Clinical outcomes and prognostic factors for patients with high-risk gastrointestinal stromal tumors treated with 3-year adjuvant imatinib.

Three years of adjuvant imatinib is the current standard for patients with high-risk gastrointestinal stromal tumors (GIST). We aimed to investigate the safety and efficacy profiles of 3-year imatinib, focusing on the prognostic value of various factors. In this registry-based study, 222 patients with high-risk GIST who underwent surgical resection followed by 3 years of adjuvant imatinib between 2010 and 2018 were included. The imatinib dose was reduced in 39 (17.6%), and 13 (5.9%) discontinued imatinib due to toxicity. With a median follow-up duration of 65.7 months, 5-year recurrence-free survival (RFS) and overall survival (OS) were 73.2% and 93.9%, respectively. Tumor rupture, tumor size of >10 cm, mitotic index of >10/50 high power fields (HPF) were independent factors for short RFS. Patient subgroups stratified by the risk factors showed distinct RFS (P < .001): patients without the above risk factors or those with only a tumor size of >10 cm showed favorable RFS (5-year RFS 83.8% and 92.3%, respectively), whereas those with tumor rupture or those with tumor size of >10 cm and mitotic index of >10/50 HPF showed prominently poor RFS (5-year RFS of 54.8% and 47.9%, respectively). Three years of adjuvant imatinib treatment was generally tolerable and effective, which were consistent with the clinical outcomes of previous reports. The presence of tumor rupture, large tumor and high mitotic count was independently associated with poor RFS. Based on these risk factors, different management strategies, such as different durations of adjuvant imatinib, deserve further investigation.

Prognostic value of natural killer cell activity for patients with HER2 + advanced gastric cancer treated with first-line fluoropyrimidine-platinum doublet plus trastuzumab.

BACKGROUND: We aimed to evaluate the prognostic value of natural killer (NK) cell activity for patients with HER2 + advanced gastric cancer (AGC) treated with first-line fluoropyrimidine-platinum doublet plus trastuzumab. METHODS: Forty-one patients with HER2 + AGC who received fluoropyrimidine-platinum doublet plus trastuzumab as first-line treatment were prospectively enrolled. NK cell activity was evaluated using the NK Vue®. RESULTS: The median age was 63.5 years, and 31 patients (75.6%) were male. Patients with low baseline NK cell activity (≤ median, n = 21) were associated worse progression-free survival (PFS) and overall survival (OS) compared with patients with high baseline NK cell activity (> median, n = 20) with a median PFS of 4.21 vs. 9.53 months (P < 0.001), and median OS of 8.15 months vs. 17.82 months (P = 0.025), respectively. In the multivariate analysis, low baseline NK cell activity was independently associated with poor PFS (HR 4.35, P = 0.007). NK cell activity recovered to a normal range in nine patients (47.4%) with a low baseline NK cell activity (n = 19) after two cycles of treatment. The median PFS and OS among patients with recovered NK cell activity were significantly better than that among patients with persistently low NK cell activity (PFS, P = 0.038; OS, P = 0.003). CONCLUSION: Our results demonstrated the prognostic value of baseline NK cell activity for patients with HER2 + AGC treated with fluoropyrimidine-platinum doublet plus trastuzumab. The association between treatment outcomes and dynamic changes in NK cell activity suggests that NK cell treatment may improve treatment outcomes, especially for patients with low baseline NK cell activity.

Functions of the Signal Transducer and Activator of Transcription 6 in a Behavioral Animal Model of Depression.

AIMS: Depression is one of the most common inflammatory and mental disorders. Signal transducer and activator of transcription 6 (STAT6) plays a crucial role in the pathology of mental disorders as well as inflammatory diseases. METHODS: Here we determined the role of STAT6 in the pathogenesis of depression using STAT6-deficient mice in a forced swimming test. RESULTS: The immobility time was significantly decreased in STAT6-deficient mice compared to wild-type mice without alteration of locomotor activity. STAT6-deficient mice exhibited a significantly enhancing dopamine and 5-hydroxytryptamine (5-HT, serotonin) in brain. In addition, the expression of serotonin transporter in the hippocampus was markedly downregulated in STAT6-deficient mice. These results provide the first evidence that STAT6 affects depressive-like behavior through downregulating monoamines, including dopamine and 5-HT in the hippocampus of brain. CONCLUSIONS: In conclusion, identification of STAT6 signaling pathways on depression might open new perspectives for antidepressant therapies.

Cognitive Ameliorating Effect of Acanthopanax koreanum Against Scopolamine-Induced Memory Impairment in Mice.

Acanthopanax koreanum Nakai (Araliaceae) is one of the most widely cultivated medicinal plants in Jeju Island, Korea, and the roots and stem bark of A. koreanum have been traditionally used as a tonic agent for general weakness. However, the use of A. koreanum for general weakness observed in the elderly, including those with declined cognitive function, has not been intensively investigated. This study was performed to investigate the effect of the ethanol extract of A. koreanum (EEAK) on cholinergic blockade-induced memory impairment in mice. To evaluate the ameliorating effects of EEAK against scopolamine-induced memory impairment, mice were orally administered EEAK (25, 50, 100, or 200 mg/kg), and several behavioral tasks, including a passive avoidance task, the Y-maze, and a novel object recognition task, were employed. Besides, western blot analysis was conducted to examine whether EEAK affected memory-associated signaling molecules, such as protein kinase B (Akt), Ca2+ /calmodulin-dependent protein kinase II (CaMKII), and cAMP response element-binding protein (CREB). The administration of EEAK (100 or 200 mg/kg, p.o.) significantly ameliorated the scopolamine-induced cognitive impairment in the passive avoidance task, the Y-maze, and the novel object recognition task. The phosphorylation levels of both Akt and CaMKII were significantly increased by approximately two-fold compared with the control group because of the administration of EEAK (100 or 200 mg/kg) (p < 0.05). Moreover, the phosphorylation level of CREB was also significantly increased compared with the control group by the administration of EEAK (200 mg/kg) (p < 0.05). The present study suggests that EEAK ameliorates the cognitive dysfunction induced by the cholinergic blockade, in part, via several memory-associated signaling molecules and may hold therapeutic potential against cognitive dysfunction, such as that presented in neurodegenerative diseases, for example, Alzheimer's disease. Copyright © 2017 John Wiley & Sons, Ltd.

4-Hydroxybenzyl methyl ether improves learning and memory in mice via the activation of dopamine D1 receptor signaling.

The phenolic compound 4-hydroxybenzyl methyl ether (HBME) is isolated from Gastrodia elata Blume (Orchidaceae). In the present study, we investigated the effect of HBME on three stages of memory (acquisition, consolidation, and retrieval) using the step-through passive avoidance task. HBME was administered at 3 time points; 1 h before the acquisition trial, immediately after the acquisition trial, and 1h before the retention trial, respectively. HBME (10 mg/kg, p.o.) markedly increased the step-through latency compared with the vehicle-treated control at all stages of memory. To clarify the mechanism of the memory-enhancing effect of HBME, an antagonism study and Western blot analysis were performed. The enhancing effects of HBME on each phase were reversed by the sub-effective dose of the dopamine D1 receptor antagonist SCH23390 (0.0125 mg/kg, s.c.), or the protein kinase A (PKA) antagonist H-89 (0.25 mg/kg, i.p.). In addition, the administration of HBME (10 mg/kg, p.o.) significantly increased the phosphorylation of the cortical and hippocampal PKA/cAMP response element-binding protein (CREB), and was reversed by the co-administration of SCH23390. HBME (10 mg/kg, p.o.) also ameliorated the memory impairment induced by SCH23390 or scopolamine. Taken together, these results suggest that the effect of HBME on cognitive functions may be partly involved in dopaminergic neurotransmitter signaling and that HBME could be a potential therapeutic agent for treating the cognitive dysfunction induced by dopaminergic or cholinergic neurotransmitter system deficits.

Nodakenin Enhances Cognitive Function and Adult Hippocampal Neurogenesis in Mice.

In our previous study, we demonstrated that nodakenin, a coumarin compound isolated from Angelica decursiva, ameliorates learning and memory impairments induced by scopolamine. In the present study, we investigated the effects of nodakenin on the cognitive function in the normal naïve mice in a passive avoidance task, and the results showed that nodakenin significantly increased the latency time in normal naïve mice. In addition, sub-chronic administration of nodakenin increased the number of 5-bromo-2-deoxyuridine (BrdU)-positive cells in the hippocampal dentate gyrus (DG) region. The percentage of BrdU and NeuN (neuronal cell marker)-immunopositive cells was also significantly increased by the nodakenin administration. Western blotting results showed that the expression levels of phosphorylated protein kinase B (Akt) and phosphorylated glycogen synthase kinase-3ß (GSK-3ß) were significantly increased in hippocampal tissue by sub-chronic nodakenin administration. These findings suggest that the sub-chronic administration of nodakenin enhances adult hippocampal neurogenesis in the DG region via Akt-GSK-3ß signaling and this increase may be associated with nodakenin's positive effect on cognitive processing.

Standardized Prunella vulgaris var. lilacina Extract Enhances Cognitive Performance in Normal Naive Mice.

Adult hippocampal neurogenesis is closely associated with neuronal plasticity, cognitive function and the etiology of neurological diseases. We previously reported that the standardized ethanolic extract of Prunella vulgaris var. lilacina (EEPV) can be used for the prevention and treatment of cognitive impairments associated with Alzheimer's disease or schizophrenia. In the present study, we investigated the effects of EEPV on cognitive ability in normal naive mice and the underlying mechanism(s) governing these effects, including adult hippocampal neurogenesis. In the passive avoidance task, sub-chronic administration of EEPV (25 or 50 mg/kg, p.o.) for 14 days markedly induced the improvement of cognitive function in mice. In addition, sub-chronic administration of EEPV (25 or 50 mg/kg) for 14 days significantly increased neural cell proliferation and the number of immature neurons, but not newly generated cell survival, in the hippocampal dentate gyrus. Increased ERK, Akt and GSK-3ß phosphorylation levels in the hippocampus were also observed after such administration. Our results indicate that EEPV may enhance cognitive function via the activation of various intracellular signaling molecules and the up-regulation of adult hippocampal neurogenesis.

Amyrin attenuates scopolamine-induced cognitive impairment in mice.

Alzheimer's disease, a neurodegenerative disorder, is characterized by progressive cognitive impairment associated with the disruption of cholinergic neurotransmission. The aim of the present study was to evaluate the effect of α- or ß-amyrin, a type of pentacyclic triterpene, on the cognitive impairment induced by scopolamine, a muscarinic acetylcholine receptor antagonist. To measure the abilities of various types of learning and memory, we conducted step-through passive avoidance task. Scopolamine induced deficits in learning and memory processes in mice, which were antagonized by a single administration of α-amyrin (2 or 4 mg/kg) or ß-amyrin (4 mg/kg), respectively. Additionally, in vitro analysis revealed that acetylcholinesterase activity was inhibited by ß-amyrin, but not by α-amyrin. Furthermore, Western blot analysis revealed that the expression levels of phosphorylated extracellular signal-regulated kinase 1/2 (pERK) and phosphorylated glycogen synthase kinase-3ß (pGSK-3ß) were significantly enhanced by a single administration of α- and ß-amyrin in the hippocampus. Finally, the memory ameliorating effects of α- or ß-amyrin on the scopolamine-induced cognitive impairments were significantly blocked by ERK inhibitor U0126. The present study suggests that α- and ß-amyrin may ameliorate the cognitive impairment induced by hypocholinergic neurotransmission via the activation of ERK as well as GSK-3ß signaling.

Danggui-Jakyak-San ameliorates memory impairment and increase neurogenesis induced by transient forebrain ischemia in mice.

BACKGROUND: Danggui-Jakyak-San (DJS), a traditional herbal prescription, has been used to treat insufficient blood supplies. Recently, regenerative medication for the treatment of cerebral ischemia has drawn the attention of many researchers. METHODS: In this study, we examined whether DJS exerts a neuronal regenerative effect in the hippocampus of a transient forebrain ischemia mice model. Transient forebrain ischemia was induced by bilateral common carotid artery occlusion (BCCAO). Animals were divided into three groups (sham, BCCAO + vehicle, and BCCAO + DJS). To test the effect of DJS on learning and memory, Morris water maze or passive avoidance test was conducted. To test neuroprotective and neurogenic effect, immunohistochemistry and Western blot analysis were used. Statistical significance was analyzed with Student t-test, one-way or two-way analysis of variance. RESULTS: We found that the administration of DJS ameliorated ischemia-induced spatial memory impairment in the Morris water maze task. Moreover, Akt/glycogen synthase kinase-3ß (GSK3ß)/ß-catenin signaling was increased by DJS, which would be one possible mechanism of DJS for neurogenesis in the hippocampal dentate gyrus region. CONCLUSIONS: These results suggest that DJS is a possible candidate for the treatment of ischemia-induced neuronal degeneration.

Prunella vulgaris attenuates prepulse inhibition deficit and attention disruption induced by MK-801 in mice.

Prunella vulgaris var. lilacina is widely distributed in Korea, Japan, China, and Europe, and it has been traditionally used to treat inflammation or hypertension. In the present study, we investigated the effects of the ethanolic extract of the spikes of Prunella vulgaris var. lilacina (EEPV) on dizocilpine (MK-801)-induced schizophrenia-like phenotype behaviors such as the disruption of prepulse inhibition and attention deficits in mice. We also determined the effect of EEPV on MK-801-induced alterations in phosphorylated extracellular signal-regulated kinase, phosphorylated protein kinase B, phospho-glycogen synthase kinase 3-ß, and phosphorylated cAMP response element-binding protein levels in the cortex and hippocampus of mice. MK-801-induced prepulse inhibition deficits were ameliorated by the administration of EEPV, as shown in the acoustic startle response test. Furthermore, EEPV attenuated the MK-801-induced attention deficits in the water finding test. We also found that EEPV attenuated the increased phosphorylated extracellular signal-regulated kinase, phosphorylated protein kinase B, or phospho-glycogen synthase kinase 3-ß levels induced by MK-801 in the cortex but not in the hippocampus. These results suggest that EEPV could be useful for treating schizophrenia because EEPV ameliorates prepulse inhibition disruption and attention deficits induced by MK-801.

Adjuvant Imatinib Treatment for 5 Years versus 3 Years in Patients with Ruptured Localized Gastrointestinal Stromal Tumor: A Retrospective Analysis.

PURPOSE: Three years of adjuvant imatinib is the standard treatment for resected gastrointestinal stromal tumors (GISTs) with rupture, but the recurrence rate is prominently high. We aimed to investigate the efficacy and safety of 5-year adjuvant imatinib compared with 3-year treatment in patients with a ruptured GIST following surgical resection. MATERIALS AND METHODS: A total of 51 patients were included in the analysis. The assessment of GIST rupture was based on Nishida's classification. Twenty patients who were diagnosed before November 2013 were treated with 5 years of imatinib, and 31 patients who were diagnosed after November 2013 were treated with 3 years of imatinib. We retrospectively compared the clinical outcomes of the two groups. RESULTS: Baseline characteristics and the incidence of the adverse events were generally comparable between the two groups. During a median follow-up duration of 43.8 months and 104.2 months in the 3- and 5-year group, 8 and 9 patients had a disease recurrence, respectively. The 5-year group showed better recurrence-free survival (RFS) than the 3-year group. In multivariate analysis, low mitotic index was a significant independent favorable prognostic factor for RFS, while 5-year imatinib treatment was marginally associated with a favorable RFS. CONCLUSION: Five years of adjuvant imatinib treatment in patients with ruptured GIST was associated with favorable survival outcomes with manageable toxicity profiles. Our findings warrant validation and confirmation in future studies.

The memory ameliorating effects of DHP1402, an herbal mixture, on cholinergic blockade-induced cognitive dysfunction in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: The seeds of Ziziphus jujuba var. spinosa (Bunge) Hu ex H.F Chow (Rhamnaceae) and the roots of Codonopsis lanceolata (Siedbold & Zucc.) Benth. & Hook. f ex Trautv. (Campanulaceae), contained in the DHP1402, have long been used for treating dementia or hypomnesia as folk medicine. AIM OF THE STUDY: It has been reported that Z. jujuba var. spinosa and C. lanceolata are effective in improving cognitive function, but via different mechanisms. Therefore, in the present study, we evaluated the synergistic effects of Z. jujuba var. spinosa and C. lanceolata on scopolamine-induced memory impairment. MATERIALS AND METHODS: Scopolamine, a cholinergic muscarinic receptor antagonist, was used to induce cognitive dysfunction. We employed several behavioral tasks to estimate the synergistic effect of the seeds of Z. jujuba var. spinosa and the roots of C. lanceolata. In addition, we introduced the Western blotting, the antagonism passive avoidance task to investigate a synergistic effect of an herbal formulation. RESULTS: Synergistic effects of a combination of Z. jujuba var. spinosa and C. lanceolata at a 5:1 ratio [(w/w), DHP1402] were observed against cognitive dysfunction in the passive avoidance and Y-maze tasks. DHP1402 also ameliorated memory deficits in a dose-dependent manner in these behavioral tasks, as well as in the Morris water maze task. According to the Western blot results, the phosphorylation levels of protein kinase A (PKA), extracellular signal-regulated kinase (ERK) and cAMP response element-binding protein (CREB) in the hippocampus were also increased in a synergistic manner after the administration of DHP1402. In addition, we found that the effects of DHP1402 on cognitive function were mediated by N-methyl-D-aspartate (NMDA) receptor signalling, based on the antagonism studies. Furthermore, we found that DHP1402 has inhibitory activity against acetylcholinesterase (AChE). CONCLUSION: DHP1402 attenuates cholinergic blockade-induced cognitive dysfunction through NMDA receptor modulation, PKA-ERK-CREB pathway activation, and AChE inhibition. Therefore, DHP1402 could be a candidate for alleviating cognitive dysfunction.

Oleanolic acid ameliorates cognitive dysfunction caused by cholinergic blockade via TrkB-dependent BDNF signaling.

Oleanolic acid is a naturally occurring triterpenoid and is widely present in food and medicinal plants. To examine the effect of oleanolic acid on memory deficits, we employed a cholinergic blockade-induced cognitive deficit mouse model. A single administration of oleanolic acid significantly increased the latency on the passive avoidance task and affected the alternation behavior on the Y-maze task and the exploration time on the novel object recognition task, indicating that oleanolic acid reverses the cognitive impairment induced by scopolamine. In accordance with previous reports, oleanolic acid enhanced extracellular-signal-regulated kinase 1/2 (ERK1/2) and cAMP response element-binding protein (CREB) phosphorylation and brain-derived neurotrophic factor (BDNF) expression in the hippocampus. Interestingly, ameliorating effect of oleanolic acid on scopolamine-induced memory impairment was abolished by N2-(2-{[(2-oxoazepan-3-yl)amino]carbonyl}phenyl)benzo[b]thiophene-2-carboxamide (ANA-12), a potent and specific inhibitor of tropomyosin receptor kinase B (TrkB), in the passive avoidance task. Similarly, oleanolic acid significantly evoked long-term potentiation in a dose-dependent manner, which was diminished by ANA-12 treatment as shown in the electrophysiology study. Together, these results imply that oleanolic acid ameliorates scopolamine-induced memory impairment by modulating the BDNF-ERK1/2-CREB pathway through TrkB activation in mice, suggesting that oleanolic acid would be a potential therapeutic agent for the treatment of cognitive deficits.

Swertisin ameliorates pre-pulse inhibition deficits and cognitive impairment induced by MK-801 in mice.

Swertisin, a plant-derived C-glucosylflavone, is known to have antidiabetic, anti-inflammatory and antioxidant effects. In the present study, we investigated in mice the effects of swertisin on glutamatergic dysfunction induced by dizocilpine (MK-801), a non-competitive N-methyl-D-aspartate receptor antagonist. In the Acoustic Startle Response test, their MK-801-induced (given 0.2 mg/kg i.p.) pre-pulse inhibition deficit was significantly attenuated by the administration of swertisin (30 mg/kg p.o.). In the Novel Object Recognition Test, the recognition memory impairments that were induced by MK-801 (0.2 mg/kg, given i.p.) were also reversed by administration of swertisin (30 mg/kg p.o.). In addition, swertisin normalized the MK-801-induced elevation of phosphorylation levels of Akt and GSK-3ß signaling molecules in the prefrontal cortex. These results indicated that swertisin may be useful in managing the symptoms of schizophrenia, including sensorimotor gating disruption and cognitive impairment, and that these behavioral outcomes may be related to Akt-GSK-3ß signaling in the prefrontal cortex.

Spinosin, a C-glycoside flavonoid, enhances cognitive performance and adult hippocampal neurogenesis in mice.

Adult neurogenesis has received much attention due to its potential role in neurological or psychiatric disorders such as Alzheimer's disease. In the present study, we examined whether spinosin, a C-glycoside flavonoid from the seeds of Zizyphus jujuba var. spinosa, affects cognitive performance and adult hippocampal neurogenesis in normal naïve mice. The subchronic administration of spinosin (5mg/kg) for 14days significantly increased the latency time in the passive avoidance task. Doublecortin and 5-bromo-2-deoxyuridine immunostaining revealed that the subchronic administration of spinosin (5mg/kg) significantly increased the proliferation and survival of neuronal cells and the number of immature neurons in the hippocampal dentate gyrus region. In addition, we observed an increase in the percentage of BrdU-incorporated cells co-localized with NeuN, a mature neuronal marker, which indicated that spinosin stimulates the differentiation of newly generated cells into mature neurons. Also, the subchronic treatment with spinosin (5mg/kg) increased the expression levels of phosphorylated extracellular-regulated kinase (ERK), phosphorylated cAMP response element-binding protein (CREB) and mature brain-derived neurotrophic factor (mBDNF) in the hippocampus. These findings demonstrate that spinosin has the potential for therapeutic use in treating the cognitive dysfunction observed in neurological or psychiatric disorders by up-regulating adult hippocampal neurogenesis or activating of the ERK-CREB-BDNF signaling pathway.

The memory-enhancing effect of erucic acid on scopolamine-induced cognitive impairment in mice.

Erucic acid is a monounsaturated omega-9 fatty acid isolated from the seed of Raphanus sativus L. that is known to normalize the accumulation of very long chain fatty acids in the brains of patients suffering from X-linked adrenoleukodystrophy. Here, we investigated whether erucic acid enhanced cognitive function or ameliorated scopolamine-induced memory impairment using the passive avoidance, Y-maze and Morris water maze tasks. Erucic acid (3mg/kg, p.o.) enhanced memory performance in normal naïve mice. In addition, erucic acid (3mg/kg, p.o.) ameliorated scopolamine-induced memory impairment, as assessed via the behavioral tasks. We then investigated the underlying mechanism of the memory-enhancing effect of erucic acid. The administration of erucic acid increased the phosphorylation levels of phosphatidylinositide 3-kinase (PI3K), protein kinase C zeta (PKCζ), extracellular signal-regulated kinase (ERK), cAMP response element-binding protein (CREB) and additional protein kinase B (Akt) in the hippocampus. These results suggest that erucic acid has an ameliorative effect in mice with scopolamine-induced memory deficits and that the effect of erucic acid is partially due to the activation of PI3K-PKCζ-ERK-CREB signaling as well as an increase in phosphorylated Akt in the hippocampus. Therefore, erucic acid may be a novel therapeutic agent for diseases associated with cognitive deficits, such as Alzheimer's disease.

Swertisin, a C-glucosylflavone, ameliorates scopolamine-induced memory impairment in mice with its adenosine A1 receptor antagonistic property.

Swertisin, a C-glucosylflavone isolated from Swertia japonica, has been known to have anti-inflammatory or antidiabetic activities. Until yet, however, its cognitive function is not investigated. In the present study, we endeavored to elucidate the effects of swertisin on cholinergic blockade-induced memory impairment. Swertisin (5 or 10mg/kg, p.o.) significantly ameliorated scopolamine-induced cognitive impairment in the several behavioral tasks. Also, single administration of swertisin (10mg/kg, p.o.) in normal naïve mice enhanced the latency time in the passive avoidance task. In addition, the ameliorating effect of swertisin on scopolamine-induced memory impairment was significantly antagonized by a sub-effective dose of N6-cyclopentyladenosine (CPA, 0.1mg/kg, i.p). The adenosine A1 receptor antagonistic property of swertisin was confirmed by receptor binding assay. Furthermore, the administration of swertisin significantly increased the phosphorylation levels of hippocampal or cortical protein kinase A (PKA, 5 or 10mg/kg) and CREB (10mg/kg), and co-administration of CPA (0.1mg/kg, i.p) blocked the increased phosphorylated levels of PKA and CREB in the both cortex and hippocampus. Taken together, these results indicate that the memory-ameliorating effects of swertisin may be, in part, mediated through the adenosinergic neurotransmitter system, and that swertisin may be useful for the treatment of cognitive dysfunction observed in several diseases such as Alzheimer's disease.

Exogenous insulin-like growth factor 2 administration enhances memory consolidation and persistence in a time-dependent manner.

Memory consolidation is an important process for the formation of long-term memory. We have previously reported that mature brain-derived neurotrophic factor enhances memory consolidation within 9h after initial learning. Recent studies suggest that insulin-like growth factor 2 (IGF2) significantly enhances memory consolidation and prevents forgetting. Thus, we hypothesized that IGF2 exerts its activity on cognitive performance in a time-dependent manner as observed in our previous study. In the one-trial step-through inhibitory avoidance task, we demonstrate that a bilateral injection of IGF2 into the dorsal hippocampus 6 or 9 h after training significantly enhanced the step-through latencies compared with the vehicle-treated controls in the retention trial, which was conducted 24 h after the acquisition trial. However, 12h post-training, IGF2 injection did not increase the step-through latencies. Intriguingly, in the retention trial at 21 days after the training, hippocampal IGF2 injection 6, 9 or 12 h after the acquisition trial significantly increased the step-through latencies compared with the vehicle-treated controls. IGF2 administration at 9 h and 12 h after the acquisition trial significantly increased discrimination index and exploration time on the novel-located object in the test trial at 24 h and 21 days, respectively, after the acquisition trial in the novel location recognition task. In addition, IGF2-induced an increase in the step-through latencies in the retention trial 24 h or 21 days, respectively, after the initial learning was completely abolished by co-injected anti-IGF2 receptor antibody. These results suggest that IGF2 enhances memory consolidation within 9h after initial learning, and increased IGF2 within the 12 h after the acquisition trial, which represents a delayed consolidation phase, is also critical for memory persistence.

Pretreatment with 5-hydroxymethyl-2-furaldehyde blocks scopolamine-induced learning deficit in contextual and spatial memory in male mice.

5-Hydroxymethyl-2-furaldehyde (5-HMF) is a compound derived from the dehydration of certain sugars. The aim of the present study was to evaluate the effect of 5-HMF on the cognitive impairment induced by scopolamine, a muscarinic receptor antagonist. To measure various cognitive functions, we conducted the step-through passive avoidance task, the Y-maze task and the Morris water maze task. A single administration of 5-HMF (5 or 10mg/kg, p.o.) significantly attenuates scopolamine-induced cognitive impairment in these behavioral tasks without changes in locomotor activity, and the effect of 5-HMF on scopolamine-induced cognitive impairment was significantly reversed by a sub-effective dose of MK-801, an NMDA receptor antagonist. In addition, a single administration of 5-HMF (10mg/kg, p.o.) enhanced the cognitive performance of normal naïve mice in the passive avoidance task. Furthermore, Western blot analysis revealed that the levels of phosphorylated Ca(2+)/calmodulin-dependent protein kinase II-α (CaMKII) and extracellular signal-regulated kinases (ERK) were significantly enhanced by the single administration of 5-HMF in the hippocampal tissues. Taken together, the present study suggests that 5-HMF may block scopolamine-induced learning deficit and enhance cognitive function via the activation of NMDA receptor signaling, including CaMKII and ERK, and would be an effective candidate against cognitive disorders, such as Alzheimer's disease.

Spinosin, a C-Glucosylflavone, from Zizyphus jujuba var. spinosa Ameliorates Aß1-42 Oligomer-Induced Memory Impairment in Mice.

Alzheimer's disease (AD) is a neurodegenerative disorder associated with progressive memory loss and neuronal cell death. Although numerous previous studies have been focused on disease progression or reverse pathological symptoms, therapeutic strategies for AD are limited. Alternatively, the identification of traditional herbal medicines or their active compounds has received much attention. The aims of the present study were to characterize the ameliorating effects of spinosin, a C-glucosylflavone isolated from Zizyphus jujuba var. spinosa, on memory impairment or the pathological changes induced through amyloid-ß1-42 oligomer (AßO) in mice. Memory impairment was induced by intracerebroventricular injection of AßO (50 µM) and spinosin (5, 10, and 20 mg/kg) was administered for 7 days. In the behavioral tasks, the subchronic administration of spinosin (20 mg/kg, p.o.) significantly ameliorated AßO-induced cognitive impairment in the passive avoidance task or the Y-maze task. To identify the effects of spinosin on the pathological changes induced through AßO, immunohistochemistry and Western blot analyses were performed. Spinosin treatment also reduced the number of activated microglia and astrocytes observed after AßO injection. In addition, spinosin rescued the AßO-induced decrease in choline acetyltransferase expression levels. These results suggest that spinosin ameliorated memory impairment induced through AßO, and these effects were regulated, in part, through neuroprotective activity via the anti-inflammatory effects of spinosin. Therefore, spinosin might be a useful agent against the amyloid b protein-induced cognitive dysfunction observed in AD patients.