五味子乙素对慢性应激抑郁大鼠海马BDNF/TrkB/CREB通路的影响

目的 研究五味子乙素对慢性应激抑郁大鼠海马脑源性神经营养因子（BDNF）/酪氨酸激酶B（TrkB）/环磷腺苷效应元件结合蛋白（CREB）信号通路的影响。方法 40只SD大鼠随机选择10只作为对照组,其余大鼠采用慢性不可预知温和应激（chronic unpredictable mild stress,CUMS）结合孤养制备抑郁症模型,造模结束后随机分为3组：模型组、盐酸氟西汀（3 mg·kg^-1）组、五味子乙素（5 mg·kg^-1）组,每天ig给药1次,连续8周。分别于造模前、造模后及给药后进行旷场、悬尾、强迫游泳行为学实验;通过苏木素-伊红（HE）染色观察大鼠海马形态学改变;免疫组织化学染色（IHC）法观察大鼠海马BDNF蛋白表达;实时荧光定量PCR（qRT-PCR）法检测大鼠海马BDNF、TrkB、CREB mRNA相对表达量;Westernblotting检测大鼠海马BDNF、TrkB、CREB蛋白相对表达量。结果 与对照组比较,模型组大鼠旷场实验水平、垂直得分显著降低（P＜0.05）,悬尾不动时间和强迫游泳漂浮时间显著增加（P＜0.05）;HE染色结果显示海马神经元结构损伤,IHC结果显示海马BDNF表达明显降低;海马BDNF、TrkB、CREB mRNA及蛋白相对表达显著降低（P＜0.05）。与模型组比较,盐酸氟西汀及五味子乙素组大鼠水平、垂直得分显著增加（P＜0.05）,不动时间和漂浮时间显著减少（P＜0.05）;海马神经元结构明显复原,海马组织中BDNF染色明显增加;BDNF、TrkB、CREB mRNA和蛋白相对表达量显著增加（P＜0.05）。结论 五味子乙素可以改善慢性应激抑郁大鼠抑郁样行为、海马区神经元数量及形态,其机制可能与上调BDNF/TrkB/CREB信号通路有关。     

Effect of antidepressant drugs on cytochrome P450 2C11 (CYP2C11) in rat liver

BackgroundRat CYP2C11 (besides CYP2C6) can be regarded as a functional counterpart of human CYP2C9. The aim of the present study was to investigate the influence of classic and novel antidepressant drugs on the activity of CYP2C11, measured as a rate of testosterone 2α- and 16α-hydroxylation.MethodsThe reaction was studied in control liver microsomes in the presence of antidepressants, as well as in microsomes from rats treated intraperitoneally (ip) with pharmacological doses of the tested drugs (imipramine, amitriptyline, clomipramine, nefazodone – 10 mg/kg ip; desipramine, fluoxetine, sertraline - 5 mg/kg ip; mirtazapine - 3 mg/kg ip) for one day or two weeks (twice a day), in the absence of antidepressants in vitro.ResultsThe investigated antidepressant drugs added to control liver microsomes produced certain inhibitory effects on CYP2C11 activity, which were moderate (sertraline, nefazodone and clomipramine: K_i = 39, 56 and 66 μM, respectively), modest (fluoxetine and amitriptyline: K_i = 98 and 108 μM, respectively) or weak (imipramine and desipramine: K_i = 191 and 212 μM, respectively). Mirtazapine had no inhibitory effect on CYP2C11 activity. One-day exposure of rats to the antidepressant drugs did not significantly change the activity of CYP2C11 in liver microsomes; however, imipramine, desipramine and fluoxetine showed a tendency to diminish the activity of CYP2C11. Of the antidepressants studied, only desipramine and fluoxetine administered chronically elevated CYP2C11 activity; those effects were positively correlated with the observed increases in the enzyme protein level.ConclusionThree different mechanisms of the antidepressants-CYP2C11 interaction are postulated: 1) a direct inhibition of CYP2C11 shown in vitro by nefazodone, SSRIs and TADs; 2) in vivo inhibition of CYP2C11 produced by one-day treatment with imipramine, desipramine and fluoxetine, which suggests inactivation of the enzyme by reactive metabolites; 3) in vivo induction of CYP2C11 produced by chronic treatment with desipramine and fluoxetine, which suggests their influence on enzyme regulation.     

芍甘木瓜汤通过BDNF/TrkB/CREB信号通路改善脑卒中偏瘫痉挛状态大鼠神经行为学研究

目的 观察芍甘木瓜汤对脑卒中偏瘫痉挛状态大鼠神经行为学的影响,并探讨对脑源性神经营养因子（BDNF）/酪氨酸蛋白激酶B（TrkB）/环磷腺苷效应元件结合蛋白（CREB）信号通路的调控机制。方法 取50只SD大鼠采用改良线栓法制作大脑中动脉梗死模型,选取建模成功大鼠随机分为模型组、巴氯芬（0.008 g/kg）组和芍甘木瓜汤低、中、高剂量（0.05、0.10、0.15 g/kg）组。另取10只SD大鼠不栓塞大脑中动脉作为假手术组,于再灌注2 h后ig给药,每天1次,连续2周,假手术组和模型组ig等量生理盐水。干预前后分别采用Zea Longa量表、改良Ashworth量表评价神经行为学、肌张力变化,采用大鼠多导生理记录仪测定上肢伸直幅度;酶联免疫法检测大鼠干预前后血清BDNF、TrkB水平;苏木素-伊红（HE）染色观察缺血半暗带脑组织病理变化,透射电镜下观察缺血半暗带脑组织神经元超微结构;实时荧光定量PCR（qRT-PCR）检测缺血半暗带脑组织BDNF、TrkB-FL、TrkB-T1、CREB mRNA表达;Western blotting检测BDNF、TrkB-FL、TrkB-T1、CREB蛋白表达及p-CREB水平。结果 干预后巴氯芬组和芍甘木瓜汤各剂量组的Zea Longa量表、改良Ashworth量表分级均较干预前和模型组（干预后）显著改善（P<0.05）,上肢伸直幅度均较干预前和模型组（干预后）均显著增加（P<0.05）,血清BDNF、TrkB水平均较干预前和模型组（干预后）显著升高（P<0.05）,缺血半暗带脑组织病理变化和神经元超微结构均较模型组明显改善。模型组缺血半暗带脑组织BDNF、TrkB-FL mRNA与蛋白表达,p-CREB蛋白水平均显著低于假手术组（P<0.05）,巴氯芬组和芍甘木瓜汤各剂量组均较模型组显著升高（P<0.05）;模型组缺血半暗带脑组织TrkB-T1 mRNA与蛋白表达显著高于假手术组（P<0.05）,巴氯芬组和芍甘木瓜汤各剂量组均较模型组显著下降（P<0.05）。各组缺血半暗带脑组织CREB mRNA表达差异无统计学意义。结论 对脑卒中偏瘫痉挛状态大鼠ig予以芍甘木瓜汤可改善其神经行为学,降低肌张力,增加血清BDNF、TrkB水平,减轻缺血半暗带脑组织病理和神经元超微结构变化,推测与激活BDNF/TrkB/CREB通路,上调BDNF、TrkB-FL mRNA与蛋白表达,下调TrkB-T1 mRNA与蛋白表达,增加p-CREB水平有关。     

淫羊藿苷对精神分裂症模型大鼠认知功能的改善作用及机制

目的:研究淫羊藿苷(ICA)对精神分裂症模型大鼠认知功能的改善作用及机制。方法:将SD大鼠分为空白对照组、模型组和ICA低、中、高剂量组(15、30、60 mg/kg),除空白对照组外,其余组大鼠均腹腔注射N-甲基-D-天冬氨酸受体拮抗剂MK-801(0.2 mg/kg)复制精神分裂症模型,每天1次,连续14天。造模成功后,ICA各剂量组大鼠灌胃相应药物,空白对照组和模型组灌胃等体积水,每天1次,连续28天。采用Morris水迷宫实验、旷场实验、强迫游泳实验和Y迷宫实验观察大鼠行为学变化;采用Nissl法染色观察大鼠海马组织病理变化;采用酶联免疫吸附法(ELISA)检测大鼠脑组织中胆碱能相关指标[乙酰胆碱(Ach)、胆碱乙酰转移酶(ChAT)、乙酰胆碱酯酶(AchE)]的水平;采用实时荧光定量聚合酶链式反应(PCR)法检测大鼠脑组织中脑源性神经营养因子(BDNF)、细胞外信号调节蛋白激酶(ERK)、环磷腺苷反应元件结合蛋白(CREB)的mRNA的表达水平;采用Western blot法检测大鼠脑组织中BDNF、ERK、CREB蛋白和凋亡相关蛋白[B淋巴细胞瘤2(Bcl-2)及其相关X蛋白(Bax)、胱天蛋白酶3(Caspase-3)]的表达或磷酸化水平。结果:与空白组比较,模型组大鼠逃避潜伏期、T1~T3时段活动路程长度、累积不动时间和脑组织中Caspase-3蛋白的表达水平均显著增加或升高(P<0.05);穿台次数、交替率、海马组织中Nissl染色阳性神经元数以及脑组织中Ach和ChAT水平、Bcl-2/Bax比值、BDNF m RNA和蛋白的表达水平、ERK和CREB mRNA的表达水平、ERK1/2和CREB磷酸化水平均显著减少或降低(P<0.05)。与模型组比较,ICA高剂量组大鼠逃避潜伏期、T1~T3段活动路程长度、累积不动时间、Nissl染色阳性神经元数、脑组织中AchE水平和Caspase-3蛋白的相对表达量均显著减少或降低(P<0.05);穿台次数、交替率,脑组织中Ach和ChAT水平、Bcl-2/Bax比值、BDNF m RNA和蛋白的表达水平、ERK和CREB mRNA的表达水平、ERK1/2和CREB的磷酸化水平均显著增加或升高(P<0.05)。ICA低、中剂量组大鼠上述部分指标较模型组显著改善(P<0.05)。结论:ICA可改善精神分裂症模型大鼠的认知功能,其作用机制可能与调节胆碱能系统、抑制神经元凋亡、促进BDNF/ERK/CREB信号通路的表达有关。     

The novel squamosamide derivative FLZ enhances BDNF/TrkB/CREB signaling and inhibits neuronal apoptosis in APP/PS1 mice

Aim:

The aim of this study was to study the effects of compound FLZ, a novel cyclic derivative of squamosamide from Annona glabra, on brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase B (TrkB)/cAMP response element-binding protein (CREB) signaling and neuronal apoptosis in the hippocampus of the amyloid precursor protein (APP)/presenilin-1 (PS1) double transgenic mice.

Methods:

APP/PS1 mice at the age of 5 months and age-matched wild-type mice (WT) were intragastrically administered FLZ (150 mg/kg) or vehicle [0.05% carboxymethyl cellulose sodium (CMC-Na)] daily for 20 weeks. The levels of BDNF in the hippocampus of WT and APP/PS1 mice were then measured by immunohistochemistry and Western blot analysis. Neuronal apoptosis in mouse hippocampus was detected by Nissl staining. Expression of NGF, NT3, pTrkB (Tyr515)/TrkB, pAkt (Ser473)/Akt, pERK/ERK, pCREB (Ser133)/CREB, Bcl-2/Bax, and active caspase-3 fragment/caspase-3 in the hippocampus of WT and APP/PS1 mice was detected by Western blot analysis.

Results:

Compared with vehicle-treated APP/PS1 mice, FLZ (150 mg/kg) significantly increased BDNF and NT3 expression in the hippocampus of APP/PS1 mice. In addition, FLZ promoted BDNF high-affinity receptor TrkB phosphorylation and activated its downstream ERK, thus increasing phosphorylation of CREB at Ser133 in the hippocampus of APP/PS1 mice. Moreover, FLZ showed neuroprotective effects on neuronal apoptosis by increasing the Bcl-2/Bax ratio and decreasing the active caspase-3 fragment/caspase-3 ratio in the hippocampus of APP/PS1 mice.

Conclusion:

FLZ exerted neuroprotection at least partly through enhancing the BDNF/TrkB/CREB pathway and inhibiting neuronal apoptosis in APP/PS1 mice, which suggests that FLZ can be explored as a potential therapeutic agent in long-term Alzheimer''s disease therapy.     

Inhibitory effect of antidepressants on B16F10 melanoma tumor growth

BackgroundAntidepressant drugs, like fluoxetine, a selective serotonin reuptake inhibitor, desipramine, a nonselective noradrenaline reuptake inhibitor, and mirtazapine, an antagonist of noradrenaline α₂ auto- and heteroreceptors, are widely used for the treatment of depressive symptoms in cancer patients. Since these antidepressants have different activities targeting the immune system, they might also modulate tumor growth in cancer patients.MethodsIn the present study, we investigated the effects of administration of antidepressant drugs: fluoxetine, desipramine and mirtazapine on B16F10 melanoma tumor growth. These drugs were administered intraperitoneally (ip) for 17 days after subcutaneous injection of B16F10 melanoma cells to male C57BL/6J mice.ResultsFluoxetine significantly inhibited melanoma solid tumor growth and desipramine tended to decrease this parameter whereas mirtazapine had no effect.ConclusionThe inhibitory effect of fluoxetine on melanoma growth was associated with an increased mitogen-induced T cell proliferation which may at least partly participate in the mechanism of the antitumor effect of this antidepressant. It appears that the inhibitory effect of fluoxetine on tumor growth is not related with changes in cytokine levels except for IL-10.     

ERK1/2 activation is involved in the neuroprotective action of P2Y13 and P2X7 receptors against glutamate excitotoxicity in cerebellar granule neurons

Cerebellar granule neurons express several types of nucleotide receptors, with the metabotropic P2Y₁₃ and the ionotropic P2X7 being the most relevant in this model. In the present study we investigated the role of P2Y₁₃ and P2X7 nucleotide receptors in ERK1/2 signalling. The nucleotidic agonists 2MeSADP (2-methylthioadenosine-5′-diphosphate) for P2Y₁₃ and BzATP (2′(3′)-O-(4-benzoylbenzoyl)adenosine-5′-triphosphate) for P2X7 receptors were coupled to ERK1/2 activation in granule neurons, being able to increase around two-fold the levels of ERK1/2 phosphorylation. These effects were sensitive to the inhibitory action of the antagonists MRS-2211 and A-438079, specific for P2Y₁₃ and P2X7 receptors, respectively. Although both receptor subtypes shared the same pattern of transient ERK1/2 phosphorylation, they differed in the intracellular cascades they triggered, being PI3K-dependent for P2Y₁₃ and calcium/calmodulin kinase II (CaMKII)-dependent for P2X7. These two different ERK-mediated pathways were involved in the neuroprotective effects displayed by both P2Y₁₃ and P2X7 receptors against apoptosis induced by an excitotoxic concentration of glutamate, in a similar manner to the neurotrophin, BDNF. In addition, P2Y₁₃ and P2X7 receptor agonists were also able to phosphorylate and activate the ERK-dependent target CREB, which could be involved in their neuroprotective effect. These results indicate that nucleotide receptors share with trophic factors the same survival routes in neurons, such as the ERK signalling route, and therefore, can contribute to the maintenance of granule neurons in conditions in which survival is being compromised.     

Fluoxetine-induced proliferation and differentiation of neural progenitor cells isolated from rat postnatal cerebellum

Previous studies have shown that the serotonin-reuptake inhibitor (SSRI) fluoxetine affects neural progenitors derived from postnatal cerebellum or adult hippocampus and stimulates their proliferation. In the human cerebellum, the proliferation of cerebellar granule cells (CGC) continues until the 11th postnatal month and could be influenced in infants by breastfeeding-delivered SSRIs. Current information about fluoxetine effects on postnatal cerebellar neural progenitors is limited. Here we report the characterization of fluoxetine actions on rat postnatal cerebellar neural progenitors. RT-PCR and immunostaining revealed the expression of serotonin transporter (SERT), 5HT(1A) receptors, tryptophan hydroxylase (TPH), and serotonin (5HT). Protracted in vitro fluoxetine treatment increased cell proliferation and differentiation. The proliferative effects of fluoxetine, 5HT, and the selective agonist of 5HT(1A) receptors trans-8-hydroxy-2-(N-n-propyl-N-3'-iodo-2'-propenyl)aminotetralin (8-OH-PIPAT) were abolished by the selective antagonist of 5HT(1A) receptors, N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cyclohexanecarboxamide trihydrochloride (WAY-100635). Furthermore, fluoxetine-induced activation of both the cAMP-response element-binding (CREB) protein and extracellular signal-regulated protein kinases (ERK1/2), which was abolished by the selective inhibitor of MAP kinase kinase (MEK) 1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio)butadiene (U0126), and increased cyclin D1 expression. All these effects were prevented by WAY-100635. Collectively, our results demonstrate that rat postnatal cerebellum contains neural progenitors capable of proliferating and differentiating in response to fluoxetine exposure, possibly through the activation of 5HT(1A) receptors. The relevance of these findings for possible SSRI effects on the developing postnatal/infant human cerebellum should be explored.     

BDNF Val66Met Impairs Fluoxetine-Induced Enhancement of Adult Hippocampus Plasticity

Recently, a single-nucleotide polymorphism (SNP) in the brain-derived neurotrophic factor (BDNF) gene (BDNF Val66Met) has been linked to the development of multiple forms of neuropsychiatric illness. This SNP, when genetically introduced into mice, recapitulates core phenotypes identified in human BDNF Val66Met carriers. In mice, this SNP also leads to elevated expression of anxiety-like behaviors that are not rescued with the prototypic selective serotonin reuptake inhibitor (SSRI), fluoxetine. A prominent hypothesis is that SSRI-induced augmentation of BDNF protein expression and the beneficial trophic effects of BDNF on neural plasticity are critical components for drug response. Thus, these mice represent a potential model to study the biological mechanism underlying treatment-resistant forms of affective disorders. To test whether the BDNF Val66Met SNP alters SSRI-induced changes in neural plasticity, we used wild-type (BDNF^Val/Val) mice, and mice homozygous for the BDNF Val66Met SNP (BDNF^Met/Met). We assessed hippocampal BDNF protein levels, survival rates of adult born cells, and synaptic plasticity (long-term potentiation, LTP) in the dentate gyrus either with or without chronic (28-day) fluoxetine treatment. BDNF^Met/Met mice had decreased basal BDNF protein levels in the hippocampus that did not significantly increase following fluoxetine treatment. BDNF^Met/Met mice had impaired survival of newly born cells and LTP in the dentate gyrus; the LTP effects remained blunted following fluoxetine treatment. The observed effects of the BDNF Val66Met SNP on hippocampal BDNF expression and synaptic plasticity provide a possible mechanistic basis by which this common BDNF SNP may impair efficacy of SSRI drug treatment.     

cAMP反应元件结合蛋白在药物依赖形成中的作用

反复应用成瘾性药物引起中枢神经系统特定部位cAMP信号系统出现适应性改变 ,cAMP反应元件结合蛋白(cyclicAMPresponseelementbindingprotein ,CREB)是受cAMP调节的主要转录因子 ,在动物产生药物依赖时脑内CREB含量及磷酸化程度发生变化 ,与动物躯体依赖和精神依赖有关。确定CERB在药物依赖中的作用有益于阐明药物依赖分子机制及采取相应的防治措施     

Antidepressants activate the lysophosphatidic acid receptor LPA1 to induce insulin-like growth factor-I receptor transactivation,stimulation of ERK1/2 signaling and cell proliferation in CHO-K1 fibroblasts

Different lines of evidence indicate that the lysophosphatidic acid (LPA) receptor LPA₁ is involved in neurogenesis, synaptic plasticity and anxiety-related behavior, but little is known on whether this receptor can be targeted by neuropsychopharmacological agents. The present study investigated the effects of different antidepressants on LPA₁ signaling. We found that in Chinese hamster ovary (CHO)-K1 fibroblasts expressing endogenous LPA₁ tricyclic and tetracyclic antidepressants and fluoxetine induced the phosphorylation of extracellular signal-regulated kinase1/2 (ERK1/2) and CREB. This response was antagonized by either LPA₁ blockade with Ki16425 and AM966 or knocking down LPA₁ with siRNA. Antidepressants induced ERK1/2 phosphorylation in human embryonic kidney (HEK)-293 cells overexpressing LPA₁, but not in wild-type cells. In PathHunter™ assay measuring receptor-β-arrestin interaction, amitriptyline, mianserin and fluoxetine failed to induce activation of LPA₂ and LPA₃ stably expressed in CHO-K1 cells. ERK1/2 stimulation by antidepressants and LPA was suppressed by pertussis toxin and inhibition of Src, phosphatidylinositol-3 kinase and insulin-like growth factor-I receptor (IGF-IR) activities. Antidepressants and LPA induced tyrosine phosphorylation of IGF-IR and insulin receptor-substrate-1 through LPA₁ and Src. Prolonged exposure of CHO-K1 fibroblasts to either mianserin, mirtazapine or LPA enhanced cell proliferation as indicated by increased [³H]-thymidine incorporation and Ki-67 immunofluorescence. This effect was inhibited by blockade of LPA₁- and ERK1/2 activity. These data provide evidence that different antidepressants induce LPA₁ activation, leading to receptor tyrosine kinase transactivation, stimulation of ERK1/2 signaling and enhanced cell proliferation.     

GPR39 (Zinc Receptor) Knockout Mice Exhibit Depression-Like Behavior and CREB/BDNF Down-Regulation in the Hippocampus

Background:

Zinc may act as a neurotransmitter in the central nervous system by activation of the GPR39 metabotropic receptors.

Methods:

In the present study, we investigated whether GPR39 knockout would cause depressive-like and/or anxiety-like behavior, as measured by the forced swim test, tail suspension test, and light/dark test. We also investigated whether lack of GPR39 would change levels of cAMP response element-binding protein (CREB),brain-derived neurotrophic factor (BDNF) and tropomyosin related kinase B (TrkB) protein in the hippocampus and frontal cortex of GPR39 knockout mice subjected to the forced swim test, as measured by Western-blot analysis.

Results:

In this study, GPR39 knockout mice showed an increased immobility time in both the forced swim test and tail suspension test, indicating depressive-like behavior and displayed anxiety-like phenotype. GPR39 knockout mice had lower CREB and BDNF levels in the hippocampus, but not in the frontal cortex, which indicates region specificity for the impaired CREB/BDNF pathway (which is important in antidepressant response) in the absence of GPR39. There were no changes in TrkB protein in either structure. In the present study, we also investigated activity in the hypothalamus-pituitary-adrenal axis under both zinc- and GPR39-deficient conditions. Zinc-deficient mice had higher serum corticosterone levels and lower glucocorticoid receptor levels in the hippocampus and frontal cortex.

Conclusions:

There were no changes in the GPR39 knockout mice in comparison with the wild-type control mice, which does not support a role of GPR39 in hypothalamus-pituitary-adrenal axis regulation. The results of this study indicate the involvement of the GPR39 Zn²⁺-sensing receptor in the pathophysiology of depression with component of anxiety.     

Chronic administration of the delta opioid receptor agonist (+)BW373U86 and antidepressants on behavior in the forced swim test and BDNF mRNA expression in rats

Rationale Selective delta opioid receptor agonists have been shown to produce antidepressant-like behavioral effects and increase brain-derived neurotrophic factor (BDNF) mRNA expression when given acutely, but the chronic effects of delta agonists have been less well characterized.Objective The present study examined the effects of chronic exposure to the delta agonist (+)BW373U86 (BW) on antidepressant-like behavior in the forced swim test and on BDNF mRNA expression in comparison to chronic treatment with the antidepressants fluoxetine, desipramine, bupropion, and tranylcypromine.Methods Sprague–Dawley rats were treated chronic ally with one of the above treatments and were tested for antidepressant effects in the forced swim test, and assayed for BDNF mRNA expression by in situ hybridization.Results Acute administration of 10 mg/kg BW produced a significant antidepressant-like effect in the forced swim test, while chronic (8- or 21-day) BW administration did not produce a significant antidepressant-like effect. When 10 mg/kg BW was administered for 8 days, it produced a significant increase in BDNF mRNA expression in the frontal cortex, while having no effect on BDNF expression when given for 21 days. Chronic bupropion and desipramine significantly decreased BDNF expression in the dentate gyrus of the hippocampus, while fluoxetine had no effect in any brain region. Chronic tranylcypromine produced a significant increase in BDNF expression in the CA1 region of the hippocampus.Conclusions Chronic exposure to BW produces tolerance to most effects, although at differential rates. In addition, increased BDNF mRNA expression does not appear to be a common effect of chronic administration of various antidepressants.     

右美托咪定对体外循环后围术期神经认知障碍老龄大鼠海马HPA轴和BDNF-ERK-CREB信号通路的影响

目的 评价右美托咪定对体外循环后围术期神经认知障碍老龄大鼠HPA轴和海马BDNF-ERK-CREB信号通路的影响.方法 选择老龄健康雄性Sprangue Dwaley大鼠120只,18～20月龄,体重400～550 g.采用随机数字表法将其分为4组(n=30):对照组(C组)、体外循环组(T组)、体外循环+右美托咪定组...     

Brain-derived neurotrophic factor prevents phencyclidine-induced apoptosis in developing brain by parallel activation of both the ERK and PI-3K/Akt pathways

Phencyclidine is an N-methyl d-aspartate receptor (NMDAR) blocker that has been reported to induce neuronal apoptosis during development and schizophrenia-like behaviors in rats later in life. Brain-derived neurotrophic factor (BDNF) has been shown to prevent neuronal death caused by NMDAR blockade, but the precise mechanism is unknown. This study examined the role of the phosphatidylinositol-3 kinase (PI3K)/Akt and extracellular signal-regulated kinase (ERK) pathways in BDNF protection of PCP-induced apoptosis in corticostriatal organotypic cultures. It was observed that BDNF inhibited PCP-induced apoptosis in a concentration-dependent fashion. BDNF effectively prevented PCP-induced inhibition of the ERK and PI-3K/Akt pathways and suppressed GSK-3β activation. Blockade of either PI-3K/Akt or ERK activation abolished BDNF protection. Western blot analysis revealed that the PI-3K inhibitor LY294002 prevented the stimulating effect of BDNF on the PI-3K/Akt pathway, but had no effect on the ERK pathway. Similarly, the ERK inhibitor PD98059 prevented the stimulating effect of BDNF on the ERK pathway, but not the PI-3K/Akt pathway. Co-application of LY294002 and PD98059 had no additional effect on BDNF-evoked activation of Akt or ERK. However, concurrent exposure to PD98059 and LY294002 caused much greater inhibition of BDNF-evoked phosphorylation of GSK-3β at serine 9 than did LY294002 alone. Finally, either BDNF or GSK-3β inhibition prevented PCP-induced suppression of cyclic-AMP response element binding protein (CREB) phosphorylation. These data demonstrate that the protective effect of BDNF against PCP-induced apoptosis is mediated by parallel activation of the PI-3K/Akt and ERK pathways, most likely involves inhibition of GSK-3β and activation of CREB.     

The neuroprotective effects of the seeds of Cassia obtusifolia on transient cerebral global ischemia in mice

The aim of this study was to determine the mechanism underlying the neuroprotective effects of the ethanolic extract of the seeds of Cassia obtusifolia (COE) (10 or 50 mg/kg/day, p.o) on transient cerebral global ischemia induced by bilateral common carotid artery occlusion (2VO) in mice. Immunohistochemical and western blot studies showed that levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in the hippocampal CA1 region at 1 day post-2VO were attenuated by COE (50 mg/kg/day, p.o), which was administered immediately after 2VO. Furthermore, OX-42 – and glial fibrillary acidic protein (GFAP)-positive cell numbers at 4 days post-2VO were markedly attenuated by COE (50 mg/kg/day, p.o) treatment for 4 days in CA1. Viable neurons detected by Nissl at 7 days post-2VO were increased by administering COE (50 mg/kg/day, p.o) for 7 days. In addition, COE increased the expressions of phosphorylated cAMP response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in CA1 in naïve-control within 1 and 6 h, respectively, and these expressions were also profoundly increased in 2VO-treated mice by COE at immediately post-2VO. These results suggest that the neuroprotective effects of COE are due to its anti-inflammatory effects and to its upregulation of BDNF expression and CREB phosphorylation.