Increased BDNF Expression Research Articles

Treadmill exercise alters ecstasy- induced long- term potentiation disruption in the hippocampus of male rats.

3, 4-methylenedioxymethamphetamine (MDMA) or ecstasy is a derivative of amphetamine that leads to long term potentiation (LTP) disruption in the hippocampal dentate gyrus (DG). Exercise has been accepted as a treatment for the improvement of neurodegenerative disease. Herein, the effects of exercise on the MDMA- induced neurotoxicity were assessed. Male Wistar rats received intraperitoneal injection of MDMA (10mg/kg) and exercised for one month on a treadmill (Simultaneously or asynchronously with MDMA). LTP and expression of BDNF were assessed using electrophysiology and western blotting methods, respectively. MDMA attenuated the field excitatory post-synaptic potential (fEPSP) slope in comparison with the control group, whereas treadmill exercise increased this parameter when compared to MDMA group. Furthermore, BDNF expression significantly decreased in MDMA group and treadmill exercise could increase that. In conclusion, results of this study suggest that synchronous exercise is able to improve MDMA-induced LTP changes through increase of BDNF expression in the hippocampus of rats.

Increased BDNF Expression in the Paraventricular Nucleus of the Hypothalamus (PVN) Abolishes Hypotensive Actions of Nucleus of the Solitary Tract (NTS) Catecholaminergic Neurons

Brain derived neurotrophic factor (BDNF) expression in the PVN increases in response to hypertensive stimuli including stress, and we have recently shown that BDNF is a significant pro‐hypertensive mediator in the PVN. However, the downstream mechanisms mediating this effect of BDNF remain to be investigated. BDNF is an important modulator of catecholaminergic neuronal function throughout the central nervous system; therefore it could potentially influence catecholaminergic input into the PVN as well. The majority of catecholaminergic projections to the PVN originate from the NTS, and these neurons have been shown to exert hypotensive actions. Here, we tested the hypothesis that increased BDNF levels in the PVN elevate blood pressure in part by diminishing the hypotensive influence of NTS catecholaminergic neurons projecting to the PVN. Sprague‐Dawley rats received bilateral PVN injections of AAV2 viral vectors expressing either green fluorescent protein (GFP) or BDNF and bilateral NTS injections of phosphate‐buffered saline (PBS) or anti‐dopamine‐β‐hydroxylase‐conjugated saporin (DSAP, 22ng in 100nL), a neurotoxin selective to noradrenaline‐ and adrenaline‐synthesizing neurons. Blood pressure was monitored with telemetry during baseline conditions and during acute restraint stress. Our results showed that BDNF treatment significantly increased resting daytime mean arterial pressure (MAP). MAP was 115±3 mmHg in the BDNF+PBS group compared with 96±2 mmHg in the GFP+PBS group (p<0.01) 3 wks after injections. Lesioning NTS catecholaminergic neurons with DSAP also increased daytime MAP in GFP‐treated rats (GFP+DSAP: 109±3 mmHg, p<0.05 vs GFP+PBS), but failed to induce further MAP increases in the BDNF group (BDNF+DSAP: 115±4 mmHg, p>0.99 vs BDNF+PBS). Furthermore, BDNF overexpression reduced spontaneous baroreflex sensitivity in rats receiving PBS injections into the NTS, and DSAP reduced baroreflex sensitivity in GFP rats. However, DSAP failed to have an effect in the BDNF group. Heart rate was increased by BDNF overexpression, and in contrast to MAP, heart rate was elevated by DSAP both in GFP‐ and BDNF‐treated rats, although the tachycardic effect was reduced in the BDNF group. Restraint stress‐induced pressor responses were significantly elevated by DSAP in GFP rats, whereas the increase in heart rate was reduced. In contrast, DSAP had no effect on either of these parameters in the BDNF group. Finally, immunohistochemistry indicated that BDNF overexpression in the PVN upregulated tyrosine hydroxylase and dopamine‐β‐hydroxylase (DBH) expressions in the NTS, and elevated DBH immunoreactivity in the PVN. In summary, our findings indicate that increased BDNF expression in the PVN abolishes the hypotensive actions of NTS catecholaminergic neurons both under baseline conditions and during stress despite a significant upregulation of catecholamine biosynthesizing enzymes in the NTS. Heart rate is differentially regulated by NTS catecholaminergic neurons during baseline conditions and stress, but these actions are also reduced by elevated BDNF levels in the PVN.Support or Funding InformationSupported by AHA 11SDG7560022 and UVM start‐up funds.

Role of GPCRs and G‐αs in the antidepressant action of ketamine

Ketamine produces rapid and robust antidepressant effects in depressed patients within hours of administration, often when traditional antidepressant compounds have failed to alleviate symptoms even after 2 months of treatment. We hypothesized that ketamine would translocate Gas from lipid rafts to non‐raft microdomains, similarly to other antidepressants but with a distinct, abbreviated treatment duration. C6 glioma and C6 cells stably transfected with G‐αs‐GFP were treated with 10uM ketamine for 15 minutes, which translocated Gas from lipid raft domains to non‐raft domains. Other NMDA antagonist did not translocate Gas from lipid raft to non‐raft domains. The ketamine induced Gas plasma membrane redistribution allows increased functional coupling of Gas and adenylyl cyclase to increase intracellular cyclic adenosine monophosphate (cAMP). Furthermore, increased intracellular cAMP increased phosphorylation of cAMP response element‐binding protein (CREB), which, in turn, increased BDNF expression. These results reveal a novel antidepressant mechanism mediated by acute ketamine treatment in glial cells that may contribute to ketamine's powerful antidepressant effect.

Deltamethrin Increases Neurite Outgrowth in Cortical Neurons through Endogenous BDNF/TrkB Pathways.

Deltamethrin (DM), a type II pyrethroid, robustly increases brain-derived neurotrophic factor (Bdnf) expression and has a neurotrophic effect in primary cultures of rat cortical neurons. In this study, we investigated the effect of DM on neurite morphology in cultured rat cortical neurons. DM significantly increased neurite outgrowth, but this increase was abolished when the BDNF scavenger tropomyosin receptor kinase B (TrkB)-Fc was added 10 min before the DM treatment. In contrast, the addition of TrkB-Fc 1 h after the treatment did not affect DM-induced neurite outgrowth. Our previous research has indicated that type II, but not type I, pyrethroids have the ability to induce Bdnf mRNA expression, but neither permethrin nor cypermethrin, which are type I and type II pyrethroids, respectively, affected neurite outgrowth in the current study. These results suggest that this effect is not due to increased Bdnf expression, and the effect is unique to DM. We previously demonstrated that calcineurin plays a role in the DM-mediated induction of Bdnf expression. However, the calcineurin inhibitor FK506 did not significantly affect DM-induced neurite outgrowth. DM-induced neurite outgrowth was abolished by U0126 and rapamycin, indicating the involvement of the mitogen-activated protein kinase (MAPK) and mammalian target of rapamycin (mTOR) pathways. Taken together, these findings suggest that DM activates endogenous BDNF/TrkB-mediated MAPK and mTOR pathways, thereby increasing neurite outgrowth.Key words: BDNF, Deltamethrin, MAPK, mTOR, Neurite outgrowth.

Control of stress-induced depressive disorders by So-ochim-tang-gamibang, a Korean herbal medicine

Ethnopharmacological relevanceSo-ochim-tang-gamibang (SOCG) is a Korean herbal medicine formula that has been applied to treat depressive moods and depression associated somatoform pain. This decoction consists of Cyperus rotundus L. (Cyperi Rhizoma), Lindera aggregata (Sims) Kosterm. (Linderae Radix), Aquilaria agallochum (Lour.) Roxb. ex Finl. (Aquilariae Resinatum Lignum), Glycyrrhiza uralensis Fisch. (Glycyrrhizae Radix) Platycodon grandiflorum (Jacq.) A. DC. (Platycodi Radix), and Citrus aurantium L. (Aurantii Fructus). The aim of this study is to assess antidepressant-like effects of SOCG and to investigate its possible cellular and molecular mechanisms. Material and methodsUsing chronic restraint stress animal model, effects of SOCG on depressive-like behaviors, corticosterone, and hippocampal expressions of a neurotrophic factor and an apoptotic marker, were investigated. Mice were exposed to restraint stress 6h per day over a period of two weeks, and orally administrated either SOCG (30, 100, or 300mg/kg/day). The depressive-like behaviors were analyzed by forced swimming test and open field test. The serum levels of corticosterone were measured by enzyme-linked immunosorbent assay. Expressions of caspase-3 and BDNF in the hippocampus were analyzed by immunofluorescence. Further, effects of SOCG were examined in corticosterone-treated PC12 cells. Cellular toxicity was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assays. Real-time PCR was applied to investigate the cellular expression levels of Bax, Bcl-2, and BDNF. The levels of caspase-3 and BDNF were examined by Western blotting. ResultsAdministration of SOCG not only reduced immobility time of restraint-stressed mice in a dose-dependent manner, but also significantly increased the distance mice moved and the number of crossings in the open field test. Further, SOCG significantly reduced the serum level of corticosterone and expression of caspase-3, while increased expression of BDNF in vivo. SOCG increased cell viability in corticosterone treated PC12 cells, which was accompanied by decreased caspase-3 expression and the ratio of Bax/Bcl-2 mRNA expression as well as increased BDNF expression in vitro. ConclusionsTaken together, our data suggested that SOCG may have potential as an antidepressant agent controlling depressive behaviors and corticosterone-induced neuronal damage caused by chronic stress.

Computational model of a positive BDNF feedback loop in hippocampal neurons following inhibitory avoidance training.

Inhibitory avoidance (IA) training in rodents initiates a molecular cascade within hippocampal neurons. This cascade contributes to the transition of short- to long-term memory (i.e., consolidation). Here, a differential equation-based model was developed to describe a positive feedback loop within this molecular cascade. The feedback loop begins with an IA-induced release of brain-derived neurotrophic factor (BDNF), which in turn leads to rapid phosphorylation of the cAMP response element-binding protein (pCREB), and a subsequent increase in the level of the β isoform of the CCAAT/enhancer binding protein (C/EBPβ). Increased levels of C/EBPβ lead to increased bdnf expression. Simulations predicted that an empirically observed delay in the BDNF-pCREB-C/EBPβ feedback loop has a profound effect on the dynamics of consolidation. The model also predicted that at least two independent self-sustaining signaling pathways downstream from the BDNF-pCREB-C/EBPβ feedback loop contribute to consolidation. Currently, the nature of these downstream pathways is unknown.

Activation of the cAMP Pathway Induces RACK1-Dependent Binding of β-Actin to BDNF Promoter.

RACK1 is a scaffolding protein that contributes to the specificity and propagation of several signaling cascades including the cAMP pathway. As such, RACK1 participates in numerous cellular functions ranging from cell migration and morphology to gene transcription. To obtain further insights on the mechanisms whereby RACK1 regulates cAMP-dependent processes, we set out to identify new binding partners of RACK1 during activation of the cAMP signaling using a proteomics strategy. We identified β-actin as a direct RACK1 binding partner and found that the association between β-actin and RACK1 is increased in response to the activation of the cAMP pathway. Furthermore, we show that cAMP-dependent increase in BDNF expression requires filamentous actin. We further report that β-actin associates with the BDNF promoter IV upon the activation of the cAMP pathway and present data to suggest that the association of β-actin with BDNF promoter IV is RACK1-dependent. Taken together, our data suggest that β-actin is a new RACK1 binding partner and that the RACK1 and β-actin association participate in the cAMP-dependent regulation of BDNF transcription.

CDK5 downregulation enhances synaptic plasticity.

CDK5 is a serine/threonine kinase that is involved in the normal function of the adult brain and plays a role in neurotransmission and synaptic plasticity. However, its over-regulation has been associated with Tau hyperphosphorylation and cognitive deficits. Our previous studies have demonstrated that CDK5 targeting using shRNA-miR provides neuroprotection and prevents cognitive deficits. Dendritic spine morphogenesis and forms of long-term synaptic plasticity-such as long-term potentiation (LTP)-have been proposed as essential processes of neuroplasticity. However, whether CDK5 participates in these processes remains controversial and depends on the experimental model. Using wild-type mice that received injections of CDK5 shRNA-miR in CA1 showed an increased LTP and recovered the PPF in deficient LTP of APPswe/PS1Δ9 transgenic mice. On mature hippocampal neurons CDK5, shRNA-miR for 12days induced increased dendritic protrusion morphogenesis, which was dependent on Rac activity. In addition, silencing of CDK5 increased BDNF expression, temporarily increased phosphorylation of CaMKII, ERK, and CREB; and facilitated calcium signaling in neurites. Together, our data suggest that CDK5 downregulation induces synaptic plasticity in mature neurons involving Ca2+ signaling and BDNF/CREB activation.

Long-Term Exercise Improves Memory Deficits via Restoration of Myelin and Microvessel Damage, and Enhancement of Neurogenesis in the Aged Gerbil Hippocampus After Ischemic Stroke

Background. The positive correlation between therapeutic exercise and memory recovery in cases of ischemia has been extensively studied; however, long-term exercise begun after ischemic neuronal death as a chronic neurorestorative strategy has not yet been thoroughly examined. Objective. The purpose of this study is to investigate possible mechanisms by which exercise ameliorates ischemia-induced memory impairment in the aged gerbil hippocampus after transient cerebral ischemia. Methods. Treadmill exercise was begun 5 days after ischemia-reperfusion (I-R) and lasted for 1 or 4 weeks. The animals were sacrificed 31 days after the induction of ischemia. Changes in short-term memory, as well as the hippocampal expression of markers of cell proliferation, neuroblast differentiation, neurogenesis, myelin and microvessel repair, and growth factors were examined by immunohistochemistry and/or western blots. Results. Four weeks of exercise facilitated memory recovery despite neuronal damage in the stratum pyramidale (SP) of the hippocampal CA1 region and in the polymorphic layer (PoL) of the dentate gyrus (DG) after I-R. Long-term exercise enhanced cell proliferation and neuroblast differentiation in a time-dependent manner, and newly generated mature cells were found in the granule cell layer of the DG, but not in the SP of the CA1 region or in the PoL of the DG. In addition, long-term exercise ameliorated ischemia-induced damage of myelin and microvessels, which was correlated with increased BDNF expression in the CA1 region and the DG. Conclusions. These results suggest that long-term treadmill exercise after I-R can restore memory function through replacement of multiple damaged structures in the ischemic aged hippocampus.

The neuroprotective effect of lithium against high dose methylphenidate: Possible role of BDNF

Methylphenidate (MPH) is a neural stimulant with unclear neurochemical and behavioral effects. Lithium is a neuroprotective agent in use clinically for the management of manic-depressive and other neurodegenerative disorders. This study investigated the protective effect of lithium on MPH-induced oxidative stress, anxiety, depression and cognition impairment. Forty-eight adult male rats were divided randomly and equally into 6 groups. Treatment groups were received MPH (10mg/kg) and various doses of lithium (75, 150 and 300mg/kg) simultaneously and also lithium (150mg/kg) alone for 21 days. Elevated Plus Maze and Forced Swim Test were used to determine the level of anxiety and depression in animals. Morris Water Maze was used to evaluate spatial learning and memory. The hippocampi of rats were isolated and the level and activity of oxidative, anti-oxidant and inflammatory factors were measured. Also brain derived neurotropic factor expression level was measured by RT-PCR and western blotting. MPH (10mg/kg) caused behaviors indicative of anxiety and depression-like phenotypes in EPM and FST and cognition impairment in MWM. While lithium in all mentioned doses inhibited these effects. Treatment with MPH significantly increased lipid peroxidation, mitochondrial GSH content and IL-1β and TNF-α levels in isolated hippocampal cells. Moreover superoxide dismutase and glutathione peroxidase activities and BDNF expression remarkably decreased. Various doses of lithium attenuated these effects and significantly mitigated MPH-induced oxidative damage, inflammation and increased BDNF expression level. Lithium has the potential to act as a neuroprotective agent against MPH induced toxicity in rat brain and this might be mediated by BDNF expression in hippocampus of rats.

Role of morphine, miR-212/132 and mu opioid receptor in the regulation of Bdnf in zebrafish embryos

BackgroundMorphine is one of the first-line therapies for the treatment of pain despite its secondary effects. It modifies the expression of epigenetic factors like miRNAs. In the present study, we analyzed miR-212 and miR-132 and their implication in morphine effects in the zebrafish Central Nervous System (CNS) through the regulation of Bdnf expression. MethodsWe used control and knock-down zebrafish embryos to assess the effects of morphine in miRNAs 212/132 and mitotic or apoptotic cells by qPCR, immunohistochemistry and TUNEL assay, respectively. Bdnf and TrkB were studied by western blot and through a primary neuron culture. A luciferase assay was performed to confirm the binding of miRNAs 212/132 to mecp2. ResultsMorphine exposure decreases miR-212 but upregulates miR-132, as wells as Bdnf and TrkB, and changes the localization of proliferative cells. However, Bdnf expression was downregulated when miRNAs 212/132 and oprm1 were knocked-down. Furthermore, we proved that these miRNAs inhibit mecp2 expression by binding to its mRNA sequence. The described effects were corroborated in a primary neuron culture from zebrafish embryos. ConclusionsWe propose a mechanism in which morphine alters the levels of miRNAs 212/132 increasing Bdnf expression through mecp2 inhibition. oprm1 is also directly involved in this regulation. The present work confirms a relationship between the opioid system and neurotrophins and shows a key role of miR-212 and miR-132 on morphine effects through the regulation of Bdnf pathway. General significance.miRNAs 212/132 are novel regulators of morphine effects on CNS. Oprm1 controls the normal expression of Bdnf.

High ω3-polyunsaturated fatty acids in fat-1 mice prevent streptozotocin-induced Purkinje cell degeneration through BDNF-mediated autophagy.

Loss of Purkinje cells has been implicated in the development of diabetic neuropathy, and this degeneration is characterized by impairment of autophagic processes. We evaluated whether fat-1 transgenic mice, a well-established animal model that endogenously synthesizes ω3 polyunsaturated fatty acids (ω3-PUFA), are protected from Purkinje cell degeneration in streptozotocin (STZ)-treated model with fat-1 mice. STZ-treated fat-1 mice did not develop hyperglycemia, motor deficits, or Purkinje cell loss. The expression of LC3 I, II, Beclin-1 and p62 were increased in the cerebellum of STZ-treated wild-type mice, and these expressions were more increased in STZ-treated fat-1 mice, but not of p62. Moreover, cerebellar Rab7, Cathepsin D, and ATP6E were increased in STZ-treated fat-1 mice. There was also increased BDNF expression in Purkinje cells without any changes in TrkB, and phosphorylation of Akt and CREB in the cerebellums of fat-1 mice. Collectively, these findings indicate that STZ-treated fat-1 mice were protected from Purkinje cell loss and exhibited increased BDNF signaling, enhancing autophagic flux activity in cerebellar Purkinje neurons. These processes may underlie Purkinje cell survival and may be potential therapeutic targets for treatment of motor deficits related to diabetic neuropathy.

Valproic acid mediates miR-124 to down-regulate a novel protein target, GNAI1

Valproic acid (VPA) is an anti-convulsant drug that is recently shown to have neuroregenerative therapeutic actions. In this study, we investigate the underlying molecular mechanism of VPA and its effects on Bdnf transcription through microRNAs (miRNAs) and their corresponding target proteins. Using in silico algorithms, we predicted from our miRNA microarray and iTRAQ data that miR-124 is likely to target at guanine nucleotide binding protein alpha inhibitor 1 (GNAI1), an adenylate cyclase inhibitor. With the reduction of GNAI1 mediated by VPA, the cAMP is enhanced to increase Bdnf expression. The levels of GNAI1 protein and Bdnf mRNA can be manipulated with either miR-124 mimic or inhibitor. In summary, we have identified a novel molecular mechanism of VPA that induces miR-124 to repress GNAI1. The implication of miR-124→GNAI1→BDNF pathway with valproic acid treatment suggests that we could repurpose an old drug, valproic acid, as a clinical application to elevate neurotrophin levels in treating neurodegenerative diseases.

Dynamic methylation driven by neuronal activity in hippocampal neurons impacts complex behavior

Epigenetic processes are well-known to play critical roles in learning and memory. Among epigenetic processes, accumulating data suggests that DNA methylation in particular is a critical determinant of learning and memory. In vitro data have suggested that DNA methyltransferase inhibitors can trigger DNA demethylation and subsequent gene expression of the brain-derived neurotrophic factor gene in an activity dependent manner. To examine if these processes occur in vivo, we chronically infused DNMT inhibitors into the hippocampus and examined the impact on behavior. We find that chronic DNMT inhibition in the hippocampus results in increased anxiety-related behavior and deficits in context-dependent fear conditioning accompanied by an increase in BDNF expression. Gene expression changes were blocked by pretreatment with the NMDA receptor antagonist AP5, suggesting that DNMT inhibition enhances gene expression in an activity-dependent manner and that, conversely, the behavior deficits and abnormal gene expression are facilitated by NMDA receptor activity. Open image in new window

3,4-Methylenedioxymethamphetamine facilitates fear extinction learning.

Acutely administered 3,4-methylenedioxymethamphetamine (MDMA, ‘ecstasy') has been proposed to have long-term positive effects on post-traumatic stress disorder (PTSD) symptoms when combined with psychotherapy. No preclinical data support a mechanistic basis for these claims. Given the persistent nature of psychotherapeutic gains facilitated by MDMA, we hypothesized that MDMA improves fear extinction learning, a key process in exposure-based therapies for PTSD. In these experiments, mice were first exposed to cued fear conditioning and treated with drug vehicle or MDMA before extinction training 2 days later. MDMA was administered systemically and also directly targeted to brain structures known to contribute to extinction. In addition to behavioral measures of extinction, changes in mRNA levels of brain-derived neurotrophic factor (Bdnf) and Fos were measured after MDMA treatment and extinction. MDMA (7.8 mg kg−1) persistently and robustly enhanced long-term extinction when administered before extinction training. MDMA increased the expression of Fos in the amygdala and medial prefrontal cortex (mPFC), whereas increases in Bdnf expression were observed only in the amygdala after extinction training. Extinction enhancements were recapitulated when MDMA (1 μg) was infused directly into the basolateral complex of the amygdala (BLA), and enhancement was abolished when BDNF signaling was inhibited before extinction. These findings suggest that MDMA enhances fear memory extinction through a BDNF-dependent mechanism, and that MDMA may be a useful adjunct to exposure-based therapies for PTSD and other anxiety disorders characterized by altered fear learning.

Acute Treatment with a Novel TRPC4/C5 Channel Inhibitor Produces Antidepressant and Anxiolytic-Like Effects in Mice.

Transient receptor potential canonical (TRPC) channels are widely expressed in brain and involved in various aspects of brain function. Both TRPC4 and TRPC5 have been implicated in innate fear function, which represents a key response to environmental stress. However, to what extent the TRPC4/C5 channels are involved in psychiatric disorders remains unexplored. Here, we tested the antidepressant and anxiolytic-like effects of a newly identified TRPC4/C5 inhibitor, M084. We show that a single intraperitoneal administration of M084 at 10 mg/kg body weight to C57BL/6 male mice significantly shortened the immobility time in forced swim test and tail suspension test within as short as 2 hours. The M084-treated mice spent more time exploring in illuminated and open areas in light/dark transition test and elevated plus maze test. In mice subjected to chronic unpredictable stress, M084 treatment reversed the enhanced immobility time in forced swim test and decreased the latency to feed in novelty suppressed feeding test. The treatment of M084 increased BDNF expression in both mRNA and protein levels, as well as phosphorylation levels of AKT and ERK, in prefrontal cortex. Our results indicate that M084 exerts rapid antidepressant and anxiolytic-like effects at least in part by acting on BDNF and its downstream signaling. We propose M084 as a lead compound for further druggability research.

Acute nicotine treatment attenuates lipopolysaccharide-induced cognitive dysfunction by increasing BDNF expression and inhibiting neuroinflammation in the rat hippocampus

Although nicotine has been shown to improve cognitive function in various studies, the mechanisms underlying acute nicotine treatment-induced neuroprotection remain incompletely understood. In this study, we evaluated the effect of acute nicotine treatment on the cognitive impairment induced by lipopolysaccharide (LPS) and explored the underlying mechanism. We found that acute nicotine injection markedly attenuated LPS-elicited cognitive deficits and suppressed the strong LPS-induced release of IL-1β, IL-6, and TNF-α into serum and the dorsal hippocampus at 4 and 24h after LPS injection. Western blot analysis indicated a clear increase in the levels of cleaved caspase-3 in LPS-treated animals but not in nicotine- or saline-treated animals. Furthermore, nicotine administration led to a significant increase in BDNF mRNA expression at 4 and 24h and in BDNF protein expression at 24h after LPS injection in the dorsal hippocampus. Taken together, acute nicotine administration attenuated LPS-induced cognitive dysfunction, and this neuroprotective effect may be related to the up-regulation of BDNF and the inhibition of neuroinflammation and apoptosis-related proteins in the dorsal hippocampus.

Lithium chloride administration prevents spatial learning and memory impairment in repeated cerebral ischemia-reperfusion mice by depressing apoptosis and increasing BDNF expression in hippocampus

Lithium has been reported to have neuroprotective effects, but the preventive and treated role on cognition impairment and the underlying mechanisms have not been determined. In the present study, C57Bl/6 mice were subjected to repeated bilateral common carotid artery occlusion to induce the learning and memory deficits. 2mmol/kg or 5mmol/kg of lithium chloride (LiCl) was injected intraperitoneally per day before (for 7 days) or post (for 28 days) the operation. This repeated cerebral ischemia-reperfusion (IR) induced dynamic overexpression of ratio of Bcl-2/Bax and BDNF in hippocampus of mice. LiCl pretreatment and treatment significantly decreased the escape latency and increased the percentage of time that the mice spent in the target quadrant in Morris water maze. 2mmol/kg LiCl evidently reversed the morphologic changes, up-regulated the survival neuron count and increased the BDNF gene and protein expression. 5mmol/kg pre-LiCl significantly increased IR-stimulated reduce of Bcl-2/Bax and p-CREB/CREB. These results described suggest that pre-Li and Li treatment may induce a pronounced prevention on cognitive impairment. These effects may relay on the inhibition of apoptosis and increasing BDNF and p-CREB expression.

OP23 – 2759: Pharmacological treatment of Rett syndrome with glatiramer acetate (Copaxone)

Background Glatiramer Acetate (GA) represents a collection of synthetic polypeptides approved for the treatment of relapsing–remitting multiple sclerosis, for patients who are 18 years or older. Its high safety profile has been documented in large cohorts of patients 10 or older. Quantitative immunofluorescence assays showed about twofold increase in neuronal expression of BDNF following GA treatment. It causes elevation of BDNF expression up to the level in naive control mice in several cortical areas in the Mecp2 mutated mouse brain. The disease progression of Mecp2 mutant mice is affected by the level of BDNF expression (Chang et al. 2006). Objective Increase in BDNF levels, caused by GA administration will lead to amelioration of RTT related symptoms. Hypothesis: The experimental treatment will be well tolerated and result in at least 20% improvement in at least one of the Rett syndrome related symptoms. Methods Study design: Phase II, dose-escalating trial. Inclusion criteria Female, ambulatory patients with genetically confirmed RTT who are 10 or more years old. Outcome measures: Gait, respiratory function, attention and memory, EEG. Objectives • Primary: To assess primary efficacy of GA in improving gait speed in patients with RTT. • Secondary: a. To evaluate secondary efficacy of GA in improving cognition (visual attention, memory and visual pursuit), autonomic (respiratory) function, encephalopathy (EEG), and quality of life. b. To assess safety and maximally tolerated dosage. Results Treatment with GA lead to significant improvement in gait speed, breath hold index and recognition memory. Seven of 10 treated girls exhibited the improvement. There was no difference in age, genetic status or Rett syndrome severity scores between those who did and who did not improve. Conclusion Treatment with GA was well-tolerated and lead to significant improvements in girls with RTT.

(251) Opioids and microglia: a murine-derived microglia stable cell line study

The development of opioid hyperalgesia following long-term opioid use is a critical impediment in treating chronic pain. Activated microglia has been identified as a critical mediator in the development of opioid hyperalgesia. The mechanism by which opioids activate microglia remains unknown. To explore this question, we used a stable cell line of mouse-derived microglial cells, which allowed us to isolate the direct effect of opioids on microglia in the absence of neurons. The BV-2 microglial cell line, derived from mouse microglial cells, was cultured in vitro. Cells were exposed to 10uM morphine for 48 hours and the degree of microglial activation was assayed with immunohistochemistry using an antibody against IBA-1 and western blot measuring BDNF expression. Standard qPCR was run to probe the expression of BDNF and opioid receptor mRNA in this cell line before and after exposure to opioids. Glial inhibitors (+) naloxone and minocycline were co-administered with morphine and the effect on microglial activation and BDNF expression was measured. BV-2 cells cultured with morphine for 48 hours caused significant increase in BDNF expression. This was blocked by co-treatment with minocycline or (+) naloxone, the opioid inactive enantiomer of naloxone. Kappa and mu opioid mRNA was detected in resting BV-2 cells, with mu opioid receptor expression increasing after morphine treatment. This study found that microglia express opioid receptors and suggest opioids are able to directly activate microglia in vitro. (+) naloxone blocked microglial activation, suggesting (+) naloxone inhibits microglial activation via a non-opioid target. Studies elucidating the molecular target of (+) naloxone in this cell line are ongoing. The development of opioid hyperalgesia following long-term opioid use is a critical impediment in treating chronic pain. Activated microglia has been identified as a critical mediator in the development of opioid hyperalgesia. The mechanism by which opioids activate microglia remains unknown. To explore this question, we used a stable cell line of mouse-derived microglial cells, which allowed us to isolate the direct effect of opioids on microglia in the absence of neurons. The BV-2 microglial cell line, derived from mouse microglial cells, was cultured in vitro. Cells were exposed to 10uM morphine for 48 hours and the degree of microglial activation was assayed with immunohistochemistry using an antibody against IBA-1 and western blot measuring BDNF expression. Standard qPCR was run to probe the expression of BDNF and opioid receptor mRNA in this cell line before and after exposure to opioids. Glial inhibitors (+) naloxone and minocycline were co-administered with morphine and the effect on microglial activation and BDNF expression was measured. BV-2 cells cultured with morphine for 48 hours caused significant increase in BDNF expression. This was blocked by co-treatment with minocycline or (+) naloxone, the opioid inactive enantiomer of naloxone. Kappa and mu opioid mRNA was detected in resting BV-2 cells, with mu opioid receptor expression increasing after morphine treatment. This study found that microglia express opioid receptors and suggest opioids are able to directly activate microglia in vitro. (+) naloxone blocked microglial activation, suggesting (+) naloxone inhibits microglial activation via a non-opioid target. Studies elucidating the molecular target of (+) naloxone in this cell line are ongoing.