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Search Results: 1 - 10 of 102 matches for " LTP "
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Function of the CaMK II on LTP of Exercise Learning
Xiyan Xie,Dan Xu,Shun Li,Yanfen Chen
International Journal of Applied Physics and Mathematics , 2013, DOI: 10.7763/ijapm.2013.v3.174
Abstract: This Ca2+/calmodulin-dependent kinase II(CaMKII) is an abundant synaptic signaling molecule that isessential for memory formation and the induction of synapticpotentiation. Additionally, CaMKII plays a prominent role insynaptic tagging and metaplasticity. The kinase becomes activein the presence of calcium and has the potential to switch to anautonomous mode of activity upon auto-phosphorylation. SinceCaMKII can be autonomously active and required for theformation of memory, CaMKII is central to the mechanism ofhippocampal, N-methyl-d-Aspartate NMDA receptordependent long-term potentiation of synaptic transmission(LTP). However, the exact reason increased activity and howthis is worked it is still matter of debate and the exact timewindow of increased activity and how this is terminated, Thereis now overwhelming evident that the expression andsignificance of CaMKII mRNA in hippocampus of rats whosespatial learning and memory function were enhanced byRegular Aerobic Exercise. Thus, regulation of Exercise of theexpression of endogenous CaMKII may constitute importantrole on CaMKII signaling on LTP during memory formation
鸟类神经系统的长时程增强
孟玮,廖素群,肖鹏,李东风
心理科学进展 , 2005,
Abstract: ?揭示学习与记忆的神经机制已成为认知科学领域的一个重要研究方向。研究过程中需根据不同实验目的选用不同实验动物。ltp(long-termpotentiation)是一种研究学习记忆突触基础的主要模型,其代表突触功能的可塑性。以往对ltp的研究主要集中于哺乳动物,但由于鸟类在生物进化上具有独特的地位及特有的学习记忆能力,因此通过某些鸟类行为模型将有利于对ltp特性及其与学习记忆相关性进行更深入的探索。
Subcutaneous Sustained-Release of Poly-Arginine Ameliorates Cognitive Impairment in a Transgenic Mouse Model of Alzheimer’s Disease  [PDF]
Gennadiy Fonar, Baruh Polis, Tomer Meirson, Alexander Maltsev, Abraham O. Samson
Advances in Alzheimer's Disease (AAD) , 2018, DOI: 10.4236/aad.2018.74011
Abstract:
Poly-arginine peptides are a promising class of bioactive compounds that are capable of crossing the blood-brain barrier (BBB) and present neuroprotective properties. In this study, we test the activity of poly-arginine peptides in a triple-transgenic mouse model of Alzheimer’s disease. To identify the best candidate, we examined the relative neuroprotective efficacy of the compounds with various lengths (R7, R9, and R11) via assessment of memory acquisition, long-term hippocampal potentiation (LTP), and cytotoxicity. Also, we explored the expression profiles of hundreds of key cell signaling proteins, and perform a high content antibody microarray comparative analysis of brain samples. The chronically treated animals with poly-arginine R9 show significantly improved acquisition of memory. This compound rescues hippocampal LTP deteriorated by Aβ at a better rate than other agents tested in this study and induces cellular pathways involved in neuroprotection and neuroplasticity. The treatment escalates the expression levels of Synapsin Ia in the mice hippocampi; however, it has no significant effect upon the rate of beta-amyloidosis. Poly-arginine R9 peptide is a well-tolerated compound that crosses the BBB and presents unique neuroprotective qualities. The substance halters the development of AD symptoms in a murine model and can be recommended for clinical investigation.
Long-Term Potentiation of Avain Neural System
鸟类神经系统的长时程增强

Meng Wei,Liao Suqun,Xiao Peng,Li Dongfeng,
孟玮
,廖素群,肖鹏,李东风

心理科学进展 , 2005,
Abstract: Neural mechanism in learning and memory is an important research field for cognitive science. It is necessary to select different kinds of animal for different purposes in studying learning and memory. LTP represents a long-lasting enhancement of synaptic function , is a kind of primary model for synaptic plasticity that underlies learning and memory. Reports on mechanism of LTP mainly came from mammalian before. Birds are special species in animal evolution and have characteristic capabilities in learning and memory. With behavior model of birds, the understanding of LTP and relationship between learning and memory and LTP were carried on.
Purification and molecular mass determination of a lipid transfer protein exuded from Vigna unguiculata seeds
Diz, Mariangela S. S.;Carvalho, André O.;Gomes, Valdirene M.;
Brazilian Journal of Plant Physiology , 2003, DOI: 10.1590/S1677-04202003000300007
Abstract: plants exude a variety of substances through their surface especially of roots and germinating seeds. some of these released compounds seem to have an inhibitory action against certain pathogens. lipid transfer proteins (ltps) are 9 kda cysteine-rich cationic peptides and are thought to play a role in the protection of plants against microbial infections. the aim of this work was to isolate and determine the molecular mass of a ltp present in the exudates of imbibed cowpea seeds. for exudation induction, 50 seeds were submerged in 50 ml sterile 100 mmol.l-1 na-acetate buffer, ph 4.5 and shaken at 30 oc for 24 h. the resulting exudate was subjected to ammonium sulphate fractionation and the pellet formed between 0 and 70 % saturation was dialysed and recovered by freeze drying. further purification steps were carried out using chromatographic methods and the molecular mass of the ltp determined. all of these steps were monitored by sds-tricine gel electrophoresis and western blotting using an anti-ltp serum. the purified ltp showed a relative molecular mass of 9 kda.
不同发展阶段的习得性长时程突触增强对新学习的影响
戴远威,许世彤,区英琦
心理学报 , 1991,
Abstract: 在慢性实验条件下观察到大鼠由学习训练所产生的海马CA_3区习得性长时程突触增强,它的不同发展阶段对新学习任务的习得有不同的作用:(1)在它的形成阶段及巩固阶段对新学习均有易化作用,虽然两个阶段突触效应增强的程度都处于相同的高水平,但后者的易化作用相对要大些,提示这两个发展阶段突触的可塑性变化是有差异的;还有,新学习任务的训练并没有引起突触效应的进一步增强,表明突触效应的长时程增强有“饱和”现象。(2)在它消退后,对新学习任务的习得没有影响。上述结果提示学习的组织形式不同,可从突触机制上影响学习的效果,并进一步证明习得性长时程突触增强是学习和记忆的神经基础。
LTP和记忆相关性研究新进展
胡家芬,管林初,匡培梓
心理科学进展 , 1998,
Abstract: 本文对近年来在LTP和记忆的相关性研究从基因和分子水平上作了一个粗略的回顾。可以看出LTP与记忆的形成有着许多共同点和高度的一致性,因此LTP是研究记忆机制一个极好的模型。
Memory maintenance by PKMζ — an evolutionary perspective
Sacktor Todd
Molecular Brain , 2012, DOI: 10.1186/1756-6606-5-31
Abstract: Long-term memory is believed to be maintained by persistent modifications of synaptic transmission within the neural circuits that mediate behavior. Thus, long-term potentiation (LTP) is widely studied as a potential physiological basis for the persistent enhancement of synaptic strength that might sustain memory. Whereas the molecular mechanisms that initially induce LTP have been extensively characterized, the mechanisms that persistently maintain the potentiation have not. Recently, however, a candidate molecular mechanism linking the maintenance of LTP and the storage of long-term memory has been identified. The persistent activity of the autonomously active, atypical protein kinase C (aPKC) isoform, PKMζ, is both necessary and sufficient for maintaining LTP. Furthermore, blocking PKMζ activity by pharmacological or dominant negative inhibitors disrupts previously stored long-term memories in a variety of neural circuits, including spatial and trace memories in the hippocampus, aversive memories in the basolateral amygdala, appetitive memories in the nucleus accumbens, habit memory in the dorsal lateral striatum, and elementary associations, extinction, and skilled sensorimotor memories in the neocortex. During LTP and memory formation, PKMζ is synthesized de novo as a constitutively active kinase. This molecular mechanism for memory storage is evolutionarily conserved. PKMζ formation through new protein synthesis likely originated in early vertebrates ~500 million years ago during the Cambrian period. Other mechanisms for forming persistently active PKM from aPKC are found in invertebrates, and inhibiting this atypical PKM disrupts long-term memory in the invertebrate model systems Drosophila melanogaster and Aplysia californica. Conversely, overexpressing PKMζ enhances memory in flies and rodents. PKMζ persistently enhances synaptic strength by maintaining increased numbers of AMPA receptors at postsynaptic sites, a mechanism that might have evolved from the general function of aPKC in trafficking membrane proteins to the apical compartment of polarized cells. This mechanism of memory may have had adaptive advantages because it is both stable and reversible, as demonstrated by the downregulation of experience-dependent, long-term increases in PKMζ after extinction and reconsolidation blockade that attenuate learned behavior. Thus, PKMζ, the “working end” of LTP, is a component of an evolutionarily conserved molecular mechanism for the persistent, yet flexible storage of long-term memory.
Estrogen’s Place in the Family of Synaptic Modulators
Enik? A. Kramár,Lulu Y. Chen,Christopher S. Rex,Christine M. Gall
Molecular and Cellular Pharmacology , 2009,
Abstract: Estrogen, in addition to its genomic effects, triggers rapid synaptic changes in hippocampus and cortex. Here we summarize evidence that the acute actions of the steroid arise from actin signaling cascades centrally involved in long-term potentiation (LTP). A 10-min infusion of E2 reversibly increased fast EPSPs and promoted theta burst-induced LTP within adult hippocampal slices. The latter effect reflected a lowered threshold and an elevated ceiling for the potentiation effect. E2’s actions on transmission and plasticity were completely blocked by latrunculin, a toxin that prevents actin polymerization. E2 also caused a reversible increase in spine concentrations of filamentous (F-) actin and markedly enhanced polymerization caused by theta burst stimulation (TBS). Estrogen activated the small GTPase RhoA, but not the related GTPase Rac, and phosphorylated (inactivated) synaptic cofilin, an actin severing protein targeted by RhoA. An inhibitor of RhoA kinase (ROCK) thoroughly suppressed the synaptic effects of E2. Collectively, these results indicate that E2 engages a RhoA >ROCK> cofilin> actin pathway also used by brain-derived neurotrophic factor and adenosine, and therefore belongs to a family of ‘synaptic modulators’ that regulate plasticity. Finally, we describe evidence that the acute signaling cascade is critical to the depression of LTP produced by ovariectomy.
Purification and molecular mass determination of a lipid transfer protein exuded from Vigna unguiculata seeds
Diz Mariangela S. S.,Carvalho André O.,Gomes Valdirene M.
Brazilian Journal of Plant Physiology , 2003,
Abstract: Plants exude a variety of substances through their surface especially of roots and germinating seeds. Some of these released compounds seem to have an inhibitory action against certain pathogens. Lipid transfer proteins (LTPs) are 9 kDa cysteine-rich cationic peptides and are thought to play a role in the protection of plants against microbial infections. The aim of this work was to isolate and determine the molecular mass of a LTP present in the exudates of imbibed cowpea seeds. For exudation induction, 50 seeds were submerged in 50 mL sterile 100 mmol.L-1 Na-acetate buffer, pH 4.5 and shaken at 30 oC for 24 h. The resulting exudate was subjected to ammonium sulphate fractionation and the pellet formed between 0 and 70 % saturation was dialysed and recovered by freeze drying. Further purification steps were carried out using chromatographic methods and the molecular mass of the LTP determined. All of these steps were monitored by SDS-Tricine gel electrophoresis and Western blotting using an anti-LTP serum. The purified LTP showed a relative molecular mass of 9 kDa.
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