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Li S, He Y, Turner D, Wei N, Ma L, Taylor DH, Taylor DT, Ji X, Wu J. Electrophysiological Phenotypes of Hippocampal Synaptic and Network Functions in Cannabinoid Receptor 2 Knockout Mice. Cannabis Cannabinoid Res 2024. [PMID: 38502778 DOI: 10.1089/can.2023.0186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024] Open
Abstract
Background: The cannabinoid receptor 2 (CB2R), a cannabinoid receptor primarily expressed in immune cells, has been found in the brain, particularly in the hippocampus, where it plays crucial roles in modulating various neural functions, including synaptic plasticity, neuroprotection, neurogenesis, anxiety and stress responses, and neuroinflammation. Despite this growing understanding, the intricate electrophysiological characteristics of hippocampal neurons in CB2R knockout (CB2R KO) mice remain elusive. Aim and Methods: This study aimed to comprehensively assess the electrophysiological traits of hippocampal synaptic and network functions in CB2R KO mice. The focus was on aspects such as synaptic transmission, short- and long-term synaptic plasticity, and neural network synchrony (theta oscillations). Results: Our findings unveiled multiple functional traits in these CB2R KO mice, notably elevated synaptic transmission in hippocampal CA1 neurons, decreased both synaptic short-term plasticity (paired-pulse facilitation) and long-term potentiation (LTP), and impaired neural network synchronization. Conclusion: In essence, this study yields insightful revelations about the influence of CB2Rs on hippocampal neural functions. By illuminating the electrophysiological modifications in CB2R KO mice, our research enriches the comprehension of CB2R involvement in hippocampal function. Such insights could hold implications for advancing our understanding of the neural mechanisms under the influence of CB2Rs within the brain.
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Affiliation(s)
- Shuangtao Li
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong, China
| | - Yongchang He
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Dharshaun Turner
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Naili Wei
- Department of Neurosurgery, First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong, China
| | - Luyao Ma
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
| | - Devin H Taylor
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
- Department of Biology, Utah Valley University, Orem, Utah, USA
| | | | - Xiaoyu Ji
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong, China
- Department of Neurosurgery, First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong, China
| | - Jie Wu
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, Guangdong, China
- Department of Neurobiology, Barrow Neurological Institute and St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA
- Department of Neurosurgery, First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong, China
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Nguyen TT, Nam GS, Kang JJ, Han GC, Kim JS, Dieterich M, Oh SY. The Differential Effects of Acute Right- vs. Left-Sided Vestibular Deafferentation on Spatial Cognition in Unilateral Labyrinthectomized Mice. Front Neurol 2021; 12:789487. [PMID: 34956067 PMCID: PMC8692718 DOI: 10.3389/fneur.2021.789487] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 10/29/2021] [Indexed: 12/02/2022] Open
Abstract
This study aimed to investigate the disparity in locomotor and spatial memory deficits caused by left- or right-sided unilateral vestibular deafferentation (UVD) using a mouse model of unilateral labyrinthectomy (UL) and to examine the effects of galvanic vestibular stimulation (GVS) on the deficits over 14 days. Five experimental groups were established: the left-sided and right-sided UL (Lt.-UL and Rt.-UL) groups, left-sided and right-sided UL with bipolar GVS with the cathode on the lesion side (Lt.-GVS and Rt.-GVS) groups, and a control group with sham surgery. We assessed the locomotor and cognitive-behavioral functions using the open field (OF), Y maze, and Morris water maze (MWM) tests before (baseline) and 3, 7, and 14 days after surgical UL in each group. On postoperative day (POD) 3, locomotion and spatial working memory were more impaired in the Lt.-UL group compared with the Rt.-UL group (p < 0.01, Tamhane test). On POD 7, there was a substantial difference between the groups; the locomotion and spatial navigation of the Lt.-UL group recovered significantly more slowly compared with those of the Rt.-UL group. Although the differences in the short-term spatial cognition and motor coordination were resolved by POD 14, the long-term spatial navigation deficits assessed by the MWM were significantly worse in the Lt.-UL group compared with the Rt.-UL group. GVS intervention accelerated the vestibular compensation in both the Lt.-GVS and Rt.-GVS groups in terms of improvement of locomotion and spatial cognition. The current data imply that right- and left-sided UVD impair spatial cognition and locomotion differently and result in different compensatory patterns. Sequential bipolar GVS when the cathode (stimulating) was assigned to the lesion side accelerated recovery for UVD-induced spatial cognition, which may have implications for managing the patients with spatial cognitive impairment, especially that induced by unilateral peripheral vestibular damage on the dominant side.
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Affiliation(s)
- Thanh Tin Nguyen
- Department of Neurology, Jeonbuk National University Hospital & School of Medicine, Jeonju, South Korea.,Department of Pharmacology, Hue University of Medicine and Pharmacy, Hue University, Hue, Vietnam
| | - Gi-Sung Nam
- Department of Otorhinolaryngology-Head and Neck Surgery, Chosun University College of Medicine, Gwangju, South Korea.,Research Institute of Clinical Medicine of Jeonbuk National University-Jeonbuk National University Hospital, Jeonju, South Korea
| | - Jin-Ju Kang
- Department of Neurology, Jeonbuk National University Hospital & School of Medicine, Jeonju, South Korea.,Research Institute of Clinical Medicine of Jeonbuk National University-Jeonbuk National University Hospital, Jeonju, South Korea
| | - Gyu Cheol Han
- Department of Otolaryngology-Head and Neck Surgery, Gachon University of Medicine and Science, Graduate School of Medicine, Incheon, South Korea
| | - Ji-Soo Kim
- Department of Neurology, Seoul National University Bundang Hospital & School of Medicine, Seoul, South Korea
| | - Marianne Dieterich
- Department of Neurology, University Hospital, Ludwig-Maximilians-Universität, Munich, Germany.,German Center for Vertigo and Balance Disorders-IFB, University Hospital, Ludwig-Maximilians-Universität, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Sun-Young Oh
- Department of Neurology, Jeonbuk National University Hospital & School of Medicine, Jeonju, South Korea.,Research Institute of Clinical Medicine of Jeonbuk National University-Jeonbuk National University Hospital, Jeonju, South Korea
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Herr DW. The Future of Neurotoxicology: A Neuroelectrophysiological Viewpoint. FRONTIERS IN TOXICOLOGY 2021; 3:1. [PMID: 34966904 PMCID: PMC8711081 DOI: 10.3389/ftox.2021.729788] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 11/29/2021] [Indexed: 11/13/2022] Open
Abstract
Neuroelectrophysiology is an old science, dating to the 18th century when electrical activity in nerves was discovered. Such discoveries have led to a variety of neurophysiological techniques, ranging from basic neuroscience to clinical applications. These clinical applications allow assessment of complex neurological functions such as (but not limited to) sensory perception (vision, hearing, somatosensory function), and muscle function. The ability to use similar techniques in both humans and animal models increases the ability to perform mechanistic research to investigate neurological problems. Good animal to human homology of many neurophysiological systems facilitates interpretation of data to provide cause-effect linkages to epidemiological findings. Mechanistic cellular research to screen for toxicity often includes gaps between cellular and whole animal/person neurophysiological changes, preventing understanding of the complete function of the nervous system. Building Adverse Outcome Pathways (AOPs) will allow us to begin to identify brain regions, timelines, neurotransmitters, etc. that may be Key Events (KE) in the Adverse Outcomes (AO). This requires an integrated strategy, from in vitro to in vivo (and hypothesis generation, testing, revision). Scientists need to determine intermediate levels of nervous system organization that are related to an AO and work both upstream and downstream using mechanistic approaches. Possibly more than any other organ, the brain will require networks of pathways/AOPs to allow sufficient predictive accuracy. Advancements in neurobiological techniques should be incorporated into these AOP-base neurotoxicological assessments, including interactions between many regions of the brain simultaneously. Coupled with advancements in optogenetic manipulation, complex functions of the nervous system (such as acquisition, attention, sensory perception, etc.) can be examined in real time. The integration of neurophysiological changes with changes in gene/protein expression can begin to provide the mechanistic underpinnings for biological changes. Establishment of linkages between changes in cellular physiology and those at the level of the AO will allow construction of biological pathways (AOPs) and allow development of higher throughput assays to test for changes to critical physiological circuits. To allow mechanistic/predictive toxicology of the nervous system to be protective of human populations, neuroelectrophysiology has a critical role in our future.
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Affiliation(s)
- David W. Herr
- Neurological and Endocrine Toxicology Branch, Public Health and Integrated Toxicology Division, CPHEA/ORD, U.S. Environmental Protection Agency, Washington, NC, United States
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4
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Nguyen TT, Nam GS, Kang JJ, Han GC, Kim JS, Dieterich M, Oh SY. Galvanic Vestibular Stimulation Improves Spatial Cognition After Unilateral Labyrinthectomy in Mice. Front Neurol 2021; 12:716795. [PMID: 34393985 PMCID: PMC8358680 DOI: 10.3389/fneur.2021.716795] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 06/29/2021] [Indexed: 11/18/2022] Open
Abstract
Objectives: To investigate the deficits of spatial memory and navigation from unilateral vestibular deafferentation (UVD) and to determine the efficacy of galvanic vestibular stimulation (GVS) for recovery from these deficits using a mouse model of unilateral labyrinthectomy (UL). Methods: Thirty-six male C57BL/6 mice were allocated into three groups that comprise a control group and two experimental groups, UVD with (GVS group) and without GVS intervention (non-GVS group). In the experimental groups, we assessed the locomotor and cognitive behavioral function before (baseline) and 3, 7, and 14 days after surgical UL, using the open field (OF), Y maze, and Morris water maze (MWM) tests. In the GVS group, the stimulations were applied for 30 min daily from postoperative day (POD) 0–4 via the electrodes inserted subcutaneously close to both bony labyrinths. Results: Locomotion and spatial cognition were significantly impaired in the mice with UVD non-GVS group compared to the control group. GVS significantly accelerated recovery of locomotion compared to the control and non-GVS groups on PODs 3 (p < 0.001) and 7 (p < 0.05, Kruskal–Wallis and Mann–Whitney U tests) in the OF and Y maze tests. The mice in the GVS group were better in spatial working memory assessed with spontaneous alternation performance and spatial reference memory assessed with place recognition during the Y maze test than those in the non-GVS group on POD 3 (p < 0.001). In addition, the recovery of long-term spatial navigation deficits during the MWM, as indicated by the escape latency and the probe trial, was significantly better in the GVS group than in the non-GVS group 2 weeks after UVD (p < 0.01). Conclusions: UVD impairs spatial memory, navigation, and motor coordination. GVS accelerated recoveries in short- and long-term spatial memory and navigation, as well as locomotor function in mice with UVD, and may be applied to the patients with acute unilateral vestibular failure.
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Affiliation(s)
- Thanh Tin Nguyen
- Jeonbuk National University College of Medicine, Jeonju, South Korea.,Department of Neurology, Jeonbuk National University Hospital & School of Medicine, Jeonju, South Korea.,Department of Pharmacology, Hue University of Medicine and Pharmacy, Hue University, Hue, Vietnam
| | - Gi-Sung Nam
- Department of Neurology, Jeonbuk National University Hospital & School of Medicine, Jeonju, South Korea.,Department of Otorhinolaryngology-Head and Neck Surgery, Chosun University College of Medicine, Kwangju, South Korea
| | - Jin-Ju Kang
- Department of Neurology, Jeonbuk National University Hospital & School of Medicine, Jeonju, South Korea.,Research Institute of Clinical Medicine of Jeonbuk National University-Jeonbuk National University Hospital, Jeonju, South Korea
| | - Gyu Cheol Han
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Gachon University of Medicine and Science, Incheon, South Korea
| | - Ji-Soo Kim
- Department of Neurology, Seoul National University Hospital & School of Medicine, Seoul, South Korea
| | - Marianne Dieterich
- Department of Neurology, University Hospital, Ludwig-Maximilians-Universität, Munich, Germany.,German Center for Vertigo and Balance Disorders-IFB, University Hospital, Ludwig-Maximilians-Universität, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Sun-Young Oh
- Jeonbuk National University College of Medicine, Jeonju, South Korea.,Department of Neurology, Jeonbuk National University Hospital & School of Medicine, Jeonju, South Korea.,Research Institute of Clinical Medicine of Jeonbuk National University-Jeonbuk National University Hospital, Jeonju, South Korea
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5
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Grant SGN. The Synaptomic Theory of Behavior and Brain Disease. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2019; 83:45-56. [PMID: 30886054 DOI: 10.1101/sqb.2018.83.037887] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The purpose of this article is to outline a new molecular and synaptic theory of behavior called the "synaptomic theory," named because it is centered on the synaptome-the complement of synapses in the brain. Synaptomic theory posits that synapses are structures of high molecular complexity and vast diversity that are observable in maps of the brain and that these synaptome maps are fundamental to behavior. Synaptome maps are a means of writing or storing information that can be retrieved by the patterns of activity that stimulate synapses. Synaptome maps have the capacity to store large amounts of information, including multiple representations within the same map. The dynamic properties of synapses allow synaptome maps to store dynamic sequences of representations that could serve to program behavioral sequences. Synaptome maps are genetically programmed and experience-dependent, thereby storing innate and learned behaviors, respectively. Although learning occurs by modification of the synapse proteome, it does not require long-term potentiation (LTP) of synaptic weight or growth of new synapses, and the theory predicts that LTP modulates information recall. The spatial architecture of synaptome maps arise from an underlying molecular hierarchy linking the genome to the supramolecular assembly of proteins into complexes and supercomplexes. This molecular hierarchy can explain how genome evolution results in the behavioral repertoire of the organism. Mutations disrupting this molecular hierarchy change the architecture of synaptome maps, potentially accounting for the behavioral phenotypes associated with neurological and psychiatric disorders.
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Affiliation(s)
- Seth G N Grant
- Genes to Cognition Program, Centre for Clinical Brain Sciences, Edinburgh University, Edinburgh BioQuarter, Edinburgh EH16 4SB, United Kingdom
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6
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Lee GW, Kim JH, Kim MS. Reduction of long-term potentiation at Schaffer collateral-CA1 synapses in the rat hippocampus at the acute stage of vestibular compensation. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2017; 21:423-428. [PMID: 28706456 PMCID: PMC5507781 DOI: 10.4196/kjpp.2017.21.4.423] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/06/2017] [Accepted: 06/12/2017] [Indexed: 11/15/2022]
Abstract
Vestibular compensation is a recovery process from vestibular symptoms over time after unilateral loss of peripheral vestibular end organs. The aim of the present study was to observe time-dependent changes in long-term potentiation (LTP) at Schaffer collateral-CA1 synapses in the CA1 area of the hippocampus during vestibular compensation. The input-output (I/O) relationships of fEPSP amplitudes and LTP induced by theta burst stimulation to Schaffer's collateral commissural fibers were evaluated from the CA1 area of hippocampal slices at 1 day, 1 week, and 1 month after unilateral labyrinthectomy (UL). The I/O relationships of fEPSPs in the CA1 area was significantly reduced within 1 week post-op and then showed a non-significant reduction at 1 month after UL. Compared with sham-operated animals, there was a significant reduction of LTP induction in the hippocampus at 1 day and 1 week after UL. However, LTP induction levels in the CA1 area of the hippocampus also returned to those of sham-operated animals 1 month following UL. These data suggest that unilateral injury of the peripheral vestibular end organs results in a transient deficit in synaptic plasticity in the CA1 hippocampal area at acute stages of vestibular compensation.
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Affiliation(s)
- Gyoung Wan Lee
- Department of Nursing, Wonkwang Health Science University, Iksan 54538, Korea
| | - Jae Hyo Kim
- Department of Meridian & Acupoint, College of Korean Medicine, Wonkwang University, Iksan 54538, Korea
| | - Min Sun Kim
- Department of Physiology, School of Medicine, Wonkwang University, Iksan 54538, Korea
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7
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Abstract
This review describes the features of Alzheimer's disease and discusses the evidence that antihypertensive therapies may be beneficial in its treatment and prevention. Drugs acting via the renin-angiotensin system are considered and it is suggested that these drugs may produce their effects via mechanisms other than by their antihypertensive actions. Using evidence from animal studies, the role of angiotensin as a neurotransmitter and its involvement in the control of normal cognitive function is described. Studies of angiotensin and human cognition are reviewed along with studies investigating the possible link between disorders of the system, either inherited or acquired, and the symptoms of Alzheimer's disease. The therapeutic potential of screening for markers of renin-angiotensin abnormality for the prediction of Alzheimer's disease is considered, as is the potential use of agents known to influence the renin-angiotensin system in the treatment or prevention of the disease.
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Affiliation(s)
- Paul R Gard
- School of Pharmacy & Biomolecular Sciences, University of Brighton, Brighton, BN2 4GJ, UK.
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Liu X, Wang C, Pan C, Yan J. Physiological Correspondence Dictates Cortical Long-Term Potentiation and Depression by Thalamic Induction. Cereb Cortex 2013; 25:545-53. [DOI: 10.1093/cercor/bht259] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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9
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Nishimura M, Nakatsuka H, Natsume K. Phase dependency of long-term potentiation induction during the intermittent bursts of carbachol-induced β oscillation in rat hippocampal slices. Biophysics (Nagoya-shi) 2012; 8:173-81. [PMID: 27493534 PMCID: PMC4629649 DOI: 10.2142/biophysics.8.173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 11/06/2012] [Indexed: 12/01/2022] Open
Abstract
The rodent hippocampus possesses theta (θ) and beta (β) rhythms, which occur intermittently as bursts. Both rhythms are related to spatial memory processing in a novel environment. θ rhythm is related to spatial memory encoding process. β rhythm is related to the match/mismatch process. In the match/mismatch process, rodent hippocampus detects a representation matching sensory inputs of the current place among the retrieved internal representations of places. Long-term synaptic potentiation (LTP) is induced in both processes. The cholinergic agent carbachol induces intermittent θ and β oscillations in in vitro slices similar to in vivo bursts. LTP is facilitated during the generation of θ oscillation, suggesting that the facilitation of LTP is dependent upon the phases of intermittent burst (burst phases) of the oscillation. However, whether this is the case for β oscillation has not yet been studied. In the present study, LTP-inducing θ-burst stimulation was administered at the different burst phases of carbachol-induced β oscillations (CIBO), and the synaptic changes were measured at CA3-CA3 pyramidal cell synapses (CA3 synapse) and at CA3-CA1 pyramidal cell synapses (CA1 synapse). At the CA3 synapse, the largest magnitude of LTP was induced at the late burst phases of CIBO. At the CA1 synapse, LTP was induced only at the late burst phases. Modulation of LTP was suppressed when CIBO was blocked by the application of atropine at both synapses. The results suggest that the bursts of hippocampal β rhythm can determine the optimal temporal period for completing with the match/mismatch process.
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Affiliation(s)
- Motoshi Nishimura
- Department of Brain Science and Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka 808-0196, Japan
| | - Hiroki Nakatsuka
- Department of Brain Science and Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka 808-0196, Japan
| | - Kiyohisa Natsume
- Department of Brain Science and Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka 808-0196, Japan; Biomedical Informatics R&D Center, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka 808-0196, Japan
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Tumor suppressor down-regulated in renal cell carcinoma 1 (DRR1) is a stress-induced actin bundling factor that modulates synaptic efficacy and cognition. Proc Natl Acad Sci U S A 2011; 108:17213-8. [PMID: 21969592 DOI: 10.1073/pnas.1103318108] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Stress has been identified as a major causal factor for many mental disorders. However, our knowledge about the chain of molecular and cellular events translating stress experience into altered behavior is still rather scant. Here, we have characterized a murine ortholog of the putative tumor suppressor gene DRR1 as a unique stress-induced protein in brain. It binds to actin, promotes bundling and stabilization of actin filaments, and impacts on actin-dependent neurite outgrowth. Endogenous DRR1 localizes to some, but not all, synapses, with preference for the presynaptic region. Hippocampal virus-mediated enhancement of DRR1 expression reduced spine density, diminished the probability of synaptic glutamate release, and altered cognitive performance. DRR1 emerges as a protein to link stress with actin dynamics, which in addition is able to act on synaptic function and cognition.
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Fu W, Lei YF, Chen JL, Xiong CM, Zhou DN, Wu GH, Chen J, Cai YL, Ruan JL. Parathelypteriside attenuates cognition deficits in d-galactose treated mice by increasing antioxidant capacity and improving long-term potentiation. Neurobiol Learn Mem 2010; 94:414-21. [DOI: 10.1016/j.nlm.2010.08.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Revised: 08/18/2010] [Accepted: 08/19/2010] [Indexed: 10/19/2022]
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12
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Khan OI, Zhao Q, Miller F, Holmes GL. Interictal spikes in developing rats cause long-standing cognitive deficits. Neurobiol Dis 2010; 39:362-71. [PMID: 20452427 PMCID: PMC2910186 DOI: 10.1016/j.nbd.2010.05.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2010] [Revised: 04/04/2010] [Accepted: 05/01/2010] [Indexed: 10/19/2022] Open
Abstract
Frequent interictal spikes are a common finding in the electroencephalograms of children with epileptic encephalopathies. While it is well recognized that interictal spikes are a biological marker of seizures and can lead to transitory cognitive impairment, whether interictal spikes can result in long-standing adverse effects on learning and memory in children is not known. Here we investigated the consequences of interictal spikes in rat pups without seizures on long-term learning and memory. Rat pups were given a low dose of flurothyl for 4h for 10 days during continuous electroencephalographic monitoring. Rats developed interictal spikes without seizures while age-matched controls under similar testing conditions had few interictal spikes. When rats were tested as adults, there was impairment in reference memory in the probe test of the Morris water maze, reference memory impairment in the four-trial radial-arm water maze and impaired long-term potentiation. Early-life interictal spikes resulted in impaired new cell formation and decreased cell counts in the hippocampus but did not cause an increase in apoptosis. This study, for the first time demonstrates that interictal spikes in rat pups without seizures can result in long-standing spatial cognitive impairment. Our findings suggest that suppressing IIS may be as important as treating seizures during brain development.
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Affiliation(s)
- Omar I Khan
- Department of Neurology, Neuroscience Center at Dartmouth, Dartmouth Medical School, Hanover, New Hampshire 03756, USA
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13
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Abstract
The remarkable versatility of the mammalian brain is made possible by a huge diversity of cellular plasticity mechanisms. These include long-term potentiation and depression at both excitatory and inhibitory synapses, as well as a variety of intrinsic and homeostatic plasticity mechanisms. A fundamental challenge for the field is to assemble our detailed knowledge of these specific mechanisms into a coherent picture of how plasticity within cortical circuits works to tune network properties.
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Affiliation(s)
- Sacha B Nelson
- Department of Biology and National Center for Behavioral Genomics, Brandeis University, MS 008, 415 South Street, Waltham, Massachusetts 02454-9110, USA
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Perez-Garcia G, Meneses A. Memory formation, amnesia, improved memory and reversed amnesia: 5-HT role. Behav Brain Res 2008; 195:17-29. [DOI: 10.1016/j.bbr.2007.11.027] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2007] [Revised: 11/27/2007] [Accepted: 11/27/2007] [Indexed: 11/16/2022]
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15
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Wang Y, Mackes J, Chan S, Haughey NJ, Guo Z, Ouyang X, Furukawa K, Ingram DK, Mattson MP. Impaired long-term depression in P2X3 deficient mice is not associated with a spatial learning deficit. J Neurochem 2007; 99:1425-34. [PMID: 17074061 DOI: 10.1111/j.1471-4159.2006.04198.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The hippocampus is a brain region critical for learning and memory processes believed to result from long-lasting changes in the function and structure of synapses. Recent findings suggest that ATP functions as a neurotransmitter or neuromodulator in the mammalian brain, where it activates several different types of ionotropic and G protein-coupled ATP receptors that transduce calcium signals. However, the roles of specific ATP receptors in synaptic plasticity have not been established. Here we show that mice lacking the P2X3 ATP receptor (P2X3KO mice) exhibit abnormalities in hippocampal synaptic plasticity that can be restored by pharmacological modification of calcium-sensitive kinase and phosphatase activities. Calcium imaging studies revealed an attenuated calcium response to ATP in hippocampal neurons from P2X3KO mice. Basal synaptic transmission, paired-pulse facilitation and long-term potentiation are normal at synapses in hippocampal slices from P2X3KO. However, long-term depression is severely impaired at CA1, CA3 and dentate gyrus synapses. Long-term depression can be partially rescued in slices treated with a protein phosphatase 1-2 A activator or by postsynaptic inhibition of calcium/calmodulin-dependent protein kinase II. Despite the deficit in hippocampal long-term depression, P2X3KO mice performed normally in water maze tests of spatial learning, suggesting that long-term depression is not critical for this type of hippocampus-dependent learning and memory.
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Affiliation(s)
- Yue Wang
- Laboratory of Neurosciences, National Institute on Aging, Baltimore, MD 21224, USA.
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16
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Abstract
Learning and memory processes are thought to underlie a variety of human psychiatric disorders, including generalised anxiety disorder and post-traumatic stress disorder. Basic research performed in laboratory animals may help to elucidate the aetiology of the respective diseases. This chapter gives a short introduction into theoretical and practical aspects of animal experiments aimed at investigating acquisition, consolidation and extinction of aversive memories. It describes the behavioural paradigms most commonly used as well as neuroanatomical, cellular and molecular correlates of aversive memories. Finally, it discusses clinical implications of the results obtained in animal experiments in respect to the development of novel pharmacotherapeutic strategies for the treatment of human patients.
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Affiliation(s)
- C T Wotjak
- Research Group Neuronal Plasticity/Mouse Behaviour, Max-Planck-Institute of Psychiatry, Kraepelinstr. 2-10, 80804 Munich, Germany.
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Diamond DM, Park CR, Woodson JC. Stress generates emotional memories and retrograde amnesia by inducing an endogenous form of hippocampal LTP. Hippocampus 2004; 14:281-91. [PMID: 15132427 DOI: 10.1002/hipo.10186] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Models of the neurobiology of memory have been based on the idea that information is stored as distributed patterns of altered synaptic weights in neuronal networks. Accordingly, studies have shown that post-training treatments that alter synaptic weights, such as the induction of long-term potentiation (LTP), can interfere with retrieval. In these studies, LTP induction has been relegated to the status of a methodological procedure that serves the sole purpose of disturbing synaptic activity in order to impair memory. This perspective has been expressed, for example, by Martin and Morris (2002: Hippocampus 12:609-636), who noted that post-training LTP impairs memory by adding "behaviorally meaningless" noise to hippocampal neural networks. However, if LTP truly is a memory storage mechanism, its induction should represent more than just a means with which to disrupt memory. Since LTP induction produces retrograde amnesia, the formation of a new memory should also produce retrograde amnesia. In the present report, we suggest that one type of learning experience, the storage of fear-related (i.e., stressful) memories, is consistent with this prediction. Studies have shown that stress produces potent effects on hippocampal physiology, generates long-lasting memories, and induces retrograde amnesia, all through mechanisms in common with LTP. Based on these findings, we have developed the hypothesis that a stressful experience generates an endogenous form of hippocampal LTP that substitutes a new memory representation for preexisting representations. In summary, our hypothesis implicates the induction of endogenous synaptic plasticity by stress in the formation of emotional memories and in retrograde amnesia.
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Affiliation(s)
- David M Diamond
- Department of Psychology, University of South Florida, 4202 E. Fowler Ave (PCD 4118G), Tampa, FL 33620, USA.
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Abstract
Activity-dependent changes in neuronal excitability and synaptic strength are thought to underlie memory encoding. In hippocampal CA1 neurons, small conductance Ca2+-activated K+ (SK) channels contribute to the afterhyperpolarization, affecting neuronal excitability. In the present study, we examined the effect of apamin-sensitive SK channels on the induction of hippocampal synaptic plasticity in response to a range of stimulation frequencies. In addition, the role of apamin-sensitive SK channels on hippocampal-dependent memory encoding and retention was also tested. The results show that blocking SK channels with apamin increased the excitability of hippocampal neurons and facilitated the induction of synaptic plasticity by shifting the modification threshold to lower frequencies. This facilitation was NMDA receptor (NMDAR) dependent and appeared to be postsynaptic. Mice treated with apamin demonstrated accelerated hippocampal-dependent spatial and nonspatial memory encoding. They required fewer trials to learn the location of a hidden platform in the Morris water maze and less time to encode object memory in an object-recognition task compared with saline-treated mice. Apamin did not influence long-term retention of spatial or nonspatial memory. These data support a role for SK channels in the modulation of hippocampal synaptic plasticity and hippocampal-dependent memory encoding.
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Cammarota M, Bevilaqua LRM, Viola H, Kerr DS, Reichmann B, Teixeira V, Bulla M, Izquierdo I, Medina JH. Participation of CaMKII in neuronal plasticity and memory formation. Cell Mol Neurobiol 2002; 22:259-67. [PMID: 12469869 DOI: 10.1023/a:1020763716886] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
1. The unique biochemical properties of Ca(2+)/calmodulin (CaM)-dependent protein kinase II have made this enzyme one of the paradigmatic models of the forever searched "memory molecule." 2. In particular, the central participation of CaMKII as a sensor of the Ca(2+) signals generated by activation of NMDA receptors after the induction of long-term plastic changes, has encouraged the use of pharmacological, genetic, biochemical, and imaging tools to unveil the role of this kinase in the acquisition, consolidation, and expression of different types of memories. 3. Here we review some of the more exciting discoveries related to the mechanisms involved in CaMKII activation and synaptic plasticity.
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Affiliation(s)
- Martín Cammarota
- Centro de Memória, Departamento de Bioquímica, ICBS, UFRGS, Porto Alegre, Brasil.
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Abstract
In this review we describe an emerging understanding of the roles of the Extracellular-signal regulated kinase/mitogen-activated protein kinase (ERK/MAPK) cascade in learning and memory. We begin by describing several behavioral memory paradigms and review data implicating ERK as an essential component of the signal transduction mechanisms subserving these processes. We then describe evidence implicating ERK as a critical player in synaptic and neuronal plasticity-a cellular role likely to underlie ERK's behavioral role in the animal. We then proceed to parsing the complexities of biochemical regulation of ERK in neurons and to a description of a few likely cellular targets of ERK. This is in order to begin discussing the possible molecular basis of ERK-mediated behavioral change. We close our review with speculations concerning how the complexities and idiosyncrasies of ERK regulation may allow for sophisticated information processing at the biochemical level in neurons-attributes that may make the ERK cascade well-suited for triggering complex and long-lasting behavioral change. Our goal in this review is not so much to portray ERK as unique regarding its role as a signal transducter in memory, but rather to use ERK as one specific example of recent studies beginning to address the molecules and signal transduction pathways subserving cognition.
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Affiliation(s)
- J Paige Adams
- Division of Neuroscience, Baylor College of Medicine, Houston, Texas 77030, USA.
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Abstract
Polymorphisms of the renin-angiotensin system are associated with cardiovascular disorders, possibly as a consequence of increased brain angiotensin II activity. Within the brain, angiotensin controls blood pressure, fluid balance and hormone secretion; it also influences behaviour: reduction of central angiotensin function has both antidepressant-like and axiolytic-like actions. Evidence concerning the role of the renin-angiotensin system in learning and memory is contradictory, although more studies support the proposal that angiotensin reduces cognitive function. Studies of renin-angiotensin system genotype and psychological status have suggested an association between the angiotensin-converting enzyme deletion allele and age related cognitive decline, but a greater prevalence of the insertion allele in Alzheimer's disease. The deletion allele has also been associated with depressive illness, as has the M allele of the angiotensinogen gene although other studies have failed to replicate these findings. The role of the brain renin-angiotensin system in human psychopathology remains to be fully explored.
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Affiliation(s)
- Paul R Gard
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton BN2 4GJ, UK.
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Diamond DM, Fleshner M, Rose GM. The enhancement of hippocampal primed burst potentiation by dehydroepiandrosterone sulfate (DHEAS) is blocked by psychological stress. Stress 1999; 3:107-21. [PMID: 10938573 DOI: 10.3109/10253899909001116] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This series of studies investigated the effects of psychological stress and the neurosteroid dehydroepiandrosterone sulfate (DHEAS) on hippocampal primed burst (PB) and long-term (LTP) potentiation, two electrophysiological models of memory. The DHEAS and stress manipulations were performed on awake rats, and then PB and LTP were recorded while the rats were anesthetized. DHEAS enhanced PB potentiation when administered to rats under non-stress conditions, but had no effect when given to stressed rats. Further study showed that DHEAS enhanced PB potentiation only when it was administered before, but not after, the rats were stressed. The DHEAS and stress manipulations had no effect on LTP. This study provides three major findings regarding stress, neurosteroids and hippocampal plasticity. First, DHEAS enhanced a threshold form of plasticity (PB potentiation), but had no effect on a supra-threshold form of plasticity (LTP). Second, stress blocked the DHEAS-induced enhancement of PB potentiation. Third, stress and DHEAS effects on the hippocampus were so durable they could be performed on awake animals and then be studied while the animals were anesthetized. That DHEAS enhanced a subset of forms of hippocampal plasticity under restricted behavioral conditions may help to resolve conflicting observations of DHEAS effects on cognition and mood in people.
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Affiliation(s)
- D M Diamond
- Department of Psychology and Neuroscience Program, University of South Florida, and Medical Research Service, Veterans Affairs Medical Center, Tampa, Florida, USA.
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Abstract
Corticosteroid hormones secreted by the adrenal cortex protect the brain against adverse events and are essential for cognitive performance. However, in recent literature, the central action of corticosteroids has mostly been portrayed as damaging and disruptive to memory formation. We argue that this paradox can be explained by appreciating the specific role of both mineralocorticoid and glucocorticoid receptors in the various stages of information processing. In addition, the context in which corticosteroid-receptor activation takes place is crucial in determining steroid-mediated effects. These effects generally favour adaptive behaviour that is most relevant to the situation. Corticosteroid effects on cognition can, however, turn from adaptive into maladaptive, when actions via the two corticosteroid-receptor types are imbalanced for a prolonged period of time.
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Affiliation(s)
- E R de Kloet
- Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research, University of Leiden, 2300 RA Leiden, Netherlands
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Abstract
Discoveries made over the past 20 years have greatly improved our understanding of how the brain functions. This article focuses on the relation between memory and cellular mechanisms of neuronal and synaptic plasticity in the hippocampus. Several studies indicate that the hippocampal formation is a crucial element of the neurobiological bases of higher cognitive function. Severe damage to the hippocampal formation is known to produce seemingly permanent anterograde amnesia. A generally accepted hypothesis in neurobiology has been that long-lasting activity-dependent changes in the efficacy of synaptic transmission in the mammalian brain are considered to be of fundamental importance for the development of neural circuitry and for the storage of information. The most compelling and reliable model for such changes has been long-term potentiation (LTP) and long-term depression (LTD) in the hippocampus. Therefore, the possibility of the discovery and development of compounds that, by modulating hippocampal synaptic plasticity, would be useful for the management of dementia and amnesia.
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Affiliation(s)
- S Akhondzadeh
- Department of Pharmacology and Therapeutics, Institute of Medicinal Plants, Tehran, Iran.
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Abstract
The water maze task has been developed to test spatial learning abilities in rats or mice, and is widely used. Though it has been reported before that numerous cognitive abilities are of importance for learning this task, poor performance is usually interpreted as an impairment of spatial memory formation. Previous investigations that tried to correlate long-term potentiation (LTP) of synaptic transmission with spatial learning abilities in rats reported that injection of drugs or specific gene deletions which blocked the expression of LTP correlated with learning impairments of spatial tasks in a water maze. Recent studies, however, have shown that pretraining enables these animals to learn such spatial tasks even though LTP was still found to be blocked. I investigated to what degree altered fear condition and stress perception could account for the impaired spatial learning when no pretraining is given. In a fear habituation task, unhandled rats preferred a dark over a well lit chamber more than handled animals did, but unhandled rats favoured the lit chamber more in an active avoidance task. They also performed poorly in a spatial water maze task compared with handled rats. Rats pretrained in a radial arm maze performed better in a water maze than non-pretrained rats. No difference between groups was found in a non-spatial water maze task. On the other hand, when pretrained in a water maze, rats performed only marginally better in a radial arm maze compared to non-pretrained animals. Since animals have to be handled to learn a radial arm maze, the difference in this task was not due to stress but most probably due to getting accustomed to the room dimensions prior to learning the spatial task. The results suggest that impaired learning of spatial tasks in the water maze can be due to increased stress and decreased fear conditioning without actually affecting spatial learning abilities. These results question the interpretations of the results of some previously published results of spatial water maze tasks.
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Affiliation(s)
- C Hölscher
- Department of Physiology, University College, Dublin, Ireland.
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Kane KA, Robinson GB. Effect of chronic nimodipine on spatial learning and on long-term potentiation. Behav Brain Res 1999; 98:95-101. [PMID: 10210526 DOI: 10.1016/s0166-4328(98)00057-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The present study examined the effect of nimodipine on a reference memory task and on the induction and maintenance of long-term potentiation (LTP) in the hippocampal dentate gyrus. Young rats, subcutaneously implanted with either a 30 mg nimodipine or placebo pellet, were trained on the Barnes circular platform task. Retention was tested 15 days following acquisition. Following behavioural testing, recording and stimulating electrodes were implanted in the granule cell layer of the dentate gyrus and the perforant path, respectively. Pre-pellet baseline evoked potentials were collected. Nimodipine or placebo pellets were again subcutaneously implanted, according to the original groupings, and post-pellet baseline evoked potentials were obtained. LTP was then induced in the granule cell population by perforant path tetanization and the decay of LTP was followed for 15 days. Nimodipine significantly decreased the number of trials to reach both the acquisition and the retention criterion on the circular platform task, but did not alter granule cell excitability, LTP threshold, or the magnitude of LTP. Sustained nimodipine administration, however, increased the decay rate of LTP of the population spike, but did not affect the decay rate for LTP of the EPSP. No significant correlations were obtained between behavioural and electrophysiological measures. These results provide further evidence against a simple direct relationship between LTP and spatial learning.
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Affiliation(s)
- K A Kane
- Psychology Department, University of New Brunswick, Fredericton, Canada.
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Port RL, Seybold KS. Manipulation of NMDA-receptor activity alters extinction of an instrumental response in rats. Physiol Behav 1998; 64:391-3. [PMID: 9748109 DOI: 10.1016/s0031-9384(98)00095-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The effects of pharmacologically manipulating N-methyl-D-aspartate(NMDA)-receptor activity were examined during extinction of an appetitive instrumental response in rats. After reaching acquisition criterion, subjects were treated with the antagonist dizocilpine maleate (MK801; 0.1 mg/kg), the agonist D-cycloserine (3 mg/kg), or vehicle-alone (control) and tested during a non-reinforced (extinction) session. The antagonist decreased the average number of responses occurring during the test session whereas the agonist increased the average number in contrast to controls. The effect on retention performance may be mediated by differential influence on the N-methyl-D-aspartate-dependent synaptic plasticity that occurs during associative learning. In conjunction with other studies, these data suggest that N-methyl-D-aspartate agonism may be an effective intervention for memory dysfunction.
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Affiliation(s)
- R L Port
- Department of Psychology, Slippery Rock University, PA 16057, USA
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