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Stepanichev M, Aniol V, Lazareva N, Gulyaeva N. Decreased Hippocampal Neurogenesis in Aged Male Wistar Rats Is Not Associated with Memory Acquisition in a Water Maze. Int J Mol Sci 2023; 24:13276. [PMID: 37686083 PMCID: PMC10487931 DOI: 10.3390/ijms241713276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/12/2023] [Accepted: 08/18/2023] [Indexed: 09/10/2023] Open
Abstract
Brain aging is associated with a progressive decrease in learning abilities, memory, attention, decision making, and sensory perception. Age-related cognitive disturbances may be related to a decrease in the functional capacities of the hippocampus. This brain region is essential for learning and memory, and the lifelong neurogenesis occurring in the subgranular zone of the dentate gyrus may be a key event mediating the mnemonic functions of the hippocampus. In the present study, we investigated whether age-related changes in hippocampal neurogenesis are associated with learning and memory disturbances. Four- and 24-month-old rats were trained to find a hidden platform in a water maze. Though the older group showed higher latency to search the platform as compared to the younger group, both groups learned the task. However, the density of proliferating (PCNA-positive), differentiating (Dcx-positive), and new neurons (pre-labeled BrdU-positive) was significantly lower in the hippocampus of aged rats as compared to young ones. This inhibition of neurogenesis could be related to increased local production of nitric oxide since the density of neurons expressing neuronal NO-synthase was higher in the aged hippocampus. Thus, we can suggest that an age-related decrease in neurogenesis is not directly associated with place learning in aged rats.
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Affiliation(s)
- Mikhail Stepanichev
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Butlerova Str., 5a, Moscow 117485, Russia; (V.A.); (N.L.); (N.G.)
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Neurochemical changes underlying cognitive impairment in olfactory bulbectomized rats and the impact of the mGlu 5-positive allosteric modulator CDPPB. Brain Res 2021; 1768:147577. [PMID: 34217728 DOI: 10.1016/j.brainres.2021.147577] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 04/17/2021] [Accepted: 06/28/2021] [Indexed: 11/23/2022]
Abstract
The olfactory bulbectomized (OBX) rat model is a well-established model of depression in which antidepressant drugs reverse deficits in the passive avoidance test 14 days after administration. Recently, the olfactory bulbectomized rat model has been proposed to be a model of Alzheimer's disease (AD), and the available data indicate similarities between the changes that typically occur in AD and those observed in OBX animals. In the present study, the occurrence of neurochemical impairments related to AD were investigated 8 months after OB ablation. The expression of the nitric oxide synthases eNOS and nNOS, receptor for advanced glycation endproducts (RAGEs) and dimethylarginine dimethylaminohydrolase (DDAH1) in the prefrontal cortices (PFCs), hippocampi and striata of olfactory bulbectomized and sham-operated rats was evaluated. Subsequently, the impact of the administration of a positive allosteric modulator of the mGlu5 receptor, CDPPB (14 days, 2.5 or 5 mg/kg), on OBX-related changes was assessed. OB ablation induced typical deficits in passive avoidance. Significant aberrations in the expression of both isoforms of NOS were observed in the hippocampus and striatum, and the expression of DDAH1 was increased in the PFCs of OBX animals. CDPPB at a dose of 5 mg/kg ameliorated cognitive impairment in the passive avoidance test and partially reversed the changes in eNOS and nNOS expression induced by the lesion. The results of this study confirm that some of the neurochemical changes observed in OBX animals may resemble those associated with AD pathology and that activation of the mGlu5 receptor may partially counteract these pathological alterations.
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Mike JK, Pathipati P, Sheldon RA, Ferriero DM. Changes in arginase isoforms in a murine model of neonatal brain hypoxia-ischemia. Pediatr Res 2021; 89:830-837. [PMID: 32464635 PMCID: PMC7704631 DOI: 10.1038/s41390-020-0978-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 04/27/2020] [Accepted: 05/12/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Arginases (ARG isoforms, ARG-1/ARG-2) are key regulatory enzymes of inflammation and tissue repair; however, their role after neonatal brain hypoxia (H) and hypoxia-ischemia (HI) remains unknown. METHODS C57BL/6 mice subjected to the Vannucci procedure on postnatal day (P9) were sacrificed at different timepoints. The degree of brain damage was assessed histologically. ARG spatiotemporal localization was determined via immunohistochemistry. ARG expression was measured by Western blot and activity spectrophotometrically. RESULTS ARG isoform expression increased during neurodevelopment (P9-P17) in the cortex and hippocampus. This was suppressed with H and HI only in the hippocampus. In the cortex, both isoforms increased with H alone and only ARG-2 increased with HI at 3 days. ARG activity during neurodevelopment remained unchanged, but increased at 1 day with H and not HI. ARG-1 localized with microglia at the injury site as early as 4 h after injury, while ARG-2 localized with neurons. CONCLUSIONS ARG isoform expression increases with age from P9 to P17, but is suppressed by injury specifically in the hippocampus and not in the cortex. Both levels and activity of ARG isoforms increase with H, while ARG-1 immunolabelling is upregulated in the HI cortex. Evidently, ARG isoforms in the brain differ in spatiotemporal localization, expression, and activity during neurodevelopment and after injury. IMPACT Arginase isoforms change during neurodevelopment and after neonatal brain HI. This is the first study investigating the key enzymes of inflammation and tissue repair called arginases following murine neonatal brain HI. The highly region- and cell-specific expression suggests the possibility of specific functions of arginases. ARG-1 in microglia at the injury site may regulate neuroinflammation, while ARG-2 in neurons of developmental structures may impact neurodevelopment. While further studies are needed to describe the exact role of ARGs after neonatal brain HI, our study adds valuable data on anatomical localization and expression of ARGs in brain during development and after stroke.
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Affiliation(s)
- Jana K Mike
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA.
| | - Praneeti Pathipati
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
| | - R Ann Sheldon
- Department of Neurology, University of California San Francisco, San Francisco, CA, USA
| | - Donna M Ferriero
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California San Francisco, San Francisco, CA, USA
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Gorny N, Kelly MP. Alterations in cyclic nucleotide signaling are implicated in healthy aging and age-related pathologies of the brain. VITAMINS AND HORMONES 2021; 115:265-316. [PMID: 33706951 DOI: 10.1016/bs.vh.2020.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
It is not only important to consider how hormones may change with age, but also how downstream signaling pathways that couple to hormone receptors may change. Among these hormone-coupled signaling pathways are the 3',5'-cyclic guanosine monophosphate (cGMP) and 3',5'-cyclic adenosine monophosphate (cAMP) intracellular second messenger cascades. Here, we test the hypothesis that dysfunction of cAMP and/or cGMP synthesis, execution, and/or degradation occurs in the brain during healthy and pathological diseases such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. Although most studies report lower cyclic nucleotide signaling in the aged brain, with further reductions noted in the context of age-related diseases, there are select examples where cAMP signaling may be elevated in select tissues. Thus, therapeutics would need to target cAMP/cGMP in a tissue-specific manner if efficacy for select symptoms is to be achieved without worsening others.
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Affiliation(s)
- Nicole Gorny
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Michy P Kelly
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States.
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Dewan N, Shukla V, Rehni AK, Koronowski KB, Klingbeil KD, Stradecki‐Cohan H, Garrett TJ, Rundek T, Perez‐Pinzon MA, Dave KR. Exposure to recurrent hypoglycemia alters hippocampal metabolism in treated streptozotocin-induced diabetic rats. CNS Neurosci Ther 2020; 26:126-135. [PMID: 31282100 PMCID: PMC6930817 DOI: 10.1111/cns.13186] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 05/31/2019] [Accepted: 06/04/2019] [Indexed: 12/13/2022] Open
Abstract
AIMS Exposure to recurrent hypoglycemia (RH) is common in diabetic patients receiving glucose-lowering therapies and is implicated in causing cognitive impairments. Despite the significant effect of RH on hippocampal function, the underlying mechanisms are currently unknown. Our goal was to determine the effect of RH exposure on hippocampal metabolism in treated streptozotocin-diabetic rats. METHODS Hyperglycemia was corrected by insulin pellet implantation. Insulin-treated diabetic (ITD) rats were exposed to mild/moderate RH once a day for 5 consecutive days. RESULTS The effect of RH on hippocampal metabolism revealed 65 significantly altered metabolites in the RH group compared with controls. Several significant differences in metabolite levels belonging to major pathways (eg, Krebs cycle, gluconeogenesis, and amino acid metabolism) were discovered in RH-exposed ITD rats when compared to a control group. Key glycolytic enzymes including hexokinase, phosphofructokinase, and pyruvate kinase were affected by RH exposure. CONCLUSION Our results demonstrate that the exposure to RH leads to metabolomics alterations in the hippocampus of insulin-treated streptozotocin-diabetic rats. Understanding how RH affects hippocampal metabolism may help attenuate the adverse effects of RH on hippocampal functions.
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Affiliation(s)
- Neelesh Dewan
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Vibha Shukla
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Ashish K. Rehni
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Kevin B. Koronowski
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
- Neuroscience ProgramUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Kyle D. Klingbeil
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Holly Stradecki‐Cohan
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
- Neuroscience ProgramUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Timothy J. Garrett
- Southeast Center for Integrated Metabolomics, Clinical and Translational Science InstituteUniversity of FloridaGainesvilleFloridaUSA
| | - Tatjana Rundek
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
- Evelyn F. McKnight Brain InstituteUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Miguel A. Perez‐Pinzon
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
- Neuroscience ProgramUniversity of Miami School of MedicineMiamiFloridaUSA
- Evelyn F. McKnight Brain InstituteUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Kunjan R. Dave
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
- Neuroscience ProgramUniversity of Miami School of MedicineMiamiFloridaUSA
- Evelyn F. McKnight Brain InstituteUniversity of Miami School of MedicineMiamiFloridaUSA
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Krystofova J, Pathipati P, Russ J, Sheldon A, Ferriero D. The Arginase Pathway in Neonatal Brain Hypoxia-Ischemia. Dev Neurosci 2019; 40:437-450. [PMID: 30995639 PMCID: PMC6784534 DOI: 10.1159/000496467] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 12/20/2018] [Indexed: 12/11/2022] Open
Abstract
Brain damage after hypoxia-ischemia (HI) occurs in an age-dependent manner. Neuroprotective strategies assumed to be effective in adults might have deleterious effects in the immature brain. In order to create effective therapies, the complex pathophysiology of HI in the developing brain requires exploring new mechanisms. Critical determinants of neuronal survival after HI are the extent of vascular dysfunction, inflammation, and oxidative stress, followed later by tissue repair. The key enzyme of these processes in the human body is arginase (ARG) that acts via the bioavailability of nitric oxide, and the synthesis of polyamines and proline. ARG is expressed throughout the brain in different cells. However, little is known about the effect of ARG in pathophysiological states of the brain, especially hypoxia-ischemia. Here, we summarize the role of ARG during neurodevelopment as well as in various brain pathologies.
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Affiliation(s)
- Jana Krystofova
- Department of Pediatrics, University of California San Francisco, San Francisco, California, USA,
| | - Praneeti Pathipati
- Department of Pediatrics, University of California San Francisco, San Francisco, California, USA
| | - Jeffrey Russ
- Department of Pediatrics, University of California San Francisco, San Francisco, California, USA
| | - Ann Sheldon
- Department of Pediatrics, University of California San Francisco, San Francisco, California, USA
| | - Donna Ferriero
- Department of Pediatrics, University of California San Francisco, San Francisco, California, USA
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Moretto J, Girard C, Demougeot C. The role of arginase in aging: A systematic review. Exp Gerontol 2019; 116:54-73. [DOI: 10.1016/j.exger.2018.12.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/07/2018] [Accepted: 12/12/2018] [Indexed: 12/15/2022]
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Nitric oxide mediated redox regulation of protein homeostasis. Cell Signal 2018; 53:348-356. [PMID: 30408515 DOI: 10.1016/j.cellsig.2018.10.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 10/27/2018] [Accepted: 10/29/2018] [Indexed: 12/12/2022]
Abstract
Nitric oxide is a versatile diffusible signaling molecule, whose biosynthesis by three NO synthases (NOS) is tightly regulated at transcriptional and posttranslational levels, availability of co-factors, and calcium binding. Above normal levels of NO have beneficial protective effects for example in the cardiovascular system, but also contribute to the pathophysiology in the context of inflammatory diseases, and to aging and neurodegeneration in the nervous system. The effect specificity relies on the functional and spatial specificity of the NOS isoenzymes, and on the duality of two major signaling mechanisms (i) activation of soluble guanylycylase (sGC)-dependent cGMP production and (ii) direct S-nitrosylation of redox sensitive cysteines of susceptible proteins. The present review summarizes the functional implications of S-nitrosylation in the context of proteostasis, and focuses on two NO target proteins, heat shock cognate of 70 kDa (Hsc70/HSPA8) and the ubiquitin 2 ligase (UBE2D), because both are modified on functionally critical cysteines and are key regulators of chaperone mediated and assisted autophagy and proteasomal protein degradation. SNO modifications of these candidates are associated with protein accumulations and adoption of a senescent phenotype of neuronal cells suggesting that S-nitrosylations of protein homeostatic machineries contribute to aging phenomena.
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Nitric oxide contributes to protein homeostasis by S-nitrosylations of the chaperone HSPA8 and the ubiquitin ligase UBE2D. Redox Biol 2018; 20:217-235. [PMID: 30368041 PMCID: PMC6202877 DOI: 10.1016/j.redox.2018.10.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 09/25/2018] [Accepted: 10/02/2018] [Indexed: 02/06/2023] Open
Abstract
Upregulations of neuronal nitric oxide synthase (nNOS) in the rodent brain have been associated with neuronal aging. To address underlying mechanisms we generated SH-SY5Y neuronal cells constitutively expressing nNOS at a level similar to mouse brain (nNOS+ versus MOCK). Initial experiments revealed S-nitrosylations (SNO) of key players of protein homeostasis: heat shock cognate HSC70/HSPA8 within its nucleotide-binding site, and UBE2D ubiquitin conjugating enzymes at the catalytic site cysteine. HSPA8 is involved in protein folding, organelle import/export and chaperone-mediated LAMP2a-dependent autophagy (CMA). A set of deep redox and full proteome analyses, plus analysis of autophagy, CMA and ubiquitination with rapamycin and starvation as stimuli confirmed the initial observations and revealed a substantial increase of SNO modifications in nNOS+ cells, in particular targeting protein networks involved in protein catabolism, ubiquitination, carbohydrate metabolism and cell cycle control. Importantly, NO-independent reversible oxidations similarly occurred in both cell lines. Functionally, nNOS caused an accumulation of proteins, including CMA substrates and loss of LAMP2a. UBE2D activity and proteasome activity were impaired, resulting in dysregulations of cell cycle checkpoint proteins. The observed changes of protein degradation pathways caused an expansion of the cytoplasm, large lysosomes, slowing of the cell cycle and suppression of proliferation suggesting a switch of the phenotype towards aging, supported by downregulations of neuronal progenitor markers but increase of senescence-associated proteins. Hence, upregulation of nNOS in neuronal cells imposes aging by SNOing of key players of ubiquitination, chaperones and of substrate proteins leading to interference with crucial steps of protein homeostasis.
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Lourenço CF, Ledo A, Caetano M, Barbosa RM, Laranjinha J. Age-Dependent Impairment of Neurovascular and Neurometabolic Coupling in the Hippocampus. Front Physiol 2018; 9:913. [PMID: 30065657 PMCID: PMC6056650 DOI: 10.3389/fphys.2018.00913] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 06/21/2018] [Indexed: 11/24/2022] Open
Abstract
Neurovascular and neurometabolic coupling are critical and complex processes underlying brain function. Perturbations in the regulation of these processes are, likely, early dysfunctional alterations in pathological brain aging and age-related neurodegeneration. Evidences support the role of nitric oxide (•NO) as a key messenger both in neurovascular coupling, by signaling from neurons to blood vessels, and in neurometabolic coupling, by modulating O2 utilization by mitochondria. In the present study, we investigated the functionality of neurovascular and neurometabolic coupling in connection to •NO signaling and in association to cognitive performance during aging. For this, we performed in vivo simultaneous measurements of •NO, O2 and cerebral blood flow (CBF) in the hippocampus of F344 rats along chronological age in response to glutamatergic activation and in correlation with cognitive performance. Firstly, it is evidenced the temporal sequence of events upon glutamate stimulation of hippocampal dentate gyrus, encompassing the local and transitory increase of •NO followed by transitory local changes of CBF and pO2. Specifically, the transient increase of •NO is followed by an increase of CBF and biphasic changes of the local pO2. We observed that, although the glutamate-induced •NO dynamics were not significantly affected by aging, the correspondent hemodynamic was progressively diminished accompanying a decline in learning and memory. Noteworthy, in spite of a compromised blood supply, in aged rats we observed an increased ΔpO2 associated to the hemodynamic response, suggestive of a decrease in the global metabolic rate of O2. Furthermore, the impairment in the neurovascular coupling observed along aging in F344 rats was mimicked in young rats by promoting an unbalance in redox status toward oxidation via intracellular generation of superoxide radical. This observation strengthens the idea that oxidative stress may have a critical role in the neurovascular uncoupling underlying brain aging and dysfunction. Overall, data supports an impairment of neurovascular response in connection with cognition decline due to oxidative environment-dependent compromised •NO signaling from neurons to vessels during aging.
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Affiliation(s)
- Cátia F Lourenço
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Ana Ledo
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Miguel Caetano
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Rui M Barbosa
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - João Laranjinha
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
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11
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Bergin DH, Jing Y, Mockett BG, Zhang H, Abraham WC, Liu P. Altered plasma arginine metabolome precedes behavioural and brain arginine metabolomic profile changes in the APPswe/PS1ΔE9 mouse model of Alzheimer's disease. Transl Psychiatry 2018; 8:108. [PMID: 29802260 PMCID: PMC5970225 DOI: 10.1038/s41398-018-0149-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 02/21/2018] [Accepted: 04/04/2018] [Indexed: 11/09/2022] Open
Abstract
While amyloid-beta (Aβ) peptides play a central role in the development of Alzheimer's disease (AD), recent evidence also implicates altered metabolism of L-arginine in the pathogenesis of AD. The present study systematically investigated how behavioural function and the brain and plasma arginine metabolic profiles changed in a chronic Aβ accumulation model using male APPswe/PS1ΔE9 transgenic (Tg) mice at 7 and 13 months of age. As compared to their wild-type (WT) littermates, Tg mice displayed age-related deficits in spatial water maze tasks and alterations in brain arginine metabolism. Interestingly, the plasma arginine metabolic profile was markedly altered in 7-month Tg mice prior to major behavioural impairment. Receiver operating characteristic curve analysis revealed that plasma putrescine and spermine significantly differentiated between Tg and WT mice. These results demonstrate the parallel development of altered brain arginine metabolism and behavioural deficits in Tg mice. The altered plasma arginine metabolic profile that preceded the behavioural and brain profile changes suggests that there may be merit in an arginine-centric set of ante-mortem biomarkers for AD.
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Affiliation(s)
- D H Bergin
- Department of Anatomy, University of Otago, Dunedin, New Zealand
- School of Pharmacy, University of Otago, Dunedin, New Zealand
- Brain Research New Zealand and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Y Jing
- Department of Anatomy, University of Otago, Dunedin, New Zealand
- Brain Research New Zealand and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - B G Mockett
- Brain Research New Zealand and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
- Department of Psychology, University of Otago, Dunedin, New Zealand
| | - H Zhang
- School of Pharmacy, University of Otago, Dunedin, New Zealand
- Brain Research New Zealand and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - W C Abraham
- Brain Research New Zealand and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
- Department of Psychology, University of Otago, Dunedin, New Zealand
| | - P Liu
- Department of Anatomy, University of Otago, Dunedin, New Zealand.
- Brain Research New Zealand and Brain Health Research Centre, University of Otago, Dunedin, New Zealand.
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12
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Kelly MP. Cyclic nucleotide signaling changes associated with normal aging and age-related diseases of the brain. Cell Signal 2018; 42:281-291. [PMID: 29175000 PMCID: PMC5732030 DOI: 10.1016/j.cellsig.2017.11.004] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 11/21/2017] [Indexed: 01/23/2023]
Abstract
Deficits in brain function that are associated with aging and age-related diseases benefit very little from currently available therapies, suggesting a better understanding of the underlying molecular mechanisms is needed to develop improved drugs. Here, we review the literature to test the hypothesis that a break down in cyclic nucleotide signaling at the level of synthesis, execution, and/or degradation may contribute to these deficits. A number of findings have been reported in both the human and animal model literature that point to brain region-specific changes in Galphas (a.k.a. Gαs or Gsα), adenylyl cyclase, 3',5'-adenosine monophosphate (cAMP) levels, protein kinase A (PKA), cAMP response element binding protein (CREB), exchange protein activated by cAMP (Epac), hyperpolarization-activated cyclic nucleotide-gated ion channels (HCNs), atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), soluble and particulate guanylyl cyclase, 3',5'-guanosine monophosphate (cGMP), protein kinase G (PKG) and phosphodiesterases (PDEs). Among the most reproducible findings are 1) elevated circulating ANP and BNP levels being associated with cognitive dysfunction or dementia independent of cardiovascular effects, 2) reduced basal and/or NMDA-stimulated cGMP levels in brain with aging or Alzheimer's disease (AD), 3) reduced adenylyl cyclase activity in hippocampus and specific cortical regions with aging or AD, 4) reduced expression/activity of PKA in temporal cortex and hippocampus with AD, 5) reduced phosphorylation of CREB in hippocampus with aging or AD, 6) reduced expression/activity of the PDE4 family in brain with aging, 7) reduced expression of PDE10A in the striatum with Huntington's disease (HD) or Parkinson's disease, and 8) beneficial effects of select PDE inhibitors, particularly PDE10 inhibitors in HD models and PDE4 and PDE5 inhibitors in aging and AD models. Although these findings generally point to a reduction in cyclic nucleotide signaling being associated with aging and age-related diseases, there are exceptions. In particular, there is evidence for increased cAMP signaling specifically in aged prefrontal cortex, AD cerebral vessels, and PD hippocampus. Thus, if cyclic nucleotide signaling is going to be targeted effectively for therapeutic gain, it will have to be manipulated in a brain region-specific manner.
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Affiliation(s)
- Michy P Kelly
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, 6439 Garners Ferry Road, VA Bldg 1, 3rd Floor, D-12, Columbia, SC 29209, United States.
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Bağcı B, Utkan T, Yazir Y, Aricioglu F, Öztürk GS, Sarioglu Y. Effects of agmatine on cognitive functions during vascular dementia in biological aging through eNOS and BDNF expression. PSYCHIAT CLIN PSYCH 2017. [DOI: 10.1080/24750573.2017.1309090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Affiliation(s)
| | - Tijen Utkan
- Department of Pharmacology and Experimental Medical Research and Application Unit, Kocaeli University Faculty of Medicine, Kocaeli, Turkey
| | - Yusufhan Yazir
- Department of Histology and Embryology and Stem Cell and Gene Therapy Research and Application Center, Kocaeli University Faculty of Medicine, Kocaeli, Turkey
| | - Feyza Aricioglu
- Faculty of Pharmacy, Department of Pharmacology and Psychopharmacology Research Unit, Marmara University, Istanbul, Turkey
| | - Gökçe Sevim Öztürk
- Department of Medical Pharmacology, Gazi University, Medical School, Ankara, Turkey
| | - Yusuf Sarioglu
- Istinye University Faculty of Medicine, Istanbul, Turkey
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14
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Knox LT, Jing Y, Bawazier-Edgecombe J, Collie ND, Zhang H, Liu P. Effects of withdrawal from repeated phencyclidine administration on behavioural function and brain arginine metabolism in rats. Pharmacol Biochem Behav 2016; 153:45-59. [PMID: 27986516 DOI: 10.1016/j.pbb.2016.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 07/20/2016] [Accepted: 12/12/2016] [Indexed: 12/13/2022]
Abstract
Phencyclidine (PCP) induces behavioural changes in humans and laboratory animals that resemble positive and negative symptoms, and cognitive impairments in schizophrenia. It has been shown repeated treatment of PCP leading to persistent symptoms even after the drug discontinuation, and there is a growing body of evidence implicating altered arginine metabolism in the pathogenesis of schizophrenia. The present study investigated the effects of withdrawal from repeated daily injection of PCP (2mg/kg) for 12 consecutive days on animals'behavioural performance and arginine metabolism in the hippocampus and prefrontal cortex in male young adult rats. Repeated PCP treatment reduced spontaneous alternations in the Y-maze and exploratory and locomotor activities in the open field under the condition of a washout period of 24h, but not 4days. Interestingly, the PCP treated rats also displayed spatial working memory deficits when tested 8-10days after withdrawal from PCP and showed altered levels of arginase activities and eight out of ten l-arginine metabolites in neurochemical- and region-specific manner. Cluster analyses showed altered relationships among l-arginine and its three main metabolites as a function of withdrawal from repeated PCP treatment in a duration-specific manner. Multiple regression analysis revealed significant neurochemical-behavioural correlations. Collectively, the results suggest both the residual and long-term effects of withdrawal from repeated PCP treatment on behavioural function and brain arginine metabolism. These findings demonstrate, for the first time, the influence of the withdrawal duration on animals' behaviour and brain arginine metabolism.
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Affiliation(s)
- Logan T Knox
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Yu Jing
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Jamal Bawazier-Edgecombe
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Nicola D Collie
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Hu Zhang
- School of Pharmacy, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Ping Liu
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand.
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15
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Effects of environmental enrichment in aged mice on anxiety-like behaviors and neuronal nitric oxide synthase expression in the brain. Biochem Biophys Res Commun 2016; 476:635-640. [DOI: 10.1016/j.bbrc.2016.06.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 06/02/2016] [Indexed: 11/20/2022]
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16
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Melatonin attenuates intermittent hypoxia-induced lipid peroxidation and local inflammation in rat adrenal medulla. Int J Mol Sci 2014; 15:18437-52. [PMID: 25314303 PMCID: PMC4227224 DOI: 10.3390/ijms151018437] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 09/26/2014] [Accepted: 10/02/2014] [Indexed: 12/28/2022] Open
Abstract
Chronic intermittent hypoxia (CIH) induces lipid peroxidation and leads to cardiovascular dysfunction, in which impaired activities of the adrenal medulla are involved. This may be caused by CIH-induced injury in the adrenal medulla, for which the mechanism is currently undefined. We tested the hypothesis that melatonin ameliorates the CIH-induced lipid peroxidation, local inflammation and cellular injury in rat adrenal medulla. Adult Sprague–Dawley rats were exposed to air (normoxic control) or hypoxia mimicking a severe recurrent sleep apnoeic condition for 14 days. The injection of melatonin (10 mg/kg) or vehicle was given before the daily hypoxic treatment. We found that levels of malondialdehyde and nitrotyrosine were significantly increased in the vehicle-treated hypoxic group, when compared with the normoxic control or hypoxic group treated with melatonin. Also, the protein levels of antioxidant enzymes (superoxide dismutase (SOD)-1 and SOD-2) were significantly lowered in the hypoxic group treated with vehicle but not in the melatonin group. In addition, the level of macrophage infiltration and the expression of inflammatory cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6) and mediators (inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2)) were elevated in the vehicle-treated hypoxic group, but were significantly ameliorated by the melatonin treatment. Moreover, the amount of apoptotic cells in the hypoxic groups was significantly less in the melatonin-treated group. In conclusion, CIH-induced lipid peroxidation causes local inflammation and cellular injury in the adrenal medulla. The antioxidant and anti-inflammatory actions of melatonin are indicative of a protective agent against adrenal damage in patients with severe obstructive sleep apnea syndrome.
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17
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Effects of acute phencyclidine administration on arginine metabolism in the hippocampus and prefrontal cortex in rats. Neuropharmacology 2014; 81:195-205. [DOI: 10.1016/j.neuropharm.2014.02.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 01/03/2014] [Accepted: 02/05/2014] [Indexed: 12/19/2022]
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18
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Liu P, Fleete MS, Jing Y, Collie ND, Curtis MA, Waldvogel HJ, Faull RLM, Abraham WC, Zhang H. Altered arginine metabolism in Alzheimer's disease brains. Neurobiol Aging 2014; 35:1992-2003. [PMID: 24746363 DOI: 10.1016/j.neurobiolaging.2014.03.013] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 02/27/2014] [Accepted: 03/14/2014] [Indexed: 12/21/2022]
Abstract
L-arginine is a semi-essential amino acid with a number of bioactive metabolites. Accumulating evidence suggests the implication of altered arginine metabolism in the pathogenesis of Alzheimer's disease (AD). The present study systematically compared the metabolic profile of L-arginine in the superior frontal gyrus, hippocampus, and cerebellum from AD (mean age 80 years) and normal (mean age 80 or 60 years) cases. The activity and protein expression of nitric oxide synthase and arginase were altered with AD and age in a region-specific manner. There were also AD- and age-related changes in the tissue concentrations of L-arginine and its downstream metabolites (L-citrulline, L-ornithine, agmatine, putrescine, spermidine, spermine, glutamate, γ-aminobutyric acid, and glutamine) in a metabolite- or region-specific manner. These findings demonstrate that arginine metabolism is dramatically altered in diverse regions of AD brains, thus meriting further investigation to understand its role in the pathogenesis and/or progression of the disease.
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Affiliation(s)
- Ping Liu
- Department of Anatomy, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand.
| | - Michael S Fleete
- Department of Anatomy, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Yu Jing
- Department of Anatomy, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Nicola D Collie
- Department of Anatomy, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Maurice A Curtis
- Centre for Brain Research and Department of Anatomy with Radiology, University of Auckland, New Zealand
| | - Henry J Waldvogel
- Centre for Brain Research and Department of Anatomy with Radiology, University of Auckland, New Zealand
| | - Richard L M Faull
- Centre for Brain Research and Department of Anatomy with Radiology, University of Auckland, New Zealand
| | - Wickliffe C Abraham
- Brain Health Research Centre, University of Otago, Dunedin, New Zealand; Department of Psychology, University of Otago, Dunedin, New Zealand
| | - Hu Zhang
- Brain Health Research Centre, University of Otago, Dunedin, New Zealand; School of Pharmacy, University of Otago, Dunedin, New Zealand
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19
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Regional variations and age-related changes in arginine metabolism in the rat brain stem and spinal cord. Neuroscience 2013; 252:98-108. [DOI: 10.1016/j.neuroscience.2013.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 07/26/2013] [Accepted: 08/01/2013] [Indexed: 01/08/2023]
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20
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Chen Q, Xiao DS. Long-term aerobic exercise increases redox-active iron through nitric oxide in rat hippocampus. Nitric Oxide 2013; 36:1-10. [PMID: 24184442 DOI: 10.1016/j.niox.2013.10.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 09/10/2013] [Accepted: 10/22/2013] [Indexed: 12/30/2022]
Abstract
Adult hippocampus is highly vulnerable to iron-induced oxidative stress. Aerobic exercise has been proposed to reduce oxidative stress but the findings in the hippocampus are conflicting. This study aimed to observe the changes of redox-active iron and concomitant regulation of cellular iron homeostasis in the hippocampus by aerobic exercise, and possible regulatory effect of nitric oxide (NO). A randomized controlled study was designed in the rats with swimming exercise treatment (for 3 months) and/or an unselective inhibitor of NO synthase (NOS) (L-NAME) treatment. The results from the bleomycin-detectable iron assay showed additional redox-active iron in the hippocampus by exercise treatment. The results from nonheme iron content assay, combined with the redox-active iron content, showed increased storage iron content by exercise treatment. NOx (nitrate plus nitrite) assay showed increased NOx content by exercise treatment. The results from the Western blot assay showed decreased ferroportin expression, no changes of TfR1 and DMT1 expressions, increased IRP1 and IRP2 expression, increased expressions of eNOS and nNOS rather than iNOS. In these effects of exercise treatment, the increased redox-active iron content, storage iron content, IRP1 and IRP2 expressions were completely reversed by L-NAME treatment, and decreased ferroportin expression was in part reversed by L-NAME. L-NAME treatment completely inhibited increased NOx and both eNOS and nNOS expression in the hippocampus. Our findings suggest that aerobic exercise could increase the redox-active iron in the hippocampus, indicating an increase in the capacity to generate hydroxyl radicals through the Fenton reactions, and aerobic exercise-induced iron accumulation in the hippocampus might mainly result from the role of the endogenous NO.
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Affiliation(s)
- Qian Chen
- Department of Histology and Embryology, School of Medical Science and Laboratory Medicine, Jiangsu University, Zhenjiang, Jiangsu Province, China
| | - De-Sheng Xiao
- Department of Preventive Medicine, School of Public Health, Guangzhou Medical University, Guangzhou, Guangdong Province, China.
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21
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A comparison of random forest regression and multiple linear regression for prediction in neuroscience. J Neurosci Methods 2013; 220:85-91. [DOI: 10.1016/j.jneumeth.2013.08.024] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 08/13/2013] [Accepted: 08/28/2013] [Indexed: 11/20/2022]
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22
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Quirié A, Demougeot C, Bertrand N, Mossiat C, Garnier P, Marie C, Prigent-Tessier A. Effect of stroke on arginase expression and localization in the rat brain. Eur J Neurosci 2013; 37:1193-202. [PMID: 23311438 DOI: 10.1111/ejn.12111] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 10/30/2012] [Accepted: 11/28/2012] [Indexed: 11/27/2022]
Abstract
Because arginase and nitric oxide (NO) synthases (NOS) compete to degrade l-arginine, arginase plays a crucial role in the modulation of NO production. Moreover, the arginase 1 isoform is a marker of M2 phenotype macrophages that play a key role in tissue remodeling and resolution of inflammation. While NO has been extensively investigated in ischemic stroke, the effect of stroke on the arginase pathway is unknown. The present study focuses on arginase expression/activity and localization before and after (1, 8, 15 and 30 days) the photothrombotic ischemic stroke model. This model results in a cortical lesion that reaches maximal volume at day 1 post-stroke and then decreases as a result of astrocytic scar formation. Before stroke, arginase 1 and 2 expressions were restricted to neurons. Stroke resulted in up-regulation of arginase 1 and increased arginase activity in the region centered on the lesion where inflammatory cells are present. These changes were associated with an early and long-lasting arginase 1 up-regulation in activated macrophages and astrocytes and a delayed arginase 1 down-regulation in neurons at the vicinity of the lesion. A linear positive correlation was observed between expressions of arginase 1 and glial fibrillary acidic protein as a marker of activated astrocytes. Moreover, the pattern of arginase 1 and brain-derived neurotrophic factor (BDNF) expressions in activated astrocytes was similar. Unlike arginase 1, arginase 2 expression was not changed by stroke. In conclusion, increased arginase 1 expression is not restricted to macrophages in inflammation elicited by stroke but also occurs in activated astrocytes where it may contribute to neuroplasticity through the control of BDNF production.
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Affiliation(s)
- Aurore Quirié
- Faculté de Pharmacie, Unité INSERM U1093 Cognition, Action et Plasticité Sensorimotrice, Dijon, France
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23
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Effects of prolonged agmatine treatment in aged male Sprague-Dawley rats. Neuroscience 2013; 234:116-24. [PMID: 23318245 DOI: 10.1016/j.neuroscience.2013.01.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 12/29/2012] [Accepted: 01/05/2013] [Indexed: 11/22/2022]
Abstract
Increasing evidence suggests that altered arginine metabolism contributes to cognitive decline during ageing. Agmatine, decarboxylated arginine, has a variety of pharmacological effects, including the modulation of behavioural function. A recent study demonstrated the beneficial effects of short-term agmatine treatment in aged rats. The present study investigated how intraperitoneal administration of agmatine (40mg/kg, once daily) over 4-6weeks affected behavioural function and neurochemistry in aged Sprague-Dawley rats. Aged rats treated with saline displayed significantly reduced exploratory activity in the open field, impaired spatial learning and memory in the water maze and object recognition memory relative to young rats. Prolonged agmatine treatment improved animals' performance in the reversal test of the water maze and object recognition memory test, and significantly suppressed age-related elevation in nitric oxide synthase activity in the dentate gyrus of the hippocampus and prefrontal cortex. However, this prolonged supplementation was unable to improve exploratory activity and spatial reference learning and memory in aged rats. These findings further demonstrate that exogenous agmatine selectively improves behavioural function in aged rats.
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24
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Gupta N, Jing Y, Collie ND, Zhang H, Liu P. Ageing alters behavioural function and brain arginine metabolism in male Sprague-Dawley rats. Neuroscience 2012; 226:178-96. [PMID: 22989918 DOI: 10.1016/j.neuroscience.2012.09.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 08/18/2012] [Accepted: 09/07/2012] [Indexed: 01/29/2023]
Abstract
A growing body of evidence suggests the involvement of L-arginine and its metabolites in the ageing and neurodegenerative processes. The present study assessed behavioural performance in 4- (young), 12- (middle-aged) and 24- (aged) month-old male Sprague-Dawley rats, and investigated age-related changes in the activity of two key arginine metabolic enzymes, nitric oxide synthase (NOS) and arginase, and the levels of L-arginine and its downstream metabolites in a number of memory-related brain structures. Aged rats were less anxious and performed poorly in the water maze task relative to the young and middle-aged rats, and both middle-aged and aged rats displayed reduced exploratory activity relative to the young ones. There were significant age-related changes in NOS and arginase activities, and the levels of L-arginine, L-citrulline, L-ornithine, agmatine, putrescine, spermidine, spermine and glutamate, but not γ-aminobutyric acid, in the CA1, CA2/3 and dentate gyrus sub-regions of the hippocampus and the prefrontal, entorhinal, perirhinal, postrhinal and temporal (an auditory cortex) cortices in a region-specific manner. Cluster analyses revealed that the nine related neurochemical variables formed distinct groups, which changed as a function of ageing. Multiple regression analyses revealed a number of significant correlations between the neurochemical and behavioural variables. The present study further supports the involvement of arginine metabolism in the ageing process, and provides further evidence of the effects of animals' behavioural experience on arginine metabolism.
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Affiliation(s)
- N Gupta
- Department of Anatomy, Brain Health Research Centre, University of Otago, P.O. Box 913, Dunedin 9054, New Zealand
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25
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Rushaidhi M, Collie N, Zhang H, Liu P. Agmatine selectively improves behavioural function in aged male Sprague–Dawley rats. Neuroscience 2012; 218:206-15. [DOI: 10.1016/j.neuroscience.2012.05.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 04/11/2012] [Accepted: 05/04/2012] [Indexed: 10/28/2022]
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26
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Badaut J, Copin JC, Fukuda AM, Gasche Y, Schaller K, da Silva RF. Increase of arginase activity in old apolipoprotein-E deficient mice under Western diet associated with changes in neurovascular unit. J Neuroinflammation 2012; 9:132. [PMID: 22709928 PMCID: PMC3419627 DOI: 10.1186/1742-2094-9-132] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 06/18/2012] [Indexed: 12/19/2022] Open
Abstract
Aging and atherosclerosis are well-recognized risk factors for cardiac and neurovascular diseases. The Apolipoprotein E deficient (ApoE-/-) mouse on a high-fat diet is a classical model of atherosclerosis, characterized by the presence of atherosclerotic plaques in extracranial vessels but not in cerebral arteries. Increase in arginase activity was shown to participate in vascular dysfunction in the peripheral arteries of atherosclerotic mice by changing the level of nitric oxide (NO). NO plays a key role in the physiological functions of the neurovascular unit (NVU). However, the regulation of arginase expression and activity in the brain was never investigated in association with changes in the NVU, ApoE deficiency and high fat diet.Fourteen-month-old ApoE-/- mice on high-fat diet exhibited deposition of lipids in the NVU, impairment of blood-brain barrier properties, astrogliosis and an increase of aquaporin 4 staining. In association with these changes, brain arginase activity was significantly increased in the old ApoE-/- mice as compared to old wild type mice, with an increase in the level of arginase type I in the blood vessels.In conclusion, aging in this classical mouse model of atherosclerosis induces an increase in the level and activity of arginase I that may impair NO synthesis and contribute to changes in the NVU leading to blood-brain barrier leakage and inflammation.
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Affiliation(s)
- Jérôme Badaut
- Departments of Pediatrics and Physiology, Linda University School of Medicine, Coleman Pavilion, Room A1120, 11175 Campus Street, Loma Linda, CA 92354, USA.
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27
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Rushaidhi M, Jing Y, Kennard J, Collie N, Williams J, Zhang H, Liu P. Aging affects l-arginine and its metabolites in memory-associated brain structures at the tissue and synaptoneurosome levels. Neuroscience 2012; 209:21-31. [DOI: 10.1016/j.neuroscience.2012.02.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 02/10/2012] [Accepted: 02/11/2012] [Indexed: 11/25/2022]
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28
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Knox LT, Jing Y, Fleete MS, Collie ND, Zhang H, Liu P. Scopolamine impairs behavioural function and arginine metabolism in the rat dentate gyrus. Neuropharmacology 2011; 61:1452-62. [DOI: 10.1016/j.neuropharm.2011.08.042] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2011] [Revised: 08/24/2011] [Accepted: 08/26/2011] [Indexed: 01/06/2023]
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29
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Hosseini M, Nemati Karimooy H, Hadjzadeh M, Safari V. Inducible nitric oxide synthase inhibitor aminoguanidine, differently affects Morris water maze tasks of ovariectomized and naïve female rats. ACTA ACUST UNITED AC 2011; 98:421-32. [DOI: 10.1556/aphysiol.98.2011.4.5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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30
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Gupta N, Zhang H, Liu P. Chronic difluoromethylornithine treatment impairs spatial learning and memory in rats. Pharmacol Biochem Behav 2011; 100:464-73. [PMID: 22024160 DOI: 10.1016/j.pbb.2011.10.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2011] [Revised: 09/21/2011] [Accepted: 10/09/2011] [Indexed: 01/08/2023]
Abstract
Recent evidence suggests that polyamines putrescine, spermidine and spermine are essential in maintaining normal cellular function. The present study investigated the effects of chronic treatment of difluoromethylornithine (DFMO, 3% in drinking water), a potent inhibitor of putrescine synthesis, for 54 consecutive days on animals'behavior and neurochemical levels in the CA1, CA2/3 and dentate gyrus sub-regions of the hippocampus and the prefrontal cortex. The DFMO group showed performance impairments in the place navigation and the probe test conducted 24 h after the training in the reference memory version of the water maze task, but not in the elevated plus maze, open field, object recognition, cued navigation and the working memory version of the water maze task when compared to the control group (drinking water only). DFMO treatment resulted in approximately 80-90% and 20% of reductions in the putrescine and spermidine levels, respectively, in the four brain regions examined, and a small reduction in agmatine level in the CA2/3, with no effects on spermine, glutamate and γ-aminobutyrate. The DFMO group showed decreased body weight relative to the control one. However, there were no significant differences between groups in the normalized brain, kidney and liver weights. The present study demonstrates that chronic treatment of DFMO depletes putrescine and decreases spermidine levels in the brain, inhibits growth, and impairs spatial learning and memory in the reference memory version of the water maze specifically. These findings merit further investigation to fully understand the functional role of endogenous polyamines in learning and memory.
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Affiliation(s)
- Neeraj Gupta
- Department of Anatomy, University of Otago, Dunedin, New Zealand
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31
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Liu P, Jing Y, Collie ND, Campbell SA, Zhang H. Pre-aggregated Aβ25–35 alters arginine metabolism in the rat hippocampus and prefrontal cortex. Neuroscience 2011; 193:269-82. [DOI: 10.1016/j.neuroscience.2011.07.054] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Revised: 07/19/2011] [Accepted: 07/22/2011] [Indexed: 10/17/2022]
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32
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Pietrelli A, López-Costa JJ, Goñi R, López EM, Brusco A, Basso N. Effects of moderate and chronic exercise on the nitrergic system and behavioral parameters in rats. Brain Res 2011; 1389:71-82. [DOI: 10.1016/j.brainres.2011.03.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 03/01/2011] [Accepted: 03/02/2011] [Indexed: 11/24/2022]
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33
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Xu J, Rong S, Xie B, Sun Z, Deng Q, Bao W, Wang D, Yao P, Huang F, Liu L. Changes in the Nitric Oxide System Contribute to Effect of Procyanidins Extracted from the Lotus Seedpod Ameliorating Memory Impairment in Cognitively Impaired Aged Rats. Rejuvenation Res 2011; 14:33-43. [DOI: 10.1089/rej.2010.1076] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Jiqu Xu
- Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
- Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, P.R. China
| | - Shuang Rong
- Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
- MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Bijun Xie
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Zhida Sun
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Qianchun Deng
- Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, P.R. China
| | - Wei Bao
- Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
- MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Di Wang
- Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
- MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Ping Yao
- Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
- MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Fenghong Huang
- Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, P.R. China
| | - Liegang Liu
- Department of Nutrition and Food Hygiene, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
- MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
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34
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Han S, Rudd JA, Hu ZY, Zhang L, Yew DT, Fang M. Analysis of neuronal nitric oxide synthase expression and increasing astrogliosis in the brain of senescence-accelerated-prone 8 mice. Int J Neurosci 2010; 120:602-8. [PMID: 20707635 DOI: 10.3109/00207454.2010.503911] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The senescence-accelerated mouse (SAM) is an autogenic senile murine model characterized by early cognitive impairment and age-related deterioration of learning and memory. The present study investigated the alternations of neuronal nitric oxide synthase (nNOS) expression in frontal cortex and hippocampus in the aging process of SAM-prone 8 (SAMP8) and SAM-resistant 1 (SAMR1) mice. The results demonstrated that the expression of nNOS was upregulated in the frontal cortex, but downregulated in the hippocampus in SAMP8. Further, age-related increases of astrogliosis were seen in the cortex and hippocampi of aged SAMP8 and SAMR1, as revealed by the expression of the astrocyte specific marker, glial fibrillary acidic protein (GFAP). Indeed, astrogliosis in aged SAMP8 was significantly greater than that of aged SAMR1. Our results suggest the possibility of a correlation between the downregulation of nitric oxide (NO) in the hippocampus and reported learning and memory deficits in SAMP8. However, the toxic effects of NO and age-related increases of astrogliosis, may have contributed to abnormal alterations in metabolism and neurochemical mechanisms in aged SAMP8.
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Affiliation(s)
- Shu Han
- Institute of Anatomy and Cell Biology, Medical College, Zhejiang University, China
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Neuroprotective and neurodegenerative effects of the chronic expression of tumor necrosis factor α in the nigrostriatal dopaminergic circuit of adult mice. Exp Neurol 2010; 227:237-51. [PMID: 21093436 DOI: 10.1016/j.expneurol.2010.11.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 09/20/2010] [Accepted: 11/09/2010] [Indexed: 12/19/2022]
Abstract
Tumor necrosis factor (TNF)-α, a pro-inflammatory cytokine, has been implicated in both neuronal death and survival in Parkinson's disease (PD). The substantia nigra (SN), a CNS region affected in PD, is particularly susceptible to inflammatory insults and possesses the highest density of microglial cells, but the effects of inflammation and in particular TNF-α on neuronal survival in this region remains controversial. Using adenoviral vectors, the CRE/loxP system and hypomorphic mice, we achieved chronic expression of two levels of TNF-α in the SN of adult mice. Chronic low expression of TNF-α levels reduced the nigrostriatal neurodegeneration mediated by intrastriatal 6-hydroxydopamine administration. Protective effects of low TNF-α level could be mediated by TNF-R1, GDNF, and IGF-1 in the SN and SOD activity in the striatum (ST). On the contrary, chronic expression of high levels of TNF-α induced progressive neuronal loss (63% at 20 days and 75% at 100 days). This effect was accompanied by gliosis and an inflammatory infiltrate composed almost exclusively by monocytes/macrophages. The finding that chronic high TNF-α had a slow and progressive neurodegenerative effect in the SN provides an animal model of PD mediated by the chronic expression of a single cytokine. In addition, it supports the view that cytokines are not detrimental or beneficial by themselves, i.e., their level and time of expression among other factors can determine its final effect on CNS damage or protection. These data support the view that new anti-parkinsonian treatments based on anti-inflammatory therapies should consider these dual effects of cytokines on their design.
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Chertok VM, Kotsyuba AE. Age-related changes in nitroxidergic neurons in some nuclei of rat medulla oblongata. Russ J Dev Biol 2010. [DOI: 10.1134/s1062360410040053] [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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37
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Cyclic GMP and nitric oxide synthase in aging and Alzheimer's disease. Mol Neurobiol 2010; 41:129-37. [PMID: 20213343 DOI: 10.1007/s12035-010-8104-x] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2009] [Accepted: 01/22/2010] [Indexed: 10/19/2022]
Abstract
Cyclic guanosine monophosphate (cGMP) is an important secondary messenger synthesized by the guanylyl cyclases which are found in the soluble (sGC) and particular isoforms. In the central nervous system, the nitric oxide (NO)-sensitive sGC isoform is the major enzyme responsible for cGMP synthesis. Phosphodiesterases (PDEs) are enzymes for hydrolysis of cGMP in the brain, and they are mainly isoforms 2, 5, and 9. The NO/cGMP signaling pathway has been shown to play an important role in the process underlying learning and memory. Aging is associated with an increase in PDE expression and activity and a decrease in cGMP concentration. In addition, aging is also associated with an enhancement of neuronal NO synthase, a lowering of endothelial, and no alteration in inducible activity. The observed changes in NMDA receptor density along with the Ca(2+)/NO/cGMP pathway underscore the lower synaptic plasticity and cognitive performance during aging. This notion is in agreement with last data indicating that inhibitors of PDE2 and PDE9 improve learning and memory in older rats. In this review, we focus on recent studies supporting the role of Ca(2+)/NO/cGMP pathway in aging and Alzheimer's disease.
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Liu P, Jing Y, Zhang H. Age-related changes in arginine and its metabolites in memory-associated brain structures. Neuroscience 2009; 164:611-28. [DOI: 10.1016/j.neuroscience.2009.08.029] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Revised: 07/13/2009] [Accepted: 08/12/2009] [Indexed: 10/20/2022]
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Bagnost T, Berthelot A, Alvergnas M, Miguet-Alfonsi C, André C, Guillaume Y, Demougeot C. Misregulation of the arginase pathway in tissues of spontaneously hypertensive rats. Hypertens Res 2009; 32:1130-5. [DOI: 10.1038/hr.2009.153] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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40
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Behavioral and neurochemical effects of acute putrescine depletion by difluoromethylornithine in rats. Neuroscience 2009; 161:691-706. [DOI: 10.1016/j.neuroscience.2009.03.075] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Revised: 03/23/2009] [Accepted: 03/28/2009] [Indexed: 11/24/2022]
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Liu P, Chary S, Devaraj R, Jing Y, Darlington CL, Smith PF, Tucker IG, Zhang H. Effects of aging on agmatine levels in memory-associated brain structures. Hippocampus 2009; 18:853-6. [PMID: 18481282 DOI: 10.1002/hipo.20448] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Agmatine is a metabolite of L-arginine by arginine decarboxylase. Recent evidence suggests that it exists in mammalian brain and is a novel neurotransmitter. The present study measured agmatine levels in several memory-associated brain structures in aged (24-month-old), middle-aged (12-month-old), and young (4-month-old) male Sprague Dawley rats using liquid chromatography/mass spectrometry. Agmatine levels were significantly decreased in the CA1, but increased in the CA2/3 and dentate gyrus, subregions of the hippocampus in aged and middle-aged rats relative to the young adults. In the prefrontal cortex, a dramatic decrease in agmatine level was found in aged rats as compared with middle-aged and young rats. There were significantly increased levels of agmatine in the entorhinal and perirhinal cortices in aged relative to middle-aged and young rats. In the postrhinal and temporal cortices, agmatine levels were significantly increased in aged and middle-aged rats as compared with young adults. The present findings, for the first time, demonstrate age-related changes in agmatine levels in memory-associated brain structures and raise a novel issue of the potential involvement of agmatine in the aging process.
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Affiliation(s)
- Ping Liu
- Department of Anatomy and Structural Biology, University of Otago, Dunedin, New Zealand.
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42
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Liu P, Smith PF, Darlington CL. Glutamate receptor subunits expression in memory-associated brain structures: Regional variations and effects of aging. Synapse 2008; 62:834-41. [DOI: 10.1002/syn.20563] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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43
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Lam PY, Cadenas E. Compromised proteasome degradation elevates neuronal nitric oxide synthase levels and induces apoptotic cell death. Arch Biochem Biophys 2008; 478:181-6. [PMID: 18706882 DOI: 10.1016/j.abb.2008.07.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Revised: 07/22/2008] [Accepted: 07/23/2008] [Indexed: 02/04/2023]
Abstract
The significance of impairment of proteasome activity in PC12 cells was examined in connection with nitrative/nitrosative stress and apoptotic cell death. Treatment of differentiated PC12 cells with MG132, a proteasome inhibitor, elicited a dose- and time-dependent increase in neuronal nitric oxide synthase (nNOS) protein levels, decreased cell viability, and increased cytotoxicity. Viability and cytotoxicity were ameliorated by L-NAME (a broad NOS inhibitor). Nitric oxide/peroxynitrite formation was increased upon treatment of PC12 cells with MG132 and decreased upon treatment with the combination of MG132 and 7-NI (a specific inhibitor of nNOS). The decreases in cell viability appeared to be effected by an activation of JNK and its effect on mitochondrial Bcl-x(L) phosphorylation. These effects are strengthened by the activation of caspase-9 along with increased caspase-3 activity upon treatment of PC12 cells with MG132. These results suggest that impairment of proteasome activity and consequent increases in nNOS levels lead to a nitrative stress that involves the coordinated response of JNK cytosolic signaling and mitochondrion-driven apoptotic pathways.
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Affiliation(s)
- Philip Y Lam
- Department of Pharmacology & Pharmaceutical Sciences, School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90089, USA
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44
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Xu L, Sun X, Tang M, Chen JDZ. Involvement of the Hippocampus and Neuronal Nitric Oxide Synapse in the Gastric Electrical Stimulation Therapy for Obesity. Obes Surg 2008; 19:475-83. [DOI: 10.1007/s11695-008-9579-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Accepted: 05/19/2008] [Indexed: 11/27/2022]
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Age-related changes in polyamines in memory-associated brain structures in rats. Neuroscience 2008; 155:789-96. [PMID: 18621105 DOI: 10.1016/j.neuroscience.2008.06.033] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2008] [Revised: 06/17/2008] [Accepted: 06/17/2008] [Indexed: 11/24/2022]
Abstract
Polyamines putrescine, spermidine and spermine are positively charged aliphatic amines and have important roles in maintaining normal cellular function, regulating neurotransmitter receptors and modulating learning and memory. Recent evidence suggests a role of putrescine in hippocampal neurogenesis, that is significantly impaired during aging. The present study measured the polyamine levels in memory-related brain structures in 24- (aged), 12- (middle-aged) and 4- (young) month-old rats using liquid chromatography/mass spectrometry and high performance liquid chromatography. In the hippocampus, the putrescine levels were significantly decreased in the CA1 and dentate gyrus, and increased in the CA2/3 with age. Significant age-related increases in the spermidine levels were found in the CA1 and CA2/3. There was no difference between groups in spermine in any sub-regions examined. In the parahippocampal region, increased putrescine level with age was observed in the entorhinal cortex, and age did not alter the spermidine levels. The spermine level was significantly decreased in the perirhinal cortex and increased in the postrhinal cortex with age. In the prefrontal cortex, there was age-related decrease in putrescine, and the spermidine and spermine levels were significantly increased with age. This study, for the first time, demonstrates age-related region-specific changes in polyamines in memory-associated structures, suggesting that polyamine system dysfunction may potentially contribute to aged-related impairments in hippocampal neurogenesis and learning and memory.
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Pritchett JS, Pulido JS, Shippy SA. Measurement of region-specific nitrate levels of the posterior chamber of the rat eye using low-flow push-pull perfusion. Anal Chem 2008; 80:5342-9. [PMID: 18549240 DOI: 10.1021/ac800238d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The determination of the presence of nitric oxide metabolites in the rat vitreous cavity in a regioselective manner is complicated by the size and shape of the eye as well as the diffusivity of the molecule and its metabolites. In this work, in vivo low-flow push-pull perfusion sampling was utilized with a rapid capillary electrophoretic assay to monitor levels of the major NO metabolite, nitrate, at the vitreoretinal interface (VRI) of normal and aged rat models. The sampling probe tips were placed in three different positions in the posterior chamber through a 29-gauge guide needle. Sampling was performed along the VRI over the optic nerve head and regions peripheral to the optic nerve head. Additionally, samples were collected from the middle vitreous region to compare to VRI sampling. A significant (P < 0.05) difference in the perfusate nitrate concentration was observed in each location, which may be due to the source of NO production or the clearance mechanism of the molecule from the vitreous cavity. Infusion of L-NAME with physiological saline led to a significant decrease (35%) in the observed nitrate level. LFPPP was then utilized to observe nitrate levels after an average of 4.5 months of aging. A 3-fold increase in the mean level of nitrate over the optic nerve head was observed in mature animals compared to younger control animals. Precise measurement of NO metabolites along the VRI may provide insights into the function of NO in maintaining homeostatic conditions and the molecular changes at the diseased retina.
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Affiliation(s)
- Jeanita S Pritchett
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607, USA
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Hirata K, Akita Y, Povalko N, Nishioka J, Yatsuga S, Matsuishi T, Koga Y. Effect of L-arginine on synaptosomal mitochondrial function. Brain Dev 2008; 30:238-45. [PMID: 17889473 DOI: 10.1016/j.braindev.2007.08.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 08/10/2007] [Accepted: 08/11/2007] [Indexed: 10/22/2022]
Abstract
OBJECTIVE Specific aim of this study is to elucidate the direct effects of L-arginine on the synaptosomal neurotransmission related to the mitochondrial respiratory function. METHODS Using isolated endbrains from wild-type mice (ICR), crude synaptosome was analyzed for their concentration of gamma-aminobutyric acid (GABA) and glutamate (Glu) with/without addition of L-arginine. We analyzed the contents of releasing amino acids evoked by high potassium condition and uptake of them in three separated fractions (cytosol, vesicles, and intact mitochondria). The oxygen consumption was also measured by oxygen electrode. RESULTS The entire uptakes of GABA and Glu were inhibited by rotenone (about 30 nmol/mg protein) with dose-dependent manner and showed a plateau at about 70% of total uptake. L-arginine inhibited the uptake of Glu logarithmically, however it showed no change in uptake of GABA. The contents of GABA and Glu in synaptosome were decreased in the presence of L-arginine. L-arginine enhanced the respiration of state II by succinate on synaptosomal respiration, although the respiration of synaptosomal mitochondrial fraction and the respiratory chains enzyme activities were almost unaffected by L-arginine. In the presence of rotenone, L-arginine decreased the uptake of Glu without changing the uptake of GABA, increased the releasing of GABA, and may modulate the excitability of neuronal state on the cytosol, cytomembrane, and/or organelles except for mitochondria. CONCLUSIONS L-arginine may modulate excitation by neurotransmitters at nerve endings, in relation to potentiated respiratory metabolism of succinate in synaptosomes. Such effects might contribute to alleviation of stroke-like symptoms in MELAS.
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Affiliation(s)
- Koji Hirata
- Department of Pediatrics and Child Health, Kurume University School of Medicine, Fukuoka, Japan
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48
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Tjong YW, Li MF, Hung MW, Fung ML. Melatonin ameliorates hippocampal nitric oxide production and large conductance calcium-activated potassium channel activity in chronic intermittent hypoxia. J Pineal Res 2008; 44:234-43. [PMID: 18339118 DOI: 10.1111/j.1600-079x.2007.00515.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Melatonin protects against hippocampal injury induced by intermittent hypoxia (IH). IH-induced oxidative stress is associated with decreases in constitutive production of nitric oxide (NO) and in the activity of large conductance calcium-activated potassium (BK) channels in hippocampal neurons. We tested the hypothesis that administration of melatonin alleviates the NO deficit and impaired BK channel activity in the hippocampus of IH rats. Sprague-Dawley rats were injected with melatonin (10 mg/kg, i.p.) or vehicle before daily IH exposure for 8 hr for 7 days. The NO and intracellular calcium ([Ca2+]i) levels in the CA1 region of hippocampal slices were measured by electrochemical microsenor and spectrofluorometry, respectively. The activity of BK channels was recorded by patch-clamping electrophysiology in dissociated CA1 neurons. Malondialdehyde levels were increased in the hippocampus of hypoxic rats and were lowered by the melatonin treatment. Levels of NO under resting and hypoxic conditions, and the protein expression of neuronal NO synthase (nNOS) were significantly reduced in the CA1 neurons of hypoxic animals compared with the normoxic controls. These deficits were mitigated in the melatonin-treated hypoxic rats with an improved [Ca2+]i response to acute hypoxia. The open probability of BK channels was decreased in the hypoxic rats and was partially restored in the melatonin-treated animals, without alterations in the expression of channel subunits and unitary conductance. Acute treatment of melatonin had no significant effects on the BK channel activity or on the [Ca2+]i response to hypoxia. Collectively, these results suggest that melatonin ameliorates the constitutive NO production and BK channel activity via an antioxidant mechanism against an IH-induced down-regulation of nNOS expression in hippocampal neurons.
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Affiliation(s)
- Y W Tjong
- Department of Physiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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Tjong YW, Li M, Hung MW, Wang K, Fung ML. Nitric oxide deficit in chronic intermittent hypoxia impairs large conductance calcium-activated potassium channel activity in rat hippocampal neurons. Free Radic Biol Med 2008; 44:547-57. [PMID: 17996205 DOI: 10.1016/j.freeradbiomed.2007.10.033] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 09/14/2007] [Accepted: 10/12/2007] [Indexed: 12/22/2022]
Abstract
Sleep apnea associated with chronic intermittent hypoxia (IH) impairs hippocampal functions but the pathogenic mechanisms involving dysfunction of nitric oxide (NO) and ionic channels remain unclear. We examined the hypothesis that hippocampal NO deficit impairs the activity of large conductance calcium-activated potassium (BK) channels in rats with chronic IH, mimicking conditions in patients with sleep apnea. A patch-clamp study was performed on hippocampal CA1 neurons acutely dissociated from IH and control rats. The levels of endogenous NO and intracellular calcium in the CA1 region of the hippocampal slices were measured respectively by electrochemical microsensors and spectrofluorometry. We found that the open probability of BK channels remarkably decreased in the CA1 pyramidal neurons in a time-dependent manner with the IH treatment, without changes in the unitary conductance and reversal potential. NO donors, SNP or DETA/NO, significantly restored the activity of BK channels in the IH neurons, which was prevented by blockade of S-nitrosylation with NEM or MTSES but not by inhibition of the cGMP pathway with ODQ or 8-bromo-cGMP. Endogenous NO levels were substantially lowered in the IH hippocampus during resting and hypoxia. Also, the level of protein expression of neuronal NO synthase was markedly lessened in the IH neurons with decreased intracellular calcium response to hypoxia. Collectively, the results suggest that the IH-induced NO deficit mediated by a down-regulation of the expression of neuronal NO synthase plays a causative role in the impaired activity of BK channels, which could account for the hippocampal injury in patients with sleep apnea.
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Affiliation(s)
- Yung-Wui Tjong
- Department of Physiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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Palumbo ML, Fosser NS, Rios H, Zorrilla Zubilete MA, Guelman LR, Cremaschi GA, Genaro AM. Loss of hippocampal neuronal nitric oxide synthase contributes to the stress-related deficit in learning and memory. J Neurochem 2007; 102:261-74. [PMID: 17419805 DOI: 10.1111/j.1471-4159.2007.04528.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nitric oxide (NO) has been involved in many pathophysiological brain processes. However, the exact role of NO in the cognitive deficit associated to chronic stress exposure has not been elucidated. In this study, we investigated the participation of hippocampal NO production and their regulation by protein kinase C (PKC) in the memory impairment induced in mice subjected to chronic mild stress model (CMS). CMS mice showed a poor learning performance in both open field and passive avoidance inhibitory task respect to control mice. Histological studies showed a morphological alteration in the hippocampus of CMS mice. On the other hand, chronic stress induced a diminished NO production by neuronal nitric oxide synthase (nNOS) correlated with an increment in gamma and zeta PKC isoenzymes. Partial restoration of nNOS activity was obtained after PKC activity blockade. NO production by inducible nitric oxide synthase isoform was not detected. The magnitude of oxidative stress, evaluated by reactive oxygen species production, after excitotoxic levels of NMDA was increased in hippocampus of CMS mice. Moreover, ROS formation was higher in the presence of nNOS inhibitor in both control and CMS mice. Finally, treatment of mice with nNOS inhibitors results in behavioural alterations similar to those observed in CMS animals. These findings suggest a novel role for nNOS showing protective activity against insults that trigger tissue toxicity leading to memory impairments.
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Affiliation(s)
- María Laura Palumbo
- CEFYBO-CONICET and 1a. Cát. de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
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