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Kim Y, Kim S, Ho WK, Lee SH. Burst firing is required for induction of Hebbian LTP at lateral perforant path to hippocampal granule cell synapses. Mol Brain 2023; 16:45. [PMID: 37217996 DOI: 10.1186/s13041-023-01034-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 05/04/2023] [Indexed: 05/24/2023] Open
Abstract
High frequency burst firing is critical in summation of back-propagating action potentials (APs) in dendrites, which may greatly depolarize dendritic membrane potential. The physiological significance of burst firings of hippocampal dentate GCs in synaptic plasticity remains unknown. We found that GCs with low input resistance could be categorized into regular-spiking (RS) and burst-spiking (BS) cells based on their initial firing frequency (Finit) upon somatic rheobase current injection, and investigated how two types of GCs differ in long-term potentiation (LTP) induced by high-frequency lateral perforant pathway (LPP) inputs. Induction of Hebbian LTP at LPP synapses required at least three postsynaptic APs at Finit higher than 100 Hz, which was met in BS but not in RS cells. The synaptically evoked burst firing was critically dependent on persistent Na+ current, which was larger in BS than RS cells. The Ca2+ source for Hebbian LTP at LPP synapses was primarily provided by L-type calcium channels. In contrast, Hebbian LTP at medial PP synapses was mediated by T-type calcium channels, and could be induced regardless of cell types or Finit of postsynaptic APs. These results suggest that intrinsic firing properties affect synaptically driven firing patterns, and that bursting behavior differentially affects Hebbian LTP mechanisms depending on the synaptic input pathway.
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Affiliation(s)
- Yoonsub Kim
- Cell Physiology Lab. Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Sooyun Kim
- Clinical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Won-Kyung Ho
- Cell Physiology Lab. Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea.
| | - Suk-Ho Lee
- Cell Physiology Lab. Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea.
- Department of Brain and Cognitive Science, Seoul National University College of Natural Science, 103 Daehak-Ro, Jongno-Gu, 03080, Seoul, Republic of Korea.
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Mechanisms Underlying Long-Term Synaptic Zinc Plasticity at Mouse Dorsal Cochlear Nucleus Glutamatergic Synapses. J Neurosci 2020; 40:4981-4996. [PMID: 32434779 DOI: 10.1523/jneurosci.0175-20.2020] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 05/13/2020] [Accepted: 05/15/2020] [Indexed: 11/21/2022] Open
Abstract
In many brain areas, such as the neocortex, limbic structures, and auditory brainstem, synaptic zinc is released from presynaptic terminals to modulate neurotransmission. As such, synaptic zinc signaling modulates sensory processing and enhances acuity for discrimination of different sensory stimuli. Whereas sensory experience causes long-term changes in synaptic zinc signaling, the mechanisms underlying this long-term synaptic zinc plasticity remain unknown. To study these mechanisms in male and female mice, we used in vitro and in vivo models of zinc plasticity observed at the zinc-rich glutamatergic dorsal cochlear nucleus (DCN) parallel fiber synapses onto cartwheel cells. High-frequency stimulation of DCN parallel fiber synapses induced LTD of synaptic zinc signaling (Z-LTD), evidenced by reduced zinc-mediated inhibition of EPSCs. Low-frequency stimulation induced LTP of synaptic zinc signaling (Z-LTP), evidenced by enhanced zinc-mediated inhibition of EPSCs. Pharmacological manipulations of Group 1 metabotropic glutamate receptors (G1 mGluRs) demonstrated that G1 mGluR activation is necessary and sufficient for inducing Z-LTD and Z-LTP. Pharmacological manipulations of Ca2+ dynamics indicated that rises in postsynaptic Ca2+ are necessary and sufficient for Z-LTD induction. Electrophysiological measurements assessing postsynaptic expression mechanisms, and imaging studies with a ratiometric extracellular zinc sensor probing zinc release, supported that Z-LTD is expressed, at least in part, via reductions in presynaptic zinc release. Finally, exposure of mice to loud sound caused G1 mGluR-dependent Z-LTD at DCN parallel fiber synapses, thus validating our in vitro results. Together, our results reveal a novel mechanism underlying activity- and experience-dependent plasticity of synaptic zinc signaling.SIGNIFICANCE STATEMENT In the neocortex, limbic structures, and auditory brainstem, glutamatergic nerve terminals corelease zinc to modulate excitatory neurotransmission and sensory responses. Moreover, sensory experience causes bidirectional, long-term changes in synaptic zinc signaling. However, the mechanisms of this long-term synaptic zinc plasticity remain unknown. Here, we identified a novel Group 1 mGluR-dependent mechanism that causes bidirectional, long-term changes in synaptic zinc signaling. Our results highlight new mechanisms of brain adaptation during sensory processing, and potentially point to mechanisms of disorders associated with pathologic adaptation, such as tinnitus.
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Wang B, Bugay V, Ling L, Chuang HH, Jaffe DB, Brenner R. Knockout of the BK β4-subunit promotes a functional coupling of BK channels and ryanodine receptors that mediate a fAHP-induced increase in excitability. J Neurophysiol 2016; 116:456-65. [PMID: 27146987 PMCID: PMC4978790 DOI: 10.1152/jn.00857.2015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 05/03/2016] [Indexed: 01/24/2023] Open
Abstract
BK channels are large-conductance calcium- and voltage-activated potassium channels with diverse properties. Knockout of the accessory BK β4-subunit in hippocampus dentate gyrus granule neurons causes BK channels to change properties from slow-gated type II channels to fast-gated type I channels that sharpen the action potential, increase the fast afterhyperpolarization (fAHP) amplitude, and increase spike frequency. Here we studied the calcium channels that contribute to fast-gated BK channel activation and increased excitability of β4 knockout neurons. By using pharmacological blockers during current-clamp recording, we find that BK channel activation during the fAHP is dependent on ryanodine receptor activation. In contrast, L-type calcium channel blocker (nifedipine) affects the BK channel-dependent repolarization phase of the action potential but has no effect on the fAHP. Reducing BK channel activation during the repolarization phase with nifedipine, or during the fAHP with ryanodine, indicated that it is the BK-mediated increase of the fAHP that confers proexcitatory effects. The proexcitatory role of the fAHP was corroborated using dynamic current clamp. Increase or decrease of the fAHP amplitude during spiking revealed an inverse relationship between fAHP amplitude and interspike interval. Finally, we show that the seizure-prone ryanodine receptor gain-of-function (R2474S) knockin mice have an unaltered repolarization phase but larger fAHP and increased AP frequency compared with their control littermates. In summary, these results indicate that an important role of the β4-subunit is to reduce ryanodine receptor-BK channel functional coupling during the fAHP component of the action potential, thereby decreasing excitability of dentate gyrus neurons.
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Affiliation(s)
- Bin Wang
- Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas; and
| | - Vladislav Bugay
- Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas; and
| | - Ling Ling
- Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas; and
| | - Hui-Hsui Chuang
- Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas; and
| | - David B Jaffe
- Department of Biology, University of Texas at San Antonio, San Antonio, Texas
| | - Robert Brenner
- Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas; and
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Hullinger R, Puglielli L. Molecular and cellular aspects of age-related cognitive decline and Alzheimer's disease. Behav Brain Res 2016; 322:191-205. [PMID: 27163751 DOI: 10.1016/j.bbr.2016.05.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/19/2016] [Accepted: 05/03/2016] [Indexed: 01/14/2023]
Abstract
As the population of people aged 60 or older continues to rise, it has become increasingly important to understand the molecular basis underlying age-related cognitive decline. In fact, a better understanding of aging biology will help us identify ways to maintain high levels of cognitive functioning throughout the aging process. Many cellular and molecular aspects of brain aging are shared with other organ systems; however, certain age-related changes are unique to the nervous system due to its structural, cellular and molecular complexity. Importantly, the brain appears to show differential changes throughout the aging process, with certain regions (e.g. frontal and temporal regions) being more vulnerable than others (e.g. brain stem). Within the medial temporal lobe, the hippocampus is especially susceptible to age-related changes. The important role of the hippocampus in age-related cognitive decline and in vulnerability to disease processes such as Alzheimer's disease has prompted this review, which will focus on the complexity of changes that characterize aging, and on the molecular connections that exist between normal aging and Alzheimer's disease. Finally, it will discuss behavioral interventions and emerging insights for promoting healthy cognitive aging.
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Affiliation(s)
- Rikki Hullinger
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Luigi Puglielli
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705, USA; Wisconsin Alzheimer's Disease Research Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Geriatric Research Education Clinical Center, VA Medical Center, Madison, WI 53705, USA.
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Role of Group II Metabotropic Glutamate Receptors (mGluR2/3) Blockade on Long-Term Potentiation in the Dentate Gyrus Region of Hippocampus in Rats Fed with High-Fat Diet. Neurochem Res 2015; 40:811-7. [DOI: 10.1007/s11064-015-1531-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 01/24/2015] [Accepted: 01/29/2015] [Indexed: 10/24/2022]
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Paula-Lima AC, Adasme T, Hidalgo C. Contribution of Ca2+ release channels to hippocampal synaptic plasticity and spatial memory: potential redox modulation. Antioxid Redox Signal 2014; 21:892-914. [PMID: 24410659 DOI: 10.1089/ars.2013.5796] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
SIGNIFICANCE Memory is an essential human cognitive function. Consequently, to unravel the cellular and molecular mechanisms responsible for the synaptic plasticity events underlying memory formation, storage and loss represents a major challenge of present-day neuroscience. RECENT ADVANCES This review article first describes the wide-ranging functions played by intracellular Ca2+ signals in the activity-dependent synaptic plasticity processes underlying hippocampal spatial memory, and next, it focuses on how the endoplasmic reticulum Ca2+ release channels, the ryanodine receptors, and the inositol 1,4,5-trisphosphate receptors contribute to these processes. We present a detailed examination of recent evidence supporting the key role played by Ca2+ release channels in synaptic plasticity, including structural plasticity, and the formation/consolidation of spatial memory in the hippocampus. CRITICAL ISSUES Changes in cellular oxidative state particularly affect the function of Ca2+ release channels and alter hippocampal synaptic plasticity and the associated memory processes. Emphasis is placed in this review on how defective Ca2+ release, presumably due to increased levels of reactive oxygen species, may cause the hippocampal functional defects that are associated to aging and Alzheimer's disease (AD). FUTURE DIRECTIONS Additional studies should examine the precise molecular mechanisms by which Ca2+ release channels contribute to hippocampal synaptic plasticity and spatial memory formation/consolidation. Future studies should test whether redox-modified Ca2+ release channels contribute toward generating the intracellular Ca2+ signals required for sustained synaptic plasticity and hippocampal spatial memory, and whether loss of redox balance and oxidative stress, by altering Ca2+ release channel function, presumably contribute to the abnormal memory processes that occur during aging and AD.
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Affiliation(s)
- Andrea C Paula-Lima
- 1 Faculty of Dentistry, Institute for Research in Dental Sciences, Universidad de Chile , Santiago, Chile
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Nebieridze N, Zhang XL, Chachua T, Velíšek L, Stanton PK, Velíšková J. β-Estradiol unmasks metabotropic receptor-mediated metaplasticity of NMDA receptor transmission in the female rat dentate gyrus. Psychoneuroendocrinology 2012; 37:1845-54. [PMID: 22541715 PMCID: PMC3432293 DOI: 10.1016/j.psyneuen.2012.03.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 02/13/2012] [Accepted: 03/26/2012] [Indexed: 02/08/2023]
Abstract
Loss of estrogen in women following menopause is associated with increased risk for cognitive decline, dementia and depression, all of which can be prevented by estradiol replacement. The dentate gyrus plays an important role in cognition, learning and memory. The gatekeeping function of the dentate gyrus to filter incoming activity into the hippocampus is modulated by estradiol in a frequency-dependent manner and involves activation of metabotropic glutamate receptors (mGluR). In the present study, we investigated whether estradiol (EB) modulates the metaplastic effect of inducing synaptic long-term potentiation (LTP) on subsequent propensity for expression of LTP in the dentate gyrus. At medial perforant path-dentate granule cell synapses in hippocampal slices of ovariectomized female rats, EB replacement was critical for an initial induction of LTP to enhance the magnitude of subsequent LTP elicited by a second high-frequency stimulation, metaplasticity, which was not present in slices from oil-treated control animals. EB enhanced expression of group I mGluRs, and the metaplastic effect of EB on LTP required activation of group I mGluRs that led to Src-family tyrosine kinase-mediated phosphorylation of NR2B subunits of N-methyl-d-aspartate receptors (NMDAR) that enhanced the magnitude of NMDAR-dependent LTP. Our data show that EB effects on LTP in the hippocampal dentate gyrus require activation of group I mGluRs, which in turn leads to functional metaplastic regulation of NR2B subunit-containing NMDARs, as opposed to direct effects of EB on NMDARs.
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Affiliation(s)
- Nino Nebieridze
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, New York, USA
| | - Xiao-lei Zhang
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, New York, USA
| | - Tamar Chachua
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, New York, USA
| | - Libor Velíšek
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, New York, USA,Department of Pediatrics, New York Medical College, Valhalla, New York, USA
| | - Patric K. Stanton
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, New York, USA,Department of Neurology, New York Medical College, Valhalla, New York, USA
| | - Jana Velíšková
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, New York, USA,Department of Obstetrics & Gynecology, New York Medical College, Valhalla, New York, USA,Correspondence: Jana Velíšková, MD, PhD, New York Medical College, Department of Cell Biology & Anatomy, Basic Medical Sciences Bldg., Room #A21, Valhalla, NY 10595, USA, , Phone: (914) 594-4840, Fax: (914) 594-4653
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8
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Synaptic properties of corticocortical connections between the primary and secondary visual cortical areas in the mouse. J Neurosci 2012; 31:16494-506. [PMID: 22090476 DOI: 10.1523/jneurosci.3664-11.2011] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Despite the importance of corticocortical connections, few published studies have investigated the functional, synaptic properties of such connections in any species, because most studies have been purely anatomical or aimed at functional features other than synaptic properties. We recently published a study of synaptic properties of connections between the primary and secondary cortical auditory areas in brain slices from the mouse, and, in the present study, we aimed to extend this by performing analogous studies of the primary and secondary visual areas (V1 and V2). We found effectively the same results. That is, connections between V1 and V2 in both directions were quite similar; in each case, the glutamatergic inputs could be classified as one of two types, Class 1B (formerly "driver") and Class 2 (formerly "modulator"). There is a clear laminar correlation for these different inputs, in terms of both the laminae of origin and those in which the recorded cells were located. Our data suggest a common pattern to the functional organization of corticocortical connectivity in the mouse cortex.
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Gagolewicz PJ, Dringenberg HC. NR2B-subunit dependent facilitation of long-term potentiation in primary visual cortex following visual discrimination training of adult rats. Eur J Neurosci 2011; 34:1222-9. [PMID: 21895803 DOI: 10.1111/j.1460-9568.2011.07842.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Long-term potentiation (LTP) is an important mechanism thought to mediate changes in synaptic connectivity following various types of experience. We examined the effects of visual discrimination training on LTP in the mature, rodent thalamocortical visual system. Adult rats underwent visual discrimination training in a modified Morris Water Maze containing a Y-maze insert, requiring rats to associate visual cues with the location of a hidden escape platform placed in one of the two goal arms of the Y-maze insert. On the day following successful task acquisition (average of nine training days), rats were anesthetized (urethane), and LTP in the thalamocortical system was characterized. In task-naïve rats, theta-burst stimulation of the lateral geniculate nucleus resulted in modest (∼40%) potentiation of field postsynaptic potentials recorded in the primary visual cortex (V1). Rats trained on the visual discrimination task showed significantly greater levels of LTP (∼60%), an effect that was not seen in rats trained to swim in the maze without a predictive association between visual cues and platform location. An antagonist of the N-methyl-d-aspartate (NMDA) receptor NR2B subunit ([R-(R *,S *)]-α-(4-hydroxyphenyl)-β-methyl-4-(phenylmethyl)-1-piperidinepropanol hydrochloride (Ro 25-6981); 2 mm, applied locally at the recording site in V1) reversed the training-induced LTP enhancement without affecting LTP in task-naïve rats. An antagonist of metabotropic glutamate receptors [(2S)-2-amino-2-[(1S,2S)-2-carboxycycloprop-1-yl]-3-(xanth-9-yl) propanoic acid (LY 341495); 2 mm] was ineffective in reversing the training-induced LTP facilitation. These data suggest that behavioral (visual) training can result in changes in plasticity exhibited by the mature, thalamocortical visual system that require activation of NMDA receptors containing the NR2B subunit.
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Affiliation(s)
- Peter J Gagolewicz
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
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Suzuki E, Sato M, Takezawa R, Usuki T, Okada T. The facilitative effects of bilobalide, a unique constituent of Ginkgo biloba, on synaptic transmission and plasticity in hippocampal subfields. J Physiol Sci 2011; 61:421-7. [PMID: 21710296 PMCID: PMC10717362 DOI: 10.1007/s12576-011-0159-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Accepted: 06/13/2011] [Indexed: 10/18/2022]
Abstract
Bilobalide, a unique constituent of Ginkgo biloba, has been reported to potentiate population spikes in hippocampal CA1 pyramidal cells and to protect the brain against cell death. In this study, the effects of bilobalide on synaptic transmission and its plasticity in rat hippocampal subfields were electrophysiologically investigated. Bilobalide (50 μM) significantly potentiated the input-output relationship at Schaffer collateral (SC)-CA1 synapses but not at medial perforant path (MPP)-dentate gyrus (DG), lateral perforant path (LPP)-DG, or mossy fiber (MF)-CA3 synapses. Facilitative effects of bilobalide on synaptic plasticity were only observed at MPP-DG synapses, in which the induction of long-term depression was blocked in the presence of bilobalide. However, no effect on synaptic plasticity was observed at SC-CA1 synapses. These results suggest that bilobalide has differential effects on synaptic efficacy in each hippocampal subfield.
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Affiliation(s)
- Etsuko Suzuki
- Department of Psychology, Faculty of Human Sciences, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo, 102-8554 Japan
| | - Makiko Sato
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo, 102-8554 Japan
| | - Ryota Takezawa
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo, 102-8554 Japan
| | - Toyonobu Usuki
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo, 102-8554 Japan
| | - Takashi Okada
- Department of Psychology, Faculty of Human Sciences, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo, 102-8554 Japan
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Differential effect of the mGlu5 receptor positive allosteric modulator ADX-47273 on early and late hippocampal LTP. Neuropharmacology 2011; 61:707-14. [DOI: 10.1016/j.neuropharm.2011.05.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 02/28/2011] [Accepted: 05/17/2011] [Indexed: 11/23/2022]
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12
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Rushworth JV, Hooper NM. Lipid Rafts: Linking Alzheimer's Amyloid-β Production, Aggregation, and Toxicity at Neuronal Membranes. Int J Alzheimers Dis 2010; 2011:603052. [PMID: 21234417 PMCID: PMC3014710 DOI: 10.4061/2011/603052] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 11/03/2010] [Indexed: 01/03/2023] Open
Abstract
Lipid rafts are membrane microdomains, enriched in cholesterol and sphingolipids, into which specific subsets of proteins and lipids partition, creating cell-signalling platforms that are vital for neuronal functions. Lipid rafts play at least three crucial roles in Alzheimer's Disease (AD), namely, in promoting the generation of the amyloid-β (Aβ) peptide, facilitating its aggregation upon neuronal membranes to form toxic oligomers and hosting specific neuronal receptors through which the AD-related neurotoxicity and memory impairments of the Aβ oligomers are transduced. Recent evidence suggests that Aβ oligomers may exert their deleterious effects through binding to, and causing the aberrant clustering of, lipid raft proteins including the cellular prion protein and glutamate receptors. The formation of these pathogenic lipid raft-based platforms may be critical for the toxic signalling mechanisms that underlie synaptic dysfunction and neuropathology in AD.
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Affiliation(s)
- Jo V. Rushworth
- Institute of Molecular and Cellular Biology, Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Nigel M. Hooper
- Institute of Molecular and Cellular Biology, Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
- Institute of Molecular and Cellular Biology, Faculty of Biological Sciences, LIGHT Laboratories, Clarendon Way, University of Leeds, Leeds LS2 9JT, UK
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Manahan-Vaughan D. MicroRNAs contribute to LTP in the hippocampus in vivo (Commentary on Wibrand et al.). Eur J Neurosci 2010; 31:634-5. [PMID: 20384809 DOI: 10.1111/j.1460-9568.2010.07140.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Denise Manahan-Vaughan
- Ruhr University Bochum, Medical Faculty, Department of Experimental Neurophysiology, Universitaetsstrasse 150, MABF 01/551, 44801 Bochum, Germany
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Zhang Z, Séguéla P. Metabotropic induction of persistent activity in layers II/III of anterior cingulate cortex. Cereb Cortex 2010; 20:2948-57. [PMID: 20348157 DOI: 10.1093/cercor/bhq043] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The anterior cingulate cortex (ACC), a limbic region associated with pain-related working memory and memory acquisition, receives a dense cholinergic innervation. To further understand the role of acetylcholine in ACC, we characterized the firing properties of pyramidal neurons following muscarinic receptor activation. Using whole-cell patch clamp recordings in acute brain slices, we report long-lasting nonsynaptic plateau potentials and persistent firing induced by carbachol (CCh) in pyramidal neurons in layers II/III of rat ACC. CCh responses were abolished by the muscarinic receptor antagonist atropine or by inhibitors of G proteins and phospholipase C. Inhibiting L-type calcium channels with nifedipine, removing extracellular calcium or chelating intracellular calcium with BAPTA also abolished plateau potentials and persistent firing. Blockade of nonselective cation channels with flufenamic acid, 2-aminoethyl diphenylborinate or SKF-96365 suppressed CCh responses and voltage-clamp recordings of CCh-sensitive currents revealed a transient receptor potential canonical-like cationic conductance. The group I metabotropic glutamate receptor (mGluR) agonist (S)-3,5-dihydroxyphenylglycine hydrate induced plateau potentials and persistent firing that were mediated by mGluR5. Our data demonstrate that receptor-operated channels drive calcium-dependent plateau potentials and persistent firing in layers II/III of ACC. Therefore, acetylcholine- and glutamate-evoked persistent activity in ACC may play a mnemonic role by allowing transient storage of information during pain processing.
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Affiliation(s)
- Zizhen Zhang
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
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Modulation of intracellular calcium mobilization and GABAergic currents through subtype-specific metabotropic glutamate receptors in neonatal rat hippocampus. Brain Res Bull 2010; 81:73-80. [DOI: 10.1016/j.brainresbull.2009.07.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2009] [Revised: 07/13/2009] [Accepted: 07/14/2009] [Indexed: 11/19/2022]
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Abstract
The induction of the most common form of LTP is well known to involve activation of N-methyl-D-aspartate receptors. However, considerable evidence has also shown that certain forms of LTP induction at excitatory synapses onto both principle cells and interneurons are dependent on activation of metabotropic glutamate receptors (mGluRs). mGluR-dependent LTP occurs in widespread areas of the brain including the neocortex, hippocampus, striatum and nucleus accumbens. mGluR-dependent forms of LTP have been found to be diverse, involving activation of mGluR1 or mGluR5 and can be of AMPAR-mediated transmission or of NMDAR-mediated transmission. Furthermore, the mGluR-dependent LTP may involve activation of other receptors, in particular, activation of NMDAR, dopamine and adenosine receptors. mGluR-dependent LTP can be expressed presynaptically or postsynaptically, and can involve a range of intracellular mediators including protein kinase C (PKC) and protein kinase A (PKA), tyrosine kinase Src and nitric oxide (NO).
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Affiliation(s)
- R Anwyl
- Department of Physiology, Faculty of Health Sciences, Trinity College, Dublin 2, Ireland.
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Ireland DR, Abraham WC. Mechanisms of Group I mGluR-Dependent Long-Term Depression of NMDA Receptor–Mediated Transmission at Schaffer Collateral–CA1 Synapses. J Neurophysiol 2009; 101:1375-85. [DOI: 10.1152/jn.90643.2008] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mechanisms underlying group I metabotropic glutamate receptor (mGluR)-dependent long-term depression (LTD) of N-methyl-d-aspartate receptor (NMDAR)-mediated synaptic currents (EPSCsNMDAR) are poorly understood. Here we investigated the effects of ( R,S)-3,5-dihydroxyphenylglycine (DHPG), a selective agonist of group I mGluRs, on the EPSCsNMDAR in area CA1 of acute hippocampal slices from 6- to 8-wk Sprague-Dawley rats. DHPG acutely and persistently depressed the isolated EPSCNMDAR and transiently slowed its decay rate. Combined antagonism of mGluR1 and mGluR5 blocked the effects of DHPG. Strong calcium buffering with intracellular BAPTA did not reduce the acute depression or LTD, making the involvement of elevated postsynaptic calcium unlikely. The acute depression and LTD were not mediated by activation of tyrosine kinases or phosphatases, nor were they dependent on protein synthesis. However, the LTD was prevented by the intracellular actin-stabilizer jasplakinolide, raising the possibility that it was associated with a lateral movement of NMDARs. Supporting this hypothesis, when the effective spatial spread of synaptically released glutamate was increased using the glutamate transporter inhibitor TBOA, the resultant EPSCNMDAR did not undergo LTD in response to DHPG. Importantly, isolation of the extrasynaptic EPSCNMDAR by blockade of synaptic NMDARs with MK-801 showed that this was not due to a potentiation of the preexisting extrasynaptic component. These findings indicate that LTD of NMDAR-mediated synaptic transmission occurs via lateral movement of receptors away from the synapse.
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