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Huang L, Zhu W, Li N, Zhang B, Dai W, Li S, Xu H. Functions and mechanisms of adenosine and its receptors in sleep regulation. Sleep Med 2024; 115:210-217. [PMID: 38373361 DOI: 10.1016/j.sleep.2024.02.012] [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: 11/06/2023] [Revised: 02/01/2024] [Accepted: 02/03/2024] [Indexed: 02/21/2024]
Abstract
Sleep is a natural and recurring state of life. Long-term insomnia can lead to physical and mental fatigue, inattention, memory loss, anxiety, depression and other symptoms, imposing immense public health and economic burden worldwide. The sleep and awakening regulation system is composed of many nerve nuclei and neurotransmitters in the brain, and it forms a neural network that interacts and restricts each other to regulate the occurrence and maintenance of sleep-wake. Adenosine (AD) is a neurotransmitter in the central nervous system and a driver of sleep. Meanwhile, the functions and mechanisms underlying sleep-promoting effects of adenosine and its receptors are still not entirely clear. However, in recent years, the increasing evidence indicated that adenosine can promote sleep through inhibiting arousal system and activating sleep-promoting system. At the same time, astrocyte-derived adenosine in modulating sleep homeostasis and sleep loss-induced related cognitive and memory deficits plays an important role. This review, therefore, summarizes the current research on the functions and possible mechanisms of adenosine and its receptors in the regulation of sleep and homeostatic control of sleep. Understanding these aspects will provide us better ideas on clinical problems such as insomnia, hypersomnia and other sleep disorders.
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Affiliation(s)
- Lishan Huang
- Geriatric Department, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, Sichuan, China.
| | - Wenwen Zhu
- Geriatric Department, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, Sichuan, China.
| | - Nanxi Li
- Geriatric Department, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, Sichuan, China.
| | - Bin Zhang
- Geriatric Department, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, Sichuan, China.
| | - Wenbin Dai
- Geriatric Department, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, Sichuan, China.
| | - Sen Li
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, China.
| | - Houping Xu
- Geriatric Department, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, Sichuan, China.
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Bhattacharya D, Górska-Andrzejak J, Abaquita TAL, Pyza E. Effects of adenosine receptor overexpression and silencing in neurons and glial cells on lifespan, fitness, and sleep of Drosophila melanogaster. Exp Brain Res 2023:10.1007/s00221-023-06649-y. [PMID: 37335362 DOI: 10.1007/s00221-023-06649-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 05/28/2023] [Indexed: 06/21/2023]
Abstract
A single adenosine receptor gene (dAdoR) has been detected in Drosophila melanogaster. However, its function in different cell types of the nervous system is mostly unknown. Therefore, we overexpressed or silenced the dAdoR gene in eye photoreceptors, all neurons, or glial cells and examined the fitness of flies, the amount and daily pattern of sleep, and the influence of dAdoR silencing on Bruchpilot (BRP) presynaptic protein. Furthermore, we examined the dAdoR and brp gene expression in young and old flies. We found that a higher level of dAdoR in the retina photoreceptors, all neurons, and glial cells negatively influenced the survival rate and lifespan of male and female Drosophila in a cell-dependent manner and to a different extent depending on the age of the flies. In old flies, expression of both dAdoR and brp was higher than in young ones. An excess of dAdoR in neurons improved climbing in older individuals. It also influenced sleep by lengthening nighttime sleep and siesta. In turn, silencing of dAdoR decreased the lifespan of flies, although it increased the survival rate of young flies. It hindered the climbing of older males and females, but did not change sleep. Silencing also affected the daily pattern of BRP abundance, especially when dAdoR expression was decreased in glial cells. The obtained results indicate the role of adenosine and dAdoR in the regulation of fitness in flies that is based on communication between neurons and glial cells, and the effect of glial cells on synapses.
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Affiliation(s)
| | | | | | - Elżbieta Pyza
- Department of Cell Biology and Imaging, Jagellonian University, Kraków, Poland.
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3
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Juvenile depletion of microglia reduces orientation but not high spatial frequency selectivity in mouse V1. Sci Rep 2022; 12:12779. [PMID: 35896554 PMCID: PMC9329297 DOI: 10.1038/s41598-022-15503-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 06/24/2022] [Indexed: 01/26/2023] Open
Abstract
Microglia contain multiple mechanisms that shape the synaptic landscape during postnatal development. Whether the synaptic changes mediated by microglia reflect the developmental refinement of neuronal responses in sensory cortices, however, remains poorly understood. In postnatal life, the development of increased orientation and spatial frequency selectivity of neuronal responses in primary visual cortex (V1) supports the emergence of high visual acuity. Here, we used the colony-stimulating factor 1 receptor (CSF1R) inhibitor PLX5622 to rapidly and durably deplete microglia in mice during the juvenile period in which increased orientation and spatial frequency selectivity emerge. Excitatory and inhibitory tuning properties were measured simultaneously using multi-photon calcium imaging in layer II/III of mouse V1. We found that microglia depletion generally increased evoked activity which, in turn, reduced orientation selectivity. Surprisingly, microglia were not required for the emergence of high spatial frequency tuned responses. In addition, microglia depletion did not perturb cortical binocularity, suggesting normal depth processing. Together, our finding that orientation and high spatial frequency selectivity in V1 are differentially supported by microglia reveal that microglia are required normal sensory processing, albeit selectively.
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Ding Z, Guo S, Luo L, Zheng Y, Gan S, Kang X, Wu X, Zhu S. Emerging Roles of Microglia in Neuro-vascular Unit: Implications of Microglia-Neurons Interactions. Front Cell Neurosci 2021; 15:706025. [PMID: 34712121 PMCID: PMC8546170 DOI: 10.3389/fncel.2021.706025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 09/10/2021] [Indexed: 12/20/2022] Open
Abstract
Microglia, which serve as the defensive interface of the nervous system, are activated in many neurological diseases. Their role as immune responding cells has been extensively studied in the past few years. Recent studies have demonstrated that neuronal feedback can be shaped by the molecular signals received and sent by microglia. Altered neuronal activity or synaptic plasticity leads to the release of various communication messages from neurons, which in turn exert effects on microglia. Research on microglia-neuron communication has thus expanded from focusing only on neurons to the neurovascular unit (NVU). This approach can be used to explore the potential mechanism of neurovascular coupling across sophisticated receptor systems and signaling cascades in health and disease. However, it remains unclear how microglia-neuron communication happens in the brain. Here, we discuss the functional contribution of microglia to synapses, neuroimmune communication, and neuronal activity. Moreover, the current state of knowledge of bidirectional control mechanisms regarding interactions between neurons and microglia are reviewed, with a focus on purinergic regulatory systems including ATP-P2RY12R signaling, ATP-adenosine-A1Rs/A2ARs, and the ATP-pannexin 1 hemichannel. This review aims to organize recent studies to highlight the multifunctional roles of microglia within the neural communication network in health and disease.
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Affiliation(s)
- Zhe Ding
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shaohui Guo
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lihui Luo
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yueying Zheng
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shuyuan Gan
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xianhui Kang
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaomin Wu
- Department of Anesthesiology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Shengmei Zhu
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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Fedotova АА, Tiaglik АB, Semyanov АV. Effect of Diet as a Factor of Exposome
on Brain Function. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021030108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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6
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Armada-Moreira A, Gomes JI, Pina CC, Savchak OK, Gonçalves-Ribeiro J, Rei N, Pinto S, Morais TP, Martins RS, Ribeiro FF, Sebastião AM, Crunelli V, Vaz SH. Going the Extra (Synaptic) Mile: Excitotoxicity as the Road Toward Neurodegenerative Diseases. Front Cell Neurosci 2020; 14:90. [PMID: 32390802 PMCID: PMC7194075 DOI: 10.3389/fncel.2020.00090] [Citation(s) in RCA: 138] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 03/26/2020] [Indexed: 12/13/2022] Open
Abstract
Excitotoxicity is a phenomenon that describes the toxic actions of excitatory neurotransmitters, primarily glutamate, where the exacerbated or prolonged activation of glutamate receptors starts a cascade of neurotoxicity that ultimately leads to the loss of neuronal function and cell death. In this process, the shift between normal physiological function and excitotoxicity is largely controlled by astrocytes since they can control the levels of glutamate on the synaptic cleft. This control is achieved through glutamate clearance from the synaptic cleft and its underlying recycling through the glutamate-glutamine cycle. The molecular mechanism that triggers excitotoxicity involves alterations in glutamate and calcium metabolism, dysfunction of glutamate transporters, and malfunction of glutamate receptors, particularly N-methyl-D-aspartic acid receptors (NMDAR). On the other hand, excitotoxicity can be regarded as a consequence of other cellular phenomena, such as mitochondrial dysfunction, physical neuronal damage, and oxidative stress. Regardless, it is known that the excessive activation of NMDAR results in the sustained influx of calcium into neurons and leads to several deleterious consequences, including mitochondrial dysfunction, reactive oxygen species (ROS) overproduction, impairment of calcium buffering, the release of pro-apoptotic factors, among others, that inevitably contribute to neuronal loss. A large body of evidence implicates NMDAR-mediated excitotoxicity as a central mechanism in the pathogenesis of many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), and epilepsy. In this review article, we explore different causes and consequences of excitotoxicity, discuss the involvement of NMDAR-mediated excitotoxicity and its downstream effects on several neurodegenerative disorders, and identify possible strategies to study new aspects of these diseases that may lead to the discovery of new therapeutic approaches. With the understanding that excitotoxicity is a common denominator in neurodegenerative diseases and other disorders, a new perspective on therapy can be considered, where the targets are not specific symptoms, but the underlying cellular phenomena of the disease.
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Affiliation(s)
- Adam Armada-Moreira
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark
| | - Joana I. Gomes
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Carolina Campos Pina
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Oksana K. Savchak
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Joana Gonçalves-Ribeiro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Nádia Rei
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Sara Pinto
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Tatiana P. Morais
- Neuroscience Division, School of Bioscience, Cardiff University, Cardiff, United Kingdom
| | - Robertta Silva Martins
- Laboratório de Neurofarmacologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Brazil
| | - Filipa F. Ribeiro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Ana M. Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
| | - Vincenzo Crunelli
- Neuroscience Division, School of Bioscience, Cardiff University, Cardiff, United Kingdom
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
| | - Sandra H. Vaz
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
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Santoni G, Maggi F, Amantini C, Marinelli O, Nabissi M, Morelli MB. Pathophysiological Role of Transient Receptor Potential Mucolipin Channel 1 in Calcium-Mediated Stress-Induced Neurodegenerative Diseases. Front Physiol 2020; 11:251. [PMID: 32265740 PMCID: PMC7105868 DOI: 10.3389/fphys.2020.00251] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 03/05/2020] [Indexed: 12/15/2022] Open
Abstract
Mucolipins (TRPML) are endosome/lysosome Ca2+ permeable channels belonging to the family of transient receptor potential channels. In mammals, there are three TRPML proteins, TRPML1, 2, and 3, encoded by MCOLN1-3 genes. Among these channels, TRPML1 is a reactive oxygen species sensor localized on the lysosomal membrane that is able to control intracellular oxidative stress due to the activation of the autophagic process. Moreover, genetic or pharmacological inhibition of the TRPML1 channel stimulates oxidative stress signaling pathways. Experimental data suggest that elevated levels of reactive species play a role in several neurological disorders. There is a need to gain better understanding of the molecular mechanisms behind these neurodegenerative diseases, considering that the main sources of free radicals are mitochondria, that mitochondria/endoplasmic reticulum and lysosomes are coupled, and that growing evidence links neurodegenerative diseases to the gain or loss of function of proteins related to lysosome homeostasis. This review examines the significant roles played by the TRPML1 channel in the alterations of calcium signaling responsible for stress-mediated neurodegenerative disorders and its potential as a new therapeutic target for ameliorating neurodegeneration in our ever-aging population.
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Affiliation(s)
- Giorgio Santoni
- Immunopathology Laboratory, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Federica Maggi
- Immunopathology Laboratory, School of Pharmacy, University of Camerino, Camerino, Italy.,Department of Molecular Medicine, Sapienza University, Rome, Italy
| | - Consuelo Amantini
- Immunopathology Laboratory, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Oliviero Marinelli
- Immunopathology Laboratory, School of Pharmacy, University of Camerino, Camerino, Italy.,Immunopathology Laboratory, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Massimo Nabissi
- Immunopathology Laboratory, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Maria Beatrice Morelli
- Immunopathology Laboratory, School of Pharmacy, University of Camerino, Camerino, Italy.,Immunopathology Laboratory, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
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8
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Burnstock G. Introduction to Purinergic Signalling in the Brain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1202:1-12. [PMID: 32034706 DOI: 10.1007/978-3-030-30651-9_1] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
ATP is a cotransmitter with glutamate, noradrenaline, GABA, acetylcholine and dopamine in the brain. There is a widespread presence of both adenosine (P1) and P2 nucleotide receptors in the brain on both neurons and glial cells. Adenosine receptors play a major role in presynaptic neuromodulation, while P2X ionotropic receptors are involved in fast synaptic transmission and synaptic plasticity. P2Y G protein-coupled receptors are largely involved in presynaptic activities, as well as mediating long-term (trophic) signalling in cell proliferation, differentiation and death during development and regeneration. Both P1 and P2 receptors participate in neuron-glial interactions. Purinergic signalling is involved in control of cerebral vascular tone and remodelling and has been implicated in learning and memory, locomotor and feeding behaviour and sleep. There is increasing interest in the involvement of purinergic signalling in the pathophysiology of the CNS, including trauma, ischaemia, epilepsy, neurodegenerative diseases, neuropsychiatric and mood disorders, and cancer, including gliomas.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Royal Free Campus, Rowland Hill Street, NW3 2PF, London, UK.
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9
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Huang W, Xu Y, Zhang Y, Zhang P, Zhang Q, Zhang Z, Xu F. Metabolomics-driven identification of adenosine deaminase as therapeutic target in a mouse model of Parkinson's disease. J Neurochem 2019; 150:282-295. [PMID: 31121068 DOI: 10.1111/jnc.14774] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/14/2019] [Accepted: 05/20/2019] [Indexed: 12/14/2022]
Abstract
Neuroinflammation is one of the driving forces of progressive neurodegeneration in Parkinson's disease (PD). The metabolomics approach has been proved highly useful in identifying potential therapeutic targets. Here, to identify inflammation-relevant treatment targets for PD, mass spectrometry-based untargeted metabolomics was applied to characterize metabolic changes in the striatum of mice with double-hit PD induced by lipopolysaccharide plus 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Seven days after the final MPTP administration, metabolites from the purine metabolism pathway, including adenosine, 1-methyladenosine, adenine, inosine, hypoxanthine, xanthine, xanthosine, and guanosine, were found to be significantly dysregulated. The metabolite-protein interaction network and changes in the concentration ratio of these metabolites indicated that adenosine and adenosine deaminase (ADA; EC 3.5.4.4) were the most promising therapeutic targets and adenosine augmentation might be a rational approach to slow PD progression. These findings were then verified in a subacute MPTP-induced PD mouse model treated with ADA inhibition alone or in conjunction with antagonism of adenosine A2A receptors (A2A R). Behavioral, biochemical, and immunohistochemical analysis demonstrated that ADA inhibition significantly ameliorated the MPTP-mediated motor disabilities, dopamine depletion, and dopaminergic cell death. Significantly enhanced neuroprotective effects were further observed when the ADA inhibitor was utilized in conjunction with an A2A R antagonist. Together, our study indicated for the first time that ADA inhibitors protected against neurodegeneration induced by the neurotoxin MPTP, and ADA inhibitors in combination with A2A R antagonists showed additive antiparkinsonian effects.
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Affiliation(s)
- Wanqiu Huang
- Key Laboratory of Drug Quality Control and Pharmacovigilance (Ministry of Education), State Key Laboratory of Natural Medicine, China Pharmaceutical University, Nanjing, P. R. China.,Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, P. R. China
| | - Yazhou Xu
- Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, P. R. China
| | - Yuxin Zhang
- Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing, P. R.China
| | - Pei Zhang
- Key Laboratory of Drug Quality Control and Pharmacovigilance (Ministry of Education), State Key Laboratory of Natural Medicine, China Pharmaceutical University, Nanjing, P. R. China.,Gunma University Initiative for Advanced Research (GIAR), Gunma University, Gunma, Japan.,Division of Physiological Chemistry 2, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Qianqian Zhang
- Key Laboratory of Drug Quality Control and Pharmacovigilance (Ministry of Education), State Key Laboratory of Natural Medicine, China Pharmaceutical University, Nanjing, P. R. China.,Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, P. R. China
| | - Zunjian Zhang
- Key Laboratory of Drug Quality Control and Pharmacovigilance (Ministry of Education), State Key Laboratory of Natural Medicine, China Pharmaceutical University, Nanjing, P. R. China.,Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, P. R. China
| | - Fengguo Xu
- Key Laboratory of Drug Quality Control and Pharmacovigilance (Ministry of Education), State Key Laboratory of Natural Medicine, China Pharmaceutical University, Nanjing, P. R. China.,Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, Nanjing, P. R. China
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10
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Chakraborty D, Fedorova OV, Bagrov AY, Kaphzan H. Selective ligands for Na+/K+-ATPase α isoforms differentially and cooperatively regulate excitability of pyramidal neurons in distinct brain regions. Neuropharmacology 2017; 117:338-351. [DOI: 10.1016/j.neuropharm.2017.02.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/24/2017] [Accepted: 02/17/2017] [Indexed: 11/28/2022]
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11
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Purdue-Smithe AC, Manson JE, Hankinson SE, Bertone-Johnson ER. A prospective study of caffeine and coffee intake and premenstrual syndrome. Am J Clin Nutr 2016; 104:499-507. [PMID: 27385613 PMCID: PMC4962155 DOI: 10.3945/ajcn.115.127027] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 06/09/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Clinically significant premenstrual syndrome (PMS) affects 15-20% of premenopausal women, substantially reducing quality of life. Women with PMS often are counseled to minimize caffeine intake, although only limited evidence supports this recommendation. OBJECTIVE We evaluated the association between total caffeine, coffee, and tea intake and the development of PMS in a case-control study nested within the prospective Nurses' Health Study II. DESIGN All participants were free from PMS at baseline (1991). PMS cases reported a new clinician-made diagnosis of PMS on biennial questionnaires between 1993 and 2005, and then confirmed symptom timing and moderate-to-severe impact and severity of symptoms with the use of a retrospective questionnaire (n = 1234). Controls did not report PMS and confirmed experiencing no symptoms or few mild symptoms with limited personal impact (n = 2426). Caffeine, coffee, and tea intake was measured by food-frequency questionnaires every 4 y, and data on smoking, body weight, and other factors were updated every 2-4 y. Logistic regression was used to evaluate the associations of total caffeine intake and frequency of coffee and tea consumption with PMS. RESULTS After adjustment for age, smoking, and other factors, total caffeine intake was not associated with PMS. The OR comparing women with the highest (quintile median = 543 mg/d) to the lowest (quintile median = 18 mg/d) caffeine intake was 0.79 (95% CI: 0.61, 1.04; P-trend = 0.31). High caffeinated coffee intake also was not associated with risk of PMS or specific symptoms, including breast tenderness (OR for ≥4 cups/d compared with <1/mo: 0.73; 95% CI: 0.48, 1.12; P-trend = 0.44). CONCLUSIONS Our findings suggest that caffeine intake is not associated with PMS, and that current recommendations for women to reduce caffeine intake may not help prevent the development of PMS.
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Affiliation(s)
- Alexandra C Purdue-Smithe
- Department of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, MA
| | - JoAnn E Manson
- Channing Division of Network Medicine and Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA; and Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA
| | - Susan E Hankinson
- Department of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, MA; Channing Division of Network Medicine and Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA
| | - Elizabeth R Bertone-Johnson
- Department of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts Amherst, Amherst, MA;
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12
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Complex formation and functional interaction between adenosine A1 receptor and type-1 metabotropic glutamate receptor. J Pharmacol Sci 2015; 128:125-30. [PMID: 26154847 DOI: 10.1016/j.jphs.2015.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Revised: 06/09/2015] [Accepted: 06/10/2015] [Indexed: 11/24/2022] Open
Abstract
The adenosine A1 receptor (A1R) is a G protein-coupled receptor (GPCR) for adenosine, a ubiquitous neuromodulator, and thus regulates neuronal excitability, as well as arousal and sensitivity to pain. In addition, we have previously described a new mode of action for A1R: in cerebellar Purkinje cells, its activation attenuates neuronal responses to glutamate, as mediated by the type-1 metabotropic glutamate receptor (mGluR1). mGluR1 is also a GPCR, and elicits such responses as long-term depression of the postsynaptic response to glutamate, a cellular basis for cerebellar motor learning. Here, we explore in greater detail the interaction between A1R and mGluR1 using non-neuronal cells. Co-immunoprecipitation and Förster resonance energy transfer (FRET) analysis reveal that A1R and mGluR1 form a complex. Furthermore, we found that mGluR1 activation inhibits A1R signaling, as measured by changes in intracellular cAMP. These findings demonstrate that A1R and mGluR1 have the intrinsic ability to form a heteromeric complex and mutually modulate signaling. This interaction may represent a new form of intriguing GPCR-mediated cellular responses.
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13
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Burnstock G. An introduction to the roles of purinergic signalling in neurodegeneration, neuroprotection and neuroregeneration. Neuropharmacology 2015; 104:4-17. [PMID: 26056033 DOI: 10.1016/j.neuropharm.2015.05.031] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 05/19/2015] [Accepted: 05/20/2015] [Indexed: 12/21/2022]
Abstract
Purinergic signalling appears to play important roles in neurodegeneration, neuroprotection and neuroregeneration. Initially there is a brief summary of the background of purinergic signalling, including release of purines and pyrimidines from neural and non-neural cells and their ectoenzymatic degradation, and the current characterisation of P1 (adenosine), and P2X (ion channel) and P2Y (G protein-coupled) nucleotide receptor subtypes. There is also coverage of the localization and roles of purinoceptors in the healthy central nervous system. The focus is then on the roles of purinergic signalling in trauma, ischaemia, stroke and in neurodegenerative diseases, including Alzheimer's, Parkinson's and Huntington's diseases, as well as multiple sclerosis and amyotrophic lateral sclerosis. Neuroprotective mechanisms involving purinergic signalling are considered and its involvement in neuroregeneration, including the role of adult neural stem/progenitor cells. This article is part of the Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London NW3 2PF, UK; Department of Pharmacology and Therapeutics, The University of Melbourne, Australia.
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14
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Sakurai S, Fukunaga A, Ichinohe T, Kaneko Y. IV ATP potentiates midazolam sedation as assessed by bispectral index. Anesth Prog 2014; 61:95-8. [PMID: 25191981 DOI: 10.2344/0003-3006-61.3.95] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In this study, by measuring bispectral index (BIS), we tested the hypothesis that intravenous adenosine 5'-triphosphate (ATP) infusion would deepen the level of midazolam-induced sedation. Ten healthy volunteers underwent 2 experiments with at least 2 weeks' interval: immediately after intravenous bolus administration of midazolam (0.04 mg/kg), they received continuous infusion of either ATP infusion (100 μg/kg/min) or placebo (saline) for 40 minutes in a double-blind, randomized, crossover manner. Changes in BIS values and responsiveness to verbal command as well as cardiorespiratory variables were observed throughout the study periods. Administration of midazolam alone reduced BIS value from control: 97 ± 1 to 68 ± 18 at 25 minutes, which was accompanied by significant cardiopulmonary depressant effects, while maintaining responsiveness to verbal command (consciousness) throughout the study period. Coadministration of ATP with midazolam further reduced BIS value to 51 ± 13, associated with complete loss of consciousness without adverse effect on the cardiorespiratory systems. We conclude that the addition of ATP infusion to midazolam significantly enhances midazolam sedation without disturbing cardiorespiratory functions.
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Affiliation(s)
- Satoru Sakurai
- Assistant Professor, Department of Dental Anesthesiology, Tokyo Dental College, Chiba, Japan
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15
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The role of alpha-2 adrenoceptors in the anticonvulsant effects of adenosine on pentylenetetrazole-induced seizure threshold in mice. Pharmacol Biochem Behav 2014; 126:36-42. [PMID: 25242809 DOI: 10.1016/j.pbb.2014.09.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Revised: 08/04/2014] [Accepted: 09/13/2014] [Indexed: 11/23/2022]
Abstract
Adenosine has anticonvulsant effects in various models of seizures. Alpha-2 adrenoceptors have also demonstrated different effects in different models of epilepsy. In this study, the role of alpha-2 adrenoceptors in the anticonvulsant effects of adenosine in mice was determined according to the method of intravenous pentylenetetrazole-induced seizure. In this study, N(6)-cyclohexyladenosine (CHA) (a selective A1 receptor agonist), clonidine (an alpha-2 adrenoceptors agonist), yohimbine (an alpha-2 adrenoceptors antagonist) and 8-cyclopentyl-1,3-dimethylxanthine (8-CPT) (a selective A1 receptor antagonist) were used. CHA at doses of 0.5, 1 and 2mg/kg significantly increased seizure threshold with the maximum anticonvulsant effect at 2mg/kg. Yohimbine (0.1, 1 and 10mg/kg), clonidine (0.1, 0.5, 1 and 2mg/kg) and 8-CPT (0.5, 1, 2 and 4mg/kg) had no effect on seizure by itself. Combination of yohimbine (10mg/kg) and CHA (0.25mg/kg) increased clonic seizure latency showing that yohimbine and CHA have an additive effect. Increasing the seizure threshold created by combining ineffective doses of yohimbine (10mg/kg) and CHA (0.25mg/kg) was completely inhibited by 8-CPT (4mg/kg) or clonidine (1 and 2mg/kg). Clonidine (0.5, 1 and 2mg/kg) inhibited the anticonvulsant effects of CHA (2mg/kg). Combination of 8-CPT (1mg/kg) and clonidine (0.5mg/kg) which completely inhibited the anticonvulsant effect of CHA (2mg/kg) indicates that 8-CPT and clonidine have an additive effect. In conclusion, adenosine and yohimbine exhibit an additive effect on the enhancement of the pentylenetetrazole-induced seizure threshold in mice, indicating the interaction of alpha-2 adrenoceptors and A1 adenosine receptors.
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16
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Pani AK, Jiao Y, Sample KJ, Smeyne RJ. Neurochemical measurement of adenosine in discrete brain regions of five strains of inbred mice. PLoS One 2014; 9:e92422. [PMID: 24642754 PMCID: PMC3958516 DOI: 10.1371/journal.pone.0092422] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 02/21/2014] [Indexed: 12/28/2022] Open
Abstract
Adenosine (ADO), a non-classical neurotransmitter and neuromodulator, and its metabolites adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP), have been shown to play an important role in a number of biochemical processes. Although their signaling is well described, it has been difficult to directly, accurately and simultaneously quantitate these purines in tissue or fluids. Here, we describe a novel method for measuring adenosine (ADO) and its metabolites using high performance liquid chromatography with electrochemical detection (HPLC-ECD). Using this chromatographic technique, we examined baseline levels of ADO and ATP, ADP and AMP in 6 different brain regions of the C57BL/6J mouse: stratum, cortex, hippocampus, olfactory bulb, substantia nigra and cerebellum and compared ADO levels in 5 different strains of mice (C57BL/6J, Swiss-Webster, FVB/NJ, 129P/J, and BALB/c). These studies demonstrate that baseline levels of purines vary significantly among the brain regions as well as between different mouse strains. These dissimilarities in purine concentrations may explain the variable phenotypes among background strains described in neurological disease models.
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Affiliation(s)
- Amar K. Pani
- Department of Developmental Neurobiology, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Yun Jiao
- Department of Developmental Neurobiology, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Kenneth J. Sample
- Department of Developmental Neurobiology, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Richard J. Smeyne
- Department of Developmental Neurobiology, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
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17
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Functional cooperation of metabotropic adenosine and glutamate receptors regulates postsynaptic plasticity in the cerebellum. J Neurosci 2014; 33:18661-71. [PMID: 24259587 DOI: 10.1523/jneurosci.5567-12.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) may form heteromeric complexes and cooperatively mediate cellular responses. Although heteromeric GPCR complexes are suggested to occur in many neurons, their contribution to neuronal function remains unclear. We address this question using two GPCRs expressed in cerebellar Purkinje cells: adenosine A1 receptor (A1R), which regulates neurotransmitter release and neuronal excitability in central neurons, and type-1 metabotropic glutamate receptor (mGluR1), which mediates cerebellar long-term depression, a form of synaptic plasticity crucial for cerebellar motor learning. We examined interaction between these GPCRs by immunocytochemical, biochemical, and Förster resonance energy transfer analyses in cultured mouse Purkinje cells and heterologous expression cells. These analyses revealed that the GPCRs closely colocalized and formed heteromeric complexes on the cell surfaces. Furthermore, our electrophysiological analysis showed that CSF levels (40-400 nm) of adenosine or synthetic A1R agonists with comparable potencies blocked mGluR1-mediated long-term depression of the postsynaptic glutamate-responsiveness (glu-LTD) of cultured Purkinje cells. A similar dose of the A1R agonist decreased the ligand affinity of mGluR1 and did not affect depolarization-induced Ca(2+) influx, which is an essential factor in inducing glu-LTD. The A1R agonist did not affect glu-LTD mimicked by direct activation of protein kinase C. These results suggest that A1R blocked glu-LTD by decreasing the ligand sensitivity of mGluR1, but not the coupling efficacy from mGluR1 to the intracellular signaling cascades. These findings provide a new insight into neuronal GPCR signaling and demonstrate a novel regulatory mechanism of synaptic plasticity.
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18
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Affiliation(s)
- Miodrag Radulovacki
- Department of Pharmacology, University of Illinois at Chicago, 835 S. Wolcott Ave., Chicago, IL 60612, USA.
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19
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Marisco PC, Carvalho FB, Rosa MM, Girardi BA, Gutierres JM, Jaques JAS, Salla APS, Pimentel VC, Schetinger MRC, Leal DBR, Mello CF, Rubin MA. Piracetam prevents scopolamine-induced memory impairment and decrease of NTPDase, 5'-nucleotidase and adenosine deaminase activities. Neurochem Res 2013; 38:1704-14. [PMID: 23677777 DOI: 10.1007/s11064-013-1072-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 04/29/2013] [Accepted: 05/07/2013] [Indexed: 11/26/2022]
Abstract
Piracetam improves cognitive function in animals and in human beings, but its mechanism of action is still not completely known. In the present study, we investigated whether enzymes involved in extracellular adenine nucleotide metabolism, adenosine triphosphate diphosphohydrolase (NTPDase), 5'-nucleotidase and adenosine deaminase (ADA) are affected by piracetam in the hippocampus and cerebral cortex of animals subjected to scopolamine-induced memory impairment. Piracetam (0.02 μmol/5 μL, intracerebroventricular, 60 min pre-training) prevented memory impairment induced by scopolamine (1 mg/kg, intraperitoneal, immediately post-training) in the inhibitory avoidance learning and in the object recognition task. Scopolamine reduced the activity of NTPDase in hippocampus (53 % for ATP and 53 % for ADP hydrolysis) and cerebral cortex (28 % for ATP hydrolysis). Scopolamine also decreased the activity of 5'-nucleotidase (43 %) and ADA (91 %) in hippocampus. The same effect was observed in the cerebral cortex for 5'-nucleotidase (38 %) and ADA (68 %) activities. Piracetam fully prevented scopolamine-induced memory impairment and decrease of NTPDase, 5'-nucleotidase and adenosine deaminase activities in synaptosomes from cerebral cortex and hippocampus. In vitro experiments show that piracetam and scopolamine did not alter enzymatic activity in cerebral cortex synaptosomes. Moreover, piracetam prevented scopolamine-induced increase of TBARS levels in hippocampus and cerebral cortex. These results suggest that piracetam-induced improvement of memory is associated with protection against oxidative stress and maintenance of NTPDase, 5'-nucleotidase and ADA activities, and suggest the purinergic system as a putative target of piracetam.
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Affiliation(s)
- Patricia C Marisco
- Graduation Program in Pharmacology, Center of Health Sciences (CCS), Federal University of Santa Maria, Santa Maria, RS, CEP 97105-900, Brazil
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20
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Chen J, Wang Y, Wang Y, Yi X, Ge R. Studies on the effect of adenosine on calcium oscillation in hippocampal neurons. Exp Ther Med 2013; 5:1165-1168. [PMID: 23596485 PMCID: PMC3627451 DOI: 10.3892/etm.2013.973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Accepted: 02/13/2013] [Indexed: 11/05/2022] Open
Abstract
Adenosine (Ade) is an antiepileptic agent. In order to investigate the possible mechanism of action of Ade, its effect on calcium (Ca2+) oscillations in hippocampal neurons of Sprague Dawley (SD) rats was explored. Primary hippocampal neurons were cultured from suckling neonatal SD rats. Cells were cultured for 7–9 days and the Ca2+ oscillations in response to perfusion with Ade were detected using confocal laser scanning microscopy in combination with Fluo-3/AM labeling. This study found that Ade inhibits the spontaneous synchronized Ca2+ oscillation frequency and amplitude in mature hippocampal neurons and such inhibition depends on the Ade dosage level to a certain extent. Ade also had a significant inhibitory effect on high potassium-induced Ca2+ oscillation frequency and amplitude. Ade had a significant inhibitory effect on high-voltage-activated Ca2+ channel-mediated Ca2+ influx and Ca2+ oscillations in neurons. This may be one of the mechanisms for Ade to exert antiepileptic effects as an endogenous substance.
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Affiliation(s)
- Jinbo Chen
- Department of Neurology, The Affiliated Hospital of Binzhou Medical University, Binzhou 256603, P.R. China
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21
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Introduction to Purinergic Signalling in the Brain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 986:1-12. [DOI: 10.1007/978-94-007-4719-7_1] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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22
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Lutas A, Yellen G. The ketogenic diet: metabolic influences on brain excitability and epilepsy. Trends Neurosci 2012; 36:32-40. [PMID: 23228828 DOI: 10.1016/j.tins.2012.11.005] [Citation(s) in RCA: 222] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 11/13/2012] [Accepted: 11/13/2012] [Indexed: 12/25/2022]
Abstract
A dietary therapy for pediatric epilepsy known as the ketogenic diet has seen a revival in its clinical use during the past decade. Although the underlying mechanism of the diet remains unknown, modern scientific approaches, such as the genetic disruption of glucose metabolism, are allowing for more detailed questions to be addressed. Recent work indicates that several mechanisms may exist for the ketogenic diet, including disruption of glutamatergic synaptic transmission, inhibition of glycolysis, and activation of ATP-sensitive potassium channels. Here, we describe on-going work in these areas that is providing a better understanding of metabolic influences on brain excitability and epilepsy.
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Affiliation(s)
- Andrew Lutas
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
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23
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Jinnah HA, Hess EJ, Wilson MC, Gage FH, Friedmann T. Localization of hypoxanthine-guanine phosphoribosyltransferase mRNA in the mouse brain by in situ hybridization. Mol Cell Neurosci 2012; 3:64-78. [PMID: 19912847 DOI: 10.1016/1044-7431(92)90010-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/1991] [Indexed: 12/24/2022] Open
Abstract
Congenital deficiency of the purine salvage enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT) in humans results in a severe neurogenetic disorder known as the Lesch-Nyhan syndrome. Since little information concerning the precise localization of HPRT in the brain is currently available, we have used in situ hybridization to examine the expression of HPRT mRNA in the mouse brain. The results showed that HPRT mRNA is expressed in many regions of the normal mouse brain, with high levels in most, but not all neurons. In contrast, glial cells did not express detectable levels of HPRT mRNA. No HPRT mRNA was detected in the brains of mutant mice carrying a deletion in the HPRT gene.
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Affiliation(s)
- H A Jinnah
- Department of Neurosciences, University of California San Diego School of Medicine, La Jolla, California 92093, USA
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24
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Girardi E, Perez Raffo G, Rodriguez de Lores Arnaiz G. Increase of 5?-nucleotidase activity in some brain subcellular fractions after the administration of the convulsant 3-mercaptopropionic acid. Neurochem Int 2012; 14:331-5. [PMID: 20504434 DOI: 10.1016/0197-0186(89)90059-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/1988] [Accepted: 10/06/1988] [Indexed: 10/27/2022]
Abstract
5?-Nucleotidase activity was studied in subcellular fractions isolated from rat brain after the administration of the convulsant 3-mercaptopropionic acid. The results obtained showed that the activity of this membrane enzyme increased in the fractions of the cerebral cortex containing nerve endings and microsomes (Mic(20) and Mic(100)) isolated during the seizure, but not in the post-seizure period. This increase could be observed at pH 7.2 and 9.0 but not at pH 6.5. 5?-Nucleotidase activity in nuclear and myelin fractions did not differ between fractions from control and treated animals. It is suggested that the alteration in enzyme activity found in some brain fractions might be involved in the actions of adenosine during the convulsive seizure.
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Affiliation(s)
- E Girardi
- Instituto de Biologia Celular, Facultad de Medicina, U. B. A., Paraguay 2155, 1121 Buenos Aires, Argentina
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25
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Shetty PK, Galeffi F, Turner DA. Cellular Links between Neuronal Activity and Energy Homeostasis. Front Pharmacol 2012; 3:43. [PMID: 22470340 PMCID: PMC3308331 DOI: 10.3389/fphar.2012.00043] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 02/24/2012] [Indexed: 12/20/2022] Open
Abstract
Neuronal activity, astrocytic responses to this activity, and energy homeostasis are linked together during baseline, conscious conditions, and short-term rapid activation (as occurs with sensory or motor function). Nervous system energy homeostasis also varies during long-term physiological conditions (i.e., development and aging) and with adaptation to pathological conditions, such as ischemia or low glucose. Neuronal activation requires increased metabolism (i.e., ATP generation) which leads initially to substrate depletion, induction of a variety of signals for enhanced astrocytic function, and increased local blood flow and substrate delivery. Energy generation (particularly in mitochondria) and use during ATP hydrolysis also lead to considerable heat generation. The local increases in blood flow noted following neuronal activation can both enhance local substrate delivery but also provides a heat sink to help cool the brain and removal of waste by-products. In this review we highlight the interactions between short-term neuronal activity and energy metabolism with an emphasis on signals and factors regulating astrocyte function and substrate supply.
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Affiliation(s)
- Pavan K Shetty
- Neurosurgery and Neurobiology, Research and Surgery Services, Durham VA Medical Center, Duke University Durham, NC, USA
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26
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Burnstock G, Krügel U, Abbracchio MP, Illes P. Purinergic signalling: from normal behaviour to pathological brain function. Prog Neurobiol 2011; 95:229-74. [PMID: 21907261 DOI: 10.1016/j.pneurobio.2011.08.006] [Citation(s) in RCA: 315] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 08/12/2011] [Accepted: 08/15/2011] [Indexed: 02/07/2023]
Abstract
Purinergic neurotransmission, involving release of ATP as an efferent neurotransmitter was first proposed in 1972. Later, ATP was recognised as a cotransmitter in peripheral nerves and more recently as a cotransmitter with glutamate, noradrenaline, GABA, acetylcholine and dopamine in the CNS. Both ATP, together with some of its enzymatic breakdown products (ADP and adenosine) and uracil nucleotides are now recognised to act via P2X ion channels and P1 and P2Y G protein-coupled receptors, which are widely expressed in the brain. They mediate both fast signalling in neurotransmission and neuromodulation and long-term (trophic) signalling in cell proliferation, differentiation and death. Purinergic signalling is prominent in neurone-glial cell interactions. In this review we discuss first the evidence implicating purinergic signalling in normal behaviour, including learning and memory, sleep and arousal, locomotor activity and exploration, feeding behaviour and mood and motivation. Then we turn to the involvement of P1 and P2 receptors in pathological brain function; firstly in trauma, ischemia and stroke, then in neurodegenerative diseases, including Alzheimer's, Parkinson's and Huntington's, as well as multiple sclerosis and amyotrophic lateral sclerosis. Finally, the role of purinergic signalling in neuropsychiatric diseases (including schizophrenia), epilepsy, migraine, cognitive impairment and neuropathic pain will be considered.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London NW3 2PF, UK.
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27
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Brent RL, Christian MS, Diener RM. Evaluation of the reproductive and developmental risks of caffeine. BIRTH DEFECTS RESEARCH. PART B, DEVELOPMENTAL AND REPRODUCTIVE TOXICOLOGY 2011; 92:152-87. [PMID: 21370398 PMCID: PMC3121964 DOI: 10.1002/bdrb.20288] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 01/18/2011] [Accepted: 01/23/2011] [Indexed: 11/12/2022]
Abstract
A risk analysis of in utero caffeine exposure is presented utilizing epidemiological studies and animal studies dealing with congenital malformation, pregnancy loss, and weight reduction. These effects are of interest to teratologists, because animal studies are useful in their evaluation. Many of the epidemiology studies did not evaluate the impact of the "pregnancy signal," which identifies healthy pregnancies and permits investigators to identify subjects with low pregnancy risks. The spontaneous abortion epidemiology studies were inconsistent and the majority did not consider the confounding introduced by not considering the pregnancy signal. The animal studies do not support the concept that caffeine is an abortafacient for the wide range of human caffeine exposures. Almost all the congenital malformation epidemiology studies were negative. Animal pharmacokinetic studies indicate that the teratogenic plasma level of caffeine has to reach or exceed 60 µg/ml, which is not attainable from ingesting large amounts of caffeine in foods and beverages. No epidemiological study described the "caffeine teratogenic syndrome." Six of the 17 recent epidemiology studies dealing with the risk of caffeine and fetal weight reduction were negative. Seven of the positive studies had growth reductions that were clinically insignificant and none of the studies cited the animal literature. Analysis of caffeine's reproductive toxicity considers reproducibility and plausibility of clinical, epidemiological, and animal data. Moderate or even high amounts of beverages and foods containing caffeine do not increase the risks of congenital malformations, miscarriage or growth retardation. Pharmacokinetic studies markedly improve the ability to perform the risk analyses.
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Affiliation(s)
- Robert L Brent
- Thomas Jefferson University, Alfred I. duPont Hospital for Children, Wilmington, Delaware 19899, USA.
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28
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Abstract
Caffeine is widely used to promote wakefulness and counteract fatigue induced by restriction of sleep, but also to counteract the effects of caffeine abstinence. Adenosine is a physiological molecule, which in the central nervous system acts predominantly as an inhibitory neuromodulator. Adenosine is also a sleep-promoting molecule. Caffeine binds to adenosine receptors, and the antagonism of the adenosinergic system is believed to be the mechanism through which caffeine counteracts sleep in humans as well as in other species. The sensitivity for caffeine varies markedly among individuals. Recently, genetic variations in genes related to adenosine metabolism have provided at least a partial explanation for this variability. The main effects of caffeine on sleep are decreased sleep latency, shortened total sleep time, decrease in power in the delta range, and sleep fragmentation. Caffeine may also decrease the accumulation of sleep propensity during waking, thus inducing long-term harmful effects on sleep quality.
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Modulation of brain-derived neurotrophic factor (BDNF) actions in the nervous system by adenosine A(2A) receptors and the role of lipid rafts. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1808:1340-9. [PMID: 20603099 DOI: 10.1016/j.bbamem.2010.06.028] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Revised: 06/23/2010] [Accepted: 06/27/2010] [Indexed: 12/11/2022]
Abstract
In this paper we review some novel aspects related to the way adenosine A(2A) receptors (A(2A)R) modulate the action of BDNF or its high-affinity receptors, the TrkB receptors, on synaptic transmission and plasticity, as well as upon cholinergic currents and GABA transporters. Evidence has been accumulating that adenosine A(2A)Rs are required for most of the synaptic actions of BDNF. In some cases, where A(2A)Rs are constitutively activated (e.g. by endogenous extracellular adenosine), the need for A(2A)R activation for the maintenance of the synaptic influences of BDNF can be envisaged from the loss of BDNF effects upon blockade of adenosine A(2A)Rs or upon removal of extracellular adenosine with adenosine deaminase. In some other cases, it is necessary to enhance extracellular adenosine levels (e.g. depolarization) or to further activate A(2A)Rs (e.g. with selective agonists) to trigger a BDNF neuromodulatory role at the synapses. Age- and cell-dependent differences may determine the above two possibilities, but in all cases it is quite clear that there is close interplay between adenosine A(2A)Rs and BDNF TrkB receptors at synapses. The role of lipid rafts in this cross-talk will be discussed. This article is part of a Special Issue entitled: "Adenosine Receptors".
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Kudryashov IE. Effects of some derivatives of purine nucleotides in the nervous tissue: Focus on adenosine and xanthine. NEUROCHEM J+ 2009. [DOI: 10.1134/s1819712409040011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Effect of acute stress on NTPDase and 5'-nucleotidase activities in brain synaptosomes in different stages of development. Int J Dev Neurosci 2009; 28:175-82. [PMID: 19932163 DOI: 10.1016/j.ijdevneu.2009.11.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 11/05/2009] [Accepted: 11/15/2009] [Indexed: 12/20/2022] Open
Abstract
The aim of the present study was to examine the effect of acute restraint stress on rat brain synaptosomal plasma membrane (SPM) ecto-nucleotidase activities at specific stages of postnatal development (15-, 30-, 60- and 90-day-old rats) by measuring the rates of ATP, ADP and AMP hydrolysis 1, 24 and 72 h post-stress. At 1 h after stress NTPDase and ecto-5'-nucleotidase activities were decreased in rats aged up to 60 days old. In adult rats elevated enzyme activities were detected, which indicated the existence of different short-term stress responses during development. A similar pattern of ATP and ADP hydrolysis changes as well as the ATP/ADP ratio in all developmental stages indicated that NTPDase3 was acutely affected after stress. The long-term effect of acute stress on NTPDase activity differed during postnatal development. In juvenile animals (15 days old) NTPDase activity was not altered. However, in later developmental stages (30 and 60 days old rats) NTPDase activity decreased and persisted for 72 h post-stress. In adult rats only ATP hydrolysis was decreased after 24 h, indicating that ecto-ATPase was affected by stress. Ecto-5'-nucleotidase hydrolysing activity was decreased within 24 h in adult rats, while in 15- and 30-day old rats it decreased 72 h post-stress. At equivalent times in pubertal rats (60 days old) a slight activation of ecto-5'-nucleotidase was detected. Our results highlight the developmental-dependence of brain ecto-nucleotidase susceptibility to acute stress and the likely existence of different mechanisms involved in time-dependent ecto-nucleotidase activity modulation following stress exposure. Clearly there are differences in the response of the purinergic system to acute restraint stress between young and adult rats.
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32
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Adenosine A1 receptors using 8-dicyclopropylmethyl-1-[11C]methyl-3-propylxanthine PET in Alzheimer’s disease. Ann Nucl Med 2009; 22:841-7. [DOI: 10.1007/s12149-008-0185-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Accepted: 06/19/2008] [Indexed: 01/18/2023]
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Antipsychotic drugs inhibit nucleotide hydrolysis in zebrafish (Danio rerio) brain membranes. Toxicol In Vitro 2008; 23:78-82. [PMID: 18996465 DOI: 10.1016/j.tiv.2008.10.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 10/15/2008] [Accepted: 10/16/2008] [Indexed: 11/20/2022]
Abstract
Haloperidol (HAL), olanzapine (OLZ), and sulpiride (SULP) are antipsychotic drugs widely used in the pharmacotherapy of psychopathological symptoms observed in schizophrenia or mood-related psychotic symptoms in affective disorders. Here, we tested the in vitro effects of different concentrations of a typical (HAL) and two atypical (OLZ and SULP) antipsychotic drugs on ectonucleotidase activities from zebrafish brain membranes. HAL inhibited ATP (28.9%) and ADP (26.5%) hydrolysis only at 250 microM. OLZ decreased ATPase activity at all concentrations tested (23.8-60.7%). SULP did not promote significant changes on ATP hydrolysis but inhibited ADP hydrolysis at 250 microM (25.6%). All drugs tested, HAL, OLZ, and SULP, did not promote any significant changes on 5'-nucleotidase activity in the brain membranes of zebrafish. These findings demonstrated that antipsychotic drugs could inhibit NTPDase activities whereas did not change 5'-nucleotidase. Such modulation can alter the adenosine levels, since the ectonucleotidase pathway is an important source of extracellular adenosine. Thus, it is possible to suggest that changes promoted by antipsychotic drugs in the bilayer membrane could alter the NTPDase activities, modulating extracellular ATP and adenosine levels.
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Calabrese EJ. Addiction and Dose Response: The Psychomotor Stimulant Theory of Addiction Reveals That Hormetic Dose Responses Are Dominant. Crit Rev Toxicol 2008; 38:599-617. [DOI: 10.1080/10408440802026315] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Gracia E, Cortés A, Meana JJ, García-Sevilla J, Herhsfield MS, Canela EI, Mallol J, Lluís C, Franco R, Casadó V. Human adenosine deaminase as an allosteric modulator of human A(1) adenosine receptor: abolishment of negative cooperativity for [H](R)-pia binding to the caudate nucleus. J Neurochem 2008; 107:161-70. [PMID: 18680557 DOI: 10.1111/j.1471-4159.2008.05602.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It has been shown that adenosine deaminase (ADA; EC 3.5.4.4) behaves as an ecto-enzyme anchored to membrane proteins, among them A(1) adenosine receptors (A(1)Rs). Bovine ADA interacts with A(1)Rs from many species and regulates agonists binding to receptors in an activity-independent form. However, it was not known whether human ADA exerted any effect on the agonist binding to human A(1)Rs, because of both technical difficulties in obtaining pure human ADA and tissues containing human A(1)Rs. In this study, human ADA was purified to homogeneity. Taking in consideration that A(1)Rs form homodimers and taking advantage of a new procedure to fit binding data to receptors dimers, which allows to calculate ligand dissociation constants and the degree of cooperativity between the two subunits in the dimer, here it is demonstrated that human ADA markedly enhances the agonist and antagonist affinity and abolishes the negative cooperativity on agonist binding to human striatal A(1)Rs. ADA also increases the ability of the agonist to decrease the forskolin-induced cAMP levels. The results show that human ADA, apart from reducing the adenosine concentration and thus preventing A(1)R desensitization, binds to A(1)R behaving as an allosteric effector that markedly enhances agonist affinity and increases receptor functionality. The physiological role of the interaction is to make receptors more sensitive to adenosine. This powerful regulation has important implications for the physiology and pharmacology of neuronal A(1)Rs.
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Affiliation(s)
- Eduard Gracia
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), University of Barcelona, Spain.
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Akula KK, Dhir A, Kulkarni S. Systemic administration of adenosine ameliorates pentylenetetrazol-induced chemical kindling and secondary behavioural and biochemical changes in mice. Fundam Clin Pharmacol 2007; 21:583-94. [DOI: 10.1111/j.1472-8206.2007.00540.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ajloo D, Saboury AA, Haghi-Asli N, Ataei-Jafarai G, Moosavi-Movahedi AA, Ahmadi M, Mahnam K, Namaki S. Kinetic, thermodynamic and statistical studies on the inhibition of adenosine deaminase by aspirin and diclofenac. J Enzyme Inhib Med Chem 2007; 22:395-406. [PMID: 17847705 DOI: 10.1080/14756360701229085] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The kinetic and thermodynamic effects of aspirin and diclofenac on the activity of adenosine deaminase (ADA) were studied in 50 mM phosphate buffer pH = 7.5 at 27 and 37 degrees C, using UV-Vis spectrophotometry and isothermal titration calorimetry (ITC). Aspirin exhibits competitive inhibition at 27 and 37 degrees C and the inhibition constants are 42.8 and 96.8 microM respectively, using spectrophotometry. Diclofenac shows competitive behavior at 27 degrees C and uncompetitive at 37 degrees C with inhibition constants of 56.4 and 30.0 microM, at respectively. The binding constant and enthalpy of binding, at 27 degrees C are 45 microM, - 64.5 kJ/mol and 61 microM, - 34.5 kJ/mol for aspirin and diclofenac. Thermodynamic data revealed that the binding process for these ADA inhibitors is enthalpy driven. QSAR studies by principal component analysis implemented in SPSS show that the large, polar, planar, and aromatic nucleoside and small, aromatic and polar non-nucleoside molecules have lower inhibition constants.
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Affiliation(s)
- Davood Ajloo
- Faculty of Chemistry, Damghan University of Basic Science, Damghan, Iran.
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Abstract
This review is focused on purinergic neurotransmission, i.e., ATP released from nerves as a transmitter or cotransmitter to act as an extracellular signaling molecule on both pre- and postjunctional membranes at neuroeffector junctions and synapses, as well as acting as a trophic factor during development and regeneration. Emphasis is placed on the physiology and pathophysiology of ATP, but extracellular roles of its breakdown product, adenosine, are also considered because of their intimate interactions. The early history of the involvement of ATP in autonomic and skeletal neuromuscular transmission and in activities in the central nervous system and ganglia is reviewed. Brief background information is given about the identification of receptor subtypes for purines and pyrimidines and about ATP storage, release, and ectoenzymatic breakdown. Evidence that ATP is a cotransmitter in most, if not all, peripheral and central neurons is presented, as well as full accounts of neurotransmission and neuromodulation in autonomic and sensory ganglia and in the brain and spinal cord. There is coverage of neuron-glia interactions and of purinergic neuroeffector transmission to nonmuscular cells. To establish the primitive and widespread nature of purinergic neurotransmission, both the ontogeny and phylogeny of purinergic signaling are considered. Finally, the pathophysiology of purinergic neurotransmission in both peripheral and central nervous systems is reviewed, and speculations are made about future developments.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neurscience Centre, Royal Free and University College Medical School, London, UK.
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Pedrazza EL, Riboldi GP, Pereira GS, Izquierdo I, Bonan CD. Habituation to an open field alters ecto-nucleotidase activities in rat hippocampal synaptosomes. Neurosci Lett 2007; 413:21-4. [PMID: 17166665 DOI: 10.1016/j.neulet.2006.11.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Revised: 11/09/2006] [Accepted: 11/12/2006] [Indexed: 11/20/2022]
Abstract
ATP and adenosine may play a role in the mechanisms of synaptic plasticity and memory formation. Previous studies have shown that ecto-nucleotidase activities are altered during memory consolidation of an aversive task named step-down inhibitory avoidance. Here we investigate ecto-nucleotidase activities in hippocampal synaptosomes of rats submitted to training and test sessions of habituation to open field, which is one of the most elementary forms of learning. There were no significant alterations on ATP, ADP and AMP hydrolysis immediately after the training session. However, immediately after the test session (0min), there was a significant increase of ATP hydrolysis (61%), but not of ADP and AMP hydrolysis. Sixty minutes after the test session, a significant increase of NTPDase (75% and 60.5% for ATP and ADP hydrolysis, respectively) and ecto-5'-nucleotidase (40%) activities was observed. This study reveals the involvement of ecto-nucleotidase activities in different learning paradigms during memory processing.
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Affiliation(s)
- Eduardo Luiz Pedrazza
- Laboratório de Neuroquímica e Psicofarmacologia, Departamento de Biologia Celular e Molecular, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul. Avenida Ipiranga, 6681, 90619-900 Porto Alegre, RS, Brazil
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Jhaveri KA, Toth LA, Sekino Y, Ramkumar V. Nitric oxide serves as an endogenous regulator of neuronal adenosine A1receptor expression. J Neurochem 2006; 99:42-53. [PMID: 16987234 DOI: 10.1111/j.1471-4159.2006.04095.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nitric oxide (NO) radicals are produced during normal cellular function, after tissue injury, and in response to immune system activation during infection. The transformation of NO to peroxynitrite is essential for mediating some of its physiological and/or cytotoxic actions. As the expression of the adenosine A1 receptor (A1AR) is regulated by oxidative stress, we evaluated the role of NO in the regulation of A1AR expression, a G protein-coupled receptor involved in cytoprotection in the central nervous system. Administration of the NO donor, S-nitrosylpenicillamine (SNAP), to pheochromocytoma 12 (PC12) cells increased A1AR protein in a time- and dose-dependent manner, with maximal induction observed with 20 microm SNAP at 24 h. The response to SNAP was attenuated by the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3 oxide (C-PTIO), and by the inhibition of nuclear factor-kappaB (NF-kappaB), implicating this transcription factor in the regulatory process. In addition SNAP also increased the degradation of Inhibitory kappaB-alpha (IkappaB-alpha), a marker of NF-kappaB activation. Furthermore, the induction of inducible nitric oxide synthase (iNOS) by lipopolysaccharide increased A1AR in PC12 cells and in mice, whereas the inhibition of NOS activity suppressed this response. We conclude that NO, via the activation of NF-kappaB, serves as an endogenous regulator of A1AR, and speculate that the induction of the A1AR could counteract the cytotoxicity of NO.
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Affiliation(s)
- Krishna A Jhaveri
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois 62794-9629, USA
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Fragata IR, Ribeiro JA, Sebastião AM. Nitric oxide mediates interactions between GABAA receptors and adenosine A1 receptors in the rat hippocampus. Eur J Pharmacol 2006; 543:32-9. [PMID: 16831416 DOI: 10.1016/j.ejphar.2006.05.043] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Revised: 05/16/2006] [Accepted: 05/18/2006] [Indexed: 10/24/2022]
Abstract
Adenosine and gamma-aminobutyric acid (GABA) are both major inhibitory neuromodulators/neurotransmitters in the CNS. We now investigated if endogenous GABA modulates adenosine A(1)-mediated action on synaptic transmission in the hippocampus. Field excitatory postsynaptic potentials (fEPSP) were recorded from the CA(1) area of rat hippocampal slices. The adenosine analogue 2-chloroadenosine (0.15-1 microM) inhibited synaptic transmission with an EC(50) of 398 nM. Blocking GABA(A) receptors with the specific antagonists, bicuculline (10 microM) or picrotoxin (10 microM) potentiated the inhibitory effect of 2-chloroadenosine. The concentration-response curve for 2-chloroadenosine was displaced to the left by a factor of 2 (EC(50)=210 nM) in the presence of bicuculline (10 microM). GABA(A) receptor blockade also potentiated the action of N(6)-cyclopentyladenosine (CPA, 10 nM), a specific adenosine A(1) receptor agonist. Prevention of adenosine accumulation with adenosine deaminase (1 U/ml) did not influence bicuculline-induced potentiation of the effect of 2-chloroadenosine. The potentiation of adenosine A(1)-mediated response by bicuculline was abolished when nitric oxide (NO) synthase was inhibited with nitroarginine (100 microM), and when guanylyl cyclase was inhibited with 1H-[1,2,4]Oxadiazolo[4,3-a] quinoxalin-1-one (ODQ, 20 microM). The NO donors, (+/-)-S-nitroso-N-acetylpencillamine (SNAP, 300 microM) and diethylamine NONate diethylammonium salt (DEA/NO, 100 microM), significantly enhanced the inhibitory action of 2-chloroadenosine (150 nM). It is concluded that the blockade of GABA(A) receptors induces a potentiation of adenosine A(1) receptor-mediated inhibitory action, an effect that involves NO acting through guanylyl cyclase. Therefore, endogenous GABA might exert an inhibitory effect over adenosine A(1)-mediated responses in the hippocampus, which may represent a physiologic regulatory mechanism between the two inhibitory mediators.
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Affiliation(s)
- Isabel R Fragata
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina e Instituto de Medicina Molecular, Universidade de Lisboa, Portugal
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Hadjicharalambous M, Georgiades E, Kilduff LP, Turner AP, Tsofliou F, Pitsiladis YP. Influence of caffeine on perception of effort, metabolism and exercise performance following a high-fat meal. J Sports Sci 2006; 24:875-87. [PMID: 16815783 DOI: 10.1080/02640410500249399] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
This study examined the effects of caffeine, co-ingested with a high fat meal, on perceptual and metabolic responses during incremental (Experiment 1) and endurance (Experiment 2) exercise performance. Trained participants performed three constant-load cycling tests at approximately 73% of maximal oxygen uptake (VO2max) for 30 min at 20 degrees C (Experiment 1, n = 8) and to the limit of tolerance at 10 degrees C (Experiment 2, n = 10). The 30 min constant-load exercise in Experiment 1 was followed by incremental exercise (15 W . min-1) to fatigue. Four hours before the first test, the participants consumed a 90% carbohydrate meal (control trial); in the remaining two tests, the participants consumed a 90% fat meal with (fat + caffeine trial) and without (fat-only trial) caffeine. Caffeine and placebo were randomly assigned and ingested 1 h before exercise. In both experiments, ratings of perceived leg exertion were significantly lower during the fat + caffeine than fat-only trial (Experiment 1: P < 0.001; Experiment 2: P < 0.01). Ratings of perceived breathlessness were significantly lower in Experiment 1 (P < 0.01) and heart rate higher in Experiment 2 (P < 0.001) on the fat + caffeine than fat-only trial. In the two experiments, oxygen uptake, ventilation, blood [glucose], [lactate] and plasma [glycerol] were significantly higher on the fat + caffeine than fat-only trial. In Experiment 2, plasma [free fatty acids], blood [pyruvate] and the [lactate]:[pyruvate] ratio were significantly higher on the fat + caffeine than fat-only trial. Time to exhaustion during incremental exercise (Experiment 1: control: 4.9, s = 1.8 min; fat-only: 5.0, s = 2.2 min; fat + caffeine: 5.0, s = 2.2 min; P > 0.05) and constant-load exercise (Experiment 2: control: 116 (88 - 145) min; fat-only: 122 (96 - 144) min; fat + caffeine: 127 (107 - 176) min; P > 0.05) was not different between the fat-only and fat + caffeine trials. In conclusion, while a number of metabolic responses were increased during exercise after caffeine ingestion, perception of effort was reduced and this may be attributed to the direct stimulatory effect of caffeine on the central nervous system. However, this caffeine-induced reduction in effort perception did not improve exercise performance.
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Franco R, Ciruela F, Casadó V, Cortes A, Canela EI, Mallol J, Agnati LF, Ferré S, Fuxe K, Lluis C. Partners for adenosine A1 receptors. J Mol Neurosci 2005; 26:221-32. [PMID: 16012195 DOI: 10.1385/jmn:26:2-3:221] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
G protein-coupled receptors (GPCRs) are targets for therapy in a variety of neurological diseases. Using adenosine A1 receptors (A1Rs) as paradigm of GPCRs, this review focuses on how protein-protein interactions, from monomers to heteromers, can contribute to hormone/neurotransmitter/neuromodulator regulation. The interaction of A1Rs with other membrane receptors, enzymes, and adaptor and scaffolding proteins is relevant for receptor traffic, internalization, and desensitization, and A1Rs are extremely important in driving signaling through different intracellular pathways. There is even the possibility of linking together GPCR heteromeric complexes with ion channel receptors in a receptor mosaic that might have special integrative value and might constitute the molecular basis for learning and memory.
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Affiliation(s)
- Rafael Franco
- Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona, Spain.
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Nicolaidis R, Bruno AN, Sarkis JJF, Souza DO. Increase of adenine nucleotide hydrolysis in rat hippocampal slices after seizures induced by quinolinic acid. Neurochem Res 2005; 30:385-90. [PMID: 16018583 DOI: 10.1007/s11064-005-2613-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Quinolinic acid (QUIN), an endogenous convulsant compound, overstimulates the glutamatergic system stimulating N-methyl-D-aspartate receptors, enhancing glutamate release and inhibiting glutamate uptake. Glutamate releases the neuroprotector adenosine, which in turn reduces glutamate release and depresses the neuronal activity. Additionally, adenine nucleotides are an important source of adenosine, by action of ecto-nucleotidases. Here we evaluated the adenine nucleotide hydrolysis in hippocampal slices of adult rats in different times after seizures induced by QUIN. After 45 min, there was an increase of ATP and ADP hydrolysis. After 5 h, there was an increase of ATP, ADP and AMP hydrolysis. After 12 h, there was an increase only of ATP hydrolysis. After 24 h, all hydrolysis returned to control levels. As slice preparations maintain tissue integrity, this study indicates, more than previously observed with synaptosomal preparations, that the extracellular production of the neuroprotector adenosine may be involved in brain responses to seizures.
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Affiliation(s)
- Rafael Nicolaidis
- Department of Biochemistry, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
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Lejeune J. Pathogenesis of mental deficiency in trisomy 21. AMERICAN JOURNAL OF MEDICAL GENETICS. SUPPLEMENT 2005; 7:20-30. [PMID: 2149947 DOI: 10.1002/ajmg.1320370705] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In trisomy 21, pathogenesis of mental retardation is still poorly understood although the knowledge of the genic content of chromosome 21 is steadily increasing. Short of discovering how to silence selectively one of the 3 chromosomes 21, no rational medication can be envisaged before pathogenesis has been unraveled, at least partially. A biochemical scheme of impairment of mental efficiency is presented. Secondarily, the possible deleterious effects of a given gene overdose are discussed. Cu/Zn SOD, cystathionine beta synthase, S 100 beta protein, phosphofructokinase, purine synthesis and adenosine pharmacology, thyroid disturbance, and elevated TSH with low rT3 as well as biopterine metabolism interferences are reviewed. It is observed that the metabolic paths controlled by these genes, although unrelated at first glance, are in fact tightly related by their effects, just as if synteny was in some way related to biochemical cooperation or mutually controlled regulation. Experiments in vitro have demonstrated a peculiar sensitivity of trisomic 21 lymphocytes to methotrexate. From this starting point, systematic research of special sensitivities has begun. Clinical observations and relevant statistical methods allow study of the speed of mental development under various medications. The interest of regulating thyroid metabolism, when needed, is exemplified. Reequilibration of monocarbon metabolism is discussed and the seemingly favourable effect of folinic acid medication in pseudo-Alzheimer complication is presented.
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Affiliation(s)
- J Lejeune
- Centre de Recherches Claude Bernard, Génétique Humaine et Maladies de l'Intelligence, Institut de Progenèse, Paris, France
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Cunha RA. Neuroprotection by adenosine in the brain: From A(1) receptor activation to A (2A) receptor blockade. Purinergic Signal 2005; 1:111-34. [PMID: 18404497 PMCID: PMC2096528 DOI: 10.1007/s11302-005-0649-1] [Citation(s) in RCA: 404] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2004] [Accepted: 11/10/2004] [Indexed: 12/11/2022] Open
Abstract
Adenosine is a neuromodulator that operates via the most abundant inhibitory adenosine A(1) receptors (A(1)Rs) and the less abundant, but widespread, facilitatory A(2A)Rs. It is commonly assumed that A(1)Rs play a key role in neuroprotection since they decrease glutamate release and hyperpolarize neurons. In fact, A(1)R activation at the onset of neuronal injury attenuates brain damage, whereas its blockade exacerbates damage in adult animals. However, there is a down-regulation of central A(1)Rs in chronic noxious situations. In contrast, A(2A)Rs are up-regulated in noxious brain conditions and their blockade confers robust brain neuroprotection in adult animals. The brain neuroprotective effect of A(2A)R antagonists is maintained in chronic noxious brain conditions without observable peripheral effects, thus justifying the interest of A(2A)R antagonists as novel protective agents in neurodegenerative diseases such as Parkinson's and Alzheimer's disease, ischemic brain damage and epilepsy. The greater interest of A(2A)R blockade compared to A(1)R activation does not mean that A(1)R activation is irrelevant for a neuroprotective strategy. In fact, it is proposed that coupling A(2A)R antagonists with strategies aimed at bursting the levels of extracellular adenosine (by inhibiting adenosine kinase) to activate A(1)Rs might constitute the more robust brain neuroprotective strategy based on the adenosine neuromodulatory system. This strategy should be useful in adult animals and especially in the elderly (where brain pathologies are prevalent) but is not valid for fetus or newborns where the impact of adenosine receptors on brain damage is different.
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Affiliation(s)
- Rodrigo A Cunha
- Center for Neuroscience of Coimbra, Institute of Biochemistry, Faculty of Medicine, University of Coimbra, Coimbra, Portugal,
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Parkinson FE, Xiong W, Zamzow CR. Astrocytes and neurons: different roles in regulating adenosine levels. Neurol Res 2005; 27:153-60. [PMID: 15829178 DOI: 10.1179/016164105x21878] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES Adenosine is an endogenous nucleoside that signals through G-protein coupled receptors. Extracellular adenosine is required for receptor activation and two pathways have been identified for formation and cellular release of adenosine. The CLASSICAL pathway relies on intracellular formation of adenosine from adenine nucleotides and cellular efflux of adenosine via equilibrative nucleoside transporters (ENTs). The ALTERNATE pathway involves cellular release of adenine nucleotides, hydrolysis via ecto-5'-nucleotidases and extracellular formation of adenosine. METHODS A rat model of cerebral ischemia and primary cultures of rat forebrain astrocytes and neurons were used. RESULTS Using a rat model of cerebral ischemia, the ENT1 inhibitor nitrobenzylmercaptopurine ribonucleoside (NBMPR) significantly increased post-ischemic forebrain adenosine levels and significantly decreased hippocampal neuron injury relative to saline-treatment. NBMPR-induced increases in adenosine receptor activation were not detected, suggesting that altering the intracellular:extracellular distribution of adenosine can affect ischemic outcome. Using primary cultures of rat forebrain astrocytes and neurons, adenosine release was evoked by ischemic-like conditions. Dipyridamole, an inhibitor of ENTs, was more effective at inhibiting adenosine release from neurons than from astrocytes. In contrast, alpha , beta-methylene ADP, an inhibitor of ecto-5'-nucleotidase, was effective at inhibiting adenosine release from astrocytes, but not from neurons. Thus, during ischemic-like conditions, neurons released adenosine via the CLASSICAL pathway, while astrocytes released adenosine via the ALTERNATE pathway. DISCUSSION These cell type differences in pathways for adenosine formation during ischemia may allow transport inhibitors to block simultaneously adenosine release from neurons and adenosine uptake into astrocytes. In principle, this could improve neuronal ATP levels without decreasing adenosine receptor activation.
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Affiliation(s)
- Fiona E Parkinson
- Department of Pharmacology and Therapeutics, University of Manitoba, A203-753 McDermot Avenue, Winnipeg MB Canada R3E 0T6.
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Krnjević K. From cAMP to adenosine: an illuminating shift of focus. Neurol Res 2005; 27:129-36. [PMID: 15829174 DOI: 10.1179/016164105x21797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
In a remarkable career, straddling five decades, John Phillis pursued with fierce determination and exceptional energy the main goal of his scientific life, to throw light on the chemical agents that control brain function. Starting in Australia, he settled in North America, first in Canada, then in the USA, where his long tenure at Wayne State brought his career to its culmination.
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Rücker B, Pereira GS, Fürstenau CR, Izquierdo I, Bonan CD, Sarkis JJF. Inhibitory avoidance task reveals differences in ectonucleotidase activities between male and female rats. Neurochem Res 2005; 29:2231-7. [PMID: 15672544 DOI: 10.1007/s11064-004-7030-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Studies demonstrated that endogenous levels of estrogen affect the long-term potentiation (LTP) and long-term depression (LTD). ATP and adenosine may play a role in the modulation of LTP. Our laboratory observed in previous studies that inhibitory avoidance task is associated with a decrease in hippocampal ectonucleotidase activities in adult male rats. To explore if ectonucleotidases are modulated in memory formation in female rats, as observed in males, we evaluated the effect of inhibitory avoidance training on synaptosomal NTP Dase and 5'-nucleotidase activities in rat hippocampus from both sexes. The results demonstrated a decrease in ATP, ADP and AMP hydrolysis (37%, 38% and 32%, respectively) immediately after training and a significant inhibition only in ATP hydrolysis (36%) 30 min post-training in male rats. There were no changes in ectonucleotidase activities from female rats. These findings provide support for the view that could exist biochemical differences in ectonucleotidase activities between males and females.
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Affiliation(s)
- Bárbara Rücker
- Departamento de Bioquimica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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