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Pesonen H, Strömmer J, Li X, Parkkari J, Tarkka IM, Astikainen P. Magnetoencephalography reveals impaired sensory gating and change detection in older adults in the somatosensory system. Neuropsychologia 2023; 190:108702. [PMID: 37838067 DOI: 10.1016/j.neuropsychologia.2023.108702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 08/31/2023] [Accepted: 10/10/2023] [Indexed: 10/16/2023]
Abstract
Brain electrophysiological responses can provide information about age-related decline in sensory-cognitive functions with high temporal accuracy. Studies have revealed impairments in early sensory gating and pre-attentive change detection mechanisms in older adults, but no magnetoencephalographic (MEG) studies have been undertaken into both non-attentive and attentive somatosensory functions and their relationship to ageing. Magnetoencephalography was utilized to record cortical somatosensory brain responses in young (20-28 yrs), middle-aged (46-56 yrs), and older adults (64-78 yrs) under active and passive somatosensory oddball conditions. A repeated standard stimulus was occasionally replaced by a deviant stimulus (p = .1), which was an electrical pulse on a different finger. We examined the amplitudes of M50 and M100 responses reflecting sensory gating, and later components reflecting change detection and attention shifting (M190 and M250 for the passive condition, and M200 and M350 for the active condition, respectively). Spatiotemporal cluster-based permutation tests revealed that older adults had significantly larger M100 component amplitudes than young adults for task-irrelevant stimuli in both passive and active condition. Older adults also showed a reduced M250 component and an altered M350 in response to deviant stimuli. The responses of middle-aged adults did not differ from those of younger adults, but this study should be repeated with a larger sample size. By demonstrating changes in both somatosensory gating and attentional shifting mechanisms, our findings extend previous research on the effects of ageing on pre-attentive and attentive brain functions.
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Affiliation(s)
- Heidi Pesonen
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.
| | - Juho Strömmer
- Centre for Interdisciplinary Brain Research, Department of Psychology, University of Jyväskylä, Jyväskylä, Finland
| | - Xueqiao Li
- Centre for Interdisciplinary Brain Research, Department of Psychology, University of Jyväskylä, Jyväskylä, Finland
| | - Jari Parkkari
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Ina M Tarkka
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Piia Astikainen
- Centre for Interdisciplinary Brain Research, Department of Psychology, University of Jyväskylä, Jyväskylä, Finland
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Mango D, Nisticò R. Acid-Sensing Ion Channel 1a Is Involved in N-Methyl D-Aspartate Receptor-Dependent Long-Term Depression in the Hippocampus. Front Pharmacol 2019; 10:555. [PMID: 31178731 PMCID: PMC6537656 DOI: 10.3389/fphar.2019.00555] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 05/02/2019] [Indexed: 11/29/2022] Open
Abstract
Acid-sensing ion channels (ASICs), members of the degenerin/epithelial Na+ channel superfamily, are largely expressed in the mammalian nervous system. ASIC1a is highly permeable to Ca2+ and are involved in many physiological processes, including synaptic plasticity, learning, and memory. To clarify the role of ASIC1a in synaptic transmission and plasticity, we investigated N-methyl D-aspartate (NMDA) receptor-dependent long-term depression (LTD) in the CA1 region of the hippocampus. We found that: (1) ASIC1a mediates a component of ASIC1a excitatory postsynaptic currents (EPSCs); (2) ASIC1a plays a role in electrical LTD induced by LFS protocol both in P13-18 and P30-40 animals; (3) ASIC1a is involved in chemical LTD induced by brief bath application of NMDA both in P13-18 and P30-40 animals; and finally (4) a functional interaction between ASIC1a and NMDA receptors occurs during LTD. These findings suggest a new role for ASIC1a in specific forms of synaptic plasticity in the mouse hippocampus.
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Affiliation(s)
- D Mango
- Laboratory of Neuropharmacology, European Brain Research Institute, Rita Levi-Montalcini Foundation, Rome, Italy
| | - R Nisticò
- Laboratory of Neuropharmacology, European Brain Research Institute, Rita Levi-Montalcini Foundation, Rome, Italy.,Department of Biology, School of Pharmacy, University of Rome Tor Vergata, Rome, Italy
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Strömmer JM, Tarkka IM, Astikainen P. Somatosensory mismatch response in young and elderly adults. Front Aging Neurosci 2014; 6:293. [PMID: 25386140 PMCID: PMC4209888 DOI: 10.3389/fnagi.2014.00293] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 10/07/2014] [Indexed: 01/23/2023] Open
Abstract
Aging is associated with cognitive decline and alterations in early perceptual processes. Studies in the auditory and visual sensory modalities have shown that the mismatch negativity [or the mismatch response (MMR)], an event-related potential (ERP) elicited by a deviant stimulus in a background of homogenous events, diminishes with aging and cognitive decline. However, the effects of aging on the somatosensory MMR (sMMR) are not known. In the current study, we recorded ERPs to electrical pulses to different fingers of the left hand in a passive oddball experiment in young (22–36 years) and elderly (66–95 years) adults engaged in a visual task. The MMR was found to deviants as compared to standards at two latency ranges: 180–220 ms and 250–290 ms post-stimulus onset. At 180–220 ms, within the young, the MMR was found at medial electrode sites, whereas aged did not show any amplitude difference between the stimulus types at the same latency range. At 250–290 ms, the MMR was evident with attenuated amplitude and narrowed scalp distribution among aged (Fz) compared to young (fronto-centrally and lateral parietal sites). Hence, the results reveal that the somatosensory change detection mechanism is altered in aging. The sMMR can be used as a reliable measure of age-related changes in sensory-cognitive functions.
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Affiliation(s)
- Juho M Strömmer
- Department of Psychology, University of Jyväskylä Jyväskylä, Finland
| | - Ina M Tarkka
- Department of Health Sciences, University of Jyväskylä Jyväskylä, Finland
| | - Piia Astikainen
- Department of Psychology, University of Jyväskylä Jyväskylä, Finland
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Lee E, Sidoryk-Wegrzynowicz M, Farina M, Rocha JBT, Aschner M. Estrogen attenuates manganese-induced glutamate transporter impairment in rat primary astrocytes. Neurotox Res 2012; 23:124-30. [PMID: 22878846 DOI: 10.1007/s12640-012-9347-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Revised: 07/26/2012] [Accepted: 07/30/2012] [Indexed: 10/28/2022]
Abstract
The astrocytic glutamate transporters (GLT-1, GLAST) are critical for removing excess glutamate from synaptic sites, thereby maintaining glutamate homeostasis within the brain. 17β-Estradiol (E2) is one of the most active estrogen hormones possessing neuroprotective effects both in in vivo and in vitro models, and it has been shown to enhance astrocytic glutamate transporter function (Liang et al. in J Neurochem 80:807-814, 2002; Pawlak et al. in Brain Res Mol Brain Res 138:1-7, 2005). However, E2 is not clinically optimal for neuroprotection given its peripheral feminizing and proliferative effects; therefore, brain selective estrogen receptor modulators (neuro SERMs) (Zhao et al. in Neuroscience 132:299-311, 2005) that specifically target estrogenic mechanisms, but lack the systemic estrogen side effects offer more promising therapeutic modality for the treatment of conditions associated with excessive synaptic glutamate levels. This review highlights recent studies from our laboratory showing that E2 and SERMs effectively reverse glutamate transport inhibition in a manganese (Mn)-induced model of glutamatergic deregulation. Specifically, we discuss mechanisms by which E2 restores the expression and activity of glutamate uptake. We advance the hypothesis that E2 and related compounds, such as tamoxifen may offer a potential therapeutic modality in neurodegenerative disorders, which are characterized by altered glutamate homeostasis.
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Affiliation(s)
- Eunsook Lee
- Department of Physiology, Meharry Medical College, Nashville, TN 37208, USA.
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Magnusson KR, Brim BL, Das SR. Selective Vulnerabilities of N-methyl-D-aspartate (NMDA) Receptors During Brain Aging. Front Aging Neurosci 2010; 2:11. [PMID: 20552049 PMCID: PMC2874396 DOI: 10.3389/fnagi.2010.00011] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Accepted: 03/02/2010] [Indexed: 01/07/2023] Open
Abstract
N-methyl-D-aspartate (NMDA) receptors are present in high density within the cerebral cortex and hippocampus and play an important role in learning and memory. NMDA receptors are negatively affected by aging, but these effects are not uniform in many different ways. This review discusses the selective age-related vulnerabilities of different binding sites of the NMDA receptor complex, different subunits that comprise the complex, and the expression and functions of the receptor within different brain regions. Spatial reference, passive avoidance, and working memory, as well as place field stability and expansion all involve NMDA receptors. Aged animals show deficiencies in these functions, as compared to young, and some studies have identified an association between age-associated changes in the expression of NMDA receptors and poor memory performance. A number of diet and drug interventions have shown potential for reversing or slowing the effects of aging on the NMDA receptor. On the other hand, there is mounting evidence that the NMDA receptors that remain within aged individuals are not always associated with good cognitive functioning. This may be due to a compensatory response of neurons to the decline in NMDA receptor expression or a change in the subunit composition of the remaining receptors. These studies suggest that developing treatments that are aimed at preventing or reversing the effects of aging on the NMDA receptor may aid in ameliorating the memory declines that are associated with aging. However, we need to be mindful of the possibility that there may also be negative consequences in aged individuals.
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Affiliation(s)
- Kathy R Magnusson
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University Corvallis, OR, USA
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Stephens ML, Quintero JE, Pomerleau F, Huettl P, Gerhardt GA. Age-related changes in glutamate release in the CA3 and dentate gyrus of the rat hippocampus. Neurobiol Aging 2009; 32:811-20. [PMID: 19535175 DOI: 10.1016/j.neurobiolaging.2009.05.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 05/01/2009] [Accepted: 05/08/2009] [Indexed: 12/31/2022]
Abstract
The present studies employed a novel microelectrode array recording technology to study glutamate release and uptake in the dentate gyrus, CA3 and CA1 hippocampal subregions in anesthetized young, late-middle aged and aged male Fischer 344 rats. The mossy fiber terminals in CA3 showed a significantly decreased amount of KCl-evoked glutamate release in aged rats compared to both young and late-middle-aged rats. Significantly more KCl-evoked glutamate release was seen from perforant path terminals in the DG of late-middle-aged rats compared young and aged rats. The DG of aged rats developed an increased glutamate uptake rate compared to the DG of young animals, indicating a possible age-related change in glutamate regulation to deal with increased glutamate release that occurred in late-middle age. No age-related changes in resting levels of glutamate were observed in the DG, CA3 and CA1. Taken together, these data support dynamic changes to glutamate regulation during aging in subregions of the mammalian hippocampus that are critical for learning and memory.
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Affiliation(s)
- Michelle L Stephens
- Department of Anatomy and Neurobiology, Center for Microelectrode Technology, Morris K. Udall Parkinson's Disease Research Center of Excellence, University of Kentucky Chandler Medical Center, Lexington, KY 40536-0098, USA
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Billard JM, Rouaud E. Deficit of NMDA receptor activation in CA1 hippocampal area of aged rats is rescued by D-cycloserine. Eur J Neurosci 2007; 25:2260-8. [PMID: 17445224 DOI: 10.1111/j.1460-9568.2007.05488.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Activation of the glycine modulatory site of the N-methyl-D-aspartate glutamate receptor (NMDAR) may reduce cognitive impairments associated with normal ageing. In order to test this hypothesis, we assessed the effects of the partial agonist D-cycloserine (DCS) on cellular activities involved in memory formation. This was performed in CA1 cellular networks of adult and aged Sprague-Dawley rat hippocampal slices using extracellular field excitatory postsynaptic potential recordings. Synaptic potentials specifically mediated by NMDAR were significantly reduced in aged animals. DCS increased the magnitude of these responses in both adult and old rats but this effect was significantly higher in the latter, thus reversing the age-related decrease in NMDAR synaptic potentials. NMDAR-mediated theta burst long-term potentiation (TBS-LTP) as well as long-term depression (LTD) of synaptic transmission, prominent models for the cellular basis of learning and memory, were also weakened in aged animals. Age-related alterations of both forms of synaptic plasticity were rescued by DCS. In addition, the DCS-induced decrease in basal fast glutamatergic neurotransmission involving the activation of inhibitory glycinergic receptors, previously reported in young rats (Rouaud & Billard, 2003), was severely attenuated in aged animals. In summary, our results indicate that the facilitation of NMDAR activation through its glycine-binding site rescues the age-related deficit of cellular mechanisms of learning and memory. Such physiological evidences suggest that this modulation site of NMDAR represents an important target to alleviate cognitive deficits associated with normal ageing.
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Affiliation(s)
- J-M Billard
- INSERM 549, 2 ter rue d'Alésia, Paris, F-75014 France.
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McGuire M, Ling L. Ventilatory long-term facilitation is greater in 1- vs. 2-mo-old awake rats. J Appl Physiol (1985) 2005; 98:1195-201. [PMID: 15591293 DOI: 10.1152/japplphysiol.00996.2004] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Respiratory long-term facilitation (LTF) declines in middle-aged vs. adult male rats. Chronic intermittent hypoxia (CIH; 5 min 11–12% O2/5 min air, 12 h/night, 7 nights) enhances LTF in adult rats. However, LTF in immature rats and the effect of early CIH are unevaluated. The present study compared LTF in 1- and 2-mo-old rats and examined the effect of neonatal CIH (initiated at 2 days after birth) on the LTF. Ventilatory LTF, elicited by 5 ( protocol 1) or 10 ( protocol 2) episodes of poikilocapnic hypoxia (5 min 12% O2/5 min air), was measured twice by plethysmography on the same male conscious rat when it was 1 and 2 mo old. In untreated (without CIH) rats, both resting ventilation (54.7 ± 0.6 vs. 43.0 ± 0.2 ml·100 g−1·min−1) and hypoxic ventilatory response (131 ± 4 vs. 66 ± 3% above baseline) were greater in 1- vs. 2-mo-old rats. Protocol 1 elicited LTF in 1-mo-old (12.5 ± 1.0% above baseline) but not 2-mo-old rats. Protocol 2 elicited a greater LTF in 1-mo-old (24.3 ± 0.8%) vs. 2-mo-old rats (18.2 ± 0.5%). In CIH-treated rats, protocol 1 also elicited LTF in 1-mo-old (13.1 ± 1.5%) but not 2-mo-old rats. Protocol 2 elicited LTF in both age groups, but LTF was enhanced by the CIH only in 1-mo-old rats (28.8 ± 0.9%). These results suggest that ventilatory LTF and hypoxic ventilatory response are greater in male rats shortly before their sexual maturity and that the neonatal CIH somewhat enhances ventilatory LTF ∼3 wk after CIH, but this enhancement does not last to adulthood.
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Affiliation(s)
- Michelle McGuire
- Div. of Sleep Medicine at BIDMC, Brigham and Women's Hospital, 75 Francis St., Boston, MA 02115, USA
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Affiliation(s)
- Steven P R Rose
- Brain and Behaviour Research Group at The Open University, Milton Keynes MK7 6AA, UK.
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Wemmie JA, Chen J, Askwith CC, Hruska-Hageman AM, Price MP, Nolan BC, Yoder PG, Lamani E, Hoshi T, Freeman JH, Welsh MJ. The acid-activated ion channel ASIC contributes to synaptic plasticity, learning, and memory. Neuron 2002; 34:463-77. [PMID: 11988176 DOI: 10.1016/s0896-6273(02)00661-x] [Citation(s) in RCA: 532] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Many central neurons possess large acid-activated currents, yet their molecular identity is unknown. We found that eliminating the acid sensing ion channel (ASIC) abolished H(+)-gated currents in hippocampal neurons. Neuronal H(+)-gated currents and transient acidification are proposed to play a role in synaptic transmission. Investigating this possibility, we found ASIC in hippocampus, in synaptosomes, and in dendrites localized at synapses. Moreover, loss of ASIC impaired hippocampal long-term potentiation. ASIC null mice had reduced excitatory postsynaptic potentials and NMDA receptor activation during high-frequency stimulation. Consistent with these findings, null mice displayed defective spatial learning and eyeblink conditioning. These results identify ASIC as a key component of acid-activated currents and implicate these currents in processes underlying synaptic plasticity, learning, and memory.
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Affiliation(s)
- John A Wemmie
- Department of Psychiatry, University of Iowa, Iowa City, IA 52242, USA
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Magnusson KR, Scanga C, Wagner AE, Dunlop C. Changes in anesthetic sensitivity and glutamate receptors in the aging canine brain. J Gerontol A Biol Sci Med Sci 2000; 55:B448-54. [PMID: 10995042 DOI: 10.1093/gerona/55.9.b448] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This study investigated whether the aging process in dogs is associated with an increased sensitivity to inhalation anesthesia and whether age-related changes in glutamate receptors are related to the increased sensitivity. The mean minimum alveolar concentration (MAC) of isoflurane was 1.82 +/- .08% for 2-3 year olds and 1.45 +/- .06% for 11 years olds, indicating that there was an increased potency of isoflurane in the older dogs as compared to the young. These older animals also showed a significant decrease in binding of [3H]glutamate and [3H]dizocilpine ([3H]MK801) to N-methyl-D-aspartate (NMDA) receptors in multiple cortical and hippocampal regions. The density of binding to NMDA receptors in the cortex, using a single concentration of ligand, correlated significantly with individual MAC values. These results demonstrate that dogs experience an increase in anesthetic potency with increased age, similar to humans, and that age-related changes in the NMDA receptor may represent one mechanism underlying this increased sensitivity to anesthesia.
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Affiliation(s)
- K R Magnusson
- Department of Anatomy & Neurobiology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523-1670, USA.
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Strosznajder JB, Zambrzycka A, Kacprzak MD, Strosznajder RP. Amyloid beta peptide 25-35 modulates hydrolysis of phosphoinositides by membrane phospholipase(s) C of adult brain cortex. J Mol Neurosci 1999; 12:101-9. [PMID: 10527454 DOI: 10.1007/bf02736924] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Phosphoinositide-specific phospholipase C (PLC) is a key enzyme in signal transduction. A subset of muscarinic cholinergic receptors are linked to G-proteins that activate phospholipase C. Cholinergic pathways are important in learning and memory, and deficits in cholinergic transmission have been implicated in Alzheimer's disease (AD). AD is also associated with increased beta-amyloid plaques. In the present study, we have investigated the effect of the amyloid beta (A beta) synthetic peptide homologous to residue 25-35 of A beta in nonaggregated and aggregated forms on the degradation of inositol phospholipids. Synaptic plasma membranes (SPM) and the cytosolic fraction from rat brain cortex served as a source of enzymes. The studies were carried out with radioactive inositol phospholipids in the presence of endogenous and 2 mM CaCl2. The enzyme(s) activity was evaluated by determination of the product formation of [3H]inositol-1-phosphate (IP1) or [3H]inositol-1,4,5-trisphosphate (IP3). Results show that the PI-PLC activity was significantly higher in cytosol compared to SPM, and this enzyme was stimulated by 2 mM CaCl2, but not by GTPgammaS or carbachol, a cholinergic receptor agonist. Activity of the SPM-bound PIP2-PLC was similar to that in cytosol and was not activated by 2 mM CaCl2. The SPM PIP2-PLC was significantly stimulated by GTPgammaS together with the cholinergic agonist, carbachol. Fresh-water-soluble A beta 25-35 activated PI-PLC in SPM markedly by two- to threefold, but this effect was absent in the presence of 2 mM CaCl2. Moreover, A beta 25-35 had no effect on basal PIP2-PLC activity and cytosolic PI-PLC and PIP2-PLC. The aggregated form of A beta 25-35 significantly inhibited PIP2-PLC only in the presence of endogenous CaCl2. It also inhibited the carbachol and GTP(gamma)S-stimulated PIP2-PLC. Our findings show that depending on the aggregation state and Ca2+ concentration, A beta modulates phosphoinositide degradation differently and exclusively in brain synaptic plasma membranes. Our data suggested that aggregated A beta peptide may be responsible for the significant impairment of phosphoinositide signaling found in brain membranes during AD.
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Affiliation(s)
- J B Strosznajder
- Department of Cellular Signalling, Medical Research Center, Polish Academy of Sciences, Warsaw
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Fluck E, Fernandes C, File SE, Curran HV, Marshall J. The influence of alcoholism and cirrhosis on benzodiazepine receptor function. Pharmacol Biochem Behav 1998; 59:949-54. [PMID: 9586854 DOI: 10.1016/s0091-3057(97)00513-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In a previous study we reported that the affinity of the platelet benzodiazepine receptor was greater in alcoholic cirrhotic patients compared with normal controls and that there were detectable ligands for the neuronal benzodiazepine receptor in plasma from both alcoholic and nonalcoholic cirrhotic patients. The aim of the present study was to assess the separate contributions of alcoholism and cirrhosis to the presence of ligands in plasma for the neuronal and peripheral benzodiazepine receptors and to changes in peripheral benzodiazepine receptor binding in platelets. These parameters were measured in 10 alcoholic cirrhotics, 9 nonalcoholic cirrhotics, 7 alcoholics with a normal liver function, and 15 nonalcoholic subjects and normal liver function. Both groups of alcoholics had been abstinent for several months and the nonalcoholic groups had abstained for 24 h before the study. The concentration of ligands for the peripheral benzodiazepine receptor were significantly higher in both cirrhotic groups compared with the other two groups, suggesting that cirrhosis was responsible for this accumulation. Furthermore, the cirrhotic patients with detectable concentrations of these ligands had significantly poorer episodic memory than those without ligands. However, the presence of ligands for the peripheral benzodiazepine receptor did not correlate with the change in receptor affinity, which was increased in the alcoholic cirrhotic group compared with all other groups. Neither cirrhosis nor alcoholism altered the peripheral benzodiazepine receptor number. The cirrhotic patients with detectable ligands for the neuronal benzodiazepine receptor showed psychomotor slowing and executive dysfunction. The results suggest that the ligands for the peripheral benzodiazepine receptor may contribute to some of the cognitive deficits seen in hepatic encephalopathy, but are not responsible for the receptor affinity change seen in the alcoholic cirrhotics. This affinity change is not solely due to the effects of alcohol and could possibly serve as a marker for those at risk for developing alcoholic cirrhosis.
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Affiliation(s)
- E Fluck
- Psychopharmacology Research Unit, UMDS, Guy's Hospital, London, UK
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Patel N, Spangler EL, Greig NH, Yu QS, Ingram DK, Meyer RC. Phenserine, a novel acetylcholinesterase inhibitor, attenuates impaired learning of rats in a 14-unit T-maze induced by blockade of the N-methyl-D-aspartate receptor. Neuroreport 1998; 9:171-6. [PMID: 9592071 DOI: 10.1097/00001756-199801050-00035] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The present study evaluated the interaction of the glutamatergic and acetylcholinergic systems in memory formation, with an overall emphasis on developing multi-system approaches for treating age-related cognitive decline and Alzheimer' s disease. Specifically, we used a 14-unit T-maze to investigate whether phenserine (PHEN), a long-acting acetylcholinesterase inhibitor, could overcome a learning deficit in rats induced by the NMDA receptor antagonist, 3-(+/-) 2-carboxypiperzin-4-yl) propyl phosphonic acid (CPP). Prior to drug treatment, 3-month-old male Fischer-344 rats were trained to criterion (13 of 15 shock avoidances) in a straight runway. Twenty-four hours later, rats were given i.p. injections of saline (SAL), CPP (9 mg/kg) + SAL or CPP + PHEN (0.25, 0.5 or 0.75 mg/kg) and received 15 massed training trials in a 14-unit T-maze. CPP significantly increased the number of errors made in the maze relative to controls, and phenserine significantly reduced the number of errors made relative to rats receiving CPP only, with the lowest dose being the most effective. These results provide further support of phenserine's potent, cognitive-enhancing properties, and suggest that combined modulation of glutamatergic and acetylcholinergic systems may be of potential benefit in developing new pharmacotherapies for Alzheimer's disease and age-related cognitive decline.
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Affiliation(s)
- N Patel
- Molecular Physiology and Genetics Section, Nathan W. Shock Laboratories, Gerontology Research Center, National Institute on Aging, National Institute of Health, Johns Hopkins University, Bayview Campus, Baltimore, MD 21224, USA
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Meyer RC, Spangler EL, Patel N, London ED, Ingram DK. Impaired learning in rats in a 14-unit T-maze by 7-nitroindazole, a neuronal nitric oxide synthase inhibitor, is attenuated by the nitric oxide donor, molsidomine. Eur J Pharmacol 1998; 341:17-22. [PMID: 9489851 DOI: 10.1016/s0014-2999(97)01428-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In previous experiments, it was demonstrated that systemic or central administration of the nitric oxide synthase (NO synthase) inhibitor, NG-nitro-L-arginine (N-Arg), produced dose-dependent learning impairments in rats in a 14-unit T-maze; and that sodium nitroprusside, a NO donor, could attenuate the impairment. Since N-Arg is not specific for neuronal NO synthase and produces hypertension, it is possible that effects on the cardiovasculature may have contributed to the impaired maze performance. In the present experiment, we have investigated the maze performance of 3-4 months old male Fischer-344 rats following treatment with 7-nitroindazole, a NO synthase inhibitor that is selective for neuronal NO synthase and does not produce hypertension. In addition, we examined the effects of the NO donor, molsidomine, which is much longer acting than sodium nitroprusside. Rats were pretrained to avoid footshock in a straight runway and received training in a 14-unit T-maze 24 h later. In an initial dose-response study, rats received intraperitoneal (i.p.) injections of either 7-nitroindazole (25, 50, or 65 mg/kg) or peanut oil 30 min prior to maze training. 7-nitroindazole produced significant, dose-dependent maze acquisition deficits, with 65 mg/kg producing the greatest learning impairment. This dose of 7-nitroindazole had no significant effect on systolic blood pressure. Following the dose-response study, rats were given i.p. injections of either 7-nitroindazole (70 mg/kg) plus saline, 7-nitroindazole (70 mg/kg) plus the NO donor, molsidomine (2 or 4 mg/kg), or peanut oil plus saline as controls. Both doses of molsidomine significantly attenuated the learning deficit induced by 7-nitroindazole relative to controls. These findings represent the first evidence that impaired learning produced by inhibition of neuronal NO synthase can be overcome by systemic administration of a NO donor.
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Affiliation(s)
- R C Meyer
- Molecular Physiology and Genetics Section, Nathan W. Shock Laboratories, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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Araki T, Kato H, Nagaki S, Shuto K, Fujiwara T, Itoyama Y. Effects of vinconate on age-related alterations in [3H]MK-801, [3H]glycine, sodium-dependent D-[3H]aspartate, [3H]FK-506 and [3H]PN200-110 binding in rats. Mech Ageing Dev 1997; 95:13-29. [PMID: 9152958 DOI: 10.1016/s0047-6374(96)01831-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We investigated the effects of age and (+/-)-methyl-3-ethyl-2,3,3a,4-tetrahydro-1 H-in-dolo[3,2,1-de] [1,5] naphthyridine-6-carboxylate hydrochloride (vinconate), an indolonaphthyridine derivative, on calcium channels, neurotransmitter receptor systems and immunophilin in Fischer rat brain using quantitative receptor autoradiography. [3H]MK-801, [3H]glycine, sodium-dependent D-[3H]aspartate, [3H]FK-506 and [3H]PN200-110 were used to label N-methyl-D-aspartate (NMDA) receptors, glycine receptors, excitatory amino acid transport sites, FK-506 binding proteins (FKBP) and voltage-dependent L-type calcium channels, respectively. [3H]Glycine and sodium-dependent D-[3H]aspartate binding significantly decreased in the frontal cortex, parietal cortex, striatum, nucleus accumbens, hippocampus, thalamus, substantia nigra and cerebellum of 24 month old rats in comparison with 6 month old animals. In contrast, [3H]MK-801, [3H]FK-506 and [3H]PN200-110 binding showed no significant changes in the brain of 24 month old rats. Intraperitoneal chronic treatment with vinconate (10 and 30 mg/kg, once a day for 4 weeks) dose-dependently ameliorated the significant reduction in [3H]glycine and sodium-dependent D-[3H]aspartate binding in the brain of 24 month old rats. These results demonstrate that glycine receptors and excitatory amino acid transport sites are more susceptible to aging processes than NMDA receptors, immunophilin and voltage-dependent L-type calcium channels. Furthermore, our findings suggest that vinconate may have a beneficial effect on age-related changes in glycine receptors and excitatory amino acid transport sites.
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Affiliation(s)
- T Araki
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
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Kelly JF, Roth GS. Chapter 9 Changes in Neurotransmitter Signal Transduction Pathways in the Aging Brain. THE AGING BRAIN 1997. [DOI: 10.1016/s1566-3124(08)60059-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Araki T, Kato H, Shuto K, Fujiwara T, Itoyama Y. Different age-related changes in NMDA and glycine receptors in the rat brain. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 1996; 1:103-107. [PMID: 21781669 DOI: 10.1016/1382-6689(95)00015-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/1995] [Accepted: 10/25/1995] [Indexed: 05/31/2023]
Abstract
We investigated the age-related changes of N-methyl-d-aspartate (NMDA) and strychnine-insensitive glycine receptors in the brain from Fischer rats aged 3 weeks (immature), 6 months (adult), 12 months (mature), 18 months (middle-aged) and 24 months (aged) using receptor autoradiography. [(3)H]MK-801 and [(3)H]glycine were used to label the NMDA receptor and the glycine receptor, respectively. In immature rats, [(3)H]MK-801 binding showed a significant decline only in the nucleus accumbens, whereas [(3)H]glycine binding exhibited a significant increase in the frontal cortex, parietal cortex, striatum and thalamus as compared with young rats. In mature, middle-aged and aged rats, [(3)H]MK-801 binding showed no significant change in the brain. In contrast, [(3)H]glycine binding showed a conspicuous reduction in the striatum and hippocampal CA3 sector and thalamus from mature rats. Thereafter, the age-related reduction in [(3)H]glycine binding was observed in all brain areas of middle-aged and aged rats. These results demonstrate that the glycine receptor in the rat brain is far more susceptible to aging processes than the NMDA receptor. Furthermore, they suggest the conspicuous differences in the developmental pattern between NMDA and glycine receptors in the rat brain after birth. These findings suggest that glycine receptor in the brain is primarily and severely affected in aging processes and this may lead to age-related neurological deficits.
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Affiliation(s)
- T Araki
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
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