, subunit isoforms, and function of GABAB receptors, and discusses the complexity of GABAB receptors, including how receptors are localized in specific subcellular compartments, the mechanism regulating cell surface expression and mobility of the receptors, and the diversity of receptor signaling through receptor crosstalk and interacting proteins.
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Affiliation(s)
- Miho TERUNUMA
- Division of Oral Biochemistry, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
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22
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Abstract
OBJECTIVE In this study, we looked for a new family of latency reversing agents. DESIGN We searched for G-protein-coupled receptors (GPCR) coexpressed with the C-C chemokine receptor type 5 (CCR5) in primary CD4 T cells that activate infected cells and boost HIV production. METHODS GPCR coexpression was unveiled by reverse transcriptase-PCR. We used fluorescence resonance energy transfer to analyze the dimerization with CCR5 of the expressed GPCR. Viral entry was measured by flow cytometry, reverse transcription by quantitative PCR, nuclear factor-kappa B translocation by immunofluorescence, long terminal repeat activation using a gene reporter assay and viral production by p24 quantification. RESULTS Gαi-coupled sphingosine-1-phophate receptor 1 (S1P1) is highly coexpressed with CCR5 on primary CD4 T cells and dimerizes with it. The presence of S1P1 had major effects neither on viral entry nor on reverse transcription. Yet, S1P1 signaling induced NFκB activation, boosting the expression of the HIV LTR. Consequently, in culture medium containing sphingosine-1-phophate, the presence of S1P1 enhanced the replication of a CCR5-, but also of a CXCR4-using HIV-1 strain. The S1P1 ligand FTY720, a drug used in multiple sclerosis treatment, inhibited HIV-1 productive infection of monocyte-derived dendritic cells and of severe combined immunodeficiency mice engrafted with human peripheral blood mononuclear cells. Conversely, S1P1 agonists were able to force latently infected peripheral blood mononuclear cells and lymph node cells to produce virions in vitro. CONCLUSION Altogether these data indicate that the presence of S1P1 facilitates HIV-1 replicative cycle by boosting viral genome transcription, S1P1 antagonists have anti-HIV effects and S1P1 agonists are HIV latency reversing agents.
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Kannampalli P, Poli SM, Boléa C, Sengupta JN. Analgesic effect of ADX71441, a positive allosteric modulator (PAM) of GABA B receptor in a rat model of bladder pain. Neuropharmacology 2017; 126:1-11. [PMID: 28823612 DOI: 10.1016/j.neuropharm.2017.08.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 07/26/2017] [Accepted: 08/16/2017] [Indexed: 01/12/2023]
Abstract
Therapeutic use of GABAB receptor agonists for conditions like chronic abdominal pain, overactive bladder (OAB) and gastroesophageal reflux disease (GERD) is severely affected by poor blood-brain barrier permeability and potential side effects. ADX71441 is a novel positive allosteric modulator (PAM) of the GABAB receptor that has shown encouraging results in pre-clinical models of anxiety, pain, OAB and alcohol addiction. The present study investigates the analgesic effect of ADX71441 to noxious stimulation of the urinary bladder and colon in rats. In female Sprague-Dawley rats, systemic (i.p), but not intrathecal (i.t), administration of ADX71441 produced a dose-dependent decrease in viscero-motor response (VMR) to graded urinary bladder distension (UBD) and colorectal distension (CRD). Additionally, intra-cerebroventricular (i.c.v.) administration of ADX71441 significantly decreased the VMRs to noxious UBD. In electrophysiology experiments, the drug did not attenuate the responses of UBD-sensitive pelvic nerve afferent (PNA) fibers to UBD. In contrast, ADX71441 significantly decreased the responses of UBD-responsive lumbosacral (LS) spinal neurons in spinal intact rats. However, ADX71441 did not attenuate these LS neurons in cervical (C1-C2) spinal transected rats. During cystometrogram (CMG) recordings, ADX71441 (i.p.) significantly decreased the VMR to slow infusion without affecting the number of voiding contraction. These results indicate that ADX71441 modulate bladder nociception via its effect at the supra-spinal sites without affecting the normal bladder motility and micturition reflex in naïve adult rats.
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Affiliation(s)
- Pradeep Kannampalli
- Division of Gastroenterology and Hepatology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Sonia-Maria Poli
- Addex Therapeutics, 14 Chemin des Aulx, CH-1228 Plan-les-Ouates, Geneva, Switzerland
| | - Christelle Boléa
- Addex Therapeutics, 14 Chemin des Aulx, CH-1228 Plan-les-Ouates, Geneva, Switzerland
| | - Jyoti N Sengupta
- Division of Gastroenterology and Hepatology, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Pediatric Gastroenterology, Medical College of Wisconsin, Milwaukee, WI, USA.
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The GABA B Positive Allosteric Modulator ADX71441 Attenuates Alcohol Self-Administration and Relapse to Alcohol Seeking in Rats. Neuropsychopharmacology 2017; 42:1789-1799. [PMID: 28294133 PMCID: PMC5520784 DOI: 10.1038/npp.2017.53] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 03/06/2017] [Accepted: 03/07/2017] [Indexed: 12/18/2022]
Abstract
GABAergic signaling is involved in modulating the reinforcing properties of alcohol, and GABAB receptors have been proposed as a potential target for clinical treatment of alcoholism. The orthosteric GABAB receptor agonist baclofen has been shown to suppress operant self-administration of alcohol in animals and alcohol use in alcohol-dependent patients, but its utility is limited by a narrow therapeutic index. We tested the effects of ADX71441, a novel GABAB receptor positive allosteric modulator, on alcohol-related behaviors in rats. We first assessed the effects of ADX71441 (1, 3, 10 and 30 mg/kg, I.P.) on both non-dependent and dependent male Wistar rats trained to self-administer 20% alcohol. We then determined the effects of ADX71441 on stress-induced as well as cue-induced relapse-like behavior. Finally, we sought to identify the brain regions through which ADX71441 may act to prevent relapse-like behavior by mapping the neuronal activation induced by stress-induced reinstatement of alcohol-seeking using c-Fos immunohistochemistry. ADX71441 dose-dependently decreased alcohol self-administration of both dependent and non-dependent animals, but its potency was higher in alcohol-dependent rats. Furthermore, both cue- and stress-induced alcohol seeking were blocked by the GABAB receptor positive allosteric modulator. Finally, pretreatment with 3 mg/kg of ADX71441 before stress-induced reinstatement significantly decreased c-Fos expression in a network of brain regions implicated in stress-induced relapse, comprising the nucleus accumbens shell, the dorsal raphe nucleus and the medial prefrontal cortex. Our findings support a causal role of GABAB receptors in alcohol reinforcement and relapse to alcohol seeking. These effects are observed in the absence of significant sedative side effects. Jointly, these observations indicate that GABAB receptor positive allosteric modulators merit being tested clinically for the treatment of alcoholism. Our data also point to a potential biomarker of target engagement for early clinical studies.
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Sadeghi M, McArthur JR, Finol-Urdaneta RK, Adams DJ. Analgesic conopeptides targeting G protein-coupled receptors reduce excitability of sensory neurons. Neuropharmacology 2017; 127:116-123. [PMID: 28533165 DOI: 10.1016/j.neuropharm.2017.05.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/16/2017] [Accepted: 05/18/2017] [Indexed: 01/28/2023]
Abstract
Conotoxins (conopeptides) are a diverse group of peptides isolated from the venom of marine cone snails. Conus peptides modulate pain by interacting with voltage-gated ion channels and G protein-coupled receptors (GPCRs). Opiate drugs targeting GPCRs have long been used, nonetheless, many undesirable side effects associated with opiates have been observed including addiction. Consequently, alternative avenues to pain management are a largely unmet need. It has been shown that various voltage-gated calcium channels (VGCCs) respond to GPCR modulation. Thus, regulation of VGCCs by GPCRs has become a valuable alternative in the management of pain. In this review, we focus on analgesic conotoxins that exert their effects via GPCR-mediated inhibition of ion channels involved in nociception and pain transmission. Specifically, α-conotoxin Vc1.1 activation of GABAB receptors and inhibition of voltage-gated calcium channels as a novel mechanism for reducing the excitability of dorsal root ganglion neurons is described. Vc1.1 and other α-conotoxins have been shown to be analgesic in different animal models of chronic pain. This review will outline the functional effects of conopeptide modulation of GPCRs and how their signalling is translated to downstream components of the pain pathways. Where available we present the proposed signalling mechanisms that couples metabotropic receptor activation to their downstream effectors to produce analgesia. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- Mahsa Sadeghi
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales, 2522, Australia
| | - Jeffrey R McArthur
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales, 2522, Australia
| | - Rocio K Finol-Urdaneta
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales, 2522, Australia
| | - David J Adams
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales, 2522, Australia.
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Influence of leptin and GABA B-receptor agonist and antagonist on neurons of the hypothalamic infundibular nucleus in the chicken. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:291-299. [PMID: 28361168 DOI: 10.1007/s00359-017-1168-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 02/27/2017] [Accepted: 03/19/2017] [Indexed: 12/24/2022]
Abstract
In birds and mammals, the neuroendocrine regulation of energy balance is conserved in many aspects. Despite significant similarities between the two groups, differences in the regulatory mechanisms were detected. The present study was performed to carry out investigations of the influence of human leptin and GABAB-receptor agonist and antagonist on the firing rate of neurons of the Nucleus infundibuli hypothalami in brain slices from juvenile chickens. For the first time, we demonstrated a clear, dose-related change in the firing rate of hypothalamic neurons in juvenile chickens after the acute application of recombinant human leptin (1, 10, and 100 nM). All investigated neurons increased their subsequent firing rate. Application of GABAB-receptor agonist baclofen (1 µM) blocked, while antagonist CGP 35348 (10 µM) increased the spontaneous neuronal activity. Simultaneous application of baclofen and leptin reduced the effect observed from single leptin application. This was not found after simultaneously application of leptin and CGP. Altogether, our results indicate that in bird brain slices, and exemplarily in those of the chicken, hypothalamic neurons show mammalian-like responsiveness after acute leptin and GABA application. GABAB-mechanisms involved in GABA release play a likely important role in the leptin-mediated effects on NI neurons via functional leptin receptors.
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Lecat-Guillet N, Monnier C, Rovira X, Kniazeff J, Lamarque L, Zwier JM, Trinquet E, Pin JP, Rondard P. FRET-Based Sensors Unravel Activation and Allosteric Modulation of the GABA B Receptor. Cell Chem Biol 2017; 24:360-370. [PMID: 28286129 DOI: 10.1016/j.chembiol.2017.02.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 11/21/2016] [Accepted: 02/10/2017] [Indexed: 01/11/2023]
Abstract
The main inhibitory neurotransmitter, γ-aminobutyric acid (GABA), modulates many synapses by activating the G protein-coupled receptor GABAB, which is a target for various therapeutic applications. It is an obligatory heterodimer made of GB1 and GB2 that can be regulated by positive allosteric modulators (PAMs). The molecular mechanism of activation of the GABAB receptor remains poorly understood. Here, we have developed FRET-based conformational GABAB sensors compatible with high-throughput screening. We identified conformational changes occurring within the extracellular and transmembrane domains upon receptor activation, which are smaller than those observed in the related metabotropic glutamate receptors. These sensors also allow discrimination between agonists of different efficacies and between PAMs that have different modes of action, which has not always been possible using conventional functional assays. Our study brings important new information on the activation mechanism of the GABAB receptor and should facilitate the screening and identification of new chemicals targeting this receptor.
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Affiliation(s)
- Nathalie Lecat-Guillet
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France
| | - Carine Monnier
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France
| | - Xavier Rovira
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France
| | - Julie Kniazeff
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France
| | | | | | | | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France.
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Lindsley CW, Emmitte KA, Hopkins CR, Bridges TM, Gregory KJ, Niswender CM, Conn PJ. Practical Strategies and Concepts in GPCR Allosteric Modulator Discovery: Recent Advances with Metabotropic Glutamate Receptors. Chem Rev 2016; 116:6707-41. [PMID: 26882314 PMCID: PMC4988345 DOI: 10.1021/acs.chemrev.5b00656] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Allosteric modulation of GPCRs has initiated a new era of basic and translational discovery, filled with therapeutic promise yet fraught with caveats. Allosteric ligands stabilize unique conformations of the GPCR that afford fundamentally new receptors, capable of novel pharmacology, unprecedented subtype selectivity, and unique signal bias. This review provides a comprehensive overview of the basics of GPCR allosteric pharmacology, medicinal chemistry, drug metabolism, and validated approaches to address each of the major challenges and caveats. Then, the review narrows focus to highlight recent advances in the discovery of allosteric ligands for metabotropic glutamate receptor subtypes 1-5 and 7 (mGlu1-5,7) highlighting key concepts ("molecular switches", signal bias, heterodimers) and practical solutions to enable the development of tool compounds and clinical candidates. The review closes with a section on late-breaking new advances with allosteric ligands for other GPCRs and emerging data for endogenous allosteric modulators.
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Affiliation(s)
- Craig W. Lindsley
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- Department of Chemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Kyle A. Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, Texas 76107, United States
| | - Corey R. Hopkins
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Thomas M. Bridges
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Karen J. Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville VIC 3052, Australia
| | - Colleen M. Niswender
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- Vanderbilt Kennedy Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - P. Jeffrey Conn
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
- Vanderbilt Kennedy Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
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29
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Zhang L, Wither RG, Lang M, Wu C, Sidorova-Darmos E, Netchev H, Matolcsy CB, Snead OC, Eubanks JH. A Role for Diminished GABA Transporter Activity in the Cortical Discharge Phenotype of MeCP2-Deficient Mice. Neuropsychopharmacology 2016; 41:1467-76. [PMID: 26499511 PMCID: PMC4832024 DOI: 10.1038/npp.2015.323] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 09/13/2015] [Accepted: 10/01/2015] [Indexed: 12/14/2022]
Abstract
Cortical network hyper-excitability is a common phenotype in mouse models lacking the transcriptional regulator methyl-CPG-binding protein 2 (MeCP2). Here, we implicate enhanced GABAB receptor activity stemming from diminished cortical expression of the GABA transporter GAT-1 in the genesis of this network hyper-excitability. We found that administering the activity-dependent GABAB receptor allosteric modulator GS-39783 to female Mecp2(+/-) mice at doses producing no effect in wild-type mice strongly potentiated their basal rates of spontaneous cortical discharge activity. Consistently, administering the GABAB receptor antagonist CGP-35348 significantly decreased basal discharge activity in these mice. Expression analysis revealed that while GABAB or extra-synaptic GABAA receptor prevalence is preserved in the MeCP2-deficient cortex, the expression of GAT-1 is significantly reduced from wild-type levels. This decrease in GAT-1 expression is consequential, as low doses of the GAT-1 inhibitor NO-711 that had no effects in wild-type mice strongly exacerbated cortical discharge activity in female Mecp2(+/-) mice. Taken together, these data indicate that the absence of MeCP2 leads to decreased cortical levels of the GAT-1 GABA transporter, which facilitates cortical network hyper-excitability in MeCP2-deficient mice by increasing the activity of cortical GABAB receptors.
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Affiliation(s)
- Liang Zhang
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,University of Toronto Epilepsy Research Program, University of Toronto, Toronto, ON, Canada,Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
| | - Robert G Wither
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Min Lang
- University of Toronto Epilepsy Research Program, University of Toronto, Toronto, ON, Canada,Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Chiping Wu
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada
| | - Elena Sidorova-Darmos
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Hristo Netchev
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada
| | - Catherine B Matolcsy
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada
| | - Orlando Carter Snead
- University of Toronto Epilepsy Research Program, University of Toronto, Toronto, ON, Canada,Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
| | - James H Eubanks
- University of Toronto Epilepsy Research Program, University of Toronto, Toronto, ON, Canada,Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada,Department of Surgery (Neurosurgery), University of Toronto, Toronto, ON, Canada,Toronto Western Hospital, 8KD-417, 60 Leonard Avenue, Toronto, ON M5T 2S8, Canada, Tel: +1 416 603 5800, ext. 2933, Fax: +1 416 603 5745, E-mail:
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30
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Li X, D'Souza MS, Niño AM, Doherty J, Cross A, Markou A. Attenuation of nicotine-taking and nicotine-seeking behavior by the mGlu2 receptor positive allosteric modulators AZD8418 and AZD8529 in rats. Psychopharmacology (Berl) 2016; 233:1801-14. [PMID: 26873083 DOI: 10.1007/s00213-016-4220-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 01/18/2016] [Indexed: 12/29/2022]
Abstract
RATIONALE Numerous medication development strategies seek to decrease nicotine consumption and prevent relapse to tobacco smoking by blocking glutamate transmission. Decreasing glutamate release by activating presynaptic inhibitory metabotropic glutamate (mGlu)2/3 receptors inhibits the reinforcing effects of nicotine and blocks cue-induced reinstatement of nicotine-seeking behavior in rats. However, the relative contribution of mGlu2 receptors in nicotine dependence is still unknown. OBJECTIVES The present study evaluated the role of mGlu2 receptors in nicotine-taking and nicotine-seeking behavior using the novel, relatively selective mGlu2 positive allosteric modulators (PAMs) AZD8418 and AZD8529. RESULTS Acute treatment with AZD8418 (0.37, 1.12, 3.73, 7.46, and 14.92 mg/kg) and AZD8529 (1.75, 5.83, 17.5, and 58.3 mg/kg) deceased nicotine self-administration and had no effect on food-maintained responding. Chronic treatment with AZD8418 attenuated nicotine self-administration, but tolerance to this effect developed quickly. The inhibition of nicotine self-administration by chronic AZD8529 administration persisted throughout the 14 days of treatment. Chronic treatment with either PAMs inhibited food self-administration. AZD8418 (acute) and AZD8529 (acute and subchronic) blocked cue-induced reinstatement of nicotine- and food-seeking behavior. CONCLUSIONS These findings indicate an important role for mGlu2 receptors in the reinforcing properties of self-administered nicotine and the motivational impact of cues that were previously associated with nicotine administration (i.e., cue-induced reinstatement of nicotine-seeking behavior). Thus, mGlu2 PAMs may be useful medications to assist people to quit tobacco smoking and prevent relapse.
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Affiliation(s)
- Xia Li
- Department of Psychiatry, M/C 0603, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0603, USA
| | - Manoranjan S D'Souza
- Department of Psychiatry, M/C 0603, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0603, USA
| | - Ana M Niño
- Department of Psychiatry, M/C 0603, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0603, USA
| | - James Doherty
- Present address: Sage Therapeutics, Cambridge, MA, 02142, USA
| | - Alan Cross
- AstraZeneca Neuroscience Innovative Medicines, Cambridge, MA, 02139, USA
| | - Athina Markou
- Department of Psychiatry, M/C 0603, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0603, USA.
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31
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Korpi ER, den Hollander B, Farooq U, Vashchinkina E, Rajkumar R, Nutt DJ, Hyytiä P, Dawe GS. Mechanisms of Action and Persistent Neuroplasticity by Drugs of Abuse. Pharmacol Rev 2015; 67:872-1004. [DOI: 10.1124/pr.115.010967] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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Pozdnyakova N, Dudarenko M, Borisova T. New effects of GABAB receptor allosteric modulator rac-BHFF on ambient GABA, uptake/release, Em and synaptic vesicle acidification in nerve terminals. Neuroscience 2015. [DOI: 10.1016/j.neuroscience.2015.07.037] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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GABAB receptor upregulates fragile X mental retardation protein expression in neurons. Sci Rep 2015; 5:10468. [PMID: 26020477 PMCID: PMC4447080 DOI: 10.1038/srep10468] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 04/15/2015] [Indexed: 12/17/2022] Open
Abstract
Fragile X mental retardation protein (FMRP) is an RNA-binding protein important for the control of translation and synaptic function. The mutation or silencing of FMRP causes Fragile X syndrome (FXS), which leads to intellectual disability and social impairment. γ-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter of the mammalian central nervous system, and its metabotropic GABAB receptor has been implicated in various mental disorders. The GABAB receptor agonist baclofen has been shown to improve FXS symptoms in a mouse model and in human patients, but the signaling events linking the GABAB receptor and FMRP are unknown. In this study, we found that GABAB receptor activation upregulated cAMP response element binding protein-dependent Fmrp expression in cultured mouse cerebellar granule neurons via two distinct mechanisms: the transactivation of insulin-like growth factor-1 receptor and activation of protein kinase C. In addition, a positive allosteric modulator of the GABAB receptor, CGP7930, stimulated Fmrp expression in neurons. These results suggest a role for GABAB receptor in Fmrp regulation and a potential interest of GABAB receptor signaling in FXS improvement.
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Brown KM, Roy KK, Hockerman GH, Doerksen RJ, Colby DA. Activation of the γ-Aminobutyric Acid Type B (GABA(B)) Receptor by Agonists and Positive Allosteric Modulators. J Med Chem 2015; 58:6336-47. [PMID: 25856547 DOI: 10.1021/jm5018913] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Since the discovery of the GABA(B) agonist and muscle relaxant baclofen, there have been substantial advancements in the development of compounds that activate the GABA(B) receptor as agonists or positive allosteric modulators. For the agonists, most of the existing structure-activity data apply to understanding the role of substituents on the backbone of GABA as well as replacing the carboxylic acid and amine groups. In the cases of the positive allosteric modulators, the allosteric binding site(s) and structure-activity relationships are less well-defined; however, multiple classes of molecules have been discovered. The recent report of the X-ray structure of the GABA(B) receptor with bound agonists and antagonists provides new insights for the development of compounds that bind the orthosteric site of this receptor. From a therapeutic perspective, these data have enabled efforts in drug discovery in areas of addiction-related behavior, the treatment of anxiety, and the control of muscle contractility.
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Affiliation(s)
- Katie M Brown
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University , West Lafayette, Indiana 47907, United States
| | - Kuldeep K Roy
- Department of Biomolecular Sciences, University of Mississippi , University, Mississippi 38677, United States
| | - Gregory H Hockerman
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University , West Lafayette, Indiana 47907, United States
| | - Robert J Doerksen
- Department of Biomolecular Sciences, University of Mississippi , University, Mississippi 38677, United States
| | - David A Colby
- Department of Biomolecular Sciences, University of Mississippi , University, Mississippi 38677, United States
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Filip M, Frankowska M, Sadakierska-Chudy A, Suder A, Szumiec Ł, Mierzejewski P, Bienkowski P, Przegaliński E, Cryan JF. GABAB receptors as a therapeutic strategy in substance use disorders: Focus on positive allosteric modulators. Neuropharmacology 2015; 88:36-47. [DOI: 10.1016/j.neuropharm.2014.06.016] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 06/10/2014] [Accepted: 06/15/2014] [Indexed: 12/16/2022]
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36
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Opportunities and challenges in the discovery of allosteric modulators of GPCRs for treating CNS disorders. Nat Rev Drug Discov 2014; 13:692-708. [PMID: 25176435 DOI: 10.1038/nrd4308] [Citation(s) in RCA: 203] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Novel allosteric modulators of G protein-coupled receptors (GPCRs) are providing fundamental advances in the development of GPCR ligands with high subtype selectivity and novel modes of efficacy that have not been possible with traditional approaches. As new allosteric modulators are advancing as drug candidates, we are developing an increased understanding of the major advantages and broad range of activities that can be achieved with these agents through selective modulation of specific signalling pathways, differential effects on GPCR homodimers versus heterodimers, and other properties. This understanding creates exciting opportunities, as well as unique challenges, in the optimization of novel therapeutic agents for disorders of the central nervous system.
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37
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Christopoulos A, Changeux JP, Catterall WA, Fabbro D, Burris TP, Cidlowski JA, Olsen RW, Peters JA, Neubig RR, Pin JP, Sexton PM, Kenakin TP, Ehlert FJ, Spedding M, Langmead CJ. International Union of Basic and Clinical Pharmacology. XC. multisite pharmacology: recommendations for the nomenclature of receptor allosterism and allosteric ligands. Pharmacol Rev 2014; 66:918-47. [PMID: 25026896 PMCID: PMC11060431 DOI: 10.1124/pr.114.008862] [Citation(s) in RCA: 151] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Allosteric interactions play vital roles in metabolic processes and signal transduction and, more recently, have become the focus of numerous pharmacological studies because of the potential for discovering more target-selective chemical probes and therapeutic agents. In addition to classic early studies on enzymes, there are now examples of small molecule allosteric modulators for all superfamilies of receptors encoded by the genome, including ligand- and voltage-gated ion channels, G protein-coupled receptors, nuclear hormone receptors, and receptor tyrosine kinases. As a consequence, a vast array of pharmacologic behaviors has been ascribed to allosteric ligands that can vary in a target-, ligand-, and cell-/tissue-dependent manner. The current article presents an overview of allostery as applied to receptor families and approaches for detecting and validating allosteric interactions and gives recommendations for the nomenclature of allosteric ligands and their properties.
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Affiliation(s)
- Arthur Christopoulos
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (A.C., P.M.S., C.J.L.); Collège de France and CNRS URA 2182, Institut Pasteur, Paris, France (J.-P.C.); Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington (W.A.C.); PIQUR Therapeutics AG, Basel, Switzerland (D.F.); Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, Louisiana (T.P.B.); Signal Transduction Laboratory, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (J.A.C.); Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California (R.W.O.); Division of Neuroscience, School of Medicine, University of Dundee, Scotland, United Kingdom (J.A.P.); Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (R.R.N.); Institut de Genomique Fonctionelle, CNRS, Montpellier, France (J.-P.P.); Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina (T.P.K.); Department of Pharmacology, University of California, Irvine, California (F.J.E.); and Research Solutions SARL, Paris, France (M.S.)
| | - Jean-Pierre Changeux
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (A.C., P.M.S., C.J.L.); Collège de France and CNRS URA 2182, Institut Pasteur, Paris, France (J.-P.C.); Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington (W.A.C.); PIQUR Therapeutics AG, Basel, Switzerland (D.F.); Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, Louisiana (T.P.B.); Signal Transduction Laboratory, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (J.A.C.); Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California (R.W.O.); Division of Neuroscience, School of Medicine, University of Dundee, Scotland, United Kingdom (J.A.P.); Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (R.R.N.); Institut de Genomique Fonctionelle, CNRS, Montpellier, France (J.-P.P.); Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina (T.P.K.); Department of Pharmacology, University of California, Irvine, California (F.J.E.); and Research Solutions SARL, Paris, France (M.S.)
| | - William A Catterall
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (A.C., P.M.S., C.J.L.); Collège de France and CNRS URA 2182, Institut Pasteur, Paris, France (J.-P.C.); Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington (W.A.C.); PIQUR Therapeutics AG, Basel, Switzerland (D.F.); Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, Louisiana (T.P.B.); Signal Transduction Laboratory, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (J.A.C.); Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California (R.W.O.); Division of Neuroscience, School of Medicine, University of Dundee, Scotland, United Kingdom (J.A.P.); Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (R.R.N.); Institut de Genomique Fonctionelle, CNRS, Montpellier, France (J.-P.P.); Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina (T.P.K.); Department of Pharmacology, University of California, Irvine, California (F.J.E.); and Research Solutions SARL, Paris, France (M.S.)
| | - Doriano Fabbro
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (A.C., P.M.S., C.J.L.); Collège de France and CNRS URA 2182, Institut Pasteur, Paris, France (J.-P.C.); Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington (W.A.C.); PIQUR Therapeutics AG, Basel, Switzerland (D.F.); Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, Louisiana (T.P.B.); Signal Transduction Laboratory, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (J.A.C.); Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California (R.W.O.); Division of Neuroscience, School of Medicine, University of Dundee, Scotland, United Kingdom (J.A.P.); Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (R.R.N.); Institut de Genomique Fonctionelle, CNRS, Montpellier, France (J.-P.P.); Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina (T.P.K.); Department of Pharmacology, University of California, Irvine, California (F.J.E.); and Research Solutions SARL, Paris, France (M.S.)
| | - Thomas P Burris
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (A.C., P.M.S., C.J.L.); Collège de France and CNRS URA 2182, Institut Pasteur, Paris, France (J.-P.C.); Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington (W.A.C.); PIQUR Therapeutics AG, Basel, Switzerland (D.F.); Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, Louisiana (T.P.B.); Signal Transduction Laboratory, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (J.A.C.); Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California (R.W.O.); Division of Neuroscience, School of Medicine, University of Dundee, Scotland, United Kingdom (J.A.P.); Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (R.R.N.); Institut de Genomique Fonctionelle, CNRS, Montpellier, France (J.-P.P.); Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina (T.P.K.); Department of Pharmacology, University of California, Irvine, California (F.J.E.); and Research Solutions SARL, Paris, France (M.S.)
| | - John A Cidlowski
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (A.C., P.M.S., C.J.L.); Collège de France and CNRS URA 2182, Institut Pasteur, Paris, France (J.-P.C.); Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington (W.A.C.); PIQUR Therapeutics AG, Basel, Switzerland (D.F.); Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, Louisiana (T.P.B.); Signal Transduction Laboratory, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (J.A.C.); Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California (R.W.O.); Division of Neuroscience, School of Medicine, University of Dundee, Scotland, United Kingdom (J.A.P.); Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (R.R.N.); Institut de Genomique Fonctionelle, CNRS, Montpellier, France (J.-P.P.); Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina (T.P.K.); Department of Pharmacology, University of California, Irvine, California (F.J.E.); and Research Solutions SARL, Paris, France (M.S.)
| | - Richard W Olsen
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (A.C., P.M.S., C.J.L.); Collège de France and CNRS URA 2182, Institut Pasteur, Paris, France (J.-P.C.); Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington (W.A.C.); PIQUR Therapeutics AG, Basel, Switzerland (D.F.); Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, Louisiana (T.P.B.); Signal Transduction Laboratory, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (J.A.C.); Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California (R.W.O.); Division of Neuroscience, School of Medicine, University of Dundee, Scotland, United Kingdom (J.A.P.); Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (R.R.N.); Institut de Genomique Fonctionelle, CNRS, Montpellier, France (J.-P.P.); Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina (T.P.K.); Department of Pharmacology, University of California, Irvine, California (F.J.E.); and Research Solutions SARL, Paris, France (M.S.)
| | - John A Peters
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (A.C., P.M.S., C.J.L.); Collège de France and CNRS URA 2182, Institut Pasteur, Paris, France (J.-P.C.); Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington (W.A.C.); PIQUR Therapeutics AG, Basel, Switzerland (D.F.); Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, Louisiana (T.P.B.); Signal Transduction Laboratory, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (J.A.C.); Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California (R.W.O.); Division of Neuroscience, School of Medicine, University of Dundee, Scotland, United Kingdom (J.A.P.); Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (R.R.N.); Institut de Genomique Fonctionelle, CNRS, Montpellier, France (J.-P.P.); Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina (T.P.K.); Department of Pharmacology, University of California, Irvine, California (F.J.E.); and Research Solutions SARL, Paris, France (M.S.)
| | - Richard R Neubig
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (A.C., P.M.S., C.J.L.); Collège de France and CNRS URA 2182, Institut Pasteur, Paris, France (J.-P.C.); Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington (W.A.C.); PIQUR Therapeutics AG, Basel, Switzerland (D.F.); Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, Louisiana (T.P.B.); Signal Transduction Laboratory, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (J.A.C.); Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California (R.W.O.); Division of Neuroscience, School of Medicine, University of Dundee, Scotland, United Kingdom (J.A.P.); Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (R.R.N.); Institut de Genomique Fonctionelle, CNRS, Montpellier, France (J.-P.P.); Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina (T.P.K.); Department of Pharmacology, University of California, Irvine, California (F.J.E.); and Research Solutions SARL, Paris, France (M.S.)
| | - Jean-Philippe Pin
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (A.C., P.M.S., C.J.L.); Collège de France and CNRS URA 2182, Institut Pasteur, Paris, France (J.-P.C.); Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington (W.A.C.); PIQUR Therapeutics AG, Basel, Switzerland (D.F.); Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, Louisiana (T.P.B.); Signal Transduction Laboratory, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (J.A.C.); Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California (R.W.O.); Division of Neuroscience, School of Medicine, University of Dundee, Scotland, United Kingdom (J.A.P.); Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (R.R.N.); Institut de Genomique Fonctionelle, CNRS, Montpellier, France (J.-P.P.); Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina (T.P.K.); Department of Pharmacology, University of California, Irvine, California (F.J.E.); and Research Solutions SARL, Paris, France (M.S.)
| | - Patrick M Sexton
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (A.C., P.M.S., C.J.L.); Collège de France and CNRS URA 2182, Institut Pasteur, Paris, France (J.-P.C.); Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington (W.A.C.); PIQUR Therapeutics AG, Basel, Switzerland (D.F.); Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, Louisiana (T.P.B.); Signal Transduction Laboratory, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (J.A.C.); Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California (R.W.O.); Division of Neuroscience, School of Medicine, University of Dundee, Scotland, United Kingdom (J.A.P.); Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (R.R.N.); Institut de Genomique Fonctionelle, CNRS, Montpellier, France (J.-P.P.); Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina (T.P.K.); Department of Pharmacology, University of California, Irvine, California (F.J.E.); and Research Solutions SARL, Paris, France (M.S.)
| | - Terry P Kenakin
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (A.C., P.M.S., C.J.L.); Collège de France and CNRS URA 2182, Institut Pasteur, Paris, France (J.-P.C.); Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington (W.A.C.); PIQUR Therapeutics AG, Basel, Switzerland (D.F.); Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, Louisiana (T.P.B.); Signal Transduction Laboratory, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (J.A.C.); Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California (R.W.O.); Division of Neuroscience, School of Medicine, University of Dundee, Scotland, United Kingdom (J.A.P.); Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (R.R.N.); Institut de Genomique Fonctionelle, CNRS, Montpellier, France (J.-P.P.); Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina (T.P.K.); Department of Pharmacology, University of California, Irvine, California (F.J.E.); and Research Solutions SARL, Paris, France (M.S.)
| | - Frederick J Ehlert
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (A.C., P.M.S., C.J.L.); Collège de France and CNRS URA 2182, Institut Pasteur, Paris, France (J.-P.C.); Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington (W.A.C.); PIQUR Therapeutics AG, Basel, Switzerland (D.F.); Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, Louisiana (T.P.B.); Signal Transduction Laboratory, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (J.A.C.); Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California (R.W.O.); Division of Neuroscience, School of Medicine, University of Dundee, Scotland, United Kingdom (J.A.P.); Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (R.R.N.); Institut de Genomique Fonctionelle, CNRS, Montpellier, France (J.-P.P.); Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina (T.P.K.); Department of Pharmacology, University of California, Irvine, California (F.J.E.); and Research Solutions SARL, Paris, France (M.S.)
| | - Michael Spedding
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (A.C., P.M.S., C.J.L.); Collège de France and CNRS URA 2182, Institut Pasteur, Paris, France (J.-P.C.); Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington (W.A.C.); PIQUR Therapeutics AG, Basel, Switzerland (D.F.); Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, Louisiana (T.P.B.); Signal Transduction Laboratory, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (J.A.C.); Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California (R.W.O.); Division of Neuroscience, School of Medicine, University of Dundee, Scotland, United Kingdom (J.A.P.); Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (R.R.N.); Institut de Genomique Fonctionelle, CNRS, Montpellier, France (J.-P.P.); Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina (T.P.K.); Department of Pharmacology, University of California, Irvine, California (F.J.E.); and Research Solutions SARL, Paris, France (M.S.)
| | - Christopher J Langmead
- Drug Discovery Biology and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia (A.C., P.M.S., C.J.L.); Collège de France and CNRS URA 2182, Institut Pasteur, Paris, France (J.-P.C.); Department of Pharmacology, School of Medicine, University of Washington, Seattle, Washington (W.A.C.); PIQUR Therapeutics AG, Basel, Switzerland (D.F.); Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, Louisiana (T.P.B.); Signal Transduction Laboratory, Molecular Endocrinology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (J.A.C.); Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California (R.W.O.); Division of Neuroscience, School of Medicine, University of Dundee, Scotland, United Kingdom (J.A.P.); Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan (R.R.N.); Institut de Genomique Fonctionelle, CNRS, Montpellier, France (J.-P.P.); Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina (T.P.K.); Department of Pharmacology, University of California, Irvine, California (F.J.E.); and Research Solutions SARL, Paris, France (M.S.)
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Abstract
INTRODUCTION There is increasing evidence encouraging the development of drugs that positively modulate the γ-aminobutyric acid type B (GABA(B)) receptor for combating addiction. Compounds that target GABA(B) receptors are unique as anti-abuse therapies because of their impact against multiple addictive drugs. AREAS COVERED The authors present the basic information concerning the drug actions of GABA and GABA(B) receptor orthosteric agonists and positive allosteric modulators (PAM). Furthermore, they discuss several recent excellent reviews and newer results pertaining to GABA(B) receptor drug effects on responses to and self-administration of: alcohol (ethanol), nicotine, cocaine, (meth)amphetamine, and opioids. Preclinical and clinical data are considered. EXPERT OPINION Clinical data exist only for baclofen and mostly for alcohol use disorders. Additional trials are needed, but effects are promising. Whether PAMs, given alone or in combination with a direct GABA(B) receptor agonist, will be clinically effective and have fewer side effects requires investigation. The sedative effects of baclofen, a Food and Drug Administration (FDA)-approved drug, become less severe over time. Based on existing data, baclofen is well-tolerated. However, genetic and physiological differences are likely to contribute to individual responses to different therapeutic agents. The more immediate development of baclofen as a therapeutic for alcohol use disorders may be of significant benefit to some individuals.
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Affiliation(s)
- Tamara J Phillips
- Oregon Health & Science University, Veterans Affairs Medical Center, Department of Behavioral Neuroscience , 3710 SW US Veterans Hospital Rd, Portland, OR 97239 , USA +1 503 220 8262 Ext. 56674 ; +1 503 721 1029 ;
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Lang M, Moradi-Chameh H, Zahid T, Gane J, Wu C, Valiante T, Zhang L. Regulating hippocampal hyperexcitability through GABAB Receptors. Physiol Rep 2014. [PMID: 24771688 PMCID: PMC4001873 DOI: 10.1002/phy2.278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Disturbances of GABAergic inhibition are a major cause of epileptic seizures. GABA exerts its actions via ionotropic GABAA receptors and metabotropic G protein‐coupled GABAB receptors. Malfunction of GABAA inhibition has long been recognized in seizure genesis but the role of GABAB receptors in controlling seizure activity is still not well understood. Here, we examined the anticonvulsive, or inhibitory effects, of GABAB receptors in a mouse model of hippocampal kindling as well as mouse hippocampal slices through the use of GS 39783, a positive allosteric GABAB receptor modulator, and CGP 55845, a selective GABAB receptor antagonist. When administered via intraperitoneal injections in kindled mice, GS 39783 (5 mg/kg) did not attenuate hippocampal EEG discharges, but did reduce aberrant hippocampal spikes, whereas CGP 55845 (10 mg/kg) prolonged hippocampal discharges and increased spike incidences. When examined in hippocampal slices, neither GS 39783 at 5 μmol/L nor the GABAB receptor agonist baclofen at 0.1 μmol/L alone significantly altered repetitive excitatory field potentials, but GS 39783 and baclofen together reversibly abolished these field potentials. In contrast, CGP 55845 at 1 μmol/L facilitated induction and incidence of these field potentials. In addition, CGP 55845 attenuated the paired pulse depression of CA3 population spikes and increased the frequency of EPSCs in individual CA3 pyramidal neurons. Collectively, these data suggest that GABABB receptors regulate hippocampal hyperexcitability by inhibiting CA3 glutamatergic synapses. We postulate that positive allosteric modulation of GABAB receptors may be effective in reducing seizure‐related hyperexcitability. GABAB positive modulator GS 39783 attenuated, whereas GABAB antagonist CGP55845 facilitated hippocampal EEG spikes in kindled mice and excitatory field potentials in hippocampal slices. We postulate that GABAB receptors may inhibit CA3 glutamate synapses and hence regulate hippocampal hyperexcitability.
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Affiliation(s)
- Min Lang
- Toronto Western Research Institute; University Health Network; Toronto Ontario Canada
| | - Homeira Moradi-Chameh
- Toronto Western Research Institute; University Health Network; Toronto Ontario Canada
- Department of Physiology; University of Tarbiat Modares; Tehran Iran
| | - Tariq Zahid
- Toronto Western Research Institute; University Health Network; Toronto Ontario Canada
| | - Jonathan Gane
- Toronto Western Research Institute; University Health Network; Toronto Ontario Canada
| | - Chiping Wu
- Toronto Western Research Institute; University Health Network; Toronto Ontario Canada
| | - Taufik Valiante
- Department of Surgery (Division of Neurosurgery); University of Toronto; Toronto Ontario Canada
| | - Liang Zhang
- Toronto Western Research Institute; University Health Network; Toronto Ontario Canada
- Department of Medicine (Division of Neurology); University of Toronto; Toronto Ontario Canada
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Kalinichev M, Palea S, Haddouk H, Royer-Urios I, Guilloteau V, Lluel P, Schneider M, Saporito M, Poli S. ADX71441, a novel, potent and selective positive allosteric modulator of the GABA(B) receptor, shows efficacy in rodent models of overactive bladder. Br J Pharmacol 2014; 171:995-1006. [PMID: 24224799 PMCID: PMC3925038 DOI: 10.1111/bph.12517] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Revised: 10/07/2013] [Accepted: 11/11/2013] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE The GABAB receptor agonist baclofen reduces urethral resistance and detrusor overactivity in patients with spasticity. However, baclofen's side effects limit its use for the treatment of overactive bladder (OAB). Here, we tested a novel GABAB positive allosteric modulator (PAM) ADX71441 in models of OAB in mice and guinea pigs. EXPERIMENTAL APPROACH Mice were left untreated or given (p.o.) vehicle (1% CMC), ADX71441 (1, 3, 10 mg kg(-1) ) or oxybutynin (100 mg kg(-1) ; Experiment 1) or vehicle (1% CMC), baclofen (1, 3, 6 mg kg(-1) ) or oxybutynin (Experiment 2). Treated mice were then overhydrated with water, challenged with furosemide, before being placed into micturition chambers and monitored for urinary parameters. In anaesthetized guinea pigs, intravesical infusion of acetic acid was used to induce OAB and the effects of ADX71441 (1, 3 mg kg(-1) ) or baclofen (1 mg kg(-1) ), administered i.v., on cystometric parameters were monitored. KEY RESULTS In mice, 10 mg kg(-1) ADX71441 increased urinary latencies, reduced the number of urinary events and the total and average urinary volumes. In guinea pigs, ADX71441 (1 and 3 mg kg(-1) ) increased the intercontraction interval (ICI) and bladder capacity (BC), and reduced micturition frequency (MF) compared to vehicle. At 3 mg kg(-1) ADX71441 completely inhibited the micturition reflex and induced overflow incontinence in five out of 10 animals. Baclofen slightly increased ICI and BC and reduced MF. CONCLUSION AND IMPLICATIONS Our findings demonstrate, for the first time, that a GABAB PAM has potential as a novel approach for the treatment of OAB.
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Affiliation(s)
| | - S Palea
- Faculté des Sciences Pharmaceutiques, UROsphereToulouse, France
| | - H Haddouk
- Addex Therapeutics SAGeneva, Switzerland
| | | | - V Guilloteau
- Faculté des Sciences Pharmaceutiques, UROsphereToulouse, France
| | - P Lluel
- Faculté des Sciences Pharmaceutiques, UROsphereToulouse, France
| | | | | | - S Poli
- Addex Therapeutics SAGeneva, Switzerland
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Effect of GABAB receptor antagonist (CGP35348) on learning and memory in albino mice. ScientificWorldJournal 2014; 2014:983651. [PMID: 24574938 PMCID: PMC3916030 DOI: 10.1155/2014/983651] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 10/27/2013] [Indexed: 01/01/2023] Open
Abstract
The present study was designed to demonstrate the potential effect of CGP 35348 (GABAB receptor antagonist) on the learning, memory formation, and neuromuscular coordination in albino mouse. Mice were intrapertoneally injected with 1 mg CGP 35348/mL of distilled water/Kg body weight, while the control animals were injected with equal volume of saline solution. A battery of neurological tests was applied following the intrapertoneal injections. Results of rota rod indicated that CGP 35348 had no effect on neuromuscular coordination in both male (P = 0.528) and female (P = 0.125) albino mice. CGP 35348 treated females demonstrated poor exploratory behavior during open filed for several parameters (time mobile (P = 0.04), time immobile (P = 0.04), rotations (P = 0.04), and anticlockwise rotations (P = 0.038)). The results for Morris water maze (MWM) retention phase indicated that CGP 35348 treated male mice took shorter latency to reach the hidden platform (P = 0.04) than control indicating improved memory. This observation was complemented by the swim strategies used by mice during training days in MWM as CGP 35348 treated males used more direct and focal approach to reach the platform as the training proceeded.
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Mugnaini C, Pedani V, Giunta D, Sechi B, Solinas M, Casti A, Castelli MP, Giorgi G, Corelli F. Synthesis, structural properties, and pharmacological evaluation of 2-(acylamino)thiophene-3-carboxamides and analogues thereof. RSC Adv 2014. [DOI: 10.1039/c3ra45546g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Mareš P, Tichá K, Mikulecká A. Anticonvulsant and behavioral effects of GABA(B) receptor positive modulator CGP7930 in immature rats. Epilepsy Behav 2013; 28:113-20. [PMID: 23708148 DOI: 10.1016/j.yebeh.2013.04.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 04/09/2013] [Accepted: 04/15/2013] [Indexed: 01/14/2023]
Abstract
Possible anticonvulsant action of GABAB receptor positive allosteric modulator CGP7930 was studied in cortical epileptic afterdischarges (ADs) in rat pups 12, 18, and 25 days old. Afterdischarges were induced by six series of stimulation of sensorimotor cortex, and CGP7930 (20 or 40 mg/kgi.p.) was administered after the first AD. In addition, the effects of CGP7930 on sensorimotor performance and behavior in open field and elevated plus maze were assessed. CGP7930 decreased duration of ADs in 12-day-old but not in older rats. Motor phenomena (movements accompanying stimulation and clonic seizures) were not changed. CGP7930 only moderately affected sensorimotor performance, altered slightly spontaneous behavior in the open field, and did not influence behavior in the elevated plus maze in terms of an adaptive form of learning or anxiety-like behavior. Marked anticonvulsant action with subtle deficits in sensorimotor performance in 12-day-old rats suggests a possible use of CGP7930 as an age-specific anticonvulsant.
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Affiliation(s)
- Pavel Mareš
- Department of Developmental Epileptology, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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Mugnaini C, Pedani V, Casu A, Lobina C, Casti A, Maccioni P, Porcu A, Giunta D, Lamponi S, Solinas M, Dragoni S, Valoti M, Colombo G, Castelli MP, Gessa GL, Corelli F. Synthesis and pharmacological characterization of 2-(acylamino)thiophene derivatives as metabolically stable, orally effective, positive allosteric modulators of the GABAB receptor. J Med Chem 2013; 56:3620-35. [PMID: 23544432 DOI: 10.1021/jm400144w] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Two recently reported hit compounds, COR627 and COR628, underpinned the development of a series of 2-(acylamino)thiophene derivatives. Some of these compounds displayed significant activity in vitro as positive allosteric modulators of the GABAB receptor by potentiating GTPγS stimulation induced by GABA at 2.5 and 25 μM while failing to exhibit intrinsic agonist activity. Compounds were also found to be effective in vivo, potentiating baclofen-induced sedation/hypnosis in DBA mice when administered either intraperitoneally or intragastrically. Although displaying a lower potency in vitro than the reference compound GS39783, the new compounds 6, 10, and 11 exhibited a higher efficacy in vivo: combination of these compounds with a per se nonsedative dose of baclofen resulted in shorter onset and longer duration of the loss of righting reflex in mice. Test compounds showed cytotoxic effects at concentrations comparable to or higher than those of GS39783 or BHF177.
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Affiliation(s)
- Claudia Mugnaini
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Via A. Moro, Siena, Italy
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Kruse LC, Linsenbardt DN, Boehm SL. Positive allosteric modulation of the GABA(B) receptor by GS39783 attenuates the locomotor stimulant actions of ethanol and potentiates the induction of locomotor sensitization. Alcohol 2012; 46:455-62. [PMID: 22560291 DOI: 10.1016/j.alcohol.2012.03.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 03/12/2012] [Accepted: 03/20/2012] [Indexed: 12/20/2022]
Abstract
Acute ethanol-induced locomotor stimulation and ethanol-induced locomotor sensitization are two behavioral assays thought to model the rewarding effects of ethanol. Recent evidence suggests that GS39783, a GABA(B) positive allosteric modulator, may be effective at reducing both the rewarding and reinforcing effects of several drugs of abuse, including ethanol. The goal of this study was to determine if GS39783 was capable of altering acute ethanol-induced stimulation, and the induction and expression of ethanol-induced locomotor sensitization, without effecting basal locomotion levels. Several doses of GS39783 (ranging from 0 to 100 mg/kg, depending on experiment) were tested on adult male DBA/2J mice in four experiments using 3-day basal locomotion and acute ethanol stimulation paradigms, and 14-day induction and expression of ethanol sensitization paradigms. The results of experiment 1 are in agreement with current literature, suggesting that 30 mg/kg doses of GS39783 and lower do not alter basal locomotor activity. In experiment 2, we found that GS39783 significantly decreased acute ethanol stimulation, but only at the 30 mg/kg dose, supporting our hypothesis and other publications suggesting that GABA(B) receptors modulate acute ethanol stimulation. Contrary to our hypothesis, GS39783 did not alter the expression of locomotor sensitization. Additionally, repeated administration of GS39783 in conjunction with ethanol unexpectedly potentiated ethanol-induced locomotor sensitization. Further study of GS39783 is warranted as it may be a more tolerable treatment for alcoholism than full agonists, due to its behavioral efficacy at doses that lack sedative side effects. Our results add to current literature suggesting that the GABA(B) receptor system is indeed involved in the modulation of ethanol-induced locomotor stimulation and sensitization.
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Affiliation(s)
- Lauren C Kruse
- Department of Psychology, Indiana Alcohol Research Center, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
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Mareš P. Anticonvulsant action of GABAB receptor positive modulator CGP7930 in immature rats. Epilepsy Res 2012; 100:49-54. [DOI: 10.1016/j.eplepsyres.2012.01.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 01/07/2012] [Accepted: 01/15/2012] [Indexed: 12/30/2022]
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Hendricson A, Matchett M, Ferrante M, Ferrante C, Hunnicutt E, Westphal R, Kostich W, Huang Y, Masias N, Hong D, Bertekap R, Burford N, Watson J, Alt A, Myslik J, Zhang L, Knox R. Design of an Automated Enhanced-Throughput Platform for Functional Characterization of Positive Allosteric Modulator-Induced Leftward Shifts in Apparent Agonist Potency In Vitro. ACTA ACUST UNITED AC 2012; 17:104-15. [DOI: 10.1177/2211068211435301] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Hensler JG, Advani T, Burke TF, Cheng K, Rice KC, Koek W. GABAB receptor-positive modulators: brain region-dependent effects. J Pharmacol Exp Ther 2011; 340:19-26. [PMID: 21954301 DOI: 10.1124/jpet.111.186577] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
This study examined the positive modulatory properties of 2,6-di-tert-butyl-4-(3-hydroxy-2,2-dimethyl-propyl)-phenol (CGP7930) and (R,S)-5,7-di-tert-butyl-3-hydroxy-3-trifluoromethyl-3H-benzofuran-2-one (rac-BHFF) at γ-aminobutyric acid B (GABA(B)) receptors in different brain regions. Using quantitative autoradiography, we measured GABA(B) receptor-stimulated binding of guanosine 5'-O-(3-[³⁵S]thiotriphosphate) ([³⁵S]GTPγS) to G proteins in medial prefrontal cortex (mPFC), hippocampus, and cerebellum. CGP7930 and rac-BHFF enhanced baclofen-stimulated [³⁵S]GTPγS binding similarly in mPFC and hippocampus, but were more effective in cerebellum. CGP7930 (100 μM) increased [³⁵S]GTPγS binding stimulated by baclofen (30 μM) from 29 to 241% above basal in mPFC and from 13 to 1530% above basal in cerebellum. Likewise, rac-BHFF (10 μM) increased baclofen-stimulated [³⁵S]GTPγS binding more in cerebellum (from 13 to 1778% above basal) than in mPFC (from 29 to 514% above basal). rac-BHFF (10 μM) in combination with γ-hydroxybutyrate (20 mM) increased [³⁵S]GTPγS binding in cerebellum but not in mPFC. rac-BHFF also enhanced the effects of 3-aminopropyl(diethoxymethyl)phosphinic acid (CGP35348). Consistent with its partial agonist properties, CGP35348 stimulated [³⁵S]GTPγS binding in mPFC when given alone (to 18% above basal), but less extensively than baclofen (140% above basal), and antagonized baclofen when given together. CGP35348 (1 mM) in combination with rac-BHFF (100 μM) produced an increase in [³⁵S]GTPγS binding that was larger in cerebellum (from 61 to 1260% above basal) than in mPFC (from 18 to 118% above basal). Taken together, the results show that GABA(B) receptor-positive modulators enhance [³⁵S]GTPγS binding stimulated by GABA(B) receptor agonists in a brain region-dependent manner. This regionally selective enhancement is further evidence of pharmacologically distinct GABA(B) receptor populations, possibly allowing for more selective therapeutic targeting of the GABA(B) system.
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Affiliation(s)
- Julie G Hensler
- Department of Pharmacology, MC 7764, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
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Molecular basis of positive allosteric modulation of GluN2B NMDA receptors by polyamines. EMBO J 2011; 30:3134-46. [PMID: 21685875 DOI: 10.1038/emboj.2011.203] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 05/26/2011] [Indexed: 12/19/2022] Open
Abstract
NMDA receptors (NMDARs) form glutamate-gated ion channels that have central roles in neuronal communication and plasticity throughout the brain. Dysfunctions of NMDARs are involved in several central nervous system disorders, including stroke, chronic pain and schizophrenia. One hallmark of NMDARs is that their activity can be allosterically regulated by a variety of extracellular small ligands. While much has been learned recently regarding allosteric inhibition of NMDARs, the structural determinants underlying positive allosteric modulation of these receptors remain poorly defined. Here, we show that polyamines, naturally occurring polycations that selectively enhance NMDARs containing the GluN2B subunit, bind at a dimer interface between GluN1 and GluN2B subunit N-terminal domains (NTDs). Polyamines act by shielding negative charges present on GluN1 and GluN2B NTD lower lobes, allowing their close apposition, an effect that in turn prevents NTD clamshell closure. Our work reveals the mechanistic basis for positive allosteric modulation of NMDARs. It provides the first example of an intersubunit binding site in this class of receptors, a discovery that holds promise for future drug interventions.
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Smith NJ, Milligan G. Allostery at G protein-coupled receptor homo- and heteromers: uncharted pharmacological landscapes. Pharmacol Rev 2011; 62:701-25. [PMID: 21079041 DOI: 10.1124/pr.110.002667] [Citation(s) in RCA: 211] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
For many years seven transmembrane domain G protein-coupled receptors (GPCRs) were thought to exist and function exclusively as monomeric units. However, evidence both from native cells and heterologous expression systems has demonstrated that GPCRs can both traffic and signal within higher-order complexes. As for other protein-protein interactions, conformational changes in one polypeptide, including those resulting from binding of pharmacological ligands, have the capacity to alter the conformation and therefore the response of the interacting protein(s), a process known as allosterism. For GPCRs, allosterism across homo- or heteromers, whether dimers or higher-order oligomers, represents an additional topographical landscape that must now be considered pharmacologically. Such effects may offer the opportunity for novel therapeutic approaches. Allosterism at GPCR heteromers is particularly exciting in that it offers additional scope to provide receptor subtype selectivity and tissue specificity as well as fine-tuning of receptor signal strength. Herein, we introduce the concept of allosterism at both GPCR homomers and heteromers and discuss the various questions that must be addressed before significant advances can be made in drug discovery at these GPCR complexes.
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Affiliation(s)
- Nicola J Smith
- Molecular Pharmacology Laboratory,University Avenue, University of Glasgow, Glasgow, Scotland
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