Ameliorative effects of endurance training and Matricaria chamomilla flowers hydroethanolic extract on cognitive deficit in type 2 diabetes rats.

Diabetes mellitus is mainly associated with degeneration of the central nervous system, which eventually leads to cognitive deficit. Although some studies suggest that exercise can improve the cognitive decline associated with diabetes, the potential effects of endurance training (ET) accompanied by Matricaria chamomilla (M.ch) flowers extract on cognitive impairment in type 2 diabetes has been poorly understood. Forty male Wistar rats were randomized into 5 equal groups of 8: healthy-sedentary (H-sed), diabetes-sedentary (D-sed), diabetes-endurance training (D-ET), diabetes-Matricaria chamomilla. (D-M.ch), and diabetes-endurance training-Matricaria chamomilla. (D-ET-M.ch). Nicotinamide (110 mg/kg, i.p.) and Streptozotocin (65 mg/kg, i.p.) were utilized to initiate type 2 diabetes. Then, ET (5 days/week) and M.ch (200 mg/kg body weight/daily) were administered for 12 weeks. After 12 weeks of the experiment, cognitive functions were assessed using the Morris Water Maze (MWM) test and a passive avoidance paradigm using a shuttle box device. Subsequently, using crystal violet staining, neuron necrosis was examined in the CA3 area of the hippocampus. Diabetic rats showed cognitive impairment following an increase in the number of necrotic cells in region CA3 of the hippocampal tissue. Also, diabetes increased serum levels of lipid peroxidation and decreased total antioxidant capacity in serum and hippocampal tissue. ET + M.ch treatment prevented the necrosis of neurons in the hippocampal tissue. Following positive changes in hippocampal tissue and serum antioxidant enzyme levels, an improvement was observed in the cognitive impairment of the diabetic rats receiving ET + M.ch. Therefore the results showed that treatment with ET + M.ch could ameliorate memory and inactive avoidance in diabetic rats. Hence, the use of ET + M.ch interventions is proposed as a new therapeutic perspective on the death of hippocampal neurons and cognitive deficit caused by diabetes.

Crocin attenuates the granular cells damages on the dentate gyrus and pyramidal neurons in the CA3 regions of the hippocampus and frontal cortex in the rat model of Alzheimer's disease.

Amyloid ß-peptides (Aß) are considered as a major hallmark of Alzheimer's disease (AD) that can induce synaptic loss and apoptosis in brain regions, particularly in the cortex and the hippocampus. Evidence suggests that crocin, as the major component of saffron, can exhibit neuromodulatory effects in AD. However, specific data related to their efficacy to attenuate the synaptic loss and neuronal death in animal models of AD are limited. Hence, we investigated the efficacy of crocin in the CA3 and dentate gyrus (DG) regions of the hippocampus and also in frontal cortex neurons employing a rat model of AD. Male Wistar rats were randomly divided into control, sham, AD model, crocin, and AD model + crocin groups, with 8 rats per group. AD model was established by injecting Aß1-42 into the frontal cortex rats, and thereafter the rats were administrated by crocin (30 mg/kg) for a duration of 12-day. The number of live cells, neuronal arborization and apoptosis were measured using a Cresyl violet, Golgi-Cox and TUNEL staining, respectively. Results showed that, the number of live cells in the hippocampus pyramidal neurons in the CA3 and granular cells in the DG regions of the AD rats significantly decreased, which was significantly rescued by crocin. Compared with the control group, the axonal, spine and dendrites arborization in the frontal cortex and CA3 region of the AD model group significantly decreased. The crocin could significantly reverse this arborization loss in the AD rats (P < 0.05). The apoptotic cell number in the CA3 and DG regions in the AD model group was significantly higher than that of the control group (P < 0.05), while crocin significantly decreased the apoptotic cell number in the AD group (P < 0.05). Conclusion. Crocin can improve the synaptic loss and neuronal death of the AD rats possibly by reducing the neuronal apoptosis.

Hyperoside alleviates epilepsy-induced neuronal damage by enhancing antioxidant levels and reducing autophagy.

ETHNOPHARMACOLOGICAL RELEVANCE: Hypericum perforatum L. (genus Hypericum, family Hypericaceae), a plant commonly used in traditional Chinese medicine, is believed to confer a wide range of benefits, including fever reduction, detoxification, calming, and pain relief via decoctions of its stems and leaves. Hyperoside (HYP), a natural compound extracted from Hypericum perforatum L., has been shown to demonstrate a wide array of bioactivities including antioxidative, anti-inflammatory, and anti-apoptotic effects. In this study, we investigated the effects of HYP on epilepsy-induced neuronal damage in mice and the associated regulatory factors. AIM OF THE STUDY: This study examined the potential therapeutic use of HYP for the treatment of neuronal damage in a mouse model of epilepsy and explored the relationships of the potential neuroprotective effects of HYP pretreatment with antioxidant levels and autophagy. MATERIALS AND METHODS: ICR mice were randomly divided into six groups: sham group, sham-HYP group, KA group, KA-HYP group, KA-HYP-DDC group and KA-CQ group. Immunohistochemical staining was used to assess changes in NeuN, IBA-1, and GFAP expression in the CA3 region of the hippocampus. Immunofluorescence staining was used to assess the effects of HYP on the number of autophagosomes that accumulated in neurons in the hippocampal CA3 region. The levels of SOD1, SOD2, LC3I/II, Beclin1, and PI3K/AKT and MAPK signaling-related proteins were detected by Western blot. RESULTS: Pretreatment with 50 mg/kg HYP protected against epilepsy-induced neuronal damage in the hippocampal CA3 region. Additionally, HYP enhanced antioxidant levels and reduced the levels of autophagy-related proteins via the PI3K/AKT and MAPK pathways. CONCLUSION: HYP protected the hippocampal CA3 region against epilepsy-induced neuronal damage via enhancing antioxidant levels and reducing autophagy. The mechanism of action may be related to the maintenance of antioxidant levels and the suppression of autophagy via the PI3K/Akt and MAPK pathways.

Holistic Recollection via Pattern Completion Involves Hippocampal Subfield CA3.

Episodic memories typically comprise multiple elements. A defining characteristic of episodic retrieval is holistic recollection, i.e., comprehensive recall of the elements a memorized event encompasses. A recent study implicated activity in the human hippocampus with holistic recollection of multi-element events based on cues (Horner et al., 2015). Here, we obtained ultra-high resolution functional neuroimaging data at 7 tesla in 30 younger adults (12 female) using the same paradigm. In accordance with anatomically inspired computational models and animal research, we found that metabolic activity in hippocampal subfield CA3 (but less pronounced in dentate gyrus) correlated with this form of mnemonic pattern completion across participants. Our study provides the first evidence in humans for a strong involvement of hippocampal subfield CA3 in holistic recollection via pattern completion.SIGNIFICANCE STATEMENT Memories of daily events usually involve multiple elements, although a single element can be sufficient to prompt recollection of the whole event. Such holistic recollection is thought to require reactivation of brain activity representing the full event from one event element ("pattern completion"). Computational and animal models suggest that mnemonic pattern completion is accomplished in a specific subregion of the hippocampus called CA3, but empirical evidence in humans was lacking. Here, we leverage the ultra-high resolution of 7 tesla neuroimaging to provide first evidence for a strong involvement of the human CA3 in holistic recollection of multi-element events via pattern completion.

Ginkgo biloba treatments reverse the impairment of conditioned suppression acquisition induced by GluN2B-NMDA and 5-HT1A receptor blockade: Modulatory effects of the circuitry of the dorsal hippocampal formation.

To improve our understanding of the effects of standardized extract of Ginkgo biloba (EGb) as a cognitive enhancer, we investigated the conditioned lick suppression-induced expression (mRNA and protein) of the GluN2B-containing N-methyl-D-aspartic acid receptor (GluN2B-NMDAR), serotonin (5-HT) 1A receptor (5-HT1AR), gamma-aminobutyric acid type A receptor (GABAAR) and glial fibrillary acidic protein (GFAP) in the dorsal hippocampal formation (dHF) of untreated and EGb-treated (0.25, 0.5 and 1.0 g.kg-1) groups of rats. To substantiate our data, we analysed the molecular changes in dHF following treatment with vehicle, with agonists or antagonists of GABAAR, GluN2B-NMDAR and 5-HT1AR or with one of these antagonists prior to EGb and fear memory acquisition. Additionally, we performed a pharmacological analysis of the drug-receptor-receptor interactions and their supplemental role in fear memory by blocking individual receptors and analysed the possible changes in expression level with each of the other receptors in the study as well as astrocytes. Our data show for the first time that EGb treatment not only upregulated GluN2B, GABAAR-α5, and GFAP compared with the control but also differentially upregulated GABAAR-α1 in the dHF and 5HT1AR in the CA3. We found that the activation of GABAARs (diazepam) and the inactivation of GluN2B-NMDARs (Ro25-6981) or 5-HT1AR ((S)-WAY100135) resulted in memory impairment. Further, higher doses of EGb treatment reversed the effect of blocking GluN2B (P < 0.001) and 5-HT1AR (P < 0.001). Here, treatment with Ro25-6981 + EGb or (S)-WAY100135 + EGb prevented the impairment of the acquisition of lick suppression in association with the upregulation or prevention of the downregulation of Grin2b expression as well as the expression of GluN2B-NMDA and/or α1 and α5 subunit-containing GABAAR in the CA1 (P < 0.0001). Our data are in line with previous findings concerning the necessity of GluN2B for fear memory formation and add to the current knowledge of the role of the GABAAR-α1 and -α5 subunits and of GluN2B as a target of cognitive enhancers. Furthermore, our data show that these receptors play a complementary role in controlling the neural circuitry in the dHF that seems to be essential to conditioned lick suppression and the modulatory effects of EGb.

Loss of function of NCOR1 and NCOR2 impairs memory through a novel GABAergic hypothalamus-CA3 projection.

Nuclear receptor corepressor 1 (NCOR1) and NCOR2 (also known as SMRT) regulate gene expression by activating histone deacetylase 3 through their deacetylase activation domain (DAD). We show that mice with DAD knock-in mutations have memory deficits, reduced anxiety levels, and reduced social interactions. Mice with NCOR1 and NORC2 depletion specifically in GABAergic neurons (NS-V mice) recapitulated the memory deficits and had reduced GABAA receptor subunit α2 (GABRA2) expression in lateral hypothalamus GABAergic (LHGABA) neurons. This was associated with LHGABA neuron hyperexcitability and impaired hippocampal long-term potentiation, through a monosynaptic LHGABA to CA3GABA projection. Optogenetic activation of this projection caused memory deficits, whereas targeted manipulation of LHGABA or CA3GABA neuron activity reversed memory deficits in NS-V mice. We describe de novo variants in NCOR1, NCOR2 or HDAC3 in patients with intellectual disability or neurodevelopmental disorders. These findings identify a hypothalamus-hippocampus projection that may link endocrine signals with synaptic plasticity through NCOR-mediated regulation of GABA signaling.

Protective effect of compound Danshen (Salvia miltiorrhiza) dripping pills alone and in combination with carbamazepine on kainic acid-induced temporal lobe epilepsy and cognitive impairment in rats.

CONTEXT: Temporal lobe epilepsy (TLE) is resistant to antiepileptic drugs (AEDs) and is associated with cognitive impairment. The modern Chinese medicine, compound Danshen dripping pills (CDDP), is clinically effective in treating epilepsy and improving cognitive impairment. OBJECTIVE: This study evaluated the protective effects of CDDP alone and in combination with carbamazepine (CBZ) on kainic acid-induced TLE and cognitive impairment in rats. MATERIALS AND METHODS: Sprague-Dawley rats were randomly divided into five groups: control (sham operated), model, CDDP, CBZ and combined. A TLE model was then created via bilateral intrahippocampal injection of 0.35 µg kainic acid (KA). Rats received CDDP (85 mg/kg), CBZ (100 mg/kg) or combined (85 mg/kg CDDP +100 mg/kg CBZ) via intragastric administration for 90 d, respectively. Seizure intensity, apoptosis and glial cell line-derived neurotrophic factor (GDNF) were measured. Furthermore, the improvement in cognitive impairment and hippocampal neuronal damage was evaluated. RESULTS: CDDP combined with CBZ significantly decreased seizure severity and frequency (p < 0.05) and ameliorated cognitive impairment (p < 0.05). The model group showed a significant reduction of neurons and Bcl-2/Bax expression in the hippocampus CA3 area (p < 0.01), the combined groups significantly reversed these change (p < 0.01). GDNF expression in the combined groups showed a clear increase over the model group (p < 0.05). CONCLUSION: These findings support the use of CDDP as an adjuvant drug for the treatment of TLE and cognitive deficit. Its mechanism might be related to an anti-apoptosis effect and up-regulation of GDNF.

Chrysophanol Relieves Cognition Deficits and Neuronal Loss Through Inhibition of Inflammation in Diabetic Mice.

Patients with diabetes mellitus are easy to experience diabetic encephalopathy (DE) and other cognition dysfunction, whereas the neural alterations in developing this disease are unknown yet. Chrysophanol (CHR) is one of traditional Chinese medicine which was reported to show protective effects in cognition dysfunction and inflammatory in previously studies. In this current study, whether CHR protects learning and memory dysfunctions induced by diabetes disease or not and underlying mechanisms were studied. DE model was induced by streptozotocin (STZ, i.p.) in ICR mice. CHR was administrated 3 days after STZ treated mice which was confirmed with diabetes for consecutive 6 days. Learning and memory function was tested by Morris water maze after the CHR injection. The morphology of neuronal cells in hippocampus CA3 region was stained by HE-staining. ELISA and Western blot assay were used to determine the levels of pro-inflammation cytokines (IL-1ß, IL-4, IL-6, TNF-α) in hippocampus. Here, we demonstrated that mice harboring diabetes mellitus induced by STZ exhibit high blood glucose, learning and memory deficits detected by Morris water maze behavior tests. Application with CHR right after developing diabetes disease rescues partial blood sugar increasing, learning and memory deficits. The data also indicated that the death rate of neurons and the number of astrocytes in hippocampus CA3 region was significantly improved in diabetic mice. Moreover, the underlying mechanisms of CHR's protective effect are likely associated with anti-inflammation by downregulating the expression of pro-inflammation cytokines (IL-1ß, IL-4, IL-6, TNF-α) in hippocampus and inhibiting the over-activation of astrocytes in hippocampus CA3 region. Therefore, application with CHR contributes to the learning and memory deficits induced by diabetes disease via inhibitory expressions of inflammatory in hippocampus region.

Temporal analysis of hippocampal CA3 gene coexpression networks in a rat model of febrile seizures.

Complex febrile seizures during infancy constitute an important risk factor for development of epilepsy. However, little is known about the alterations induced by febrile seizures that make the brain susceptible to epileptic activity. In this context, the use of animal models of hyperthermic seizures (HS) could allow the temporal analysis of brain molecular changes that arise after febrile seizures. Here, we investigated temporal changes in hippocampal gene coexpression networks during the development of rats submitted to HS. Total RNA samples were obtained from the ventral hippocampal CA3 region at four time points after HS at postnatal day (P) 11 and later used for gene expression profiling. Temporal endpoints were selected for investigating the acute (P12), latent (P30 and P60) and chronic (P120) stages of the HS model. A weighted gene coexpression network analysis was used to characterize modules of coexpressed genes, as these modules might contain genes with similar functions. The transcriptome analysis pipeline consisted of building gene coexpression networks, identifying network modules and hubs, performing gene-trait correlations and examining changes in module connectivity. Modules were functionally enriched to identify functions associated with HS. Our data showed that HS induce changes in developmental, cell adhesion and immune pathways, such as Wnt, Hippo, Notch, Jak-Stat and Mapk. Interestingly, modules involved in cell adhesion, neuronal differentiation and synaptic transmission were activated as early as 1 day after HS. These results suggest that HS trigger transcriptional alterations that could lead to persistent neurogenesis, tissue remodeling and inflammation in the CA3 hippocampus, making the brain prone to epileptic activity.

Afferent specific role of NMDA receptors for the circuit integration of hippocampal neurogliaform cells.

Appropriate integration of GABAergic interneurons into nascent cortical circuits is critical for ensuring normal information processing within the brain. Network and cognitive deficits associated with neurological disorders, such as schizophrenia, that result from NMDA receptor-hypofunction have been mainly attributed to dysfunction of parvalbumin-expressing interneurons that paradoxically express low levels of synaptic NMDA receptors. Here, we reveal that throughout postnatal development, thalamic, and entorhinal cortical inputs onto hippocampal neurogliaform cells are characterized by a large NMDA receptor-mediated component. This NMDA receptor-signaling is prerequisite for developmental programs ultimately responsible for the appropriate long-range AMPAR-mediated recruitment of neurogliaform cells. In contrast, AMPAR-mediated input at local Schaffer-collateral synapses on neurogliaform cells remains normal following NMDA receptor-ablation. These afferent specific deficits potentially impact neurogliaform cell mediated inhibition within the hippocampus and our findings reveal circuit loci implicating this relatively understudied interneuron subtype in the etiology of neurodevelopmental disorders characterized by NMDA receptor-hypofunction.Proper brain function depends on the correct assembly of excitatory and inhibitory neurons into neural circuits. Here the authors show that during early postnatal development in mice, NMDAR signaling via activity of long-range synaptic inputs onto neurogliaform cells is required for their appropriate integration into the hippocampal circuitry.

Changes in the content of fatty acids in CA1 and CA3 areas of the hippocampus of Krushinsky-Molodkina rats after single and fivefold audiogenic seizures.

Audiogenic seizures (AS) are generalized seizures evoked by high frequency sounds. Since the hippocampus is involved in the generation and maintenance of seizures, the effect of AS on the composition and content of fatty acids in the CA1 and CA3 hippocampal areas of AS-susceptible Krushinsky-Molodkina (KM) rats on days 1, 3, and 14 after single and fivefold seizures were examined. The total content of all fatty acids in field СА1 was found to be lower compared with the control at all times of observation after both a single seizure or fivefold seizures. The total content of fatty acids in field СА3 decreased at all times of examination after a single seizure, whereas it remained unchanged on days 3 and 14 following five AS. The content of omega-3 fatty acids in both fields at all times of observation after a single seizure and fivefold AS did not significantly differ from that in intact animals. The absence of significant changes in the content of stearic and α-linolenic acids and a considerable decrease in the levels of palmitic, oleic, and eicosapentaenoic acids were common to both fields at all times after both a single seizure or fivefold AS. The changes in the content of fatty acids in the СА3 and СА1 fields of the brain of AS-susceptible rats indicate that fatty acids are involved in both the development of seizure activity and neuroprotective anticonvulsive processes.

[Effect of Electroacupuncture Combined with Rehabilitation Training on Neurological Function and Expression of Neuronal Growth Associated Protein 43 and Synaptophysin in Rats with Focal Cerebral Ischemia/Reperfusion Injury].

OBJECTIVE: To observe the effect of electroacupuncture (EA) combined with rehabilitation training on motor function and expression of neuronal growth associated protein 43 (GAP-43) and synaptophysin (SYP) in hippocampal CA 3 region in rats with focal cerebral ischemia/reperfusion injury (CI/RI). METHODS: A total of 46 SD rats were randomized into normal control, CI/RI model, rehabilitation training (RT), paralysis-side (unilateral)-EA+RT, and bilateral-EA+RT groups (n=6 in the normal control group, and n=10 in each of the other group). The CI/RI model was established by occlusion of the middle cerebral artery (MCAO) and reperfusion. EA (5 Hz/10 Hz, 2 mA) was applied to the unilateral "Quchi" (LI 11) and "Housanli" (ST 36) on the affected side or bilateral LI 11 and ST 36 for 30 min, once daily for two weeks except the Sunday. The neurological deficit severity (Zea Longa score) was assessed 24 h, 7 and 14 days after modeling. The immunoactivity of GAP-43 and SYP in the CA 3 region of the hippocampus was detected using immunohistochemistry. Pathological changes of the prefrontal cortex was observed after H.E. staining. RESULTS: Following modeling, the neurological deficit scores of the model, RT, unilateral-EA+RT and bilateral-EA+RT groups were gradually decreased, and were significantly lower on day 7 and 14 in the bilateral-EA+RT group and on day 14 in the unilateral-EA+RT group than in the model group (P<0.05). The effect of the bilateral-EA+RT group was obviously superior to those of both RT and unilateral EA+RT groups in improving neurological function (P<0.05). Results of immunohistochemical staining displayed that the expression levels of GAP-43 and SYP in the CA 3 region of hippocampus were significantly up-regulated in the model group than in the normal control group (P<0.05), and further obviously up-regulated in both unilateral-and bilateral-EA+RT groups (P<0.05). No significant changes of GAP-43 and SYP protein expression in the RT group compared with the model group (P>0.05), and the expression levels of GAP-43 and SYP protein in the bilateral-EA+RT were significantly higher than those in the unilateral EA+RT group (P<0.05). H.E. staining showed that the ischemic injury of cells (neuronal apoptosis and enlargement of intercellular space) of the prefrontal cortex was relatively milder in the EA+RT groups. CONCLUSIONS: EA plus RT can promote the recovery of motor function in CI/RI rats, which may be associated with its function in increasing the expression of GAP-43 and SYP in hippocampal CA 3 region. The effects of bilateral-EA+RT is obviously better than those of unilateral EA+RT.

Alterations in Hippocampal Oxidative Stress, Expression of AMPA Receptor GluR2 Subunit and Associated Spatial Memory Loss by Bacopa monnieri Extract (CDRI-08) in Streptozotocin-Induced Diabetes Mellitus Type 2 Mice.

Bacopa monnieri extract has been implicated in the recovery of memory impairments due to various neurological disorders in animal models and humans. However, the precise molecular mechanism of the role of CDRI-08, a well characterized fraction of Bacopa monnieri extract, in recovery of the diabetes mellitus-induced memory impairments is not known. Here, we demonstrate that DM2 mice treated orally with lower dose of CDRI-08 (50- or 100 mg/kg BW) is able to significantly enhance spatial memory in STZ-DM2 mice and this is correlated with a significant decline in oxidative stress and up regulation of the AMPA receptor GluR2 subunit gene expression in the hippocampus. Treatment of DM2 mice with its higher dose (150 mg/kg BW or above) shows anti-diabetic effect in addition to its ability to recover the spatial memory impairment by reversing the DM2-induced elevated oxidative stress and decreased GluR2 subunit expression near to their values in normal and CDRI-08 treated control mice. Our results provide evidences towards molecular basis of the memory enhancing and anti diabetic role of the Bacopa monnieri extract in STZ-induced DM2 mice, which may have therapeutic implications.

Protective effect of hispidulin on kainic acid-induced seizures and neurotoxicity in rats.

Hispidulin is a flavonoid compound which is an active ingredient in a number of traditional Chinese medicinal herbs, and it has been reported to inhibit glutamate release. The purpose of this study was to investigate whether hispidulin protects against seizures induced by kainic acid, a glutamate analog with excitotoxic properties. The results indicated that intraperitoneally administering hispidulin (10 or 50mg/kg) to rats 30 min before intraperitoneally injecting kainic acid (15 mg/kg) increased seizure latency and decreased seizure score. In addition, hispidulin substantially attenuated kainic acid-induced hippocampal neuronal cell death, and this protective effect was accompanied by the suppression of microglial activation and the production of proinflammatory cytokines such as interleukin-1ß, interleukin-6, and tumor necrosis factor-α in the hippocampus. Moreover, hispidulin reduced kainic acid-induced c-Fos expression and the activation of mitogen-activated protein kinases in the hippocampus. These data suggest that hispidulin has considerable antiepileptic, neuroprotective, and antiinflammatory effects on kainic acid-induced seizures in rats.

Blood-brain barrier breakdown in the aging human hippocampus.

The blood-brain barrier (BBB) limits entry of blood-derived products, pathogens, and cells into the brain that is essential for normal neuronal functioning and information processing. Post-mortem tissue analysis indicates BBB damage in Alzheimer's disease (AD). The timing of BBB breakdown remains, however, elusive. Using an advanced dynamic contrast-enhanced MRI protocol with high spatial and temporal resolutions to quantify regional BBB permeability in the living human brain, we show an age-dependent BBB breakdown in the hippocampus, a region critical for learning and memory that is affected early in AD. The BBB breakdown in the hippocampus and its CA1 and dentate gyrus subdivisions worsened with mild cognitive impairment that correlated with injury to BBB-associated pericytes, as shown by the cerebrospinal fluid analysis. Our data suggest that BBB breakdown is an early event in the aging human brain that begins in the hippocampus and may contribute to cognitive impairment.

[Effects of Electroacupuncture Intervention Combined with Gastrodin on Expression of Proteins Related to Proliferation-differentiation of Neural Stem Cells in Hippocampal CA 1 and CA 3 Regions in Focal Cerebral Ischemia Rats].

OBJECTIVE: To observe the effect of electroacupuncture(EA) combined with medication on changes of expression of Nestin, glial fibrillary acidic protein (GFAP) and neuron specific enolase (NSE) in the hippocampal CA 1 and CA 3 regions of focal cerebral ischemia (FC1) rats, so as to analyze its mechanisms underlying neuroprotection. METHODS: Fifty male SD rats were randomly divided into normal control, model, EA, medication, and EA+ medication groups (n = 10 in each group). The FCI model was established by middle cerebral artery occlusion (MCAO) with thread embolus. EA (2 Hz, 2 V) was applied to the left "Hegu"(LI 4) and "Quchi" (LI 11) for 30 min, once daily for 14 days after MCAO. Rats of the medication group were given with intraperitoneal injection of gastrodin (10 mg/kg). The expression of Nestin, GFAP and NSE in the hippocampal CA 1 and CA 3 regions were detected by immunohistochemistry. RESULTS: Compared with the normal control group, the numbers of Nestin- and GFAP-immunoreaction (IR) positive cells in both CA 1 and CA 3 regions of the hippocampus were significantly increased in the model ciroup (P<0.05), while those of NSE-IR positive cells in both CA 1 and CA 3 regions were significantly decreased in the mdlgroup (P<0.05). After EA and medication interventions, the numbers of Nestin- and NSE-IR positive cells in the CA 1 and CA 3 regions were evidently increased and GFAP-IR positive neurons were considerably reduced in the EA, medication and EA+ medication groups (P<0.05). The effects of EA+ medication were significantly superior to those of both EA and simple medication in up-regulating the number of Nestin- and NSE-IR positive cells and down-regulating the number of GFAP positive neurons in CA 1 and CA 3-regions (P<0.05). CONCLUSION: EA and EA intervention combined with gastrodin can significantly up-regulate the number of Nestin- and NSE-IR positive cells, and down-regulate the number of GFAP positive cells in the CA 1 and CA 3 regions of hippocampus in focal cerebral ischemia rats, which may contribute to their effects in promoting the differentiation and proliferation of mature neurons in the hippocampus for improving cerebral functions. The effects of EA+ medication are obviously better than simple EA intervention.

Patterns of TRPM7 expression in hypothalamic and hippocampal neurons in modeling of nutritional magnesium deficiency.

Patterns of expression of TRPM7, the major cellular magnesium transporters in neurons of the hypothalamic region and hippocampus, were studied immunohistochemically. Multidirectional nature and different levels of the expression of the above antigen were revealed during modeled magnesium deficiency with regard to structural and functional features of neuron organization in the hypothalamic paraventricular and supraoptic nuclei as well as hippocampal field CA1 and CA3. Changes in the structural characteristics of neurons in the studied areas (absolute and relative indicators) and TRPM7 expression patterns were quantitatively analyzed considering the data on the role of the studied antigen in magnesium homeostasis, cell damage, and compensation.

The pattern of glutamate-induced nitric oxide dynamics in vivo and its correlation with nNOS expression in rat hippocampus, cerebral cortex and striatum.

Nitric oxide (NO) is a diffusible intercellular messenger, acting via volume signaling in the brain and, therefore, the knowledge of its temporal dynamics is determinant to the understanding of its neurobiological role. However, such an analysis in vivo is challenging and indirect or static approaches are mostly used to infer NO bioactivity. In the present work we measured the glutamate-dependent NO temporal dynamics in vivo in the hippocampus (CA1, CA3 and DG subregions), cerebral cortex and striatum, using NO selective microelectrodes. Concurrently, the immunolocalization of nNOS was evaluated in each region. A transitory increase in NO levels occurred at higher amplitudes in the striatum and hippocampus relatively to the cortex. In the hippocampus, subtle differences in the profiles of NO signals were observed along the trisynaptic loop, with CA1 exhibiting the largest signals. The topography of NO temporal dynamics did not fully overlap with the pattern of the density of nNOS expression, suggesting that, complementary to the distribution of nNOS, the local regulation of NO synthesis as well as the decay pathways critically determine the effective NO concentration sensed by a target within the diffusional spread of this free radical. In sum, the rate and pattern of NO changes here shown, by incorporating regulatory mechanisms and processes that affect NO synthesis and decay, provide refined information critical for the understanding of NO multiple actions in the brain.

Chronic fluoxetine treatment reduces parvalbumin expression and perineuronal nets in gamma-aminobutyric acidergic interneurons of the frontal cortex in adult mice.

BACKGROUND: The selective serotonin reuptake inhibitor fluoxetine (FLX) is widely used to treat depression and anxiety disorders, but cellular mechanisms underlying the antidepressant effect of FLX remain largely unknown. The generally accepted effect of chronic FLX treatment is increased adult neurogenesis in the hippocampal dentate gyrus. It was recently demonstrated that FLX treatments can reverse the established neuronal maturation of granule cells in the hippocampal dentate gyrus and of gamma-aminobutyric acidergic (GABAergic) interneurons in the basolateral amygdala. However, it is not clear whether this dematuration effect of FLX occurs in other brain regions. Thus, in this study, we used immunohistological analysis to assess the effect of FLX treatment on GABAergic interneurons in the medial frontal cortex (mFC) and reticular thalamic nucleus (RTN). RESULTS: Immunofluorescence analysis for perineuronal nets (PNNs), which is a marker of neuronal maturation, and for parvalbumin, calretinin, and somatostatin, which are markers for specific GABAergic interneuron type, showed lower number of parvalbumin-positive (+) cells and PNN+/parvalbumin+ cells in the mFC of FLX-treated mice compared to vehicle-treated mice. However, FLX treatment had no effect on the number of cells expressing calretinin and somatostatin in the mFC. In the RTN, the number of PNN+ cells and parvalbumin+ cells was unaltered by FLX treatments. Furthermore, the number of total GABA+ cells and apoptotic cells in the mFC was similar between vehicle- and FLX-treated mice, suggesting that FLX treatment did not induce cell death in this region. Rather, our findings suggest that the decreased number of parvalbumin+ cells in the mFC was due to a decreased expression of parvalbumin proteins in the interneurons. CONCLUSIONS: This study indicates that FLX decreases the levels of parvalbumin, a mature marker of fast-spiking interneurons, and PNNs in parvalbumin+ interneurons in the mFC, suggesting that FLX treatment induces a dematuration of this type of neurons. Induction of a juvenile-like state in fast-spiking inhibitory interneurons in these regions might be involved in the therapeutic mechanism of this antidepressant drug and/or some of its adverse effects.

The analog of Ginkgo biloba extract 761 is a protective factor of cognitive impairment induced by chronic fluorosis.

Ginkgo biloba extract EGb761 is widely used to treat patients with learning and memory impairment in Alzheimer's disease and Parkinson's disease in China. However, it is not yet clear whether the analog of EGb761 (EGb) has a protective effect on the learning and memory damage induced by chronic fluorosis. In this study, 30 Wistar rats were randomly divided into three groups: a control group, a sodium fluoride (NaF) + EGb group, and a NaF group. The rats were administered 0.5 ml water containing NaF (100 mg/l) and EGb (120 mg/kg) per day via gavage. After 3 months, the rats' capacity for learning and memory was tested using a Y-maze. Damage to hippocampal neurons was evaluated by histological examination of the CA3 area. Superoxide dismutase (SOD) activity and the levels of glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) were measured. Furthermore, the expression levels of Bcl-2 and Bax and the levels of cleaved Caspase3 in the hippocampus were evaluated by RT-PCR and Western blotting. The results showed that EGb could improve learning and memory abilities, enhance the activities of SOD and GSH-Px, attenuate the level of MDA, upregulate the ratio of Bcl-2/Bax, and downregulate the level of cleaved Caspase3.