1
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Jami SA, Wilkinson BJ, Guglietta R, Hartel N, Babiec WE, Graham NA, Coba MP, O'Dell TJ. Functional and phosphoproteomic analysis of β-adrenergic receptor signaling at excitatory synapses in the CA1 region of the ventral hippocampus. Sci Rep 2023; 13:7493. [PMID: 37161045 PMCID: PMC10170123 DOI: 10.1038/s41598-023-34401-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 04/28/2023] [Indexed: 05/11/2023] Open
Abstract
Activation of β-adrenergic receptors (β-ARs) not only enhances learning and memory but also facilitates the induction of long-term potentiation (LTP), a form of synaptic plasticity involved in memory formation. To identify the mechanisms underlying β-AR-dependent forms of LTP we examined the effects of the β-AR agonist isoproterenol on LTP induction at excitatory synapses onto CA1 pyramidal cells in the ventral hippocampus. LTP induction at these synapses is inhibited by activation of SK-type K+ channels, suggesting that β-AR activation might facilitate LTP induction by inhibiting SK channels. However, although the SK channel blocker apamin enhanced LTP induction, it did not fully mimic the effects of isoproterenol. We therefore searched for potential alternative mechanisms using liquid chromatography-tandem mass spectrometry to determine how β-AR activation regulates phosphorylation of postsynaptic density (PSD) proteins. Strikingly, β-AR activation regulated hundreds of phosphorylation sites in PSD proteins that have diverse roles in dendritic spine structure and function. Moreover, within the core scaffold machinery of the PSD, β-AR activation increased phosphorylation at several sites previously shown to be phosphorylated after LTP induction. Together, our results suggest that β-AR activation recruits a diverse set of signaling pathways that likely act in a concerted fashion to regulate LTP induction.
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Affiliation(s)
- Shekib A Jami
- Molecular, Cellular, and Integrative Physiology Interdepartmental PhD Program, University of California, Los Angeles, Los Angeles, CA, USA
| | | | - Ryan Guglietta
- Interdepartmental PhD Program for Neuroscience, University of California, Los Angeles, Los Angeles, CA, USA
| | - Nicolas Hartel
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, USA
| | - Walter E Babiec
- Undergraduate Interdepartmental Program for Neuroscience, University of California, Los Angeles, Los Angeles, CA, USA
| | - Nicholas A Graham
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, USA
| | - Marcelo P Coba
- Zilkha Neurogenetic Institute, Los Angeles, CA, USA
- Department of Psychiatry and Behavioral Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Thomas J O'Dell
- Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, USA.
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
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2
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Li S. The β-adrenergic hypothesis of synaptic and microglial impairment in Alzheimer's disease. J Neurochem 2023; 165:289-302. [PMID: 36799441 DOI: 10.1111/jnc.15782] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 02/06/2023] [Accepted: 02/13/2023] [Indexed: 02/18/2023]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease originating partly from amyloid β protein-induced synaptic failure. As damaging of noradrenergic neurons in the locus coeruleus (LC) occurs at the prodromal stage of AD, activation of adrenergic receptors could serve as the first line of defense against the onset of the disease. Activation of β2 -ARs strengthens long-term potentiation (LTP) and synaptic activity, thus improving learning and memory. Physical stimulation of animals exposed to an enriched environment (EE) leads to the activation of β2 -ARs and prevents synaptic dysfunction. EE also suppresses neuroinflammation, suggesting that β2 -AR agonists may play a neuroprotective role. The β2 -AR agonists used for respiratory diseases have been shown to have an anti-inflammatory effect. Epidemiological studies further support the beneficial effects of β2 -AR agonists on several neurodegenerative diseases. Thus, I propose that β2 -AR agonists may provide therapeutic value in combination with novel treatments for AD.
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Affiliation(s)
- Shaomin Li
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
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3
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Wiegert JS, Pulin M, Gee CE, Oertner TG. The fate of hippocampal synapses depends on the sequence of plasticity-inducing events. eLife 2018; 7:39151. [PMID: 30311904 PMCID: PMC6205809 DOI: 10.7554/elife.39151] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 10/11/2018] [Indexed: 01/31/2023] Open
Abstract
Synapses change their strength in response to specific activity patterns. This functional plasticity is assumed to be the brain’s primary mechanism for information storage. We used optogenetic stimulation of rat hippocampal slice cultures to induce long-term potentiation (LTP), long-term depression (LTD), or both forms of plasticity in sequence. Two-photon imaging of spine calcium signals allowed us to identify stimulated synapses and to follow their fate for the next 7 days. We found that plasticity-inducing protocols affected the synapse’s chance for survival: LTP increased synaptic stability, LTD destabilized synapses, and the effect of the last stimulation protocol was dominant over earlier stimulations. Interestingly, most potentiated synapses were resistant to depression-inducing protocols delivered 24 hr later. Our findings suggest that activity-dependent changes in the transmission strength of individual synapses are transient, but have long-lasting consequences for synaptic lifetime.
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Affiliation(s)
- J Simon Wiegert
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Mauro Pulin
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christine Elizabeth Gee
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thomas G Oertner
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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4
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Nguyen PV, Gelinas JN. Noradrenergic gating of long-lasting synaptic potentiation in the hippocampus: from neurobiology to translational biomedicine. J Neurogenet 2018; 32:171-182. [DOI: 10.1080/01677063.2018.1497630] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Peter V. Nguyen
- Department of Physiology and Institute of Neuroscience & Mental Health, University of Alberta School of Medicine, Edmonton, Canada
| | - Jennifer N. Gelinas
- Department of Neurology and Institute for Genomic Medicine, College of Physicians & Surgeons of Columbia University, New York, NY,USA
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5
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Hagena H, Hansen N, Manahan-Vaughan D. β-Adrenergic Control of Hippocampal Function: Subserving the Choreography of Synaptic Information Storage and Memory. Cereb Cortex 2016; 26:1349-64. [PMID: 26804338 PMCID: PMC4785955 DOI: 10.1093/cercor/bhv330] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Noradrenaline (NA) is a key neuromodulator for the regulation of behavioral state and cognition. It supports learning by increasing arousal and vigilance, whereby new experiences are “earmarked” for encoding. Within the hippocampus, experience-dependent information storage occurs by means of synaptic plasticity. Furthermore, novel spatial, contextual, or associative learning drives changes in synaptic strength, reflected by the strengthening of long-term potentiation (LTP) or long-term depression (LTD). NA acting on β-adrenergic receptors (β-AR) is a key determinant as to whether new experiences result in persistent hippocampal synaptic plasticity. This can even dictate the direction of change of synaptic strength. The different hippocampal subfields play different roles in encoding components of a spatial representation through LTP and LTD. Strikingly, the sensitivity of synaptic plasticity in these subfields to β-adrenergic control is very distinct (dentate gyrus > CA3 > CA1). Moreover, NA released from the locus coeruleus that acts on β-AR leads to hippocampal LTD and an enhancement of LTD-related memory processing. We propose that NA acting on hippocampal β-AR, that is graded according to the novelty or saliency of the experience, determines the content and persistency of synaptic information storage in the hippocampal subfields and therefore of spatial memories.
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Affiliation(s)
- Hardy Hagena
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Niels Hansen
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
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6
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O'Dell TJ, Connor SA, Guglietta R, Nguyen PV. β-Adrenergic receptor signaling and modulation of long-term potentiation in the mammalian hippocampus. ACTA ACUST UNITED AC 2015; 22:461-71. [PMID: 26286656 PMCID: PMC4561407 DOI: 10.1101/lm.031088.113] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 06/02/2015] [Indexed: 02/06/2023]
Abstract
Encoding new information in the brain requires changes in synaptic strength. Neuromodulatory transmitters can facilitate synaptic plasticity by modifying the actions and expression of specific signaling cascades, transmitter receptors and their associated signaling complexes, genes, and effector proteins. One critical neuromodulator in the mammalian brain is norepinephrine (NE), which regulates multiple brain functions such as attention, perception, arousal, sleep, learning, and memory. The mammalian hippocampus receives noradrenergic innervation and hippocampal neurons express β-adrenergic receptors, which are known to play important roles in gating the induction of long-lasting forms of synaptic potentiation. These forms of long-term potentiation (LTP) are believed to importantly contribute to long-term storage of spatial and contextual memories in the brain. In this review, we highlight the contributions of noradrenergic signaling in general and β-adrenergic receptors in particular, toward modulating hippocampal LTP. We focus on the roles of NE and β-adrenergic receptors in altering the efficacies of specific signaling molecules such as NMDA and AMPA receptors, protein phosphatases, and translation initiation factors. Also, the roles of β-adrenergic receptors in regulating synaptic "tagging" and "capture" of LTP within synaptic networks of the hippocampus are reviewed. Understanding the molecular and cellular bases of noradrenergic signaling will enrich our grasp of how the brain makes new, enduring memories, and may shed light on credible strategies for improving mental health through treatment of specific disorders linked to perturbed memory processing and dysfunctional noradrenergic synaptic transmission.
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Affiliation(s)
- Thomas J O'Dell
- Department of Physiology, David Geffen School of Medicine and Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Steven A Connor
- Department of Physiology, University of Alberta School of Medicine, Edmonton, Alberta T6G 2H7, Canada
| | - Ryan Guglietta
- Interdepartmental Ph.D. Program for Neuroscience, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Peter V Nguyen
- Department of Physiology, University of Alberta School of Medicine, Edmonton, Alberta T6G 2H7, Canada Department of Psychiatry, University of Alberta School of Medicine, Edmonton, Alberta T6G 2H7, Canada Department of Neuroscience & Mental Health Institute, University of Alberta School of Medicine, Edmonton, Alberta T6G 2H7, Canada
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7
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Wójtowicz T, Mozrzymas JW. Diverse impact of neuronal activity at θ frequency on hippocampal long-term plasticity. J Neurosci Res 2015; 93:1330-44. [PMID: 25789967 DOI: 10.1002/jnr.23581] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/05/2015] [Accepted: 02/10/2015] [Indexed: 12/29/2022]
Abstract
Brain oscillatory activity is considered an essential aspect of brain function, and its frequency can vary from <1 Hz to >200 Hz, depending on the brain states and projection. Episodes of rhythmic activity accompany hippocampus-dependent learning and memory in vivo. Therefore, long-term synaptic potentiation (LTP) and long-term depression, which are considered viable substrates of learning and memory, are often experimentally studied in paradigms of patterned high-frequency (>50 Hz) and low-frequency (<5 Hz) stimulation. However, the impact of intermediate frequencies on neuronal plasticity remains less well understood. In particular, hippocampal neurons are specifically tuned for activity at θ frequency (4-8 Hz); this band contributes significantly to electroencephalographic signals, and it is likely to be involved in shaping synaptic strength in hippocampal circuits. Here, we review in vitro and in vivo studies showing that variation of θ-activity duration may affect long-term modification of synaptic strength and neuronal excitability in the hippocampus. Such θ-pulse-induced neuronal plasticity 1) is long-lasting, 2) may be built on previously stabilized potentiation in the synapse, 3) may produce opposite changes in synaptic strength, and 4) requires complex molecular machinery. Apparently innocuous episodes of low-frequency synaptic activity may have a profound impact on network signaling, thereby contributing to information processing in the hippocampus and beyond. In addition, θ-pulse-induced LTP might be an advantageous protocol in studies of specific molecular mechanisms of synaptic plasticity.
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Affiliation(s)
- Tomasz Wójtowicz
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University, Wroclaw, Poland
| | - Jerzy W Mozrzymas
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University, Wroclaw, Poland
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8
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Ghanemi A, Hu X. Elements toward novel therapeutic targeting of the adrenergic system. Neuropeptides 2015; 49:25-35. [PMID: 25481798 DOI: 10.1016/j.npep.2014.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 10/30/2014] [Accepted: 11/19/2014] [Indexed: 01/14/2023]
Abstract
Adrenergic receptors belong to the family of the G protein coupled receptors that represent important targets in the modern pharmacotherapies. Studies on different physiological and pathophysiological properties of the adrenergic system have led to novel evidences and theories that suggest novel possible targeting of such system in a variety of pathologies and disorders, even beyond the classical known therapeutic possibilities. Herein, those advances have been illustrated with selected concepts and different examples. Furthermore, we illustrated the applications and the therapeutic implications that such findings and advances might have in the contexts of experimental pharmacology, therapeutics and clinic. We hope that the content of this work will guide researches devoted to the adrenergic aspects that combine neurosciences with pharmacology.
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Affiliation(s)
- Abdelaziz Ghanemi
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming 650223, China; University of Chinese Academy of Science, Beijing, China.
| | - Xintian Hu
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming 650223, China; Key State Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Science, Beijing, China.
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9
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O'Dell TJ, Connor SA, Gelinas JN, Nguyen PV. Viagra for your synapses: Enhancement of hippocampal long-term potentiation by activation of beta-adrenergic receptors. Cell Signal 2010; 22:728-36. [PMID: 20043991 PMCID: PMC2826554 DOI: 10.1016/j.cellsig.2009.12.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 12/04/2009] [Accepted: 12/18/2009] [Indexed: 02/08/2023]
Abstract
Beta-adrenergic receptors (beta-ARs) critically modulate long-lasting synaptic plasticity and long-term memory storage in the mammalian brain. Synaptic plasticity is widely believed to mediate memory storage at the cellular level. Long-term potentiation (LTP) is one type of synaptic plasticity that has been linked to memory storage. Activation of beta-ARs can enhance LTP and facilitate long-term memory storage. Interestingly, many of the molecular signaling pathways that are critical for beta-adrenergic modulation of LTP mirror those required for the persistence of memory. In this article, we review the roles of signaling cascades and translation regulation in enabling beta-ARs to control expression of long-lasting LTP in the rodent hippocampus. These include the cyclic-AMP/protein kinase-A (cAMP-PKA) and extracellular signal-regulated protein kinase cascades, two key pathways known to link transmitter receptors with translation regulation. Future research directions are discussed, with emphasis on defining the roles of signaling complexes (e.g. PSD-95) and glutamatergic receptors in controlling the efficacy of beta-AR modulation of LTP.
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Affiliation(s)
- Thomas J. O'Dell
- Department of Physiology, David Geffen School of Medicine, University of California at Los Angeles, Center for the Health Sciences, Box 951751, Los Angeles, CA 90095-1751, USA
| | - Steven A. Connor
- Centre for Neuroscience, University of Alberta School of Medicine, Edmonton, Alberta, T6G 2H7, Canada
| | - Jennifer N. Gelinas
- Division of Neurology, Department of Pediatrics, University of British Columbia, Faculty of Medicine, Vancouver, BC, V6H 3V4, Canada
| | - Peter V. Nguyen
- Department of Physiology, University of Alberta School of Medicine, Edmonton, Alberta, T6G 2H7, Canada
- Centre for Neuroscience, University of Alberta School of Medicine, Edmonton, Alberta, T6G 2H7, Canada
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10
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Bidirectional regulation of hippocampal long-term synaptic plasticity and its influence on opposing forms of memory. J Neurosci 2010; 30:3813-25. [PMID: 20220016 DOI: 10.1523/jneurosci.1330-09.2010] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Reference memory characterizes the long-term storage of information acquired through numerous trials. In contrast, working memory represents the short-term acquisition of trial-unique information. A number of studies in the rodent hippocampus have focused on the contribution of long-term synaptic potentiation (LTP) to long-term reference memory. In contrast, little is known about the synaptic plasticity correlates of hippocampal-based components of working memory. Here, we described a mouse with selective expression of a dominant-negative mutant of the regulatory subunit of protein kinase A (PKA) only in two regions of the hippocampus, the dentate gyrus and area CA1. This mouse showed a deficit in several forms of LTP in both hippocampal subregions and a lowered threshold for the consolidation of long-term synaptic depression (LTD). When trained with one trial per day in a water maze task, mutant mice displayed a deficit in consolidation of long-term memory. In contrast, these mice proved to be more flexible after a transfer test and also showed a delay-dependent increased performance in working memory, when repetitive information (proactive interference) was presented. We suggest that through its bidirectional control over synaptic plasticity PKA can regulate opposing forms of memory. The defect in L-LTP disrupts long-term memory consolidation. The persistence of LTD may allow acquisition of new information by restricting the body of previously stored information and suppressing interference.
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11
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Huang YY, Kandel ER. Low-frequency stimulation induces a pathway-specific late phase of LTP in the amygdala that is mediated by PKA and dependent on protein synthesis. Learn Mem 2007; 14:497-503. [PMID: 17626908 PMCID: PMC1934345 DOI: 10.1101/lm.593407] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Activity-dependent changes in synaptic efficacy are thought to be the key cellular mechanism for the formation and storage of both explicit and implicit memory. Different patterns of stimulation can elicit different changes in the efficiency on excitatory synaptic transmission. Here, we examined the synaptic changes in the amygdala of adult mice produced by low-frequency stimulation (1 Hz, 15 min, LFS). We first compared the synaptic changes induced by LFS in three different synaptic pathways of amygdala: cortical-lateral amygdala, thalamic-lateral amygdala, and lateral-basolateral amygdala pathways. We find that the plastic changes induced by LFS are different between synaptic pathways. Low-frequency stimulation selectively elicits a slow onset and protein synthesis-dependent late-phase LTP in the cortical-lateral amygdala pathway, but not in the thalamic-lateral or lateral-basolateral pathways. We next analyzed LTP induced by LFS in the cortical-lateral amygdala pathway and found that three PKA-coupling neurotransmitter receptors are involved: 5-HT4, Dopamine D1, and beta-adrenergic receptors. Antagonists of these receptors block the LFS L-LTP, but the effects of agonists of these receptors are clearly different. These results indicate that the threshold for the induction of LFS L-LTP is different among these pathways and that the maintenance of LFS L-LTP requires a cross-talk among multiple neurotransmitters.
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Affiliation(s)
- Yan-You Huang
- Center for Neurobiology and Behavior, College of Physicians and Surgeons of Columbia University, New York State Psychiatric Institute, New York, New York 10032, USA
- Corresponding authors.E-mail ; fax (212) 543-5474.E-mail ; fax (212) 543-5474
| | - Eric R. Kandel
- Center for Neurobiology and Behavior, College of Physicians and Surgeons of Columbia University, New York State Psychiatric Institute, New York, New York 10032, USA
- Kavli Institute for Brain Science, College of Physicians and Surgeons of Columbia University, New York State Psychiatric Institute, New York, New York 10032, USA
- Howard Hughes Medical Institute, New York, New York 10032, USA
- Corresponding authors.E-mail ; fax (212) 543-5474.E-mail ; fax (212) 543-5474
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12
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Etkin A, Alarcón JM, Weisberg SP, Touzani K, Huang YY, Nordheim A, Kandel ER. A Role in Learning for SRF: Deletion in the Adult Forebrain Disrupts LTD and the Formation of an Immediate Memory of a Novel Context. Neuron 2006; 50:127-43. [PMID: 16600861 DOI: 10.1016/j.neuron.2006.03.013] [Citation(s) in RCA: 173] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2005] [Revised: 12/13/2005] [Accepted: 02/16/2006] [Indexed: 11/17/2022]
Abstract
Whereas significant insight exists as to how LTP-related changes can contribute to the formation of long-term memory, little is known about the role of hippocampal LTD-like changes in learning and memory storage. We describe a mouse lacking the transcription factor SRF in the adult forebrain. This mouse could not acquire a hippocampus-based immediate memory for a novel context even across a few minute timespan, which led to a profound but selective deficit in explicit spatial memory. These animals were also impaired in the induction of LTD, including LTD triggered by a cholinergic agonist. Moreover, genes regulating two processes essential for LTD-calcium release from intracellular stores and phosphatase activation-were abnormally expressed in knockouts. These findings suggest that for the hippocampus to form associative spatial memories through LTP-like processes, it must first undergo learning of the context per se through exploration and the learning of familiarity, which requires LTD-like processes.
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MESH Headings
- Animals
- Animals, Newborn
- Behavior, Animal
- Blotting, Northern/methods
- Carbachol/pharmacology
- Cholinergic Agonists/pharmacology
- Clathrin Heavy Chains/metabolism
- Discrimination, Psychological/physiology
- Dose-Response Relationship, Radiation
- Early Growth Response Protein 1/metabolism
- Electric Stimulation/methods
- Enzyme Inhibitors/pharmacology
- Exploratory Behavior/physiology
- Gene Expression/genetics
- Gene Expression Regulation, Developmental/physiology
- Habituation, Psychophysiologic/physiology
- Hippocampus/metabolism
- Immunohistochemistry/methods
- In Situ Hybridization/methods
- Indoles/pharmacology
- Learning/physiology
- Long-Term Synaptic Depression/genetics
- Long-Term Synaptic Depression/physiology
- Maze Learning/physiology
- Memory, Short-Term/physiology
- Mice
- Mice, Knockout
- Models, Neurological
- Olfactory Bulb/physiology
- Prosencephalon/physiology
- RNA, Messenger/metabolism
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Serum Response Factor/deficiency
- Serum Response Factor/physiology
- Time Factors
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Affiliation(s)
- Amit Etkin
- Center for Neurobiology and Behavior, Columbia University Medical Center, 1051 Riverside Drive, New York, New York 10032, USA
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13
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Hillman KL, Doze VA, Porter JE. Functional characterization of the beta-adrenergic receptor subtypes expressed by CA1 pyramidal cells in the rat hippocampus. J Pharmacol Exp Ther 2005; 314:561-7. [PMID: 15908513 DOI: 10.1124/jpet.105.084947] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recent studies have demonstrated that activation of the beta-adrenergic receptor (AR) using the selective beta-AR agonist isoproterenol (ISO) facilitates pyramidal cell long-term potentiation in the cornu ammonis 1 (CA1) region of the rat hippocampus. We have previously analyzed beta-AR genomic expression patterns of 17 CA1 pyramidal cells using single cell reverse transcription-polymerase chain reaction, demonstrating that all samples expressed the beta2-AR transcript, with four of the 17 cells additionally expressing mRNA for the beta1-AR subtype. However, it has not been determined which beta-AR subtypes are functionally expressed in CA1 for these same pyramidal neurons. Using cell-attached recordings, we tested the ability of ISO to increase pyramidal cell action potential (AP) frequency in the presence of subtype-selective beta-AR antagonists. ICI-118,551 [(+/-)-1-[2,3-(dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol] and butoxamine [alpha-[1-(t-butylamino)ethyl]-2,5-dimethoxybenzyl alcohol) hydrochloride], agents that selectively block the beta2-AR, produced significant parallel rightward shifts in the concentration-response curves for ISO. From these curves, apparent equilibrium dissociation constant (K(b)) values of 0.3 nM for ICI-118,551 and 355 nM for butoxamine were calculated using Schild regression analysis. Conversely, effective concentrations of the selective beta1-AR antagonists CGP 20712A [(+/-)-2-hydroxy-5-[2-([2-hydroxy-3-(4-[1-methyl-4-(trifluoromethyl)-1H-imidazol-2-yl]phenoxy)propyl]amino)ethoxy]-benzamide methanesulfonate] and atenolol [4-[2'-hydroxy-3'-(isopropyl-amino)propoxy]phenylacetamide] did not significantly affect the pyramidal cell response to ISO. However, at higher concentrations, atenolol significantly decreased the potency for ISO-mediated AP frequencies. From these curves, an apparent atenolol K(b) value of 3162 nM was calculated. This pharmacological profile for subtype-selective beta-AR antagonists indicates that beta2-AR activation is mediating the increased AP frequency. Knowledge of functional AR expression in CA1 pyramidal neurons will aid future long-term potentiation studies by allowing selective manipulation of specific beta-AR subtypes.
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MESH Headings
- Action Potentials/drug effects
- Adrenergic beta-Agonists/pharmacology
- Adrenergic beta-Antagonists/pharmacology
- Animals
- Electrophysiology
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/physiology
- Hippocampus/cytology
- Hippocampus/drug effects
- Isoproterenol/pharmacology
- Male
- Pyramidal Cells/drug effects
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Rats
- Rats, Sprague-Dawley
- Receptors, Adrenergic, beta/biosynthesis
- Receptors, Adrenergic, beta/classification
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta-2/drug effects
- Receptors, Adrenergic, beta-2/physiology
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Kristin L Hillman
- Department of Pharmacology, Physiology and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, 501 North Columbia Rd., Grand Forks, ND 58202-9037, USA
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14
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Huang YY, Kandel ER. Theta frequency stimulation up-regulates the synaptic strength of the pathway from CA1 to subiculum region of hippocampus. Proc Natl Acad Sci U S A 2004; 102:232-7. [PMID: 15623558 PMCID: PMC539311 DOI: 10.1073/pnas.0408368102] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The subiculum (SB) is the principal target of the axons of the CA1 pyramidal cells and serves as the final relay in the trisynaptic loop between the entorhinal cortex and the hippocampus. We have examined synaptic plasticity in the synaptic pathway between the CA1 pyramidal cells and the SB in hippocampal slices and compared it under the same experimental condition with the synaptic plasticity in Shaffer collateral pathway (CA3-CA1). We find that the frequency response curve of synaptic strength induced by prolonged low-frequency stimulation (1-5 Hz) is systematically up-shifted from Shaffer collateral to the CA1-SB pathway. The up-regulation of synaptic strength is mediated by the activity-dependent modulation by beta-adrenergic transmission. Because the CA3-CA1 and the CA1-SB synaptic pathways are in series and the beta-adrenergic modulation is region-specific, this modulation seems to be involved in the selective control of signal transmission between the different regions of hippocampus.
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Affiliation(s)
- Yan-You Huang
- Center for Neurobiology and Behavior, College of Physicians and Surgeons of Columbia University, New York State Psychiatric Institute, 1051 Riverside Drive, New York, NY 10032, USA
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15
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Grishin AA, Gee CE, Gerber U, Benquet P. Differential calcium-dependent modulation of NMDA currents in CA1 and CA3 hippocampal pyramidal cells. J Neurosci 2004; 24:350-5. [PMID: 14724233 PMCID: PMC6729976 DOI: 10.1523/jneurosci.4933-03.2004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Neuronal Ca2+ influx via NMDA receptors (NMDARs) is essential for the development and plasticity of synapses but also triggers excitotoxic cell death when critical intracellular levels are exceeded. Therefore, finely equilibrated mechanisms are necessary to ensure that NMDAR function is maintained within a homeostatic range. Here we describe a pronounced difference in the modulation of NMDA currents in two closely related hippocampal cell types, the CA1 and the CA3 pyramidal cells (PCs). Manipulations that increase intracellular Ca2+ levels strongly depressed NMDA currents in CA3 with only minor effects in CA1 PCs. Furthermore, activation of G(q)-coupled metabotropic receptors potentiated NMDA currents in CA1 PCs but depressed them in CA3 PCs. Interestingly, the CA3 type modulation of NMDARs could be converted into CA1-like behavior, and vice versa, by increasing Ca2+ buffering in CA3 cells or decreasing Ca2+ buffering in CA1 cells, respectively. Our data suggest that a differential Ca2+ sensitivity of the regulatory cascades targeting NMDARs plays a key role in determining the direction and magnitude of NMDA responses in various types of neurons. These findings may have important implications for NMDA receptor-dependent synaptic plasticity and the differential sensitivity of CA1 and CA3 PCs to NMDAR-dependent ischemic cell death.
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Affiliation(s)
- Anton A Grishin
- Brain Research Institute, University of Zurich, CH-8057 Zurich, Switzerland
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16
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Xu J, Paquet M, Lau AG, Wood JD, Ross CA, Hall RA. beta 1-adrenergic receptor association with the synaptic scaffolding protein membrane-associated guanylate kinase inverted-2 (MAGI-2). Differential regulation of receptor internalization by MAGI-2 and PSD-95. J Biol Chem 2001; 276:41310-7. [PMID: 11526121 DOI: 10.1074/jbc.m107480200] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The beta1-adrenergic receptor (beta1AR) is known to be localized to synapses and to modulate synaptic plasticity in many brain regions, but the molecular mechanisms determining beta1AR subcellular localization are not fully understood. Using overlay and pull-down techniques, we found that the beta1AR carboxyl terminus associates with MAGI-2 (membrane-associated guanylate kinase inverted-2), a protein also known as S-SCAM (synaptic scaffolding molecule). MAGI-2 is a multidomain scaffolding protein that contains nine potential protein-protein interaction modules, including 6 PDZ domains, 2 WW domains, and a guanylate kinase-like domain. The beta1AR carboxyl terminus binds with high affinity to the first PDZ domain of MAGI-2, with the last few amino acids of the beta1AR carboxyl terminus being the key determinants of the interaction. In cells, the association of full-length beta1AR with MAGI-2 occurs constitutively and is enhanced by agonist stimulation of the receptor, as assessed by both co-immunoprecipitation experiments and immunofluorescence co-localization studies. Agonist-induced internalization of the beta1AR is markedly increased by co-expression with MAGI-2. Strikingly, this result is the opposite of the effect of co-expression with PSD-95, a previously reported binding partner of the beta1AR. Further cellular experiments revealed that MAGI-2 has no effect on beta1AR oligomerization but does promote association of beta1AR with the cytoplasmic signaling protein beta-catenin, a known MAGI-2 binding partner. These data reveal that MAGI-2 is a specific beta1AR binding partner that modulates beta1AR function and facilitates the physical association of the beta1AR with intracellular proteins involved in signal transduction and synaptic regulation.
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Affiliation(s)
- J Xu
- Department of Pharmacology, Rollins Research Center, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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17
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Hu LA, Tang Y, Miller WE, Cong M, Lau AG, Lefkowitz RJ, Hall RA. beta 1-adrenergic receptor association with PSD-95. Inhibition of receptor internalization and facilitation of beta 1-adrenergic receptor interaction with N-methyl-D-aspartate receptors. J Biol Chem 2000; 275:38659-66. [PMID: 10995758 DOI: 10.1074/jbc.m005938200] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The beta(1)-adrenergic receptor (beta(1)AR) is the most abundant subtype of beta-adrenergic receptor in the mammalian brain and is known to potently regulate synaptic plasticity. To search for potential neuronal beta(1)AR-interacting proteins, we screened a rat brain cDNA library using the beta(1)AR carboxyl terminus (beta(1)AR-CT) as bait in the yeast two-hybrid system. These screens identified PSD-95, a multiple PDZ domain-containing scaffolding protein, as a specific binding partner of the beta(1)AR-CT. This interaction was confirmed by in vitro fusion protein pull-down and blot overlay experiments, which demonstrated that the beta(1)AR-CT binds specifically to the third PDZ domain of PSD-95. Furthermore, the full-length beta(1)AR associates with PSD-95 in cells, as determined by co-immunoprecipitation experiments and immunofluorescence co-localization studies. The interaction between beta(1)AR and PSD-95 is mediated by the last few amino acids of the beta(1)AR, and mutation of the beta(1)AR carboxyl terminus eliminated the binding and disrupted the co-localization of the beta(1)AR and PSD-95 in cells. Agonist-induced internalization of the beta(1)AR in HEK-293 cells was markedly attenuated by PSD-95 co-expression, whereas co-expression of PSD-95 has no significant effect on either desensitization of the beta(1)AR or beta(1)AR-induced cAMP accumulation. Furthermore, PSD-95 facilitated the formation of a complex between the beta(1)AR and N-methyl-d-aspartate receptors, as assessed by co-immunoprecipitation. These data reveal that PSD-95 is a specific beta(1)AR binding partner that modulates beta(1)AR function and facilitates physical association of the beta(1)AR with synaptic proteins, such as the N-methyl-d-aspartate receptors, which are known to be regulated by beta(1)AR stimulation.
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Affiliation(s)
- L A Hu
- Howard Hughes Medical Institute, Departments of Medicine and Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
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Moody TD, Carlisle HJ, O'Dell TJ. A nitric oxide-independent and beta-adrenergic receptor-sensitive form of metaplasticity limits theta-frequency stimulation-induced LTP in the hippocampal CA1 region. Learn Mem 1999; 6:619-33. [PMID: 10641766 PMCID: PMC311307 DOI: 10.1101/lm.6.6.619] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The induction of long-term potentiation (LTP) and long-term depression (LTD) at excitatory synapses in the hippocampus can be strongly modulated by patterns of synaptic stimulation that otherwise have no direct effect on synaptic strength. Likewise, patterns of synaptic stimulation that induce LTP or LTD not only modify synaptic strength but can also induce lasting changes that regulate how synapses will respond to subsequent trains of stimulation. Collectively known as metaplasticity, these activity-dependent processes that regulate LTP and LTD induction allow the recent history of synaptic activity to influence the induction of activity-dependent changes in synaptic strength and may thus have an important role in information storage during memory formation. To explore the cellular and molecular mechanisms underlying metaplasticity, we investigated the role of metaplasticity in the induction of LTP by theta-frequency (5-Hz) synaptic stimulation in the hippocampal CA1 region. Our results show that brief trains of theta-frequency stimulation not only induce LTP but also activate a process that inhibits the induction of additional LTP at potentiated synapses. Unlike other forms of metaplasticity, the inhibition of LTP induction at potentiated synapses does not appear to arise from activity-dependent changes in NMDA receptor function, does not require nitric oxide signaling, and is strongly modulated by beta-adrenergic receptor activation. Together with previous findings, our results indicate that mechanistically distinct forms of metaplasticity regulate LTP induction and suggest that one way modulatory transmitters may act to regulate synaptic plasticity is by modulating metaplasticity.
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Affiliation(s)
- T D Moody
- Interdepartmental Ph.D. Program for Neuroscience, School of Medicine, University of California at Los Angeles, 90095, USA
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