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Li N, Xiao K, Mi X, Li N, Guo L, Wang X, Sun Y, Li GD, Zhou Y. Ghrelin signaling in dCA1 suppresses neuronal excitability and impairs memory acquisition via PI3K/Akt/GSK-3β cascades. Neuropharmacology 2022; 203:108871. [PMID: 34742928 DOI: 10.1016/j.neuropharm.2021.108871] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 11/01/2021] [Accepted: 11/01/2021] [Indexed: 12/22/2022]
Abstract
Ghrelin is a circulating peptide hormone that promotes feeding and regulates metabolism in humans and rodents. The action of ghrelin is mediated by the growth hormone secretagogue receptor type 1a (GHSR-1a) that is widely distributed in the brain, including the hippocampus. Studies have demonstrated the critical role of hippocampal ghrelin/GHS-R1a signaling in synaptic physiology and memory. However, those findings are controversial, and the mechanism underlying ghrelin modulation of learning and memory is uncertain. Here, we report that micro-infusion of ghrelin in the CA1 region of the dorsal hippocampus during training specifically impairs memory acquisition. The activation of GHS-R1a and the subsequent PI3K/Akt/GSK3β signaling cascades are involved in this process. Moreover, we report that bath application of ghrelin suppresses the intrinsic excitability of dCA1 pyramidal neurons through activating GHS-R1a, and PI3K inhibitor LY294002 blocks ghrelin's effect. However, LY294002 fails to rescue ghrelin-induced LTP impairment. Our findings support an adverse effect of ghrelin-dependent activation of GHS-R1a on memory acquisition, and suggest that PI3K/Akt/GSK3β signaling-dependent repression of neuronal intrinsic excitability is an important novel mechanism underlying memory inhibition of ghrelin in the hippocampus.
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Affiliation(s)
- Nan Li
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China
| | - Kewei Xiao
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China
| | - Xue Mi
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China
| | - Na Li
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China
| | - Li Guo
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China
| | - Xiaorong Wang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China
| | - Yuxiang Sun
- Department of Nutrition, Texas A&M University, College Station, TX, 77843, United States
| | - Guo-Dong Li
- Department of Surgery, Valley Presbyterian Hospital, Van Nuys, CA, 91405, United States
| | - Yu Zhou
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China; Institute of Brain Sciences and Related Disorders, Qingdao University, Qingdao, Shandong, 266071, China; Department of Rehabilitation Medicine, Affiliated Hospital of Qingdao University, Qingdao, Shangdong, 266000, China.
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Abstract
While effective teaching is critical to passing on knowledge and skill to surgical trainees, the actual learning must be done by the trainees. Neural pathways are created as memories which are consolidated, refined, forgotten, and subsequently retrieved. Knowledge and skill build on previous memories as learners gain additional experience. Learning will be greatly enhanced when teachers: 1) praise student efforts, 2) offer individualized feedback, and 3) consistently challenge (assess) trainees. Coaxing learners to put forth more effort creates stronger memories that are easier to retrieve. Detailed feedback leads to refining neural pathways and enhance learning efficiency. Challenging learners with quizzes, assessments, and questions makes it clear to both learner and teacher what the trainee knows and does not know - and additional efforts, feedback, and assessments offer opportunities for learners to master surgical knowledge and skill.
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Zhu S, Chen P, Chen M, Ruan J, Ren W, Zhang X, Gao Y, Li Y. Alcohol inhibits morphine/cocaine reward memory acquisition and reconsolidation in rats. Psychopharmacology (Berl) 2020; 237:1043-1053. [PMID: 31912191 DOI: 10.1007/s00213-019-05433-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 12/11/2019] [Indexed: 01/05/2023]
Abstract
RATIONALE AND OBJECTIVE Alcohol is a recreational substance that is generally socially acceptable and legal in most areas worldwide. An alcohol overdose will produce an inhibitory effect on the brain and impair cognition and memory. In this study, we examined the effect of alcohol on the acquisition, consolidation, and reconsolidation of drug reward memory induced by morphine and cocaine in rats. METHODS Rats were trained to acquire morphine sulfate (10 mg/kg, s.c.) and cocaine (10 mg/kg, i.p.) conditioned place preference (CPP) via an unbiased CPP paradigm. Vehicle or alcohol (0.25, 0.75, 1.5 g/kg, i.p.) was administered at various time-points, including 30 min before each CPP conditioning session (acquisition), immediately after each CPP conditioning session (consolidation), immediately after the reactivation of CPP (reconsolidation with re-exposure), or without reactivation to the drug-paired context (reconsolidation without re-exposure). Conditioning scores were recorded before or after each conditioning session or memory reactivation. RESULTS Alcohol at a dose of 1.5 g/kg but not 0.25 g/kg or 0.75 g/kg significantly inhibited the acquisition and reconsolidation of morphine- and cocaine-associated memory. In contrast, alcohol had no effect on the consolidation of morphine- or cocaine-induced CPP. CONCLUSIONS The results suggested that pre-exposure alcohol dose-dependently attenuated morphine- or cocaine-induced place preference and prevented drug reinstatement in rats by disrupting memory reconsolidation, which may be explained by the inhibitory effect of alcohol on dopaminergic and glutamatergic neurotransmission.
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Affiliation(s)
- Shimin Zhu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, Hubei, China
| | - Pingping Chen
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, Hubei, China
| | - Mingzhu Chen
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, Hubei, China
| | - Jiawei Ruan
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, Hubei, China
| | - Wanying Ren
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, Hubei, China
| | - Xinyu Zhang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, Hubei, China
| | - Yang Gao
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, Hubei, China
| | - Yanqin Li
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, Hubei, China.
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De Zeeuw CI, Canto CB. Sleep deprivation directly following eyeblink-conditioning impairs memory consolidation. Neurobiol Learn Mem 2020; 170:107165. [PMID: 31953233 PMCID: PMC7184677 DOI: 10.1016/j.nlm.2020.107165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 12/05/2019] [Accepted: 01/12/2020] [Indexed: 10/31/2022]
Abstract
The relation between sleep and different forms of memory formation continues to be a relevant topic in our daily life. Sleep has been found to affect cerebellum-dependent procedural memory formation, but it remains to be elucidated to what extent the level of sleep deprivation directly after motor training also influences our ability to store and retrieve memories. Here, we studied the effect of disturbed sleep in mice during two different time-windows, one covering the first four hours following eyeblink conditioning (EBC) and another window following the next period of four hours. Compared to control mice with sleep ad libitum, the percentage of conditioned responses and their amplitude were impaired when mice were deprived of sleep directly after conditioning. This impairment was still significant when the learned EBC responses were extinguished and later reacquired. However, consolidation of eyeblink responses was not affected when mice were deprived later than four hours after acquisition, not even when tested during a different day-night cycle for control. Moreover, mice that slept longer directly following EBC showed a tendency for more conditioned responses. Our data indicate that consolidation of motor memories can benefit from sleep directly following memory formation.
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Affiliation(s)
- Chris I De Zeeuw
- Netherlands Institute for Neuroscience, KNAW, 1105 BA Amsterdam, the Netherlands; Department of Neuroscience, Erasmus MC, 3000 CA Rotterdam, the Netherlands
| | - Cathrin B Canto
- Netherlands Institute for Neuroscience, KNAW, 1105 BA Amsterdam, the Netherlands; Department of Neuroscience, Erasmus MC, 3000 CA Rotterdam, the Netherlands.
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van Goethem NP, Paes D, Puzzo D, Fedele E, Rebosio C, Gulisano W, Palmeri A, Wennogle LP, Peng Y, Bertrand D, Prickaerts J. Antagonizing α7 nicotinic receptors with methyllycaconitine (MLA) potentiates receptor activity and memory acquisition. Cell Signal 2019; 62:109338. [PMID: 31176021 DOI: 10.1016/j.cellsig.2019.06.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/03/2019] [Accepted: 06/03/2019] [Indexed: 12/11/2022]
Abstract
α7 nicotinic acetylcholine receptors (α7nAChRs) have been targeted to improve cognition in different neurological and psychiatric disorders. Nevertheless, no α7nAChR activating ligand has been clinically approved. Here, we investigated the effects of antagonizing α7nAChRs using the selective antagonist methyllycaconitine (MLA) on receptor activity in vitro and cognitive functioning in vivo. Picomolar concentrations of MLA significantly potentiated receptor responses in electrophysiological experiments mimicking the in vivo situation. Furthermore, microdialysis studies showed that MLA administration substantially increased hippocampal glutamate efflux which is related to memory processes. Accordingly, pre-tetanus administration of low MLA concentrations produced longer lasting potentiation (long-term potentiation, LTP) in studies examining hippocampal plasticity. Moreover, low doses of MLA improved acquisition, but not consolidation memory processes in rats. While the focus to enhance cognition by modulating α7nAChRs lies on agonists and positive modulators, antagonists at low doses should provide a novel approach to improve cognition in neurological and psychiatric disorders.
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Affiliation(s)
- Nick P van Goethem
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, 6200, MD, Maastricht, The Netherlands
| | - Dean Paes
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, 6200, MD, Maastricht, The Netherlands
| | - Daniela Puzzo
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, 95124 Catania, Italy
| | - Ernesto Fedele
- Department of Pharmacy, Section of Pharmacology and Toxicology, School of Medical and Pharmaceutical Sciences, Centre of Excellence for Biomedical Research, University of Genoa, 16148 Genoa, Italy; IRCCS Polyclinic Hospital San Martino, 16132 Genoa, Italy
| | - Claudia Rebosio
- Department of Pharmacy, Section of Pharmacology and Toxicology, School of Medical and Pharmaceutical Sciences, Centre of Excellence for Biomedical Research, University of Genoa, 16148 Genoa, Italy
| | - Walter Gulisano
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, 95124 Catania, Italy
| | - Agostino Palmeri
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, 95124 Catania, Italy
| | | | - Youyi Peng
- Intra-Cellular Therapies, Inc., New York 10016, United States
| | - Daniel Bertrand
- HiQScreen Sàrl, 6, rte de Compois, 1222, Vésenaz, Geneva, Switzerland
| | - Jos Prickaerts
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, 6200, MD, Maastricht, The Netherlands.
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Uhernik AL, Montoya ZT, Balkissoon CD, Smith JP. Learning and memory is modulated by cannabidiol when administered during trace fear-conditioning. Neurobiol Learn Mem 2018; 149:68-76. [PMID: 29432803 DOI: 10.1016/j.nlm.2018.02.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 01/25/2018] [Accepted: 02/08/2018] [Indexed: 12/29/2022]
Abstract
Cannabidiol (CBD) is thought to have therapeutic potential for treating psychiatric conditions that affect cognitive aspects of learning and memory, including anxiety and post-traumatic stress disorder (PTSD). Studies have shown that CBD enhances extinction of fear memory when given after conditioning. This led us to hypothesize that CBD, if administered prior to fear conditioning, might modulate cognitive learning and memory processes in additional ways that would further guide its potential use for treating PTSD. Therefore, we designed a study to investigate effects of CBD on fear learning and memory when administered to mice prior to administering a trace fear conditioning protocol which imposes cognitive demands on the learning and memory process. We show that CBD-treated animals had increased levels of freezing during conditioning, enhanced generalized fear, inhibited cue-dependent memory extinction, slightly increased levels of freezing during an auditory-cued memory test, and increased contextual fear memory. Because synaptic plasticity is the fundamental mechanism of learning and memory, we also evaluated the impact of CBD on trace conditioning-dependent dendritic spine plasticity which occurred in the dorsal lateral amygdala and CA1 region of the ventral hippocampus. We showed that CBD mildly enhanced spine densities independent of conditioning, and inhibited conditioning-dependent spine increases in the hippocampi, but not the amygdala of fear conditioned animals. Overall, the memory-modulating effects of a single pre-conditioning dose of CBD, which we show here, demonstrate the need to more fully characterize its basic effects on memory, suggest caution when using it clinically as an anxiolytic, and point to a need for more research into its potential as a therapeutic for treating memory-loss disorders.
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Affiliation(s)
- A L Uhernik
- Colorado State University-Pueblo, United States
| | - Z T Montoya
- Colorado State University-Pueblo, United States
| | | | - J P Smith
- Colorado State University-Pueblo, United States.
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Leão LKR, Herculano AM, Maximino C, Brasil Costa A, Gouveia A, Batista EO, Rocha FF, Crespo-Lopez ME, Borges R, Oliveira K. Mauritia flexuosa L. protects against deficits in memory acquisition and oxidative stress in rat hippocampus induced by methylmercury exposure. Nutr Neurosci 2016; 20:297-304. [PMID: 26869022 DOI: 10.1080/1028415x.2015.1133030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
OBJECTIVE Methylmercury (MeHg) is the most toxic form of mercury that can affect humans through the food chain by bioaccumulation. Human organism is capable of triggering visual and cognitive disorders, neurodegeneration, as well as increased production of reactive species of O2 and depletion of natural anti-oxidant agents. In this context, Mauritia flexuosa L., a fruit rich in compounds with anti-oxidant properties, emerged as an important strategy to prevent the MeHg damages. So, this work has aimed to elucidate the protective effect of Mauritia flexuosa L. on the damage caused by the exposure of rats to MeHg. METHODS In order to evaluate the effect of MeHg on rat aversive memory acquisition and panic-like behavior, we have used elevated T-maze apparatus and after behavioral test, the hippocampus was removed to perfom lipid peroxidation. RESULTS Our results demonstrated that the exposure to MeHg caused deficits in inhibitory avoidance acquisition (aversive conditioning) and in the learning process, and increased levels of lipid peroxidation in hippocampus tissue. However, the pretreatment with feed enriched with Mauritia flexuosa L. showed a protective effect against cognitive deficits caused by MeHg and also prevented the occurrence of cytoplasmic membrane damage induced by lipid peroxidation in the hippocampal region. DISCUSSION Therefore, this study suggests that Mauritia flexuosa L. represents an important strategy to prevent neurocytotoxics and behavioral effects of MeHg.
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Affiliation(s)
- Luana K R Leão
- a Laboratório de Neuroendocrinologia, Instituto de Ciências Biológicas , Universidade Federal do Pará , Brazil
| | - Anderson M Herculano
- a Laboratório de Neuroendocrinologia, Instituto de Ciências Biológicas , Universidade Federal do Pará , Brazil
| | - Caio Maximino
- a Laboratório de Neuroendocrinologia, Instituto de Ciências Biológicas , Universidade Federal do Pará , Brazil
| | - Alódia Brasil Costa
- a Laboratório de Neuroendocrinologia, Instituto de Ciências Biológicas , Universidade Federal do Pará , Brazil
| | - Amauri Gouveia
- b Laboratório de Neurociências e Comportamento, Núcleo de Teoria e Pesquisa do Comportamento , Universidade Federal do Pará , Brazil
| | - Evander O Batista
- c Laboratório de Protozoologia, Núcleo de Medicina Tropical , Universidade Federal do Pará , Brazil
| | - Fernando F Rocha
- d Laboratório de Neurofisiologia Eduardo Oswaldo Cruz, Instituto de Ciências Biológicas , Universidade Federal do Pará , Brazil
| | - Maria Elena Crespo-Lopez
- e Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas , Universidade Federal do Pará , Brazil
| | - Rosivaldo Borges
- f Laboratório de Química Farmacêutica, Faculdade de Farmácia, Instituto de Ciências da Saúde , Universidade Federal do Pará , Brazil
| | - Karen Oliveira
- a Laboratório de Neuroendocrinologia, Instituto de Ciências Biológicas , Universidade Federal do Pará , Brazil
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