Ischemic long-term-potentiation(iLTP): perspectives to set the threshold of neural plasticity toward therapy

The precise role of neural plasticity under pathological conditions remains not well understood. It appears to be well accepted, however, that changes in the ability of neurons to express plasticity accompany neurological diseases. Here, we discuss recent experimental evidence, which suggests that synaptic plasticity induced by a pathological stimulus, i.e., ischemic long-term-potentiation（i LTP） of excitatory synapses, could play an important role for post-stroke recovery by influencing the post-lesional reorganization of surviving neuronal networks.

Effects of the ephedra alkaloid methylephedrine on the basal evoked potential transportation and the long-term potentiation (LTP) in the rat hippocampal dentate granule cells in vivo

Objective The effect of the ephedra/ephedrine alkaloid methylephedrine(dl-methylephedrine hydrochloride for testing in this paper)on cognitive related synaptic plasticity was investigated by recording extracellular field evoked potentials and its LTP in hippocampal dentate granule cells in urethane-anaesthetized rats in vivo.Methods Single pathway recording of evoked field potentials was made from the dentate granule cells of hippocampal hemisphere in response to stimulation of the ipsilateral medial perforant path(MPP).Two parameters,the amplitude of population spike(PS amplitude)and the latency of the PS,were employed to evaluate the effects of drug on the overall changes in cellular responses.Results The present study show that methylephedrine 90 mg·kg-1 intraperitoneally,about 1/3 LD50,could increase the latency of the PS in hippocampal dentate granule cells by constant single stimulation of the MPP as the basal ransportation.However,the 30 mg·kg-1 and 10 mg·kg-1 dosage had no effect on the latency,and there are no influences of PS amplitude for all examinational groups.The methylephedrine 90 mg·kg-1 group significant enhanced the development of amplitude LTP in hippocampal dentate granule cells that induced by 60 Hz,60 pulses conditional tetanus in medial perforant path area.Also,the 30 mg·kg-1 group can promoted the maintenance of LTP induced by this tetanus,but no promotion on PS amplitude LTP appeared in this dosage and no any changes been found in 10 mg·kg-1 dosage group.Conclusions The ephedra/ephedrine alkaloid methylephedrine can modulate the synaptic plasticity in the lateral perforant path.A possible mechanism of methylephedrine on hippocampal LTP is been discussed.

Mitochondria–cGAS–STING axis is a potential therapeutic target for senescence-dependent inflammaging-associated neurodegeneration

The word “senescence” comes from the Latin senescens, meaning “to begin to age”, and is characterized by a long-lasting but reversible block in proliferation, resulting from stress-induced cell cycle arrest of previously replication-competent cells.

Normalized Solutions of Nonlinear Choquard Equations with Nonconstant Potential

In this paper,we mainly focus on a type of nonlinear Choquard equations with nonconstant potential.Under appropriate hypotheses on potential function and nonlinear terms,we prove that the above Choquard equation with prescribed 2-norm has some normalized solutions by introducing variational methods.

Understanding the local structure and thermophysical behavior of Mg-La liquid alloys via machine learning potential

The local structure and thermophysical behavior of Mg-La liquid alloys were in-depth understood using deep potential molecular dynamic(DPMD) simulation driven via machine learning to promote the development of Mg-La alloys. The robustness of the trained deep potential(DP) model was thoroughly evaluated through several aspects, including root-mean-square errors(RMSEs), energy and force data, and structural information comparison results;the results indicate the carefully trained DP model is reliable. The component and temperature dependence of the local structure in the Mg-La liquid alloy was analyzed. The effect of Mg content in the system on the first coordination shell of the atomic pairs is the same as that of temperature. The pre-peak demonstrated in the structure factor indicates the presence of a medium-range ordered structure in the Mg-La liquid alloy, which is particularly pronounced in the 80at% Mg system and disappears at elevated temperatures. The density, self-diffusion coefficient, and shear viscosity for the Mg-La liquid alloy were predicted via DPMD simulation, the evolution patterns with Mg content and temperature were subsequently discussed, and a database was established accordingly. Finally, the mixing enthalpy and elemental activity of the Mg-La liquid alloy at 1200 K were reliably evaluated,which provides new guidance for related studies.

Identifying Three Shapes of Potential Vorticity Streamers Using Mask R-CNN

Potential vorticity(PV)streamers are elongated filaments of high PV intrusions that generally exhibit three distinct shapes:ordinarily southwestward,hook,and treble-clef,each with significant influences on weather.These PV streamers are most frequent over arid and semi-arid Central Asia in the mid–high latitudes.This study applied the Mask Region-based Convolutional Neural Network algorithm(Mask R-CNN)to PV streamers on the dynamical tropopause during the warm season(May to September)over the years 2000–04 to train a weighted variational model capable of identifying these different shapes.The trained model demonstrated a strong ability to distinguish between the three shapes.A climatological analysis of PV streamers over Central Asia spanning 2000 to 2021 revealed an increasingly deep and pronounced reversal of circulation from ordinary to treble-clef shapes.The treble-clef shape featured a PV tower and distinct cut-off low in the troposphere,but the associated upward motions and precipitation were confined within approximately 1200 km to the east of the PV tower.Although the hook-shape PV streamers were linked to a weaker cut-off low,the extent of upward motion and precipitation was nearly double that of the treble-clef category.In contrast,the ordinary PV streamer was primarily associated with tropopause Rossby wave breaking and exhibited relatively shallow characteristics,which resulted in moderate upward motion and precipitation to 500 km to its east.

Carboniferous-Early Permian heterogeneous distribution of porous carbonate reservoirs in the Central Uplift of the South Yellow Sea Basin and its hydrocarbon potential analysis

Mesozoic-Palaeozoic marine carbonate rocks are crucial hydrocarbon reservoirs in the Central Uplift area of the South Yellow Sea Basin(SYSB).Due to the scarcity of boreholes and the significant heterogeneity of carbonate reservoirs,the distribution of porous carbonate reservoirs and their related key controlling factors remain unclear.In this study,factors affecting the distribution of porous Carboniferous-Early Permian carbonate reservoirs in the SYSB were investigated through seismic inversion and isotope analysis.The log-seismic characteristics of porous carbonate reservoirs,sensitive lithology parameters,and physical property parameters were extracted and analyzed.The pre-stack simultaneous inversion technique was applied to predict the lithology and physical properties of porous carbonate reservoirs.Moreover,the sedimentary of carbonate was analyzed using isotopes of carbon,oxygen,and strontium.The results show that porous carbonate reservoirs are mainly developed in the open platform sediments with porosities of 3%-5%and are mainly distributed in the paleo-highland(Huanglong Formation and Chuanshan Formation)and the slope of paleo-highland(Hezhou Formation).The porous carbonate reservoirs of the Qixia Formation are only locally developed.In addition,the negativeδ13C excursions indicate a warm and humid tropical climate with three sea-level fluctuations in the study area from the Carboniferous to Early Permian.The favorable conditions for developing porous carbonate rocks include the sedimentary environment and diagenetic process.The primary pore tends to form in high-energy environments of the paleo-highland,and the secondary pore is increased by dissolution during the syngenetic or quasi-syngenetic period.According to the hydrocarbon potential analysis,the Late Ordovician Wufeng Formation and Lower Silurian Gaojiabian Formation are the source rocks in the high-maturity-over-maturity stage,the Carboniferous-Lower Permian carbonate is the good reservoirs,and the Late Permian Longtan-Dalong Formation is the stable seal,ensuring a huge hydrocarbon accumulation potential in SYSB.The methods proposed in this study can be applied to other carbonate-dominated strata worldwide.

Aniracetam attenuates H_2O_2-induced deficiency of neuron viability, mi-tochondria potential and hippocampal long-term potentiation of mice in vitro

Objective It is known that free radicals are involved in neurodegeneration and cognitive dysfunction, as seen in Alzheimer＇s disease （AD） and aging. The present study examines the protective effects of aniracetam against H2O2- induced toxicity to neuron viability, mitochondria potential and hippocampal long-term potentiation （LTP）. Methods Tetrazolium salt 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide （MTT） was used to detect neuronal viability. MitoTracker Red （CMX Ros）, a fluorescent stain for mitochondria, was used to measure mitochondria potential. Electrophysiological technique was carried out to record hippocampual LTE Results H2O2 exposure impaired the viability of neurons, reduced mitochondria potential, and decreased LTP in the CA region of hippocampus. These deficient effects were significantly rescued by pre-treatment with aniracetam （10 ～100μmol/L）. Conclusion These results indicate that aniracetam has a strong neuroprotective effect against H2O2-induced toxicity, which could partly explain the mechanism of its clinical application in neurodegenerative diseases.

Effects of Chronic Administration of Melatonin on Spatial Learning Ability and Long-term Potentiation in Lead-exposed and Control Rats

Objective To explore the changes in spatial learning performance and long-term potentiation （LTP） which is recognized as a component of the cellular basis of learning and memory in normal and lead-exposed rats after administration of melatonin （MT） for two months. Methods Experiment was performed in adult male Wistar rats （12 controls, 12 exposed to melatonin treatment, 10 exposed to lead and 10 exposed to lead and melatonin treatment）. The lead-exposed rats received 0.2% lead acetate solution from their birth day while the control rats drank tap water. Melatonin （3 mg/kg） or vehicle was administered to the control and lead-exposed rats from the time of their weaning by gastric gavage each day for 60 days, depending on their groups. At the age of 81-90 days, all the animals were subjected to Morris water maze test and then used for extracellular recording of LTP in the dentate gyrus （DG） area of the hippocampus in vivo. Results Low dose of melatonin given from weaning for two months impaired LTP in the DG area of hippocampus and induced learning and memory deficit in the control rats. When melatonin was administered over a prolonged period to the lead-exposed rats, it exacerbated LTP impairment, learning and memory deficit induced by lead. Conclusion Melatonin is not suitable for normal and lead-exposed children.

基于OD-LTP的振动条件下串联型故障电弧检测方法研究

当三相异步电动机发生机械振动时,主回路中接触不良的电气接触点在振动作用下会产生串联型故障电弧,进而影响电路安全甚至引发电气火灾。而振动条件会加剧了故障电弧信号的复杂性,因此本文以回路电流信号为研究对象,提出了一种振动条件下的高实时性串联型故障电弧检测方法。首先通过构建滑动记忆矩阵对实验电流数据进行动态保存,其次通过正交方向改进局部三值化模式(orthogonality direction local ternary pattern,OD-LTP)提取滑动记忆矩阵的纹理特征,最终将统计的OD-LTP图像的灰度分布直方图幅值作为特征向量,通过基于沙猫群优化(sand cat swarm optimization,SCSO)的支持向量机(support vector machine,SVM)建立振动串联型故障电弧检测模型。本文通过对比不同矩阵参数,得到最佳的滑动记忆矩阵尺寸,最终所提方法对故障电弧识别的准确率达到99.2%。通过对不同工况、不同特征提取方法对比分析,表明本文提出方法不仅适用于不同工况运行的工业电机变频器系统,其相对于其他特征提取方法也具有较高的实时性。

Effects of Exposure to Aluminum on Long-term Potentiation and AMPA Receptor Subunits in Rats in vivo

Objective To explore the effects of exposure to aluminum （AI） on long-term potentiation （LTP） and AMPA receptor subunits in rats in vivo. Methods Different dosages of aluminum-maltolate complex [Al（mal）3] were given to rats via acute intracerebroventricular （i.c.v.） injection and subchronic intraperitoneal （i.p.） injection. Following AI exposure, the hippocampal LTP were recorded by field potentiation technique in vivo and the expression of AMPAR subunit proteins （GluR1 and GluR2） in both total and membrane-enriched extracts from the CA1 area of rat hippocampus were detected by Western blot assay. Results Acute AI treatment produced dose-dependent suppression of LTP in the rat hippocampus and dose-dependent decreases of GluRz and GluR2 in membrane extracts; however, no similar changes were found in the total cell extracts, which suggests decreased trafficking of AMPA receptor subunits from intracellular pools to synaptic sites in the hippocampus. The dose-dependent suppressive effects on LTP and the expression of AMPA receptor subunits both in the membrane and in total extracts were found after subchronic AI treatment, indicating a decrease in AMPA receptor subunit trafficking from intracellular pools to synaptic sites and an additional reduction in the expression of the subunits. Conclusion Al（mal）3 obviously and dose-dependently suppressed LTP in the rat hippocampal CA1 region in vivo, and this suppression may be related to both trafficking and decreases in the expression of AMPA receptor subunit proteins. However, the mechanisms underlying these observations need further investigation.

The RAS/PI3K Pathway is Involved in the Impairment of Long-term Potentiation Induced by Acute Aluminum Treatment in Rats

Objective To explore the role of RAS/PI3K pathway in the impairment of long-term potentiation （LTP） induced by acute aluminum （AI） treatment in rats in vivo. Methods First, different dosages of aluminum-maltolate complex [Al（mal）3] were given to rats via acute intracerebroventricular （i.c.v.） injection. Following AI exposure, the RAS activity of rat hippocampus were detected by ELISA assay after the hippocampal LTP recording by field potentiation technique in vivo. Second, the antagonism on the aluminum-induced suppression of hippocampal LTP was observed after the treatment of the RAS activator epidermal growth factor （EGF）. Finally, the antagonism on the downstream molecules （PKB activity and the phosphorylation of GluR1 $831 and $845） were tested by ELISA and West-blot assays at the same time. Results With the increasing aluminum dosage, a gradually decreasing in RAS activity of the rat hippocampus was produced after a gradually suppressing on LTP. The aluminum-induced early suppression of hippocampal LTP was antagonized by the RAS activator epidermal growth factor （EGF）. And the EGF treatment produced changes similar to those observed for LTP between the groups on PKB activity as well as the phosphorylation of GluR1 S831 and s845. Conclusion The RAS-PI3K/PKB-GluR1 S831 and S845 signal transduction pathway may be involved in the inhibition of hippocampal LTP by aluminum exposure in rats. However, the mechanisms underlying this observation need further investigation.

Active fraction combination from Liuwei Dihuang decoction(LW-AFC) ameliorates corticosterone-induced long-term potentiation impairment in mice in vivo

Liuwei Dihuang decoction(LW), a classic formula in traditional Chinese medicine(TCM), has been used for nearly one thousand years for various diseases with characteristic features of kidney yin deficiency. LW consists of 6herbs including Dihuang[prepared root of Rehmannia glutinosa(Gaertn) DC], Shanyao(rhizome of Dioscorea polystachya Turcz), Shanzhuyu(fruit of Cornus officinalis Siebold Zucc), Mudanpi(root bark of Paeonia × suffruticosa Andrews),Zexie(rhizome of Alisma plantago-aquatica L) and Fuling(scleorotia of Wolfiporia extensa(Peck) Ginns)LW-active fraction combination(LW-AFC) is extracted from LW, it is effective for the treatment of kidney yin deficiency in many animal models. There are 3 fractions in LW-AFC, a polysaccharide fraction(LWB-B), a glycoside fraction(LWD-b) and an oligosaccharide fraction(CA-30). Our previous results indicate that LW-AFC has similar pharmacological effects to LW, modulating the balance of the NIM network. LW-AFC has positive effects in many animal models of kidney deficiency or disturbance of the NIM network. LW-AFC could improve the cognitive ability in Alzheimer′s disease(AD) animal models(APP/PS1, SAMP8), where modulating immune function and balancing the NIM network may play an important role in its cognition improving effects. Our study also showed that LW-AFC had protective effects on stress-induced disturbances of the NIM network. However, the underlying mechanisms remain elusive and need further investigation. OBJECTIVE This study evaluated the effects of LW-AFC and the active fractions(polysaccharide, LWB-B;glycoside, LWD-b;oligosaccharide,CA-30) on corticosterone(Cort)-induced long-term potentiation(LTP) impairment in vivo. METHODS LTP was used to evaluate the synaptic plasticity. LW-AFC was orally administered for seven days. The active fractions were given by either chronic administration(ig, ip, 7 d) or single administration(icv, ig, ip). Cort was injected subcutaneously 1 h before the high-frequency stimulation(HFS) to induce LTP impairment. Moreover, in order to research on the possible effective pathways, an antibiotic cocktail and an immunosuppressant were also used. RESULTS Chronic administration(ig) of LW-AFC and its three active fractions could ameliorate Cort-induced LTP impairment. Single administration(icv, ig, ip) of any of the active fractions had no effect on Cort-induced LTP impairment, while chronic administration(ig, ip) of LWB-B or LWD-b showed positive effects against Cort. Interestingly, CA-30 only showed protective effects via ig administration,and there was little effect when CA-30 was administered ip In addition, when the intestinal microbiota was disrupted by application of the antibiotic cocktail, CA-30 showed little protective effects against Cort. The effects of LW-AFC were also abolished when the immune function was inhibited. In the hippocampal tissue, Cort treatment increased corticosterone and glutamate, and LW-AFC could inhibit the Cort-induced elevation of corticosterone and glutamate;there was little change in D-serine in Cort-treated animals, but LW-AFC could increase the D-serine levels. CONCLUSION LW-AFC and its three active fractions could ameliorate Cort-induced LTP impairment. Their protective effects are unlikely by a direct way, and immune modulation might be the common pathway. CA-30 could protect LTP from impairment via modulating the intestinal microbiota. Decreasing corticosterone and glutamate and increasing D-serine in the Cort-treated animals’ hippocampal tissue might be one of the mechanisms for the neural protective effects of LW-AFC. Further study is needed to understand the underlying mechanisms.

Electric stimulation at sciatic nerve evokes long-term potentiation of cornu dorsale medullae spinalis field potential in rats at various developmental phases

BACKGROUND： Long-term potentiation of cornu dorsale medullae spinalis field potential in adult rats has already been reported; however, there is lack of correlated researches on naenonate, infant and adult rats which have different responses to pain conduction information.OBJECTIVE： To observe the various effects of electric stimulation at sciatic nerve on long-term potentiation of evoked field potential at superficial layer of cornu dorsale medullae spinalis of rats at various developmental phases and analyze manifestations of pain conduction information at superficial layers （ Ⅰ - Ⅱ）of cornu dorsale medullae spinalis in immature rats.DESIGN： Grouping controlled study.SETTING： Department of Physiology, Medical College of Wuhan University.MATERIALS： The experiment was carried out in the Laboratory of Physiology （provincial laboratory）,Medical College of Wuhan University from March 2006 to May 2007. A total of 27 healthy male Sprague-Dawley （SD） rats, 17- 90 days old, SPF grade, weighing 41 -200 g, were provided by Experimental Animal Center, Medical College of Wuhan University.METHODS： Based on their birthdays, rats were divided into naenonate group （17 - 20 days old, weighing 41-52 g, n =10）, infant group （35 - 50 days old, weighing 87 - 125 g, n =10） and adult group （60 - 90 days old, weighing 180 -200 g, n =7）. Left sciatic nerve was separated and stimulated with single square wave （15 V, 0.5 ms）. Meanwhile, evoked field potential was recorded at superficial layers of lateral T13 - L1 cornu dorsale medullae spinalis and then stimulated with high-frequent and high-intensive tetanizing current （30 -40 V, 0.5 ms, 100 Hz, 1s per bundle, 10s in bundle interval） four times. After the operation, onset of long-term potentiation was observed; meanwhile, amplitude changes and latency of field potential were analyzed.MAIN OUTCOME MEASURES： Amplitude and latency changes of field potential at superficial layers of cornu dorsale medullae spinalis of rats in the three groups.RESULTS： A total of 27 accepted rats were involved in the final analysis. ① Amplitude changes： Electric stimulation at sciatic nerve with high-frequent and high-intensive tetanizing current could induce evoked field potential at superficial layers （Ⅰ-Ⅱ ） of cornu dorsale medullae spinalis in the three groups.Long-term potentiation in the naenonate group manifested that amplitude of A-kind never fiber was raised and there was significant difference （P〈0.05）. In addition, average amplitude was increased and there was obviously significant difference （P〈0.01）. Long-term potentiation in the infant group manifested that amplitude of C-kind never fiber was raised and there was significant difference （P〈0.01）; while, long-term potentiation in the adult group manifested that amplitude of C-kind never fiber was raised and there was significant difference （P〈0.01）. Otherwise, latencies in the three groups were all shortened. ② Latency changes： Average latency of A-kind nerve fiber in the naenonate group was shortened and there was significant difference （P〈0.01）; in addition, evoked potential of C-kind nerve fiber was low and latency was immovable. There was no significant difference before and after high-frequent and high-intensive electric stimulation （P〉0.05）. Average latency of C-kind nerve fiber in the infant group was shortened and there was significant difference （P〈0.01）; in addition, evoked potential of A-kind nerve fiber was stable and latency was immovable. There was no significant difference before and after high-frequent and high-intensive electric stimulation （P〉0.05）. Average latency of C-kind nerve fiber in the adult group was shortened and there was significant difference （P〈0.01）; in addition, evoked potential of A-kind nerve fiber was stable and latency was immovable. There was no significant difference before and after high-frequent and high-intensive electric stimulation.CONCLUSION： Evoked field potential at superficial layer of comu dorsale medullae spinalis can be recorded through electric stimulation at sciatic nerve. Single stimulation and tetanizing electric stimulation can cause different characteristics of evoked field potential in rats at various developmental phases.Superficial layer of cornu dorsale medullae spinalis of naenonate rats is mainly caused by A-kind nerve fiber which participants in pain conduction and formation of pain sensitivity; however, that of infant and adult rats mainly depends on C-kind nerve fiber.

Effect of Aluminum on Long-Term Potentiation and Its Relation to L-arg-No-pathway in Hippocampal CA3 Area of Rats

Experiments were performed on 64 Sprague-Dawley rats under ure-thane anesthesia. Extracellular recording method was used to investigate the effect of aluminum (Al)microinjected into CA3 on long-term potentiation (LTP) in this area. The relationship between the inhibitory effect of Al and L-arginine-NO pathway was also studied. Microinjection of Al (0. 5 mol/L, 1 μl ) into CA3 could block the induction of LTP in CA3. Microinjection of Al (0. 5 mol/L, 1 μl) into CA3 after LTP was induced could also decrease the amplitude of population spike (PS). The inhibitory effect of Al on LTP in CA3 could be enhanced by preinjection of NG-nitro-L-arginine (0. 3 mol/L, 1 μl). Preinjection of L-arginine (0. 3 mol/L, 1 μl) into CA3 could antagonize the inhibitory effect of Al on LTP. These results suggest that Al could block the induction of LTP and decrease the amplitude of PS potentiated in CA3. The effect of Al might be antagonized by L-arginine-NO pathway.

Long-term potentiation-based screening identifies neuronal PYGM as a synaptic plasticity regulator participating in Alzheimer's disease

Synaptic dysfunction is an important pathological hallmark and cause of Alzheimer's disease(AD).High-frequency stimulation(HFS)-induced long-term potentiation(LTP)has been widely used to study synaptic plasticity,with impaired LTP found to be associated with AD.However,the exact molecular mechanism underlying synaptic plasticity has yet to be completely elucidated.Whether genes regulating synaptic plasticity are altered in AD and contribute to disease onset also remains unclear.Herein,we induced LTP in the hippocampal CA1 region of wildtype(WT)and AD model mice by administering HFS to the CA3 region and then studied transcriptome changes in the CA1 region.We identified 89 genes that may participate in normal synaptic plasticity by screening HFS-induced differentially expressed genes(DEGs)in mice with normal LTP,and 43 genes that may contribute to synaptic dysfunction in AD by comparing HFS-induced DEGs in mice with normal LTP and AD mice with impaired LTP.We further refined the 43 genes down to 14 by screening for genes with altered expression in pathological-stage AD mice without HFS induction.Among them,we found that the expression of Pygm,which catabolizes glycogen,was also decreased in AD patients.We further demonstrated that down-regulation of PYGM in neurons impaired synaptic plasticity and cognition in WT mice,while its overexpression attenuated synaptic dysfunction and cognitive deficits in AD mice.Moreover,we showed that PYGM directly regulated energy generation in neurons.Our study not only indicates that PYGM-mediated energy production in neurons plays an important role in synaptic function,but also provides a novel LTP-based strategy to systematically identify genes regulating synaptic plasticity under physiological and pathological conditions.

PKMζ knockdown disrupts post-ischemic long-term potentiation via inhibiting postsynaptic expression of aminomethyl phosphonic acid receptors

Post-ischemic long-term potentiation （i-LTP） is a pathological form of plasticity that was observed in glutamate receptor-mediated neurotransmission after stroke and may exert a detrimental effect via facilitating excitotoxic damage. The mechanism underlying i-LTP, however, remains less understood. By employing electrophysiological recording and immunofluorescence assay on hippocampal slices and cultured neurons, we found that protein kinase M（（PKMζ）, an atypical protein kinase C isoform, was involved in enhancing aminomethyl phosphonic acid （AMPA） receptor （AMPAR） expression after i-LTP induction. PKMζ knockdown attenuated postsynaptic expression of AMPA receptors and disrupted i-LTP. Consistently, we observed less neuronal death of cultured hippocampal cells with PKMζ knockdown. Meanwhile, these findings indicate that PKMζ plays an important role in i-LTP by regulating postsynaptic expression of AMPA receptors. This work adds new knowledge to the mechanism of i-LTP, and thus is helpful to find the potential target for clinical therapy of ischemic stroke.

The mechanisms underlying long-term potentiation of C-fiber evoked field potentials in spinal dorsal horn

Long-term potentiation(LTP) of C-fiber evoked field potentials in spinal dorsal horn is first reported in 1995.Since then,the mechanisms underlying the long-lasting enhancement in synaptic transmission between primary afferent C-fibers and neurons in spinal dorsal horn have been investigated by different laboratories.In this article,the related data were summarized and discussed.

Correlating learning and memory improvements to long-term potentiation in patients with brain injury

BACKGROUND： Brain injury patients often exhibit learning and memory functional deficits. Long-term potentiation （LTP） is a representative index for studying learning and memory cellular models; the LTP index correlates to neural plasticity. OBJECTIVE： This study was designed to investigate correlations of learning and memory functions to LTP in brain injury patients, and to summarize the research advancements in mechanisms underlying brain functional improvements after rehabilitation intervention. RETRIEVAL STRATEGY： Using the terms ＂brain injuries, rehabilitation, learning and memory, long-term potentiation＂, manuscripts that were published from 2000-2007 were retrieved from the PubMed database. At the same time, manuscripts published from 2000-2007 were also retrieved from the Database of Chinese Scientific and Technical Periodicals with the same terms in the Chinese language. A total of 64 manuscripts were obtained and primarily screened. Inclusion criteria： studies on learning and memory, as well as LTP in brain injury patients, and studies focused on the effects of rehabilitation intervention on the two indices; studies that were recently published or in high-impact journals. Exclusion criteria： repetitive studies. LITERATURE EVALUATION： The included manuscripts primarily focused on correlations between learning and memory and LTP, the effects of brain injury on learning and memory, as well as LTP, and the effects of rehabilitation intervention on learning and memory after brain injury. The included 39 manuscripts were clinical, basic experimental, or review studies. DATA SYNTHESIS： Learning and memory closely correlates to LTP. The neurobiological basis of learning and memory is central nervous system plasticity, which involves neural networks, neural circuits, and synaptic connections, in particular, synaptic plasticity. LTP is considered to be an ideal model for studying synaptic plasticity, and it is also a classic model for studying neural plasticity of learning and memory. Brain injury patients clinically present with various manifestations, such as paralysis and sensory disability, which closely correlate to injured regions. In addition, learning and memory abilities decrease in brain injury patients and LTP decreases following brain injury. Brain tissue injury will lead to brain functional deficits. Hippocampal LTP is very sensitive. Difficulties in LTP induction are apparent even prior to morphological changes in brain tissue. There are no specific treatments for learning and memory functional deficits following brain injury. At present, behavioral and compensative therapies are the typical forms of rehabilitation. These results indicate that rehabilitation promotes learning and memory functional recovery in brain injury patients by speeding up LTP formation in the hippocampal CA3 region. CONCLUSION： Rehabilitation intervention increases LTP formation in the hippocampal CA3 region and recovers learning and memory functions in brain injury patients.

LW-AFC and its active components ameliorate corticosterone-induced long-term potentiation impairment in mice

OBJECTIVE LW-AFC is extracted from the classical traditional Chinese medicinal prescription-Liuwei Dihuang Decoction.Previous studies have showed that LW-AFC could improve learning&memory ability in amny animal models.In this study,we focused on evaluating the effect of several main active components fromLW-AFC(B-B;loganin,LOG;morroniside,MOR;paeoniflorin,PF and stachyose,STA)on LTP.METHODS In vivo recording of LTP was used in this study to evaluate the effects of LW-AFC and it′s active components on coticorsterone(Cort)induced LTP impairment.RESULTS The results showed that LW-AFC could ameliorate Cort-induced LTP impairment.The effect of LW-AFC was abolished when the immune function was inhibited.Single administration(ig,ip,icv)of any of the components had no effect on Cort-induced LTP impairment.Consecutively intragastric administration or intraperitoneal injections(chronic administration)of B-B,LOG,MOR or PF for 7 d showed protective effect on Cort-induced LTP impairment.Intragastric administration of STA for 7 d protected LTP from impairment induced by Cort,while there was little improving effect when STA was administrated via intraperitoneal injection.In addition,when the intestinal microbiota was disrupted by applying the antibiotic cocktail,STA showed little protective effect against Cort.CONCLUSION In conclusion,LW-AFC and it′s components showed positive effects against cort induced LTP impairment,it seems that all displayed protective effects via indirectly,immune modulation might be the common pathway for all components;the exact pathways are different in each component,B-B,LOG,MOR and PF could be absorbed into the bloods tream and then modulate the peripheral immune function,while STA could not be absorbed and modulates the immune function via modulating intestinal microbiota.Further studies are needed to invesgate the underlying mechanisms and the synergetic effects of all components.