1
|
Pereira-Figueiredo D, Nascimento AA, Cunha-Rodrigues MC, Brito R, Calaza KC. Caffeine and Its Neuroprotective Role in Ischemic Events: A Mechanism Dependent on Adenosine Receptors. Cell Mol Neurobiol 2021; 42:1693-1725. [PMID: 33730305 DOI: 10.1007/s10571-021-01077-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 03/05/2021] [Indexed: 02/07/2023]
Abstract
Ischemia is characterized by a transient, insufficient, or permanent interruption of blood flow to a tissue, which leads to an inadequate glucose and oxygen supply. The nervous tissue is highly active, and it closely depends on glucose and oxygen to satisfy its metabolic demand. Therefore, ischemic conditions promote cell death and lead to a secondary wave of cell damage that progressively spreads to the neighborhood areas, called penumbra. Brain ischemia is one of the main causes of deaths and summed with retinal ischemia comprises one of the principal reasons of disability. Although several studies have been performed to investigate the mechanisms of damage to find protective/preventive interventions, an effective treatment does not exist yet. Adenosine is a well-described neuromodulator in the central nervous system (CNS), and acts through four subtypes of G-protein-coupled receptors. Adenosine receptors, especially A1 and A2A receptors, are the main targets of caffeine in daily consumption doses. Accordingly, caffeine has been greatly studied in the context of CNS pathologies. In fact, adenosine system, as well as caffeine, is involved in neuroprotection effects in different pathological situations. Therefore, the present review focuses on the role of adenosine/caffeine in CNS, brain and retina, ischemic events.
Collapse
Affiliation(s)
- D Pereira-Figueiredo
- Neurobiology of the Retina Laboratory, Biomedical Sciences Program, Biomedical Institute, Fluminense Federal University, Niterói, RJ, Brazil
| | - A A Nascimento
- Neurobiology of the Retina Laboratory, Program of Neurosciences, Institute of Biology, Fluminense Federal University, Niterói, RJ, Brazil
| | - M C Cunha-Rodrigues
- Neurobiology of the Retina Laboratory, Program of Neurosciences, Institute of Biology, Fluminense Federal University, Niterói, RJ, Brazil
| | - R Brito
- Laboratory of Neuronal Physiology and Pathology, Cellular and Molecular Biology Department, Institute of Biology, Fluminense Federal University, Niterói, RJ, Brazil
| | - K C Calaza
- Neurobiology of the Retina Laboratory, Biomedical Sciences Program, Biomedical Institute, Fluminense Federal University, Niterói, RJ, Brazil. .,Neurobiology of the Retina Laboratory, Program of Neurosciences, Institute of Biology, Fluminense Federal University, Niterói, RJ, Brazil. .,Neurobiology Department, Biology Institute of Fluminense Federal University, Niteroi, RJ, Brazil.
| |
Collapse
|
2
|
Godoy PA, Ramírez-Molina O, Fuentealba J. Exploring the Role of P2X Receptors in Alzheimer's Disease. Front Pharmacol 2019; 10:1330. [PMID: 31787900 PMCID: PMC6854869 DOI: 10.3389/fphar.2019.01330] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 10/18/2019] [Indexed: 01/01/2023] Open
Abstract
Several studies have pointed to soluble oligomers of beta amyloid peptide (SOAβ) as the principal neurotoxic agents responsible for the generation of synaptotoxic events that can explain the main symptoms of Alzheimer’s disease (AD). Among the toxic features associated with SOAβ, one of the most notorious is the formation of a non-selective pore-like structure in the plasma membrane, which may partly explain the overload of intracellular Ca2+. There is evidence that the pore causes leakage of key intracellular compounds, such as adenosine triphosphate (ATP), to the extracellular milieu. Extracellular ATP activates P2X receptors (P2XR), which are ligand-gated ion channels (LGICs) widely expressed in both neuron and glial cells and act as neuromodulators of synaptic activity by promoting Ca2+ entry and facilitating neurotransmitter release. There is abundant evidence correlating the overexpression of these receptors to neurodegenerative diseases, including AD, thus opening the possibility that P2XR could potentiate the toxic mechanisms induced by SOAβ and contribute to intracellular Ca2+ overload in neurons and other mechanisms related to glial activation and inflammation. In this review, we correlate scientific evidence related to the main toxic effects induced by SOAβ and those that are mediated by purinergic P2XR. The data suggest that these purinergic receptors participate in the deleterious cellular and molecular effects of SOAβ that lead to the pathogenesis of AD. This information sheds light on the participation of new components in SOAβ toxicity that could be interesting as pharmacological targets for the development of molecular or chemical compounds able to modulate them.
Collapse
Affiliation(s)
- Pamela Andrea Godoy
- Neuroactive Compounds Screening Laboratory,Departamento de Fisiología, Facultad de Cs. Biológicas, Universidad de Concepción, Concepción, Chile
| | - Oscar Ramírez-Molina
- Neuroactive Compounds Screening Laboratory,Departamento de Fisiología, Facultad de Cs. Biológicas, Universidad de Concepción, Concepción, Chile
| | - Jorge Fuentealba
- Neuroactive Compounds Screening Laboratory,Departamento de Fisiología, Facultad de Cs. Biológicas, Universidad de Concepción, Concepción, Chile
| |
Collapse
|
3
|
Mancini JE, Ortiz G, Potilinstki C, Salica JP, Lopez ES, Croxatto JO, Gallo JE. Possible neuroprotective role of P2X2 in the retina of diabetic rats. Diabetol Metab Syndr 2018; 10:31. [PMID: 29682007 PMCID: PMC5898034 DOI: 10.1186/s13098-018-0332-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 04/04/2018] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Purinergic receptors are expressed in different tissues including the retina. These receptors are involved in processes like cell growth, proliferation, activation and survival. ATP is the major activator of P2 receptors. In diabetes, there is a constant ATP production and this rise of ATP leads to a persistent activation of purinergic receptors. Antagonists of these receptors are used to evaluate their inhibition effects. Recently, the P2X2 has been reported to have a neuroprotective role. METHODS We carried out a study in groups of diabetic and non-diabetic rats (N = 5) treated with intraperitoneal injections of PPADS, at 9 and 24 weeks of diabetes. Control group received only the buffer. Animals were euthanized at 34 weeks of diabetes or at a matching age. Rat retinas were analyzed with immunohistochemistry and western blot using antibodies against GFAP, P2X2, P2Y2 and VEGF-A. RESULTS Diabetic animals treated with PPADS disclosed a much more extended staining of VEGF-A than diabetics without treatment. A lower protein expression of VEGF-A was found at the retina of diabetic animals without treatment of purinergic antagonists compared to diabetics with the antagonist treatment. Inhibition of P2X2 receptor by PPADS decreases cell death in the diabetic rat retina. CONCLUSION Results might be useful for better understanding the pathophysiology of diabetic retinopathy.
Collapse
Affiliation(s)
- Jorge E. Mancini
- Department of Ophthalmology, Nanomedicine & Vision Group, Facultad de Ciencias Biomédicas, Universidad Austral, Av. Juan D. Perón 1500, B1629AHJ Pilar, Buenos Aires Argentina
- Instituto de Investigaciones en Medicina Traslacional (IIMT), Universidad Austral, Consejo Nacional de Investigaciones Científicas y Técnicas (UA-CONICET), Pilar, Buenos Aires, Argentina
| | - Gustavo Ortiz
- Department of Ophthalmology, Nanomedicine & Vision Group, Facultad de Ciencias Biomédicas, Universidad Austral, Av. Juan D. Perón 1500, B1629AHJ Pilar, Buenos Aires Argentina
- Instituto de Investigaciones en Medicina Traslacional (IIMT), Universidad Austral, Consejo Nacional de Investigaciones Científicas y Técnicas (UA-CONICET), Pilar, Buenos Aires, Argentina
| | - Constanza Potilinstki
- Department of Ophthalmology, Nanomedicine & Vision Group, Facultad de Ciencias Biomédicas, Universidad Austral, Av. Juan D. Perón 1500, B1629AHJ Pilar, Buenos Aires Argentina
- Instituto de Investigaciones en Medicina Traslacional (IIMT), Universidad Austral, Consejo Nacional de Investigaciones Científicas y Técnicas (UA-CONICET), Pilar, Buenos Aires, Argentina
| | - Juan P. Salica
- Department of Ophthalmology, Nanomedicine & Vision Group, Facultad de Ciencias Biomédicas, Universidad Austral, Av. Juan D. Perón 1500, B1629AHJ Pilar, Buenos Aires Argentina
- Instituto de Investigaciones en Medicina Traslacional (IIMT), Universidad Austral, Consejo Nacional de Investigaciones Científicas y Técnicas (UA-CONICET), Pilar, Buenos Aires, Argentina
| | - Emiliano S. Lopez
- Department of Ophthalmology, Nanomedicine & Vision Group, Facultad de Ciencias Biomédicas, Universidad Austral, Av. Juan D. Perón 1500, B1629AHJ Pilar, Buenos Aires Argentina
- Instituto de Investigaciones en Medicina Traslacional (IIMT), Universidad Austral, Consejo Nacional de Investigaciones Científicas y Técnicas (UA-CONICET), Pilar, Buenos Aires, Argentina
| | - J. Oscar Croxatto
- Department of Ocular Pathology, Fundación Oftalmlógica Argentina “Jorge Malbran”, Buenos Aires, Argentina
- Instituto de Investigaciones en Medicina Traslacional (IIMT), Universidad Austral, Consejo Nacional de Investigaciones Científicas y Técnicas (UA-CONICET), Pilar, Buenos Aires, Argentina
| | - Juan E. Gallo
- Department of Ophthalmology, Nanomedicine & Vision Group, Facultad de Ciencias Biomédicas, Universidad Austral, Av. Juan D. Perón 1500, B1629AHJ Pilar, Buenos Aires Argentina
- Instituto de Investigaciones en Medicina Traslacional (IIMT), Universidad Austral, Consejo Nacional de Investigaciones Científicas y Técnicas (UA-CONICET), Pilar, Buenos Aires, Argentina
| |
Collapse
|
4
|
He J, Bai K, Hong B, Zhang F, Zheng S. Docosahexaenoic acid attenuates carbon tetrachloride-induced hepatic fibrosis in rats. Int Immunopharmacol 2017; 53:56-62. [PMID: 29035816 DOI: 10.1016/j.intimp.2017.09.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 09/15/2017] [Accepted: 09/15/2017] [Indexed: 02/07/2023]
Abstract
Fish oil containing docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) has been reported to exert beneficial health effects, including hepatoprotection. However, the effect of DHA alone has not been well studied, and the mechanism is not fully understood. In the present study, we reported the protective effect of DHA on carbon tetrachloride (CCl4) induced hepatic fibrosis. Compared with the control group, the CCl4 group showed hepatic damage as evidenced by histological changes and elevation in serum transaminase activity, fibrosis, inflammation and oxidative stress levels. These pathophysiological changes were attenuated by chronic DHA supplementation. The anti-fibrotic effect of DHA was accompanied by reductions in gene and protein expression of α-smooth muscle actin (α-SMA), fibronectin, and collagen in the liver tissue. DHA also attenuated CCl4-induced elevation of lipid peroxidation (LPO) and decrease of glutathione (GSH)/oxidized GSH (GSSG) ratio. The upregulated inflammatory cytokines tumor necrosis factor (TNF)-α, interferon (IFN)-γ and interleukin (IL)-6 by CCl4 were also ameliorated by DHA. Peroxisome proliferator-activated receptor (PPAR)-γ upregulation and type I and II receptors for transforming growth factor (TGF)-β (Tβ-RI and Tβ-RII) and platelet-derived growth factor (PDGF)-β receptor (PDGF-βR) downregulation on both mRNA and protein levels were observed by DHA treatment compared to CCl4 group. Moreover, in vitro study showed that DHA inhibited HSC activation, being associated with elevating PPARγ level and reducing the phosphorylation levels of Smad2/3 and ERKs, which are downstream intermediates of TGFβ and PDGF receptors, respectively. Taken together, the hepatoprotective, anti-inflammatory and anti-fibrotic effects of DHA appeared to be multifactorial. Further, one of the mechanisms of the anti-fibrotic effect of chronic DHA supplementation is probably through PPARγ signaling to interrupt TGFβ/Smad and PDGF/ERK pathways in HSCs.
Collapse
Affiliation(s)
- Jianlin He
- Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210029, PR China; Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, PR China
| | - Kaikai Bai
- Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, PR China
| | - Bihong Hong
- Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, PR China
| | - Feng Zhang
- Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210029, PR China
| | - Shizhong Zheng
- Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210029, PR China.
| |
Collapse
|
5
|
Burnstock G. Purinergic Signalling: Therapeutic Developments. Front Pharmacol 2017; 8:661. [PMID: 28993732 PMCID: PMC5622197 DOI: 10.3389/fphar.2017.00661] [Citation(s) in RCA: 263] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 09/05/2017] [Indexed: 12/15/2022] Open
Abstract
Purinergic signalling, i.e., the role of nucleotides as extracellular signalling molecules, was proposed in 1972. However, this concept was not well accepted until the early 1990's when receptor subtypes for purines and pyrimidines were cloned and characterised, which includes four subtypes of the P1 (adenosine) receptor, seven subtypes of P2X ion channel receptors and 8 subtypes of the P2Y G protein-coupled receptor. Early studies were largely concerned with the physiology, pharmacology and biochemistry of purinergic signalling. More recently, the focus has been on the pathophysiology and therapeutic potential. There was early recognition of the use of P1 receptor agonists for the treatment of supraventricular tachycardia and A2A receptor antagonists are promising for the treatment of Parkinson's disease. Clopidogrel, a P2Y12 antagonist, is widely used for the treatment of thrombosis and stroke, blocking P2Y12 receptor-mediated platelet aggregation. Diquafosol, a long acting P2Y2 receptor agonist, is being used for the treatment of dry eye. P2X3 receptor antagonists have been developed that are orally bioavailable and stable in vivo and are currently in clinical trials for the treatment of chronic cough, bladder incontinence, visceral pain and hypertension. Antagonists to P2X7 receptors are being investigated for the treatment of inflammatory disorders, including neurodegenerative diseases. Other investigations are in progress for the use of purinergic agents for the treatment of osteoporosis, myocardial infarction, irritable bowel syndrome, epilepsy, atherosclerosis, depression, autism, diabetes, and cancer.
Collapse
Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical SchoolLondon, United Kingdom
- Department of Pharmacology and Therapeutics, The University of Melbourne, MelbourneVIC, Australia
| |
Collapse
|
6
|
Cheng MC, Pan TM. Glyceryl 1,3-Dipalmitate Produced from Lactobacillus paracasei subspecies. paracasei NTU 101 Inhibits Oxygen-Glucose Deprivation and Reperfusion-Induced Oxidative Stress via Upregulation of Peroxisome Proliferator-Activated Receptor γ in Neuronal SH-SY5Y Cells. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:7926-7933. [PMID: 28829589 DOI: 10.1021/acs.jafc.7b02728] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Glyceryl 1,3-dipalmitate (GD) purified from Lactobacillus paracasei subsp. paracasei NTU 101-fermented products has been demonstrated to possess neuroprotective properties. We determined the effect of GD on oxygen-glucose deprivation and reperfusion (OGD/R)-induced SH-SY5Y neuroblastoma cell death. GD ameliorated OGD/R-induced apoptosis by elevating the protein expression of nuclear peroxisome proliferator-activated receptor γ (PPARγ) and nuclear factor erythroid 2-related factor 2 (Nrf2), thereby attenuating reactive oxygen species (ROS) generation. Pretreatment with GD reduced nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) expression from 1.54 ± 0.27 to 0.84 ± 0.46, thereby attenuating the induction of pro-inflammatory mediators, and increased the plasma membrane Ca2+ ATPase (PMCA) levels from 0.81 ± 0.02 to 1.08 ± 0.06, thus reducing the levels of cytosolic Ca2+; this also correlated with reduced cell death. We conclude that GD prevents SH-SY5Y cells from injury after OGD/R insult, possibly by modulating oxidative stress and inflammatory response.
Collapse
Affiliation(s)
- Meng-Chun Cheng
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University , Number 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Tzu-Ming Pan
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University , Number 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan
| |
Collapse
|
7
|
Landa-Juárez AY, Ortiz MI, Castañeda-Hernández G, Chávez-Piña AE. Participation of potassium channels in the antinociceptive effect of docosahexaenoic acid in the rat formalin test. Eur J Pharmacol 2016; 793:95-100. [DOI: 10.1016/j.ejphar.2016.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 11/03/2016] [Accepted: 11/04/2016] [Indexed: 01/25/2023]
|
8
|
Kocsis K, Frank R, Szabó J, Knapp L, Kis Z, Farkas T, Vécsei L, Toldi J. Acetyl-l-carnitine restores synaptic transmission and enhances the inducibility of stable LTP after oxygen-glucose deprivation. Neuroscience 2016; 332:203-11. [PMID: 27378558 DOI: 10.1016/j.neuroscience.2016.06.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 06/09/2016] [Accepted: 06/24/2016] [Indexed: 11/26/2022]
Abstract
Hypoxic circumstances result in functional and structural impairments of the brain. Oxygen-glucose deprivation (OGD) on hippocampal slices is a technique widely used to investigate the consequences of ischemic stroke and the potential neuroprotective effects of different drugs. Acetyl-l-carnitine (ALC) is a naturally occurring substance in the body, and it can therefore be administered safely even in relatively high doses. In previous experiments, ALC pretreatment proved to be effective against global hypoperfusion. In the present study, we investigated whether ALC can be protective in an OGD model. We are not aware of any earlier study in which the long-term potentiation (LTP) function on hippocampal slices was measured after OGD. Therefore, we set out to determine whether an effective ALC concentration has an effect on synaptic plasticity after OGD in the hippocampal CA1 subfield of rats. A further aim was to investigate the mechanism underlying the protective effect of this compound. The experiments revealed that ALC is neuroprotective against OGD in a dose-dependent manner, which is manifested not only in the regeneration of the impaired synaptic transmission after the OGD, but also in the inducibility and stability of the LTP. In the case of the most effective concentration of ALC (500μM), use of a phosphoinositide 3-kinase (PI3K) inhibitor (LY294002) revealed that the PI3K/Akt signaling pathway has a key role in the restoration of the synaptic transmission and plasticity reached by ALC treatment.
Collapse
Affiliation(s)
- Kitti Kocsis
- Department of Physiology, Anatomy and Neuroscience, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary; MTA-SZTE Neuroscience Research Group, University of Szeged, Szeged, Hungary
| | - Rita Frank
- Department of Physiology, Anatomy and Neuroscience, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary
| | - József Szabó
- Department of Physiology, Anatomy and Neuroscience, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary
| | - Levente Knapp
- Department of Physiology, Anatomy and Neuroscience, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary
| | - Zsolt Kis
- Department of Physiology, Anatomy and Neuroscience, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary
| | - Tamás Farkas
- Department of Physiology, Anatomy and Neuroscience, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary
| | - László Vécsei
- Department of Neurology, Faculty of Medicine, University of Szeged, Semmelweis u. 6, H-6725 Szeged, Hungary; MTA-SZTE Neuroscience Research Group, University of Szeged, Szeged, Hungary
| | - József Toldi
- Department of Physiology, Anatomy and Neuroscience, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary; MTA-SZTE Neuroscience Research Group, University of Szeged, Szeged, Hungary.
| |
Collapse
|
9
|
Glutathione-Induced Calcium Shifts in Chick Retinal Glial Cells. PLoS One 2016; 11:e0153677. [PMID: 27078878 PMCID: PMC4831842 DOI: 10.1371/journal.pone.0153677] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 04/01/2016] [Indexed: 11/30/2022] Open
Abstract
Neuroglia interactions are essential for the nervous system and in the retina Müller cells interact with most of the neurons in a symbiotic manner. Glutathione (GSH) is a low-molecular weight compound that undertakes major antioxidant roles in neurons and glia, however, whether this compound could act as a signaling molecule in neurons and/or glia is currently unknown. Here we used embryonic avian retina to obtain mixed retinal cells or purified Müller glia cells in culture to evaluate calcium shifts induced by GSH. A dose response curve (0.1–10mM) showed that 5–10mM GSH, induced calcium shifts exclusively in glial cells (later labeled and identified as 2M6 positive cells), while neurons responded to 50mM KCl (labeled as βIII tubulin positive cells). BBG 100nM, a P2X7 blocker, inhibited the effects of GSH on Müller glia. However, addition of DNQX 70μM and MK-801 20μM, non-NMDA and NMDA blockers, had no effect on GSH calcium induced shift. Oxidized glutathione (GSSG) at 5mM failed to induce calcium mobilization in glia cells, indicating that the antioxidant and/or structural features of GSH are essential to promote elevations in cytoplasmic calcium levels. Indeed, a short GSH pulse (60s) protects Müller glia from oxidative damage after 30 min of incubation with 0.1% H2O2. Finally, GSH induced GABA release from chick embryonic retina, mixed neuron-glia or from Müller cell cultures, which were inhibited by BBG or in the absence of sodium. GSH also induced propidium iodide uptake in Müller cells in culture in a P2X7 receptor dependent manner. Our data suggest that GSH, in addition to antioxidant effects, could act signaling calcium shifts at the millimolar range particularly in Müller glia, and could regulate the release of GABA, with additional protective effects on retinal neuron-glial circuit.
Collapse
|
10
|
Adenosine A2B receptor activation stimulates glucose uptake in the mouse forebrain. Purinergic Signal 2015; 11:561-9. [PMID: 26446689 DOI: 10.1007/s11302-015-9474-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 09/23/2015] [Indexed: 01/08/2023] Open
Abstract
ATP consumption during intense neuronal activity leads to peaks of both extracellular adenosine levels and increased glucose uptake in the brain. Here, we investigated the hypothesis that the activation of the low-affinity adenosine receptor, the A2B receptor (A(2B)R), promotes glucose uptake in neurons and astrocytes, thereby linking brain activity with energy metabolism. To this end, we mapped the spatiotemporal accumulation of the fluorescent-labelled deoxyglucose, 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG), in superfused acute hippocampal slices of C57Bl/6j mice. Bath application of the A(2B)R agonist BAY606583 (300 nM) triggered an immediate and stable (>10 min) increase of the velocity of 2-NBDG accumulation throughout hippocampal slices. This was abolished with the pretreatment with the selective A(2B)R antagonist, MRS1754 (200 nM), and was also absent in A(2B)R null-mutant mice. In mouse primary astrocytic or neuronal cultures, BAY606583 similarly increased (3)H-deoxyglucose uptake in the following 20 min incubation period, which was again abolished by a pretreatment with MRS1754. Finally, incubation of hippocampal, frontocortical, or striatal slices of C57Bl/6j mice at 37 °C, with either MRS1754 (200 nM) or adenosine deaminase (3 U/mL) significantly reduced glucose uptake. Furthermore, A(2B)R blockade diminished newly synthesized glycogen content and at least in the striatum, increased lactate release. In conclusion, we report here that A(2B)R activation is associated with an instant and tonic increase of glucose transport into neurons and astrocytes in the mouse brain. These prompt further investigations to evaluate the clinical potential of this novel glucoregulator mechanism.
Collapse
|