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The Case for Clinical Trials with Novel GABAergic Drugs in Diabetes Mellitus and Obesity. Life (Basel) 2022; 12:life12020322. [PMID: 35207609 PMCID: PMC8876029 DOI: 10.3390/life12020322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 02/09/2022] [Accepted: 02/16/2022] [Indexed: 11/17/2022] Open
Abstract
Obesity and diabetes mellitus have become the surprising menaces of relative economic well-being worldwide. Gamma amino butyric acid (GABA) has a prominent role in the control of blood glucose, energy homeostasis as well as food intake at several levels of regulation. The effects of GABA in the body are exerted through ionotropic GABAA and metabotropic GABAB receptors. This treatise will focus on the pharmacologic targeting of GABAA receptors to reap beneficial therapeutic effects in diabetes mellitus and obesity. A new crop of drugs selectively targeting GABAA receptors has been under investigation for efficacy in stroke recovery and cognitive deficits associated with schizophrenia. Although these trials have produced mixed outcomes the compounds are safe to use in humans. Preclinical evidence is summarized here to support the rationale of testing some of these compounds in diabetic patients receiving insulin in order to achieve better control of blood glucose levels and to combat the decline of cognitive performance. Potential therapeutic benefits could be achieved (i) By resetting the hypoglycemic counter-regulatory response; (ii) Through trophic actions on pancreatic islets, (iii) By the mobilization of antioxidant defence mechanisms in the brain. Furthermore, preclinical proof-of-concept work, as well as clinical trials that apply the novel GABAA compounds in eating disorders, e.g., olanzapine-induced weight-gain, also appear warranted.
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Sexton CA, Penzinger R, Mortensen M, Bright DP, Smart TG. Structural determinants and regulation of spontaneous activity in GABA A receptors. Nat Commun 2021; 12:5457. [PMID: 34526505 PMCID: PMC8443696 DOI: 10.1038/s41467-021-25633-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/24/2021] [Indexed: 11/25/2022] Open
Abstract
GABAA receptors are vital for controlling neuronal excitability and can display significant levels of constitutive activity that contributes to tonic inhibition. However, the mechanisms underlying spontaneity are poorly understood. Here we demonstrate a strict requirement for β3 subunit incorporation into receptors for spontaneous gating, facilitated by α4, α6 and δ subunits. The crucial molecular determinant involves four amino acids (GKER) in the β3 subunit's extracellular domain, which interacts with adjacent receptor subunits to promote transition to activated, open channel conformations. Spontaneous activity is further regulated by β3 subunit phosphorylation and by allosteric modulators including neurosteroids and benzodiazepines. Promoting spontaneous activity reduced neuronal excitability, indicating that spontaneous currents will alter neural network activity. This study demonstrates how regional diversity in GABAA receptor isoform, protein kinase activity, and neurosteroid levels, can impact on tonic inhibition through the modulation of spontaneous GABAA receptor gating.
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Affiliation(s)
- Craig A Sexton
- Department of Neuroscience, Physiology & Pharmacology, UCL, London, UK
| | - Reka Penzinger
- Department of Neuroscience, Physiology & Pharmacology, UCL, London, UK
| | - Martin Mortensen
- Department of Neuroscience, Physiology & Pharmacology, UCL, London, UK
| | - Damian P Bright
- Department of Neuroscience, Physiology & Pharmacology, UCL, London, UK
| | - Trevor G Smart
- Department of Neuroscience, Physiology & Pharmacology, UCL, London, UK.
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Lan Z, Zhang W, Xu J, Lu W. GABA A receptor-mediated inhibition of Dahlgren cells electrical activity in the olive flounder, Paralichthys olivaceus. Gen Comp Endocrinol 2021; 306:113753. [PMID: 33711316 DOI: 10.1016/j.ygcen.2021.113753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 02/10/2021] [Accepted: 02/28/2021] [Indexed: 11/24/2022]
Abstract
γ-Aminobutyric acid (GABA) is a major inhibitory neurotransmitter in the central nervous system. We investigated its potential role as a neurotransmitter in the neuroendocrine Dahlgren cell population of the caudal neurosecretory system (CNSS) of the flounder Paralichthys olivaceus. The application of GABA in vitro resulted in a decrease in electrical activity of Dahlgren cells, followed by an increase of the number of silent cells, together with a decreased firing frequency of all three activity patterns (tonic, phasic, bursting). GABAA receptor agonist etomidate decreased Dahlgren cell firing activity, in a similar way to GABA. The response to GABA was blocked by the GABAA receptor antagonist bicuculline. GABAA receptor gamma2 subunit (Gabrg2) and chloride channel (Clcn2) mRNA expression were significantly upregulated in the CNSS after GABA superfusion. These data suggest that GABA may modulate CNSS activity in vivo mediated by GABAA receptors.
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Affiliation(s)
- Zhaohui Lan
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, China
| | - Wei Zhang
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, China
| | - Jinling Xu
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China
| | - Weiqun Lu
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, China.
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Falk-Petersen CB, Tsonkov TM, Nielsen MS, Harpsøe K, Bundgaard C, Frølund B, Kristiansen U, Gloriam DE, Wellendorph P. Discovery of a new class of orthosteric antagonists with nanomolar potency at extrasynaptic GABA A receptors. Sci Rep 2020; 10:10078. [PMID: 32572053 PMCID: PMC7308271 DOI: 10.1038/s41598-020-66821-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 05/20/2020] [Indexed: 02/06/2023] Open
Abstract
Brain GABAΑ receptors are ionotropic receptors belonging to the class of Cys-loop receptors and are important drug targets for the treatment of anxiety and sleep disorders. By screening a compound library (2,112 compounds) at recombinant human α4β1δ GABAΑ receptors heterologously expressed in a HEK cell line, we identified a scaffold of spirocyclic compounds with nanomolar antagonist activity at GABAΑ receptors. The initial screening hit 2027 (IC50 of 1.03 μM) was used for analogue search resulting in 018 (IC50 of 0.088 μM). 018 was most potent at α3,4,5-subunit containing receptors, thus showing preference for forebrain-expressed extrasynaptic receptors. Schild analysis of 018 at recombinant human α4β1δ receptors and displacement of [3H]muscimol binding in rat cortical homogenate independently confirmed a competitive profile. The antagonist profile of 018 was further validated by whole-cell patch-clamp electrophysiology, where kinetic studies revealed a slow dissociation rate and a shallow hill slope was observed. Membrane permeability studies showed that 2027 and 018 do not cross membranes, thus making the compounds less attractive for studying central GABAΑ receptors effects, but conversely more attractive as tool compounds in relation to emerging peripheral GABAΑ receptor-mediated effects of GABA e.g. in the immune system.
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Affiliation(s)
- Christina Birkedahl Falk-Petersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark
| | - Tsonko M Tsonkov
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark
| | - Malene Sofie Nielsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark
| | - Kasper Harpsøe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark
| | | | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark
| | - Uffe Kristiansen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark
| | - David E Gloriam
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen Ø, Denmark.
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Sukumaran NP, Amalraj A, Gopi S. Neuropharmacological and cognitive effects of Bacopa monnieri (L.) Wettst - A review on its mechanistic aspects. Complement Ther Med 2019; 44:68-82. [PMID: 31126578 DOI: 10.1016/j.ctim.2019.03.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 03/23/2019] [Accepted: 03/25/2019] [Indexed: 12/14/2022] Open
Abstract
Bacopa monnieri (L.) - (BM) is a perennial, creeping herb which is widely used in traditional ayurvedic medicine as a neural tonic to improve intelligence and memory. Research into the biological effects of this plant has burgeoned in recent years, promising its neuroprotective and memory boosting ability among others. In this context, an extensive literature survey allows an insight into the participation of numerous signaling pathways and oxidative mechanism involved in the mitigation of oxidative stress, along with other indirect mechanisms modulated by bioactive molecules of BM to improve the cognitive action by their synergistic potential and cellular multiplicity mechanism. This multi-faceted review describes the novel mechanisms that underlie the unfounded but long flaunted promises of BM and thereby direct a way to harness this acquired knowledge to develop innovative approaches to manipulate its intracellular pathways.
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Affiliation(s)
| | - Augustine Amalraj
- R&D Centre, Aurea Biolabs (P) Ltd, Kolenchery, Cochin 682 311, Kerala, India
| | - Sreeraj Gopi
- R&D Centre, Aurea Biolabs (P) Ltd, Kolenchery, Cochin 682 311, Kerala, India.
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Kumari E, Shang Y, Cheng Z, Zhang T. U1 snRNA over-expression affects neural oscillations and short-term memory deficits in mice. Cogn Neurodyn 2019; 13:313-323. [PMID: 31354878 DOI: 10.1007/s11571-019-09528-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 02/15/2019] [Accepted: 03/14/2019] [Indexed: 12/12/2022] Open
Abstract
Small nuclear RNAs (snRNAs) and other RNA spliceosomal components are involved in neurological and psychiatric disorders. U1 snRNA has recently been demonstrated to be altered in pathology in some neurodegenerative diseases, but whether it has a causative role is not clear. Here we have studied this by overexpressing U1 snRNA in mice and measured their hippocampal oscillatory patterns and brain functions. Novel object recognition test showed that the recognition index was significantly decreased in the U1 snRNA over-expression mice compared to that in the C57BL mice. U1 snRNA over-expression regulated not only the pattern of neural oscillations but also the expression of neuron excitatory and inhibitory proteins. Here we show that U1 snRNA over-expression contains the shrinkage distribution of theta-power, theta-phase lock synchronization, and theta and low-gamma cross-frequency coupling in the hippocampus. The alternations of neuron receptors by the U1 snRNA overexpression also modulated the decreasing of recognition index, the energy distribution of theta power spectrum with the reductions of theta phase synchronization and phase-amplitude coupling between theta and low-gamma. Linking these all together, our results suggest that U1 snRNA overexpression particularly causes a deficit in short-term memory. These findings make a bedrock of our research that U1 snRNA bridges the gap about the mechanism behind short-term memory based on the molecular and mesoscopic level.
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Affiliation(s)
- Ekta Kumari
- 1College of Life Sciences and Key Laboratory of Bioactive Materials Ministry of Education, Nankai University, No. 94 Weijin Road, Tianjin, 300071 People's Republic of China
| | - Yingchun Shang
- 1College of Life Sciences and Key Laboratory of Bioactive Materials Ministry of Education, Nankai University, No. 94 Weijin Road, Tianjin, 300071 People's Republic of China
| | - Zhi Cheng
- 1College of Life Sciences and Key Laboratory of Bioactive Materials Ministry of Education, Nankai University, No. 94 Weijin Road, Tianjin, 300071 People's Republic of China.,2State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300071 People's Republic of China
| | - Tao Zhang
- 1College of Life Sciences and Key Laboratory of Bioactive Materials Ministry of Education, Nankai University, No. 94 Weijin Road, Tianjin, 300071 People's Republic of China
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Golovko AI, Ivanov MB, Golovko ES, Dolgo-Saburov VB, Zatsepin EP. The Neurochemical Mechanisms of the Pharmacological Activities of Inverse Agonists of the Benzodiazepine Binding Site. NEUROCHEM J+ 2018. [DOI: 10.1134/s1819712418030042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Persistent therapeutic effect of a novel α5-GABA A receptor antagonist in rodent preclinical models of vascular cognitive impairment. Eur J Pharmacol 2018; 834:118-125. [PMID: 30012500 DOI: 10.1016/j.ejphar.2018.07.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 07/10/2018] [Accepted: 07/12/2018] [Indexed: 01/28/2023]
Abstract
This study examined the potential of the selective extra-synaptic α5-GABAA receptor inhibitor S44819 (Egis-13529) to improve cognitive performance in preclinical models of vascular cognitive impairment (VCI). Chronic hypoperfusion of the brain in mice was induced by permanent occlusion of the right common carotid artery (rUCO). rUCO induced impairments of cognitive function in the object recognition test (OR) and the rewarded T-maze (RTM). In both tests, a single oral treatment with S44819 (OR - 0.1-3 mg/kg, RTM - 1-3 mg/kg p.o.) significantly reduced the effect of rUCO. Long-term treatment with S44819 (1-10 mg/kg twice daily p.o. for 14 days), that was initiated 24 h after surgery and was followed by a 10- or 13-day wash-out period, fully prevented the decline of cognitive performance of rUCO mice. In rats, occlusion of the middle cerebral artery (MCA) for 30 min caused a significantly diminished performance in the OR. This was prevented by S44819 given p.o. 15 mg/kg twice daily for 8 days, starting 7 days after surgery and tested following a 7-day wash-out period. Taken together, S44819 markedly and stably improved reference and working memory impaired by rUCO in mice. In rats, the compound effectively suppressed the development of cognitive impairment after mild stroke. In conclusion, as longer-term administration led to a persistent reversal of the cognitive deficits, it appears that S44819 may have symptomatic, as well as disease-modifying effects in models of VCI. Proof of concept is therefore provided for testing S44819 in the therapy of VCI and post-stroke dementia in humans.
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