Prolonged anesthesia alters brain synaptic architecture.

Prolonged medically induced coma (pMIC) is carried out routinely in intensive care medicine. pMIC leads to cognitive impairment, yet the underlying neuromorphological correlates are still unknown, as no direct studies of MIC exceeding ∼6 h on neural circuits exist. Here, we establish pMIC (up to 24 h) in adolescent and mature mice, and combine longitudinal two-photon imaging of cortical synapses with repeated behavioral object recognition assessments. We find that pMIC affects object recognition, and that it is associated with enhanced synaptic turnover, generated by enhanced synapse formation during pMIC, while the postanesthetic period is dominated by synaptic loss. Our results demonstrate major side effects of prolonged anesthesia on neural circuit structure.

Visual Agnosia Mimicking Memory Impairment: A Case Report of Posterior Cortical Atrophy.

Vision specialists will benefit from increased awareness of posterior cortical atrophy (PCA) syndrome. Failure to adequately identify the chief complaint as a visual symptom may lead to incorrect diagnosis or diagnostic delay. A previously healthy, 59-year-old woman presented with a 5-year history of 'losing her stuff'. Upon psychiatric and neuro-ophthalmological evaluation, this symptom was better recognised as a feature of visual agnosia and simultanagnosia. She also presented with multiple previously unrecognised symptoms indicative of higher visual processing dysfunction, such as alexia without agraphia, ocular motor apraxia, optic ataxia, prosopagnosia, akinetopsia and topographagnosia, so further assessment to investigate for PCA was carried out. After a work-up including cognitive assessment, brain structural/functional imaging, and laboratory tests she was diagnosed with visual-variant Alzheimer's disease. Patients with PCA merit a detailed review of their symptoms, as well as the use of office tests such as cognitive evaluation tools, different types of perimetry, colour vision tests, and non-delayed psychiatric consultation for correct management and assessment. This report will emphasise five key aspects to be considered when evaluating patients with PCA.

Multifunctionality of Clausena harmandiana Extract and Its Active Constituents against Alzheimer's Disease.

This study was designed to investigate the effects of the root-bark extract of Clausena harmandiana (CH) and its active constituents (nordentatin and 7-methoxyheptaphylline) on pharmacological activities regarding selected targets associated with AD, namely, its antioxidant activity, inhibition of Aß aggregation, acetylcholinesterase (AChE) activity, and neuroprotective effects. The effect of the CH extract on the cognitive impairment induced by scopolamine was also evaluated in mice. The effects of the CH extract and its active constituents on radical scavenging, Aß aggregation, and AChE activity were investigated with a 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) assay, a thioflavin-T assay, and Ellman's method. The neuroprotective effects of the extract against hydrogen-peroxide and Aß toxicity were evaluated with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. In addition, the effects on cognitive impairment induced by scopolamine in mice were evaluated using Morris-water-maze and modified-Y-maze test models. The results of the present study demonstrate that the root-bark extract of CH shows multimodal actions relevant to the AD pathological cascade, including antioxidant effects, the inhibition of Aß aggregation, the inhibition of AChE function, and neuroprotection against oxidative stress and Aß toxicity. The extracts could improve both the short- and long-term memory deficits induced by scopolamine in mice.

Genetic inhibition of PDK1 robustly reduces plaque deposition and ameliorates gliosis in the 5×FAD mouse model of Alzheimer's disease.

AIMS: Abundant recent evidence has shown that 3-phosphoinositide-dependent protein kinase 1 (PDK1) is activated in Alzheimer's disease (AD). However, it remains unknown whether inhibition of PDK1 in neurons may affect AD-like pathology in animal models of AD. Here, we aim to examine the effects of specific inactivation of neuronal PDK1 on pathology and behaviour in 5×FAD mice and to identify the underlying molecular mechanisms. METHODS: The Cre-loxP system was employed to generate Pdk1 cKO/5×FAD mice, in which PDK1 is inactivated in excitatory neurons in the adult forebrain. Cellular and behavioural techniques were used to examine plaque burden, inflammatory responses and spatial working memory in mice. Biochemical and molecular analyses were conducted to investigate relevant mechanisms. RESULTS: First, Aß deposition was massively decreased and gliosis was highly attenuated in Pdk1 cKO/5×FAD mice compared with 5×FAD mice. Second, memory deficits were significantly improved in Pdk1 cKO/5×FAD mice. Third, APP levels were notably decreased in Pdk1 cKO/5×FAD mice. Fourth, mammalian target of rapamycin (mTOR) signalling and ribosome biogenesis were reduced in Pdk1 cKO/5×FAD mice. CONCLUSIONS: Neuron-specific deletion of PDK1 robustly ameliorates AD-like pathology and improves spatial working memory in 5×FAD mice. We propose that genetic approach to inhibit PDK1 may be an effective strategy to slow AD.

Dietary omega-3 fatty acids prevent neonatal seizure-induced early alterations in the hippocampal glutamatergic system and memory deficits in adulthood.

OBJECTIVE: We investigated the influence of dietary omega-3 polyunsaturated fatty acids (n-3 PUFAs) on glutamatergic system modulation after a single episode of neonatal seizures and their possible effects on seizure-induced long-lasting behavioral deficits. METHODS: Male Wistar rats receiving an omega-3 diet (n-3) or an n-3 deficient diet (D) from the prenatal period were subjected to a kainate-induced seizure model at P7. Glutamate transporter activity and immunocontents (GLT-1 and GLAST) were assessed in the hippocampus at 12, 24, and 48 h after the seizure episode. Fluorescence intensity for glial cells (GFAP) and neurons (NeuN) was assessed 24 h after seizure in the hippocampus. Behavioral analysis (elevated-plus maze and inhibitory avoidance memory task) was performed at 60 days of age. RESULTS: The D group showed a decrease in glutamate uptake 24 h after seizure. In this group only, the GLT1 content increased at 12 h, followed by a decrease at 24 h. GLAST increased up to 24 h after seizure. GFAP fluorescence was higher, and NeuN fluorescence decreased, in the D group independent of seizures. In adulthood, the D group presented memory deficits independent of seizures, but short-term memory (1.5 h after a training session) was abolished in the D group treated with kainate. SIGNIFICANCE: N-3 PUFA positively influenced the glutamatergic system during seizure and prevented seizure-related memory deficits in adulthood.

Long-Term Effect of Porcine Brain Enzyme Hydrolysate Intake on Scopolamine-Induced Memory Impairment in Rats.

No study has revealed the effect of porcine brain enzyme hydrolysate (PBEH) on memory impairment. We aimed to examine the hypothesis that PBEH intake modulates memory deficits and cognitive behavior in scopolamine (SC)-induced amnesia rats, and its mechanism, including gut microbiota changes, was determined. Sprague-Dawley male rats had intraperitoneal injections of SC (2 mg/kg body weight/day) at 30 min after daily feeding of casein (MD-control), PBEH (7 mg total nitrogen/mL) at 0.053 mL (Low-PBEH), 0.159 mL (Medium-PBEH), 0.478 mL (High-PBEH), or 10 mg donepezil (Positive-control) per kilogram body weight per day through a feeding needle for six weeks. The Normal-control rats had casein feeding without SC injection. PBEH dose-dependently protected against memory deficits determined by passive avoidance test, Y-maze, water-maze, and novel object recognition test in SC-induced rats compared to the MD-control. The High-PBEH group had a similar memory function to the Positive-control group. Systemic insulin resistance determined by HOMA-IR was lower in the PBEH groups than in the Normal-control but not the Positive-control. In parallel with systemic insulin resistance, decreased cholesterol and increased glycogen contents in the hippocampus in the Medium-PBEH and High-PBEH represented reduced brain insulin resistance. PBEH intake prevented the increment of serum TNF-α and IL-1ß concentrations in the SC-injected rats. Hippocampal lipid peroxide and TNF-α contents and mRNA TNF-α and IL-1ß expression were dose-dependently reduced in PBEH and Positive-control. PBEH decreased the hippocampal acetylcholinesterase activity compared to the MD-control, but not as much as the Positive-control. PBEH intake increased the α-diversity of the gut microbiota compared to the MD-control, and the gut microbiota community was separated from MD-control. In metagenome function analysis, PBEH increased the energy metabolism-related pathways of the gut microbiota, including citric acid cycle, oxidative phosphorylation, glycolysis, and amino acid metabolism, which were lower in the MD-control than the Normal-control. In conclusion, alleviated memory deficit by PBEH was associated potentially with not only reducing acetylcholinesterase activity but also improving brain insulin resistance and neuroinflammation potentially through modulating gut microbiota. PBEH intake (1.5-4.5 mL of 7 mg total nitrogen/mL for human equivalent) can be a potential therapeutic agent for improving memory impairment.

Amelioration of oxidative stress, cholinergic dysfunction, and neuroinflammation in scopolamine-induced amnesic rats fed with pomegranate seed.

OBJECTIVE: This study aimed to investigate the effects of pomegranate (Punica granatum L.) seed hydro-ethanolic extract (PSE) on cholinergic dysfunction, neuroinflammation, and oxidative stress in the scopolamine-induced amnesic rats. METHODS: The rats were given PSE (200, 400, and 800 mg/kg, gavage) for 3 weeks. In the third week, scopolamine was administered 30 min before the Morris water maze (MWM) and passive avoidance (PA) tests. Oxidative stress indicators, acetylcholinesterase (AChE) activity, and mRNA expression of necrosis factor (TNF)-α, interleukin (IL)-1ß, AChE, and M1 acetylcholine receptor (CHRM1) in the brain, were measured. RESULTS: PSE reduced the time (maximum 173%) and distance (maximum 332%) required to reach the platform during MWM learning (P < 0.001). In the prob test (P < 0.001), it increased the target area time (maximum 44%) and distance (maximum 30%). PSE also increased delay and light time (maximums of 86 and 48%, respectively) (P < 0.001), while decreasing the time in dark region of PA (maximums 727%) (P < 0.001). PSE also reduced malondialdehyde and AChE in the cortex (maximum 168 and 171%, respectively) and hippocampus (maximum 151 and 182%, respectively) (P < 0.001). In the PSE-treated groups, the levels of thiol and superoxide dismutase were increased in the cortex (maximum 54 and 65%, respectively) and hippocampus (maximum 90 and 51%, respectively) (P < 0.001). TNF-α, IL-1ß, and AChE expressions in the hippocampus were reduced by PSE (maximum 114, 137, and 106%, respectively, P < 0.01). Meanwhile, CHMR expression was increased (66%). CONCLUSION: PSE successfully alleviated scopolamine-induced memory and learning deficits in rats which is probably via modulating cholinergic system function, oxidative stress, and inflammatory cytokines.

Effects of the Bark Resin Extract of Garcinia nigrolineata on Chronic Stress-Induced Memory Deficit in Mice Model and the In Vitro Monoamine Oxidases and ß-Amyloid Aggregation Inhibitory Activities of Its Prenylated Xanthone Constituents.

The present study describes investigation of the effects of the bark resin extract of Garcinia nigrolineata (Clusiaceae) on the cognitive function and the induction of oxidative stress in both frontal cortex and hippocampus by unpredictable chronic mild stress (UCMS). By using behavioral mouse models, i.e., the Y-maze test, the Novel Object Recognition Test (NORT), and the Morris Water Maze Test (MWMT), it was found that the negative impact of repeated mild stress-induced learning and memory deficit through brain oxidative stress in the UCMS mice was reversed by treatment with the bark resin extract G. nigrolineata. Moreover, the prenylated xanthones viz. cowagarcinone C, cowaxanthone, α-mangostin, cowaxanthone B, cowanin, fuscaxanthone A, fuscaxanthone B, xanthochymusxanthones A, 7-O-methylgarcinone E, and cowagarcinone A, isolated from the bark resin of G. nigrolineata, were assayed for their inhibitory activities against ß-amyloid (Aß) aggregation and monoamine oxidase enzymes (MAOs).

The Effects of Demographic Characteristics, Memory Deficits, and Executive Functioning Impairments in Failure to Respond to Fluvoxamine among Patients with Obsessive-Compulsive Disorder in Iran.

Background: Identifying treatment-response predictors could help improve treatment protocols as well as appropriately tailoring them to each subject, leading to a more desirable and accelerated recovery in patients. Thus, the present study aimed to investigate the role of demographic characteristics, memory deficits, and executive functioning impairments in failure to respond to fluvoxamine among patients with obsessive-compulsive disorder (OCD). Methods: This 2-group design (treatment-responsive and treatment-resistant) experimental study explored 76 participants who had received fluvoxamine monotherapy for OCD for ≥6 months. The study participants were from Iran. Four data collection tools were used in this study (ie, Demographic Data Form, WMS-III, WCST, and Y-BOCS). The achieved data were analyzed in SPSS-16 by descriptive statistics, such as mean and standard deviation and frequency and percentages, as well as an independent samples t-test, a chi-square test, and a Fisher exact test at P <0.05. Results: The present study findings indicated that 56 (81.2%) out of 76 patients with OCD responded to fluvoxamine treatment. A significant difference between the study groups highlighted age as an influential factor in providing a positive therapeutic response to fluvoxamine (P=0.048). However, the groups did not significantly differ in terms of gender (P=0.272), marital status (P=0.753), educational level (P=0.332), disease duration (P=0.276), and occupational status (P=0.473). While there was no significant difference between the groups (P=0.639) in terms of memory deficits (P=0.639), the response rate to fluvoxamine treatment was significantly higher in those with a healthy executive functioning, compared with patients with impairments in this respect (P=0.043). Conclusion: The obtained data suggested that fluvoxamine has a favorable efficacy in the treatment of OCD, and especially in young patients with healthy executive functioning.

Complement C3 mediates early hippocampal neurodegeneration and memory impairment in experimental multiple sclerosis.

Memory impairment is one of the disabling manifestations of multiple sclerosis (MS) possibly present from the early stages of the disease and for which there is no specific treatment. Hippocampal synaptic dysfunction and dendritic loss, associated with microglial activation, can underlie memory deficits, yet the molecular mechanisms driving such hippocampal neurodegeneration need to be elucidated. In early-stage experimental autoimmune encephalomyelitis (EAE) female mice, we assessed the expression level of molecules involved in microglia-neuron interactions within the dentate gyrus and found overexpression of genes of the complement pathway. Compared to sham immunized mice, the central element of the complement cascade, C3, showed the strongest and 10-fold upregulation, while there was no increase of downstream factors such as the terminal component C5. The combination of in situ hybridization with immunofluorescence showed that C3 transcripts were essentially produced by activated microglia. Pharmacological inhibition of C3 activity, by daily administration of rosmarinic acid, was sufficient to prevent early dendritic loss, microglia-mediated phagocytosis of synapses in the dentate gyrus, and memory impairment in EAE mice, while morphological markers of microglial activation were still observed. In line, when EAE was induced in C3 deficient mice (C3KO), dendrites and spines of the dentate gyrus as well as memory abilities were preserved. Altogether, these data highlight the central role of microglial C3 in early hippocampal neurodegeneration and memory impairment in EAE and, therefore, pave the way toward new neuroprotective strategies in MS to prevent cognitive deficit using complement inhibitors.

Alterations in neural oscillations related to working memory deficit in temporal lobe epilepsy.

OBJECTIVE: Working memory (WM) is critical for higher level cognition, but the underlying neural mechanisms are not fully understood. Impaired WM affects routine daily activities and is observed in patients with temporal lobe epilepsy (TLE). This study investigated neural oscillations associated with different WM phases, to determine the specific neural activity linked with the phases of WM impairment. METHODS: Patients with TLE (n = 52) and healthy volunteers (n = 35) completed a WM task, during which 34-channel electroencephalogram signals were recorded. Characteristic neural oscillation patterns during each WM phase were compared between the 2 groups. RESULTS: Patients with TLE showed decreased theta power during the encoding phase of WM, which was associated with reduced accuracy in the WM task. Altered theta power in the frontal region of the brain during the encoding phase was associated with a longer reaction time. CONCLUSIONS: Alterations in theta oscillation are related to WM impairment in patients with TLE and may serve as an early marker for evaluating WM deficits. SIGNIFICANCE: This study provides an early marker for evaluating WM deficits in TLE.

Folic acid attenuated learning and memory impairment via inhibition of oxidative damage and acetylcholinesterase activity in hypothyroid rats.

Hypothyroidism has been reported to be associated with cognitive decline. Considering the role of folic acid (FA) in cognitive performance, the present study was designed to investigate the effects of FA on hypothyroidism-induced cognitive impairment, oxidative damage, and alterations in acetylcholinesterase (AChE) activity in rat model of propylthiouracil (PTU)-induced hypothyroidism. In this study, PTU (0.05% in drinking water) and FA (5, 10, and 15 mg/kg, oral gavage) were administered for the rats during 7 weeks. Then, behavioral performance was tested using Morris water maze (MWM) and passive avoidance (PA) tasks. Finally, oxidative stress indicators and AChE activity were assayed in the brain tissues. The impairing effect of hypothyroidism on cognitive performance was markedly alleviated by FA especially at higher doses. In the MWM test, FA reduced escape latency and travelled distance, compared to the non-treated hypothyroid group. In the PA test, latency to enter dark chamber was significantly enhanced by FA compared to the non-treated hypothyroid group (p < 0.05-p < 0.001). Besides, FA attenuated AChE activity and malondialdehyde level but it increased activity of superoxide dismutase enzyme and total thiol content (p < 0.05-p < 0.001). In conclusion, our findings revealed that FA could improve learning and memory ability in hypothyroid rats. The observed protective effects may have been mediated through regulation of oxidative stress and AChE activity.

Punicalagin effect on total sleep deprivation memory deficit in male Wistar rats.

Sleep deprivation has deteriorating effects on cognitive functions and activation of brain inflammation mechanisms has been reported by some studies following total sleep deprivation. Some studies have reported the health benefits of punicalagin, a main abstract from Punica granatum L., including those for the treatment of Alzheimer's disease. The antioxidant characteristic of punicalagin and the fact that sleep deprivation accelerates mediators of inflammation led us to further explore the possible neuroprotective role of punicalagin in total sleep deprivation memory impairment in a rat model. In this study, male Wistar rats were implanted with a canula in the lateral ventricle to receive intracerebroventricular injections (drug or vehicle). The animals were trained for the passive avoidance test and then received intracerebroventricular injections of different doses of punicalagin (0.001, 0.01, or 0.1 µg/rat). Then, they were placed in the sleep deprivation apparatus for 24 hours and tested afterwards for memory retrieval and locomotion. Our results indicated that 24 hours of total sleep deprivation impaired memory processes. PG microinjection before TSD did not prevent the deteriorating effect of total sleep deprivation on memory, and only showed a tendency of restoring the memory impairment. Comparison of the locomotor activity between the animals in different groups showed a significant increase in the total sleep deprivation sham groups that received two of the highest doses of punicalagin. Considering the reported beneficial actions of PG by other studies, further investigation is needed into the possible effects of PG in memory alterations.

Neuroprotective Effect and Antioxidant Potency of Fermented Cultured Wild Ginseng Root Extracts of Panax ginseng C.A. Meyer in Mice.

Wild ginseng has better pharmacological effects than cultivated ginseng. However, its industrialization is limited by the inability to grow wild ginseng on a large scale. Herein, we demonstrate how to optimize ginseng production through cultivation, and how to enhance the concentrations of specific ginsenosides through fermentation. In the study, we also evaluated the ability of fermented cultured wild ginseng root extract (HLJG0701-ß) to inhibit acetylcholinesterase (AChE), as well as its neuroprotective effects and antioxidant activity. In invitro tests, HLJG0701-ß inhibited AChE activity and exerted neuroprotective and antioxidant effects (showing increased catalyst activity but decreased reactive oxygen species concentration). In invivo tests, after HLJG0701-ß was orally administered at doses of 0, 125, 250, and 500 mg/kg in an animal model of memory impairment, behavioral evaluation (Morris water maze test and Y-maze task test) was performed. The levels of AChE, acetylcholine (ACh), blood catalase (CAT), and malondialdehyde (MDA) in brain tissues were measured. The results showed that HLJG0701-ß produced the best results at a dose of 250 mg/kg or more. The neuroprotective mechanism of HLJG0701-ß was determined to involve the inhibition of AChE activity and a decrease in oxidative stress. In summary, both invitro and invivo tests confirmed that HJG0701-ß administration can lead to memory improvement.

Effect of different parietal hypoperfusion on neuropsychological characteristics in mild cognitive impairment.

BACKGROUND: In early-stage amnestic mild cognitive impairment (aMCI), differences in the neuropsychological characteristics of each individual are subtle. We investigated differences in neuropsychological performance between aMCI patients with and without hypoperfusion in the medial parietal regions (MP). We further compared patients with hypoperfusion in the left and right lateral parietal regions. METHODS: We examined 165 aMCI patients (mean age: 76.8 ± 5.5 years; 87 women) who had undergone neuropsychological measurement and single-photon emission computed tomography. We classified participants into two subgroups with and without hypoperfusion: MP hypoperfusion (+) and MP hypoperfusion (-); classification was based on Z-scores (calculated by three-dimensional stereotactic surface projection technique) of three regions of interest in the parietal lobes (i.e. MP regions including posterior cingulate cortex and precuneus and left and right inferior parietal lobules (lateral parietal regions)). The MP hypoperfusion (-) group was classified into left lateral parietal hypoperfusion (+) and right lateral parietal hypoperfusion (+) subgroups. We performed either univariate or multivariate ancova to compare neuropsychological scores for continuous variables between groups and examined dichotomous variables using χ2 tests. RESULTS: In the overall aMCI sample, scores on logical memory delayed recall in the MP hypoperfusion (+) group were significantly lower than those in the MP hypoperfusion (-) group. Total scores on Rey-Osterrieth Complex Figure Test delayed recall were also marginally lower in the MP hypoperfusion (+) group than in the MP hypoperfusion (-) group. Comparisons of neuropsychological test scores between the left and right lateral parietal hypoperfusion (+) groups revealed no significant differences. CONCLUSIONS: The present findings suggest that MP hypoperfusion (+) is associated with more robust memory deficits than MP hypoperfusion (-). Combining neuropsychological tests and single-photon emission computed tomography findings may be useful for early detection of cognitive decline in aMCI.

Drebrin expression patterns in patients with refractory temporal lobe epilepsy and hippocampal sclerosis.

OBJECTIVE: Drebrins are crucial for synaptic function and dendritic spine development, remodeling, and maintenance. In temporal lobe epilepsy (TLE) patients, a significant hippocampal synaptic reorganization occurs, and synaptic reorganization has been associated with hippocampal hyperexcitability. This study aimed to evaluate, in TLE patients, the hippocampal expression of drebrin using immunohistochemistry with DAS2 or M2F6 antibodies that recognize adult (drebrin A) or adult and embryonic (pan-drebrin) isoforms, respectively. METHODS: Hippocampal sections from drug-resistant TLE patients with hippocampal sclerosis (HS; TLE, n = 33), of whom 31 presented with type 1 HS and two with type 2 HS, and autopsy control cases (n = 20) were assayed by immunohistochemistry and evaluated for neuron density, and drebrin A and pan-drebrin expression. Double-labeling immunofluorescences were performed to localize drebrin A-positive spines in dendrites (MAP2), and to evaluate whether drebrin colocalizes with inhibitory (GAD65) and excitatory (VGlut1) presynaptic markers. RESULTS: Compared to controls, TLE patients had increased pan-drebrin in all hippocampal subfields and increased drebrin A-immunopositive area in all hippocampal subfields but CA1. Drebrin-positive spine density followed the same pattern as total drebrin quantification. Confocal microscopy indicated juxtaposition of drebrin-positive spines with VGlut1-positive puncta, but not with GAD65-positive puncta. Drebrin expression in the dentate gyrus of TLE cases was associated negatively with seizure frequency and positively with verbal memory. TLE patients with lower drebrin-immunopositive area in inner molecular layer (IML) than in outer molecular layer (OML) had a lower seizure frequency than those with higher or comparable drebrin-immunopositive area in IML compared with OML. SIGNIFICANCE: Our results suggest that changes in drebrin-positive spines and drebrin expression in the dentate gyrus of TLE patients are associated with lower seizure frequency, more preserved verbal memory, and a better postsurgical outcome.

Icariin Ameliorates Amyloid Pathologies by Maintaining Homeostasis of Autophagic Systems in Aß1-42-Injected Rats.

Macroautophagy, a sole pathway for dysfunctional organelles or aggregated proteins turnover, has been implicated in the early development of Alzheimer's disease (AD). Previous studies have found that reversal of autophagy dysfunction in APP transgenic mice ameliorates amyloid pathologies. Icariin (ICA), the main component from traditional Chinese herb Epimedium brevicornu Maxim., can reduce accumulations of amyloid-ß (Aß) peptide in vivo and in vitro, but the mechanism remains unclear. Here, we explored the effects of ICA on autophagy-lysosomal pathway in intracerebroventricular (icv) injection of human Aß1-42 peptide rats. We demonstrated that feeding the rats with ICA (30 mg/kg, 60 mg/kg and 90 mg/kg rat, per os) for 4 weeks rescued the Aß1-42-induced spatial memory impairments, reduced endogenous rat Aß42 tested by ELISA and decreased Aß accumulation using 6E10 antibody. Furthermore, Aß1-42 induced strong autophagy response, however ICA decreased the levels of microtubule-associated protein 1 light chain 3 (LC3) II/LC3I, Beclin1, Cathepsin D (Cat D) and brain lysosomal Cathepsin D activity. We also observed that ICA enhanced the phosphorylation of protein kinase B (PKB/AKT) and p70 ribosomal protein S6 kinase (p70S6K). In addition, ICA arrested Aß1-42-induced cells loss, mitochondrias damage, nuclear membranes unclear and abundant nucleas chromatin agglutinates in hippocampus, lessened the expression of Cleaved-caspase-3, brain oxidative stress, astroglial activation. These findings suggest that ICA can ameliorate amyloid pathologies with improving autophagy-lysosome function and Chinese materia medica may be potential for AD treatment.

Donepezil Attenuates Obesity-Associated Oxidative Stress and Central Inflammation and Improves Memory Deficit in Mice Fed a High-Fat Diet.

BACKGROUND/AIMS: Obesity is associated with chronic inflammation and cognitive decline, and is considered a major risk factor for neurodegeneration. Meanwhile, neuroinflammation is important in the pathogenesis and progression of neurodegenerative diseases. METHODS: In this study, we tested the hypothesis that donepezil would attenuate central inflammation and oxidative damage and improve memory deficit in high-fat diet (HFD)-fed mice. After 16 weeks on a HFD, C57BL/6J mice were given either donepezil (3 mg/kg, i.p.) or saline for 4 weeks in parallel to a control diet (CD) group. Thereafter, the step-through test was used to assess learning and memory function. RESULTS: In the brain of HFD-fed mice, levels of the proinflammatory cytokines interleukin 16 and tumor necrosis factor α were reduced by donepezil treatment. Similarly, HFD-induced protein levels of advanced glycation end-products and oxidative stress in the brain were significantly decreased by donepezil treatment. CONCLUSION: Our results indicate that donepezil may reverse obesity-related central inflammation and oxidative damage and improve memory deficit in HFD-fed mice.

TNF-α Differentially Regulates Synaptic Plasticity in the Hippocampus and Spinal Cord by Microglia-Dependent Mechanisms after Peripheral Nerve Injury.

Clinical studies show that chronic pain is accompanied by memory deficits and reduction in hippocampal volume. Experimental studies show that spared nerve injury (SNI) of the sciatic nerve induces long-term potentiation (LTP) at C-fiber synapses in spinal dorsal horn, but impairs LTP in the hippocampus. The opposite changes may contribute to neuropathic pain and memory deficits, respectively. However, the cellular and molecular mechanisms underlying the functional synaptic changes are unclear. Here, we show that the dendrite lengths and spine densities are reduced significantly in hippocampal CA1 pyramidal neurons, but increased in spinal neurokinin-1-positive neurons in mice after SNI, indicating that the excitatory synaptic connectivity is reduced in hippocampus but enhanced in spinal dorsal horn in this neuropathic pain model. Mechanistically, tumor necrosis factor-alpha (TNF-α) is upregulated in bilateral hippocampus and in ipsilateral spinal dorsal horn, whereas brain-derived neurotrophic factor (BDNF) is decreased in the hippocampus but increased in the ipsilateral spinal dorsal horn after SNI. Importantly, the SNI-induced opposite changes in synaptic connectivity and BDNF expression are prevented by genetic deletion of TNF receptor 1 in vivo and are mimicked by TNF-α in cultured slices. Furthermore, SNI activated microglia in both spinal dorsal horn and hippocampus; pharmacological inhibition or genetic ablation of microglia prevented the region-dependent synaptic changes, neuropathic pain, and memory deficits induced by SNI. The data suggest that neuropathic pain involves different structural synaptic alterations in spinal and hippocampal neurons that are mediated by overproduction of TNF-α and microglial activation and may underlie chronic pain and memory deficits. SIGNIFICANCE STATEMENT: Chronic pain is often accompanied by memory deficits. Previous studies have shown that peripheral nerve injury produces both neuropathic pain and memory deficits and induces long-term potentiation (LTP) at C-fiber synapses in spinal dorsal horn (SDH) but inhibits LTP in hippocampus. The opposite changes in synaptic plasticity may contribute to chronic pain and memory deficits, respectively. However, the structural and molecular bases of these alterations of synaptic plasticity are unclear. Here, we show that the complexity of excitatory synaptic connectivity and brain-derived neurotrophic factor (BDNF) expression are enhanced in SDH but reduced in the hippocampus in neuropathic pain and the opposite changes depend on tumor necrosis factor-alpha/tumor necrosis factor receptor 1 signaling and microglial activation. The region-dependent synaptic alterations may underlie chronic neuropathic pain and memory deficits induced by peripheral nerve injury.

GPR30 activation improves memory and facilitates DHPG-induced LTD in the hippocampal CA3 of middle-aged mice.

Reduced estrogen levels and decreased expression of related receptors are typical cerebral features of aging. The G protein-coupled estrogen receptor 1 (GPER1, also known as GPR30) is considered a novel therapeutic target for neurodegenerative diseases. In this study, we demonstrated that hippocampal GPR30 expression was reduced in middle-aged mice compared with young adult mice. GPR30 agonist G1 improved both fear and spatial memory in both male and female middle-aged mice, but not in young adult mice, which were blocked by the GPR30 antagonist G15. Interestingly, a group I metabotropic glutamate receptor (mGluR) agonist, 3,5-dihydroxyphenylglycine (DHPG)-induced long-term depression (LTD) in mossy fiber-cornu ammonis 3 (MF-CA3) synapses but not Schaffer collateral-CA1 (SC-CA1) synapses was facilitated in brain slices from G1-treated middle-aged mice. Long-term potentiation (LTP) in SC-CA1 synapses was not affected in slices from G1-treated mice. The effects of GPR30 activation on memory and DHPG-LTD in MF-CA3 synapses were further confirmed by viral expression of GPR30 in the CA3. The regulation of hippocampal synaptic plasticity by G1 treatment might be related to brain-derived neurotrophic factor (BDNF)-tropomyosin receptor kinase B (TrkB) signaling, as G15 also blocked G1-induced activation of the BDNF-TrkB pathway. Moreover, we found that DHPG triggered GluA internalization in slices from G1-treated mice but not control mice. Pharmacological experiments showed that G1-mediated facilitation of DHPG-induced LTD in MF-CA3 synapses was dependent on protein kinase B (Akt), mammalian target of rapamycin (mTor), and TrkB signaling. In conclusion, our results indicate that GPR30 activation improves memory in middle-aged mice, likely through facilitating synaptic plasticity in the CA3. This study provides novel evidence that GPR30 activation can improve memory in middle-aged animals.