The rapid antidepressant effect of acupuncture on two animal models of depression by inhibiting M1-Ach receptors regulates synaptic plasticity in the prefrontal cortex.

BACKGROUND: It is unclear whether acupuncture has a rapid antidepressant effect and what is the main mechanism. METHODS: In this study, forced swimming stress test (FST) in mice were divided into five groups: control group, acupuncture group, scopolamine group, arecoline group, and acupuncture + arecoline group. Chronic unpredictable mild stress (CUMS) model rats were divided into six groups: naïve (non-CUMS) group, CUMS group, acupuncture group, scopolamine group, arecoline group, and acupuncture + arecoline group. Twenty-four hours after the end of treatment, FST was conducted in mice and rats. The expression of M1-AchR, AMPA receptors (GluR1 and GluR2), BDNF, mTOR, p-mTOR, synapsin I, and PSD95 in the prefrontal cortex was determined by western blot. The spine density of neurons in the prefrontal cortex was detected by golgi staining. RESULTS: The results showed that acupuncture reduced the immobility time of FST in two depression models. Acupuncture inhibited the expression of M1-AchR and promoted the expression of GluR1, GluR2, BDNF, p-mTOR, synapsin I, PSD95, and increased the density of neuron dendritic spine in the prefrontal cortex. CONCLUSIONS: The rapid antidepressant effect of acupuncture may be activating the "glutamate tide" - AMPA receptor activation - BDNF release - mTORC1 pathway activation through inhibiting the expression of M1-AchR in the prefrontal cortex, thereby increasing the expression of synaptic proteins and regulating synaptic plasticity.

Investigation of effects of quercetin and low-level laser therapy in cisplatin-induced in vitro peripheral neuropathy model.

Chemotherapy-induced peripheral neuropathy (CIPN) is one of the dose-dependent side effects of cisplatin. The loss of sensory neurons is observed in CIPN. There are many methods to minimalize CIPN symptoms such as pharmacological agents and photobiostimulation but the mechanisms of these methods are unclear. Our study is aimed at determining the effects of quercetin and low-level laser therapy (LLLT) in undifferentiated and nerve growth factor-differentiated PC12 cells in cisplatin-induced peripheral neuropathy. PC12 cells with cisplatin were co-treated with quercetin and LLLT (diode pumped all-solid-state laser, 670 nm, output 500 mW, and the laser beam surface area was 1.96 cm2). The effects of quercetin and LLLT on GAP-43 and Synapsin I expressions were analyzed by real-time PCR, cell viability was assessed by MTT assay, Annexin and dead assay measured the induction of apoptosis, the alterations in mitopotential were assessed by mitopotential assay, and lactate dehydrogenase activity in cells was analyzed. All experiment data were analyzed by the Tukey test and applied as a post hoc test, and statistical evaluation was made. Our results indicated that cisplatin increased apoptosis (24,210 ± 2189, 46,504 ± 8246) cells, mitochondrial dysfunction (44,312 ± 0.751, 68,788 ± 1271), and LDH activity (62,821 ± 8245, 87,838 ± 8116). Furthermore, it decreased cell viability (42,447 ± 1780, 36,140 ± 3682) and inhibited GAP-43 and Synapsin I genes in undifferentiated and differentiated PC12 cells. However, apoptosis, the alterations in mitopotential, and lactate dehydrogenase activity decreased by applications of quercetin and LLLT. It has been recommended that quercetin and low-level laser therapy roles on cisplatin-induced peripheral neuropathy should be investigated in vivo, and the relationship between quercetin and low-level laser therapy should be molecular.

Inhibition of Synaptic Glutamate Exocytosis and Prevention of Glutamate Neurotoxicity by Eupatilin from Artemisia argyi in the Rat Cortex.

The inhibition of synaptic glutamate release to maintain glutamate homeostasis contributes to the alleviation of neuronal cell injury, and accumulating evidence suggests that natural products can repress glutamate levels and associated excitotoxicity. In this study, we investigated whether eupatilin, a constituent of Artemisia argyi, affected glutamate release in rat cortical nerve terminals (synaptosomes). Additionally, we evaluated the effect of eupatilin in an animal model of kainic acid (KA) excitotoxicity, particularly on the levels of glutamate and N-methyl-D-aspartate (NMDA) receptor subunits (GluN2A and GluN2B). We found that eupatilin decreased depolarization-evoked glutamate release from rat cortical synaptosomes and that this effect was accompanied by a reduction in cytosolic Ca2+ elevation, inhibition of P/Q-type Ca2+ channels, decreased synapsin I Ca2+-dependent phosphorylation and no detectable effect on the membrane potential. In a KA-induced glutamate excitotoxicity rat model, the administration of eupatilin before KA administration prevented neuronal cell degeneration, glutamate elevation, glutamate-generating enzyme glutaminase increase, excitatory amino acid transporter (EAAT) decrease, GluN2A protein decrease and GluN2B protein increase in the rat cortex. Taken together, the results suggest that eupatilin depresses glutamate exocytosis from cerebrocortical synaptosomes by decreasing P/Q-type Ca2+ channels and synapsin I phosphorylation and alleviates glutamate excitotoxicity caused by KA by preventing glutamatergic alterations in the rat cortex. Thus, this study suggests that eupatilin can be considered a potential therapeutic agent in the treatment of brain impairment associated with glutamate excitotoxicity.

Lead exposure represses mitochondrial metabolism by activation of heme-binding protein BACH1 in differentiated SH-SY5Y cell.

Exposure to lead (Pb), a known toxin causing developmental neurotoxicity, can impair neurogenesis and oxidative phosphorylation (OXPHOS), but the mechanism is not clarified. In the current study, we aim to explore the effects of Pb on the differentiation of SH-SY5Y cells and investigate the role of heme and heme-binding protein BACH1 during differentiation. We found that Pb exposure caused a shift from OXPHOS to glycolysis, resulting in neurogenesis impairment by decreasing neurite growth and downregulation of PSD95 and Synapsin-1 in differentiated SH-SY5Y cells. Heme reduction mediated this mitochondria metabolism repression caused by Pb depending on BACH1 activation. Hemin supplement alleviated Pb-induced OXPHOS damage and adenosine triphosphate (ATP) reduction in differentiated SH-SY5Y cells, and further protected for Pb-induced damage of synapse. Heme binding factor BACH1 was negatively regulated by heme content and BACH1 knockout rescued the Pb-induced transcription and expression decline of genes related to OXPHOS and abrogated Pb-induced growth inhibition of axon promotion and synapse formation. Collectively, the present study demonstrates that heme deficiency mediates OXPHOS damage caused by Pb through BACH1 activation, resulting in neurogenesis impairment.

[Effects of pre-moxibustion on expression of phosphorylated Tau protein and related protein kinases in hippocampal CA3 region of AD rats].

OBJECTIVE: To observe the effect of pre-moxibustion at "Baihui"(GV20), "Shenshu"(BL23) and "Zusanli"(ST36) on expression of Tau protein and related protein kinases as glycogen synthase kinase-3ß (GSK-3ß), etc. in the hippocampal CA3 region of Alzheimer's disease (AD) rats, so as to explore its mechanism underlying prevention and treatment of AD cognitive impairment. METHODS: Male SD rats were randomly divided into 4 groups: normal control, sham operation， model and pre-moxibustion，with 9 rats in each group. Rats of the pre-moxibustion group received moxibustion of GV20, BL23 and ST36 for 15 min, once a day, 6 days a week for 3 weeks. After completion of moxibustion, the AD model was reproduced by injection of amyloid beta-peptide 25-35(Aß 25-35) aggregation solution 1 µL (5 µg/µL) into the bilateral hippocampus, rats of the sham operation group received injection of the same dose of normal saline into the hippocampus. The spatial learning-memory ability was detected using Morris water maze test, and changes of the ultrastructure of hippocampal neurons were observed using electron microscope, and those of histopathological changes of hippocampus tissue observed using hematoxylin eosin (H.E.) staining. The expression levels of hippocampal GSK-3ß, p-Tau, CDK5 and Synapsin I proteins were detected by Western blot and immunohistochemistry, respectively. RESULTS: No significances were found between the normal control and sham groups in all the indexes (P>0.05). Compared with the control group, the escape latency of place navigation test of Morris water maze test, expression of GSK-3ß and CDK5 and the immunoactivity of GSK-3ß, CDK5 and p-Tau were significantly increased (P<0.01), and the residence time in the platform quadrant and the number of platform crossing of spatial prob test and the expression of Synapsin Ⅰ significantly reduced in the model group (P<0.01). Following the intervention, the increase of escape latency, expression of GSK-3ß and CDK5 and the immunoactivity of GSK-3ß, CDK5 and p-Tau, and the decrease of residence time in the platform quadrant, number of platform crossing and the expression of Synapsin Ⅰ were reversed in the pre-moxibustion group (P<0.05, P<0.01). Outcomes of ultrastructure and histopathological observations respectively showed edema of hippocampal nerve cells at varying degrees, moderate edema of the cytoplasma, chromatin condensation at the edge of the nucleus, partial mitochondrial vacuole-like degeneration, fracture of tubular crest, edema and expansion of Golgi body, disappearance of polarity, fracture of the rough endoplasmic reticulum, degeneration of ribosome and partial myelin axon and reduced synaptic vesicles in the presynaptic capsule; and reduced number of neurons with shrank body, disappearance of nucleolus and blurred nuclear boundary and vacuole-like degeneration in some of them in the model group, which were relatively milder in the pre-moxibustion group. CONCLUSION: Pre-moxibustion at GV20, BL23 and ST36 plays a role in slowing down the occurrence and development of cognitive impairment in AD rats, which may be related to its functions in inhibiting tau protein hyperphosphorylation and reducing the expression of some related protein kinases in the hippocampus.

Environmental cadmium exposure during gestation impairs fetal brain and cognitive function of adult offspring via reducing placenta-derived E2 level.

Early-life exposure to environmental cadmium (Cd) is known to cause developmental disorders, yet the effect and mechanism of gestational exposure to Cd on the offspring's cognitive function remains unclear. Placenta as a well-established target organ for Cd-impaired fetal development, its role in estrogen regulation and offspring cognitive function is unknown. Our in vivo experiments found that gestational Cd exposure impaired cognitive function in adult male offspring, accompanied with lowered 17ß-estradiol (E2) level in the male fetal brain upon Cd exposure. Correspondingly, the expression of synapse-associated proteins including brain-derived neurotrophic factor (BDNF), post-synaptic density protein 95 (PSD95) and synapsin-1 were downregulated, which were reversed when supplemented with E2 hormone during gestation. Further observation showed placental estrogen synthesis inhibition and general control non-derepressible 2 (GCN2) signaling activation upon Cd exposure, whereas placental estrogen synthesis could be restored through inhibiting GCN2 activity. Based on ovariectomy (OVX) of pregnant mice, we confirmed that Cd exposure reduced E2 level in fetal brain via inhibiting placenta-derived estrogen synthesis. The aforementioned Cd-induced fetal brain injury and cognitive impairment in adult offspring were significantly alleviated when pregnant dams were supplemented with anti-stress agent N-Acetyl-l-cysteine. In summary, Cd disrupted placenta-derived estrogen synthesis via activating GCN2 signaling, and thereby caused cognitive impairment in adult offspring mice. Our findings suggest that placenta-derived estrogen may be an effect marker of environmental toxicants-evoked cognitive dysfunction in adult offspring and suggest that environmental toxicants may affect the fetal brain development via placenta-fetal-brain axis.

High gestational folic acid supplementation prevents hypoxia-ischemia-induced caspase-3 augmenting without changing synapsin and H3 methylation levels in the rat hippocampus.

Perinatal asphyxia is a peripartum event that can cause permanent sequelae to the newborns, affecting the brain development. Recently, it has been demonstrated that epigenetics mechanisms play an important role in this injury and that folic acid (FA) supplementation during pregnancy can affect these epigenetics modifications as well as gene expression. We have identified both positive and negative effects of FA treatment in rats submitted to a model of neonatal hypoxia-ischemia (HI). Considering that FA supplementation is already used in pregnant women and that HI occurs in the peripartum period, this study was designated to evaluate how gestational FA supplementation and neonatal HI affect: apoptosis (caspase-3) and expression of synaptic proteins (synapsin and PSD-95) and the methylation of histone H3 lysine (K) 4 and 27 in the rat hippocampus. Pregnant Wistar rats were divided according to the diets: standard (SD), supplemented with 2 mg/kg of FA or with 20 mg/kg of FA. HI procedure was performed at the 7th PND. Protein expression and H3 methylation were evaluated at the 60th PND in the rats' hippocampus. Neonatal HI increased caspase-3 expression decreased synapsin expression and reduced H3K4me2, -me3 and H3K27me2, -me3 in the ipsilateral hippocampus. FA only prevented the augment in caspase-3 expression. In conclusion, neonatal HI caused lasting effects on caspase-3-mediated cell death (prevented by the FA) and synaptic proteins in the rats' hippocampus. This is the first study to show that histone modifications may contribute to these pathological findings in the hippocampus of HI animals.

Docosahexaenoic acid prevents palmitate-induced insulin-dependent impairments of neuronal health.

The importance of fatty acids (FAs) for healthy brain development and function has become more evident in the past decades. However, most studies focus on the hypothalamus as an important FA-sensing brain region involved in energy homeostasis. Less work has been done to evaluate the effects of FAs on brain regions such as the hippocampus or cortex, two important centres of learning, memory formation, and cognition. Furthermore, the mechanisms of how FAs modulate the neuronal development and function are incompletely understood. Therefore, this study examined the effects of the saturated FA palmitic acid (PA) and the polyunsaturated FA docosahexaenoic acid (DHA) on primary hippocampal and cortical cultures isolated from P0/P1 Sprague Dawley rat pups. Exposure to PA, but not DHA, resulted in severe morphological changes in primary neurons such as cell body swelling, axonal and dendritic blebbing, and a reduction in synaptic innervation, compromising healthy cell function and excitability. Pharmacological assessment revealed that the PA-mediated alterations were caused by overactivation of neuronal insulin signaling, demonstrated by insulin stimulation and phosphoinositide 3-kinase inhibition. Remarkably, co-exposure to DHA prevented all PA-induced morphological changes. This work provides new insights into how FAs can affect the cytoskeletal rearrangements and neuronal function via modulation of insulin signaling.

Astroglial changes in the zona incerta in response to motor cortex stimulation in a rat model of chronic neuropathy.

Although astrocytes are known to regulate synaptic transmission and affect new memory formation by influencing long-term potentiation and functional synaptic plasticity, their role in pain modulation is poorly understood. Motor cortex stimulation (MCS) has been used to reduce neuropathic pain through the incertothalamic pathway, including the primary motor cortex (M1) and the zona incerta (ZI). However, there has been no in-depth study of these modulatory effects and region-specific changes in neural plasticity. In this study, we investigated the effects of MCS-induced pain modulation as well as the relationship between the ZI neuroplasticity and MCS-induced pain alleviation in neuropathic pain (NP). MCS-induced threshold changes were evaluated after daily MCS. Then, the morphological changes of glial cells were compared by tissue staining. In order to quantify the neuroplasticity, MAP2, PSD95, and synapsin in the ZI and M1 were measured and analyzed with western blot. In behavioral test, repetitive MCS reduced NP in nerve-injured rats. We also observed recovered GFAP expression in the NP with MCS rats. In the NP with sham MCS rats, increased CD68 level was observed. In the NP with MCS group, increased mGluR1 expression was observed. Analysis of synaptogenesis-related molecules in the M1 and ZI revealed that synaptic changes occured in the M1, and increased astrocytes in the ZI were more closely associated with pain alleviation after MCS. Our findings suggest that MCS may modulate the astrocyte activities in the ZI and synaptic changes in the M1. Our results may provide new insight into the important and numerous roles of astrocytes in the formation and function.

A Synthetic Snake-Venom-Based Tripeptide Protects PC12 Cells from the Neurotoxicity of Acrolein by Improving Axonal Plasticity and Bioenergetics.

The synthetic peptide p-BTX-I is based on the native peptide (formed by glutamic acid, valine and tryptophan) isolated from Bothrops atrox venom. We have previously demonstrated its neuroprotective and neurotrophic properties in PC12 cells treated with the dopaminergic neurotoxin 1-methyl-4-phenylpyridinium (MPP+). Now, we have investigated the neuroprotective effects and mechanisms of p-BTX-I against the toxicity of acrolein in PC12 cells. Studies have demonstrated that acrolein might play an important role in the etiology of Alzheimer's disease (AD), which is characterized by neuronal and synaptic loss. Our results showed that not only acrolein reduced cell differentiation and cell viability, but also altered the expression of markers of synaptic communication (synapsin I), energy metabolism (AMPK-α, Sirt I and glucose uptake), and cytoskeleton (ß-III-tubulin). Treatment with p-BTX-I increased the percentage of differentiation in cells treated with acrolein and significantly attenuated cell viability loss, besides counteracting the negative effects of acrolein on synapsin I, AMPK-α, Sirt I, glucose uptake, and ß-III-tubulin. Additionally, p-BTX-I alone increased the expression of apolipoprotein E (apoE) gene, associated with the proteolytic degradation of ß-amyloid peptide aggregates, a hallmark of AD. Taken together, these findings demonstrate that p-BTX-I protects against acrolein-induced neurotoxicity and might be a tool for the development of novel drugs for the treatment of neurodegenerative diseases.

Leucine-rich repeat kinase 2 phosphorylation on synapsin I regulates glutamate release at pre-synaptic sites.

Leucine-rich repeat kinase 2 (LRRK2) is a large multidomain scaffolding protein with kinase and GTPase activities involved in synaptic vesicle (SV) dynamics. While its role in Parkinson's disease has been largely investigated, little is known about LRRK2 physiological role and until now few proteins have been described as substrates. We have previously demonstrated that LRRK2 through its WD40 domain interacts with synapsin I, an important SV-associated phosphoprotein involved in neuronal development and in the regulation of neurotransmitter release. To test whether synapsin I is substrate for LRRK2 and characterize the properties of its phosphorylation, we used in vitro kinase and binding assays as well as cellular model and site-direct mutagenesis. Using synaptosomes in superfusion, patch-clamp recordings in autaptic WT and synapsin I KO cortical neurons and SypHy assay on primary cortical culture from wild-type and BAC human LRRK2 G2019S mice we characterized the role of LRRK2 kinase activity on glutamate release and SV trafficking. Here we reported that synapsin I is phosphorylated by LRRK2 and demonstrated that the interaction between LRRK2 WD40 domain and synapsin I is crucial for this phosphorylation. Moreover, we showed that LRRK2 phosphorylation of synapsin I at threonine 337 and 339 significantly reduces synapsin I-SV/actin interactions. Using complementary experimental approaches, we demonstrated that LRRK2 controls glutamate release and SV dynamics in a kinase activity and synapsin I-dependent manner. Our findings show that synapsin I is a LRRK2 substrate and describe a novel mechanisms of regulation of glutamate release by LRRK2 kinase activity.

Cornel iridoid glycoside induces autophagy to protect against tau oligomer neurotoxicity induced by the activation of glycogen synthase kinase-3ß.

Tau oligomers are the etiologic molecules of Alzheimer's disease, and correlate strongly with neuronal loss and exhibit neurotoxicity. Recent evidence indicates that small tau oligomers are the most relevant toxic aggregate species. The aim of the present study was to investigate the mechanisms of cornel iridoid glycoside (CIG) on tau oligomers and cognitive functions. We injected wortmannin and GF-109203X (WM/GFX, 200 µM each) into the lateral ventricles to induce tau oligomer and memory impairment in rats. When orally administered with CIG at 60 and 120 mg/kg/day for 14 days, CIG decreased the escape latency in the Morris water maze test. We also found that CIG restored the expression of presynaptic p-synapsin, synaptophysin, and postsynaptic density-95 (PSD-95) decreased by WM/GFX in rat cortex. CIG reduced the accumulation of tau oligomers in the brain of WM/GFX rats and in cells transfected with wild type glycogen synthase kinase-3ß (wtGSK-3ß). In addition, CIG up-regulated the levels of ATG7, ATG12, Beclin-1, and LC3II in vivo and in vitro, suggesting the restoration of autophagy function. These results suggest that CIG could ameliorate memory deficits and regulate memory-associated synaptic proteins through the clearance of tau oligomers accumulation. Moreover, CIG clears tau oligomers by restoring autophagy function.

Exposure to thiamethoxam during the larval phase affects synapsin levels in the brain of the honey bee.

Thiamethoxam (TMX) is a neurotoxic insecticide widely used for insect pest control. TMX and other neonicotinoids are reported to be potential causes of honey bee decline. Due to its systematic action, TMX may be recovered in pollen, bee bread, nectar, and honey, which make bees likely to be exposed to contaminated diet. In this study, we used immunolabeling to demonstrate that sublethal concentrations of TMX decrease the protein levels of synapsin in the mushroom bodies (MBs) and the antennal lobes (ALs) of pupae and newly emerged worker bees that were exposed through the food to TMX during the larval phase. A decrease in the synapsin level was observed in the MBs of pupae previously exposed to 0.001 and 1.44 ng/µL and in newly emerged bees previously exposed to 1.44 ng/µL and no changes were observed in the optical lobes (OLs). In the ALs, the decrease was observed in pupae and newly emerged bees exposed to 1.44 ng/µL. Because the MBs and ALs are brain structures involved in stimuli reception, learning, and memory consolidation and because synapsin is important for the regulation of neurotransmitter release, we hypothesize that exposure to sublethal concentrations of TMX during the larval stage may cause neurophysiological disorders in honey bees.

Neuroprotective Effect of Dichloromethane Extraction From Piper nigrum L. and Piper longum L. on Permanent Focal Cerebral Ischemia Injury in Rats.

BACKGROUND: Piper nigrum L. and Piper longum L. consist a classic formula in traditional Chinese Hui medicine and are widely used in treatment of stroke. To examine the therapeutic effect of neuron injury after apoplexy, we used a permanent middle cerebral artery occlusion model in rats to investigate the effects of dichloromethane fraction (DF) of Piper nigrum L. and Piper longum L. MATERIALS AND METHODS: After subjecting the rats to permanent middle cerebral artery occlusion, DF (100 and 200 mg/kg) were administered for 14 days. Neurological deficits and the degree of cerebral tissue injury was detected by 2,3,5-Triphenyltetrazolium Chloride Staining Hematoxylin and eosin staining and Nissl staining. Postsynaptic density protein 95 (PSD-95), synapsin-I (syn-I), and α-synuclein (α-syn) were stained by immunohistochemistry. PSD-95, Ca2+/calmodulin (CaM)-dependent protein kinase II (CaMK II), phosphorylated CaMK II (p-CaMK II), CaM, N-methyl D-aspartate receptor subtype 2B (NR2B) expression were detected by Western blot. Meanwhile, phytochemical profile of DF was determined through ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). RESULTS: DF alleviated neurological deficits and markedly prevented ischemia-induced cellular damage. Immunohistochemical micrographs revealed that PSD-95 and syn-I proteins increased, and α-syn presented reduced expression in brain samples from the sham group. Western blot analyses revealed that the model group exhibited a noticeable reduction in PSD-95, p-CaMK II, CaM, and NR2B. The DF-treated model group exhibited increased PSD-95, p-CaMK II, CaM, and NR2B. UPLC-Q-TOF/MS analysis revealed eight main components of DF, of which piperine accounted for the largest proportion.

Gi protein functions in thalamic neurons to decrease orofacial nociceptive response.

Orofacial pain includes neuronal pathways that project from the trigeminal nucleus to and through the thalamus. What role the ventroposterior thalamic complex (VP) has on orofacial pain transmission is not understood. To begin to address this question an inhibitory G protein (Gi) designer receptor exclusively activated by a designer drug (DREADD) was transfected in cells of the VP using adeno-associated virus isotype 8. Virus infected cells were identified by a fluorescent tag and immunostaining. Cells were silenced after injecting the designer drug clozapine-n-oxide, which binds the designer receptor activating Gi. Facial rubbing and local field potentials (LFP) in the VP were then recorded in awake, free moving Sprague Dawley rats after formalin injection of the masseter muscle to induce nociception. Formalin injection significantly increased LFP and the nociceptive behavioral response. Activation of DREADD Gi with clozapine-n-oxide significantly reduced LFP in the VP and reduced the orofacial nociceptive response. Because DREADD silencing can result from Gi-coupled inwardly-rectifying potassium channels (GIRK), the GIRK channel blocker tertiapin-Q was injected. Injection of GIRK blocker resulted in an increase in the nociceptive response and increased LFP activity. Immunostaining of the VP for glutamate vesicular transporter (VGLUT2) and gamma-aminobutyric acid vesicular transporter (VGAT) indicated a majority of the virally transfected cells were excitatory (VGLUT2 positive) and a minority were inhibitory (VGAT positive). We conclude first, that inhibition of the excitatory neurons within the VP reduced electrical activity and the orofacial nociceptive response and that the effect on excitatory neurons overwhelmed any change resulting from inhibitor neurons. Second, inhibition of LFP and nociception was due, in part, to GIRK activation.

Frontal cortical control of posterior sensory and association cortices through the claustrum.

The claustrum is a telencephalic gray matter nucleus that is richly interconnected with the neocortex. This structure subserves top-down executive functions that require frontal cortical control of posterior cortical regions. However, functional anatomical support for the claustrum allowing for long-range intercortical communication is lacking. To test this, we performed a channelrhodopsin-assisted long-circuit mapping strategy in mouse brain slices. We find that anterior cingulate cortex input to the claustrum is transiently amplified by claustrum neurons that, in turn, project to parietal association cortex or to primary and secondary visual cortices. Additionally, we observe that claustrum drive of cortical neurons in parietal association cortex is layer-specific, eliciting action potential generation briefly in layers II/III, IV, and VI but not V. These data are the first to provide a functional anatomical substrate through claustrum that may underlie top-down functions, such as executive attention or working memory, providing critical insight to this most interconnected and enigmatic nucleus.

Ginkgo biloba Extract EGb761 Attenuates Hyperhomocysteinemia-induced AD Like Tau Hyperphosphorylation and Cognitive Impairment in Rats.

BACKGROUND: Ginkgo biloba extract EGb761 has shown the neuroprotective effects on Alzheimer's disease (AD) through the protection against the Aß-induced neurotoxicity. However, it is not completedly clear whether EGb761 attenuates tau hyperphosphorylation, another of the most prominent mechanisms underlying the pathology of AD. METHODS: we employed hyperhomocysteinemia (HHcy) to mimic AD like pathological alterations and memory deficits in rats as model, and injected EGb761 with or after HHcy injection as prevention and treatment, injected saline as control. We measured the status of oxidative damage and spatial and learning memory in rats. Then we detected the level of memory-related proteins, tau phosphorylation and the level and activity of tau kinase (GSK-3ß) and phosphatase (PP2A) by Western blotting and Immunohistochemistry. RESULTS: We found that EGb761 could significantly antagonize HHcy-induced oxidative damage, recover PP2Ac and GSK3ß activities deregulated by HHcy. Furthermore, tau was hyperphosphorylated at Thr231, Ser262, Ser396, and Ser404, most common PP2Ac and GSK3ß targeted sites in the hippocampus and prefrontal cortex of HHcy rats, whereas EGb761 recovered the tau phosphorylation at those sites. Behavioral tests revealed that EGb761 rescued HHcy-induced spatial reference memory deficit and upregulated the expression of synapse-associated protein PSD95 and synapsin-1. CONCLUSION: EGb761 might be a promising drug to treat AD through its anti-oxidative activity and decreasing tau hyperphosphorylation besides the protection against the Aß-induced neurotoxicity.

Whey protein concentrate supplementation protects rat brain against aging-induced oxidative stress and neurodegeneration.

Whey protein concentrate (WPC) is a rich source of sulfur-containing amino acids and is consumed as a functional food, incorporating a wide range of nutritional attributes. The purpose of this study is to evaluate the neuroprotective effect of WPC on rat brain during aging. Young (4 months) and old (24 months) male Wistar rats were supplemented with WPC (300 mg/kg body weight) for 28 days. Biomarkers of oxidative stress and antioxidant capacity in terms of ferric reducing antioxidant potential (FRAP), lipid hydroperoxide (LHP), total thiol (T-SH), protein carbonyl (PC), reactive oxygen species (ROS), nitric oxide (NO), and acetylcholinesterase (AChE) activity were measured in brain of control and experimental (WPC supplemented) groups. In addition, gene expression and histopathological studies were also performed. The results indicate that WPC augmented the level of FRAP, T-SH, and AChE in old rats as compared with the old control. Furthermore, WPC-treated groups exhibited significant reduction in LHP, PC, ROS, and NO levels in aged rats. WPC supplementation also downregulated the expression of inflammatory markers (tumor necrosis factor alpha, interleukin (IL)-1ß, IL-6), and upregulated the expression of marker genes associated with autophagy (Atg3, Beclin-1, LC3B) and neurodegeneration (neuron specific enolase, Synapsin-I, MBP-2). The findings suggested WPC to be a potential functional nutritional food supplement that prevents the progression of age-related oxidative damage in Wistar rats.

Effects of ERK1/2 kinases inactivation on the nigrostriatal system of Krushinsky-Molodkina rats genetically prone to audiogenic seizures.

Recently, we demonstrated that inhibition of ERK1/2 activity by SL-327 treatment blocks seizure behavior in Krushinsky-Molodkina (KM) rats, which was mediated by altering of GABA and glutamate release mechanism in the hippocampus. Basal ganglia representing various subcortical cell groups play a significant role in the regulation of motor activity, including epileptiform seizures. OBJECTIVES:  To verify if nigrostriatal system could be also affected by SL-327 treatment we analyzed the expression of tyrosine hydroxylase, D1 and D2 dopamine receptors, NR2B subunit of NMDA receptor as well as vesicular glutamate transporter VGLUT2 and glutamic acid decarboxylases GAD65/67 in the striatum and substantia nigra of KM rats. METHODS: Animals were injected i.p. with SL-327 (50 mg/kg) 60 min before audio stimulation. After audiogenic stimulation the brains of control and SL 327 treated rats were removed for further immunohistochemical and biochemical analysis. RESULTS:  Obtained results demonstrated a decrease activity in synapsin I, and accumulation of VGLUT2 in the striatum after blockade of audiogenic seizure (AGS) by SL 327 that could lead to inhibition of glutamate release. While in the striatum GAD65/67 level was diminished, in the substantia nigra GAD65/67 was increased showing enhanced inhibitory output to the compact part of the substantia nigra. Analysis of dopaminergic system showed a significant reduction of tyrosine hydroxylase activity and expression in the substantia nigra, and decreased D1 and D2 receptor expression in the striatum. In summary, we propose that changes in the nigrostriatal system could be mediated by inhibitory effect of SL 327 on AGS expression.

Vanadium exposure-induced striatal learning and memory alterations in rats.

Occupational and environmental exposure to vanadium has been associated with toxicities in reproductive, respiratory, and cardiovascular systems. The knowledge on whether and how vanadium exposure caused neurobehavioral changes remains incomplete. This study was designed to investigate the changes in learning and memory following drinking water exposure to vanadium, and to conduct the preliminary study on underlying mechanisms. Male Sprague-Dawley rats were exposed to vanadium dissolved in drinking water at the concentration of 0.0, 0.5, 1.0 and 2.0g/L, as the control, low-, medium-, and high- dose groups, respectively, for 12 weeks. The results by the Morris water maze test showed that the time for the testing animal to find the platform in the high exposed group was increased by 82.9% and 49.7%, as compared to animals in control and low-dose groups (p<0.05). There were significantly fewer rats in the medium- and high- dose groups than in the control group who were capable of crossing the platform (p<0.05). Quantitation of vanadium by atomic absorption spectrophotometry revealed a significant dose-dependent accumulation of vanadium in striatum (r=0.931, p<0.01). Histopathological examination further demonstrated a degenerative damage in vanadium-exposed striatum. Interestingly, with the increase of the dose of vanadium, the contents of neurotransmitter ACh, 5-HT and GABA in the striatum increased; however, the levels of Syn1 was significantly reduced in the exposed groups compared with controls (p<0.05). These data suggest that vanadium exposure apparently reduces the animals' learning ability. This could be due partly to vanadium's accumulation in striatum and the ensuing toxicity to striatal structure and synaptic plasticity. Further research is warranted for mechanistic understanding of vanadium-induced neurotoxicity.