黄芪总苷和MK-801对宫内窘迫后认知障碍的作用

目的：研究黄芪总苷和地卓西平马来酸（MK-801）对宫内窘迫后的缺氧后新生鼠的Tau蛋白磷酸化程度的影响。方法：采用2×3析因设计：即宫内窘迫（2水平：无处置、施行宫内窘迫即夹闭孕鼠的子宫动脉2/3 持续10 min）和药物（3水平：生理盐水、MK-801、黄芪总苷）的所有组合。新生鼠生长至12周时留取海马,高效液相色谱（HPLC）检测谷氨酸（Glu）含量,IHC-SP检测p-AT8^Ser202与GSK-3β^1H8表达。结果：黄芪总苷可降低宫内窘迫诱发的Glu浓度升高;MK-801对海马中Glu的浓度无明显影响。宫内窘迫可增加海马内磷酸化程度的Tau蛋白p-AT8^Ser202以及促进Tau蛋白磷酸化程度的调控蛋白GSK-3β^1H8的表达;黄芪总苷和MK-801可减缓p-AT8^Ser202磷酸化程度。结论：黄芪总苷可以通过降低海马Glu浓度减缓Tau蛋白的磷酸化;GSK-3β是该信号通路的关键蛋白;黄芪总苷改善由于宫内窘迫诱发导致缺氧后的学习记忆能力低下的效果优于MK-801。     

二精丸影响肾阴虚动物记忆障碍机制的实验研究

目的 探讨二精丸有效部位影响肾阴虚模型大鼠学习记忆障碍机制.方法 使用附子、肉桂等热性中药复制大鼠肾阴虚记忆障碍模型.二精方总黄酮和总多糖灌胃给药结束后Morris水迷宫法测定各组的学习记忆能力,采用免疫组织化学法检测大鼠海马BCL-2、Bax表达及Tau蛋白异常磷酸化水平.结果 二精丸总黄酮和总多糖能显著恢复海马区BCL-2和Bax表达,能显著抑制模型大鼠海马区Tau蛋白Ser199/202、Ser396两个磷酸化位点异常磷酸化.结论 二精丸总黄酮和总多糖可能通过恢复海马区BCL-2和Bax表达和抑制模型大鼠海马区Tau蛋白Ser199/202、Ser396两个磷酸化位点异常磷酸化来提高肾阴虚模型大鼠的学习记忆能力.     

人参皂甙Rb1通过提高PP2A活性抑制冈田酸诱导的大鼠海马神经元Tau蛋白AD样异常磷酸化

目的 研究人参皂甙Rb1对冈田酸诱导的海马神经元Tau蛋白过度磷酸化的抑制作用及其可能机制。方法用不同浓度的Rb1预处理大鼠后，向海马背侧一次性注射适量OA，建立Tau蛋白过度磷酸化的大鼠模型。通过Bieschowski’s染色、免疫组化和western-blot观察大鼠海马神经元突起和Tau蛋白磷酸化水平的变化；检测蛋白磷酸酯酶PP2A和胆碱乙酰转移酶(T-chE)活性，探讨Rb1作用的可能机制。结果模型组大鼠海马神经元神经原纤维排列紊乱，轴突断裂；Tau蛋白磷酸化水平和总Tau含量增多，PP2A活性明显受抑制，但T-chE活性无改变；Rb1预处理的大鼠，神经原纤维走行规则，轴突较完整，Tau磷酸化和总Tau水平比模型鼠下降，PP2A活性明显增高，但T—chE活性无明显改变。结论。Rb1可以减轻OA诱导的大鼠海马神经元Tau蛋白过度磷酸化，其机制可能主要与提高PP2A活性有关；Rb1对T-chE则无明显影响。     

拟人参皂苷-F11对SAMP8小鼠认知障碍的改善作用及机制

目的阿尔茨海默病(AD)是一种常见的、以认知障碍为主要症状的中枢神经系统退行性疾病。β-淀粉样蛋白(Aβ)聚集形成的淀粉样斑块(SP)和过度磷酸化的Tau蛋白引发的神经原纤维缠结(NFT)是AD临床上的主要病理特征。拟人参皂苷F11(PF11)是西洋参茎叶中分离提取的一种三萜皂苷化合物,本文通过自发快速老化(SAMP8)模型小鼠,从Aβ沉积和Tau过度磷酸化等方面,结合神经行为学、免疫组织化学和蛋白质免疫印迹等手段,进一步评价PF11对AD模型动物认知障碍的改善作用及潜在机制。方法灌胃给予6月龄雄性SAMP 8快速衰老小鼠PF11(2,8和32 mg·kg~(-1)),在给药3个月后进行行为学实验,并检测APP和β-分泌酶(BACE1)、晚期内含体Rab7和循环内含体Rab11的表达。结果灌胃给予PF11(8和32 mg·kg~(-1))3个月可以显著改善SAMP8小鼠的识别记忆和空间学习记忆障碍,显著增加SAMP8小鼠海马和皮质中突触后致密蛋白95的水平;显著降低SAMP8小鼠海马和皮质中胞浆淀粉样蛋白前体蛋白(APP)和β-分泌酶(BACE1)的水平,减少海马和皮质中APP与晚期内含体(LE)的共定位,从而降低脑内Aβ的沉积;PF11可以显著提高SAMP8小鼠海马和皮质中异常降低的亮氨酸羧甲基转移酶(LCMT-1)水平,增加甲基化蛋白磷酸酶2A(PP2A)的水平,从而减少过度磷酸化的Tau。结论 PF11能够明显改善SAMP8小鼠的认知障碍,其机制与抑制海马和皮质脑区中APP淀粉样剪切途径进而减少Aβ沉积,以及增加PP2A活力进而减少Tau蛋白的过度磷酸化相关。     

人参皂苷Rg1和Rb1促进PC12细胞释放谷氨酸的作用机制

目的研究人参皂苷(ginsenosides)Rg1和Rb1促进PC12细胞释放谷氨酸作用的机制。方法HPLC法测量PC12细胞释放谷氨酸的含量。细胞免疫染色法和Western blotting法检测人参皂苷Rg1和Rb1对突触蛋白(synapsins)磷酸化水平的影响。结果人参皂苷Rg1(10 μmol·L^-1)和Rb1(10 μmol·L^-1)均可明显促进PC12细胞中谷氨酸的释放。加入蛋白激酶A(PKA)抑制剂H89可抑制Rb1诱导的谷氨酸释放增加；但H89不能抑制Rg1诱导的谷氨酸释放增加。Rb1可升高PC12细胞中突触蛋白的磷酸化水平，H89可抑制这种作用；而Rg1对突触蛋白磷酸化水平无明显作用。结论Rb1可介导PKA活化以诱导突触蛋白磷酸化升高，进而引起谷氨酸释放增加；并提示Rg1促进谷氨酸释放的作用可能与突触蛋白磷酸化无关。     

人参皂苷Rg1对慢性应激抑郁模型大鼠谷氨酸及其受体表达的影响

目的：观察人参皂苷Rg1对慢性应激抑郁模型大鼠脑内海马、前额叶皮质区谷氨酸及其不同类型受体表达的影响，探讨其潜在的抗抑郁机制。方法：将SD大鼠随机分为5组：正常组、模型组、氟西汀组（10 mg·kg^-1）、人参皂苷Rg1低、高剂量组（25、50 mg·kg^-1）。采用慢性不可预见性温和应激的方法建立抑郁大鼠模型，于造模同时灌胃给药，共21天。造模结束后采用Morris水迷宫和旷场实验评价大鼠的抑郁样行为，HE染色观察大鼠海马、前额叶皮质区病理改变情况，HPLC法检测谷氨酸含量，Western-blotting法检测离子型谷氨酸受体NMDAR1、代谢型谷氨酸受体mGluR1的蛋白表达情况。结果：与正常组比较，模型组大鼠抑郁样行为显著，海马、前额叶皮质区均存在较为明显的损伤，谷氨酸含量显著升高，NMDAR1、mGluR1蛋白表达均显著上调；在给予人参皂苷Rg1干预后，模型大鼠的抑郁样行为得到缓解，海马、前额叶皮质区损伤减轻，谷氨酸含量下降，NMDAR1、mGluR1蛋白表达水平明显逆转。结论：人参皂苷Rg1对大鼠抑郁症状有明显的改善作用，并能减轻海马和前额叶皮质损伤，其机制可能与调节脑内谷氨酸含量，并抑制其受体表达有关。     

人参皂苷Rb1可能通过CDK5途径减轻Aβ25-35诱导的胎鼠海马神经元tau蛋白过度磷酸化

观察人参皂苷Rb1对Aβ_25-35诱导的海马神经元tau蛋白过度磷酸化的影响，并探讨其对周期依赖性蛋白激酶(cyclin-dependent kinase 5，CDK5)及激动亚基p25/p35的可能作用。通过蛋白免疫印迹法和免疫细胞化学染色法检测胎鼠海马神经元tau蛋白在Thr²⁰⁵、Ser³⁹⁶和Ser⁴⁰⁴位点的磷酸化水平，及CDK5的两个亚基cdk5和p25/p35的蛋白水平。20 μmol·L^-1凝聚态Aβ_25-35作用于海马神经元12 h，可使海马神经元tau蛋白在Thr²⁰⁵、Ser³⁹⁶和Ser⁴⁰⁴位点的磷酸化水平增高，p25的数量增多，但并不影响cdk5亚基的表达。人参皂苷Rb1可减轻凝聚态Aβ_25-35诱导的海马神经元tau蛋白的过度磷酸化，抑制p35的降解并减少海马神经元p25的生成。人参皂苷Rb1可能通过CDK5途径减轻Aβ_25-35诱导的胎鼠海马神经元tau蛋白过度磷酸化。     

抑郁症大鼠海马-杏仁核pMAP-2表达改变及人参皂苷Rb1的干预作用

目的 研究人参皂苷Rb1对抑郁大鼠海马-杏仁核组织微管相关蛋白-2（MAP-2）磷酸化的影响,探讨人参皂苷Rb1抗抑郁作用的可能机制。方法 选用30只成年Wistar大鼠,随机分为对照组、模型组和治疗组。采用慢性不可预性温和应激结合孤养方法建立大鼠抑郁症模型,治疗组同时给予人参皂苷Rb1。采用Western blot方法检测海马、杏仁核组织MAP-2及pMAP-2表达,Real-time PCR检测mRNA表达。结果 模型组大鼠海马和杏仁核组织MAP-2磷酸化程度和mRNA表达水平明显低于对照组（P < 0.05）,治疗组表达明显升高,但仍低于对照组（P < 0.05）。结论 人参皂苷Rb1抗抑郁作用可能与影响海马、杏仁核MAP-2磷酸化有关     

氯化锂抑制β-淀粉样蛋白诱导细胞Tau蛋白磷酸化

目的探讨GSK-3β抑制剂氯化锂(LiCl)在β-淀粉样蛋白25～35片断(Aβ25-35)诱导的细胞Tau蛋白磷酸化中的作用及机制。方法MTT法观察不同浓度的LiCl(1、5、10、20mmol.L-1)单独作用24h,对SH-SY5Y细胞存活率的影响;20μmol.L-1的凝聚态Aβ25-35作用于SH-SY5Y细胞不同时间点,蛋白免疫印迹法研究Tau蛋白磷酸化位点(Ser199、Ser396及Tau1)水平的变化;LiCl(20mmol.L-1)预处理细胞1h后,观察Aβ的作用有无变化及可能的作用机制。结果不同浓度的LiCl作用24h后,MTT法示细胞存活率无明显变化(P>0.05);20μmol.L-1Aβ25-35作用不同时间点后,Tau蛋白在Ser396、Ser199位点的磷酸化水平在3h逐渐增加,6h达到最高峰,12h后又逐渐下降,在这3个时间点的增加量均具有统计学意义(P<0.05),而对非磷酸化Tau1没有影响(P>0.05);LiCl预处理可抑制Aβ25-35的作用(P<0.05),并可诱导失活形式的GSK-3β在Ser9位点的磷酸化(p-GSK-3βSer9)表达增高。结论GSK-3β参与了Aβ25-35诱导细胞Tau蛋白磷酸化的作用,LiCl可通过诱导失活形式的p-GSK-3βSer9表达增高而抑制GSK-3β的活性,进而抑制Aβ诱导的细胞Tau蛋白磷酸化。该实验为研究AD的发病机制及探索有效治疗药物提供了重要的理论基础。     

人参皂苷Rg1对Aβ_(25-35)诱导大鼠海马神经元tau蛋白异常磷酸化的影响

目的探讨人参皂苷Rg1对Aβ2535所致大鼠海马神经tau蛋白异常磷酸化的抑制作用及其可能机制。方法应用脑立体定向技术向成年大鼠海马背侧注射凝聚态Aβ25355nmol制备AD样大鼠模型,术后分别给予腹腔内注射不同浓度的人参皂苷Rg1(625、125、25μmol·kg-1)处理,14d后处死,采用镀银染色方法观察海马组织神经元病理改变;免疫组织化学染色方法和免疫蛋白印迹技术显示大鼠脑内[pS396]tau、[pSpS199/202]tau、[pT231]tau的表达水平情况,以及总tau蛋白的水平(tau5);免疫蛋白印迹技术检测海马组织中GSK3β和磷酸化GSK3β的水平变化。结果凝聚态Aβ2535注射组神经元纤维走行紊乱,增粗、肿胀密集成宽带状,轴突深染;而人参皂苷Rg1对神经元具有明显的保护作用,脑内总tau的水平下降,[pS396]tau、[pSpS199/202]tau、[pT231]tau的表达明显低于Aβ2535注射组(P<001),以25μmol·kg-1保护作用最明显;GSK3β和磷酸化GSK3β的水平亦明显低于Aβ2535注射组,与正常和假注射组差异无显著性(P>005),以25μmol·kg-1作用最明显。结论人参皂苷Rg1对Aβ2535诱导的AD样大鼠海马神经元具有保护作用,其机制可能是通过阻断GSK3β的活性而降低磷酸化tau蛋白的表达而实现的。     

β-淀粉样蛋白对大鼠学习记忆、病理及tau蛋白磷酸化的影响

目的研究大鼠海马区内注射β-淀粉样蛋白（Aβ）的神经毒性,建立阿尔茨海默病（AD）动物模型,探讨Aβ毒性机制。方法选取雌性成年SD大鼠24只,随机分为止常对照组、生理盐水组、AD组,每组8只。Morris水迷宫检测大鼠学习记忆功能,HE染色及B ielschowsk i染色法观察海马神经元形态,免疫组化法观察tau蛋白异常磷酸化变化。结果与正常对照组大鼠相比,AD组大鼠水迷富测试结果明显减退（P〈0.01）;海马CA1区神经元纤维形态紊乱,tau蛋白磷酸化阳性细胞数明显增多（P〈0.01）。结论大鼠海马内注射凝集态Aβ可产生神经毒性作用,能较好地模拟AD行为和病理表现,其神经毒性可能是通过tau蛋白的异常磷酸化起作用。     

Effects of repeated electroconvulsive shock on serotonin1A receptor binding and receptor-mediated hypothermia in the rat.

Chronic treatment with electroconvulsive shock or antidepressant drugs has been reported to attenuate the hypothermia induced by 8-hydroxy-2-(di-n-propyl)aminotetralin (8-OH-DPAT), a serotonin1A receptor agonist. In the present study, the binding of [3H]8-OH-DPAT to serotonin1A receptors was assessed after treatment of rats with electroconvulsive shock. The effect of electroconvulsive shock on 8-OH-DPAT-induced hypothermia also was evaluated. Male rats were handled or received electroconvulsive shock for either 1 or 10 days and were killed 2 days later. Ten days of electroconvulsive shock decreased beta-adrenergic receptor binding in the cerebral cortex, as previously reported. However, the binding of [3H]8-OH-DPAT to serotonin1A receptors in the cortex or hippocampus was not affected by repeated electroconvulsive shock. In the hypothalamus, 10 days (but not 1 day) of electroconvulsive shock significantly decreased the binding of [3H]8-OH-DPAT. In addition, 10 days of electroconvulsive shock resulted in an attenuation of the hypothermic response to 8-OH-DPAT, when compared to the response in handled controls. The electroconvulsive shock-induced suppression of the hypothermic response to 8-OH-DPAT was no longer evident 2 weeks after the last of 10 daily treatments. A single shock did not affect the hypothermic response to 8-OH-DPAT. The electroconvulsive shock-induced decrease in the binding of [3H]8-OH-DPAT in the hypothalamus may be related tot the electroconvulsive shock-induced attenuation of the hypothermic response to 8-OH-DPAT.     

Dehydroevodiamine attenuates tau hyperphosphorylation and spatial memory deficit induced by activation of glycogen synthase kinase-3 in rats

Tau hyperphosphorylation and memory deficit are characteristic alterations of Alzheimer's disease (AD), and glycogen synthase kinase-3 (GSK-3) plays a crucial role in these AD-like changes. We have reported that activation of GSK-3 through ventricular injection of wortmannin and GF-109203X (WT/GFX, 100 microM each) induces tau hyperphosphorylation and memory impairment of rats [Liu, S.J. et al., 2003. Overactivation of glycogen synthase kinase-3 by inhibition of phosphoinositol-3 kinase and protein kinase C leads to hyperphosphorylation of tau and impairment of spatial memory. J. Neurochem. 87, 1333-1344]. By using this model, we explored in the present study the effects of dehydroevodiamine (DHED), a quinazoline alkaloid isolated from Evodia rutaecarpa Bentham, on the memory retention, tau phosphorylation and the activity of GSK-3. We found that pre-administration of DHED through vena caudalis for 1 week efficiently improved the WT/GFX-induced spatial memory retention impairment of the rats; it also antagonized tau hyperphosphorylation at multiple AD sites and arrested the overactivation of GSK-3 induced by WT/GFX. Our study gave the first in vivo evidence that DHED could suppress the overactivation of GSK-3 and improve tau hyperphosphorylation and spatial memory deficit of the rats, suggesting that this chemical may be served as a candidate for arresting AD-like pathological and behavioral alterations.     

Investigation on the mechanisms for the suppression of cell proliferation in the dentate gyrus of the hippocampus in ACTH treated rats

We previously reported that adrenocorticotropic hormone (ACTH)-treated rats serve as a valuable animal model for tricyclic antidepressant-resistant depressive conditions. The present study was undertaken to investigate the changes in neurogenesis in the hippocampus of ACTH-treated rats. Chronic treatment of ACTH decreased the number of bromodeoxyuridine-labeled cells in the dentate gyrus, and the coadministration of imipramine and lithium, and electroconvulsive stimuli recovered these reductions. Furthermore, chronic ACTH treatment also decreased the expression of brain-derived neurotrophic factor, and the coadministration of imipramine and lithium, and electroconvulsive stimuli recovered these reductions. These results suggest that antidepressant-resistant depression is caused by the suppression of neurogenesis, and the coadministration of imipramine and lithium, and electroconvulsive stimuli exert an antidepressant-like effect by recovering proliferative signals and neurogenesis.     

The effect of repeated electroconvulsive shock on GABA synthesis and release in regions of rat brain.

1 The release of endogenous gamma-aminobutyric acid (GABA) from slices of rat cortex, hippocampus and striatum prepared both 30 min and 24 h after the last of a series of electroconvulsive shocks (5 seizures given spread out over 10 days) has been investigated. 2 No change in spontaneous (basal) release was observed. However, 30 min after the last convulsion, K+-evoked GABA release above basal release was inhibited in both hippocampus (20%) and striatum (33%) but not in the cortex. Release was still inhibited in striatum (22%) 24 h after the last seizure. 3 In confirmation of an earlier report, chronic electroconvulsive shock was found to increase basal GABA content in striatum and inhibit synthesis by 34%. The synthesis rate was also inhibited in the hippocampus (44%) but not in the cortex. 4 Glutamic acid decarboxylase activity was unchanged in all regions after repeated electroconvulsive shock treatment. 5 It is proposed that repeated electroconvulsive shocks lead to a substantial inhibition of release in the striatum and hippocampus and a long-term inhibition of GABA synthesis in these regions. Such changes may be associated with the altered monoamine biochemistry and function observed after repeated electroconvulsive shock and with the mechanism of the antidepressant action of electroconvulsive therapy.     

Serum dopamine-beta-hydroxylase in depressed patients and the effect of electroconvulsive shock treatment

Serum dopamine-beta-hydroxylase (DBH) activity was studied in unipolar and bipolar depressed patients who were free of medication and in normal controls. No significant difference was found. A second group of depressed patients were studied during a course of electroconvulsive shock treatment (ECT). A small, but significant, increase in DBH activity was found 5 min after a single modified convulsion, suggesting release of DBH into the circulation. Also a small, but significant, increase in the baseline level of DBH activity was found at the ninth treatment compared to the first treatment. A single electroconvulsive shock administered to rats produced a significant elevation of both plasma epinephrine and norepinephrine at 1 and 5 min post convulsion and a significant, but smaller, elevation of plasma DBH at 5 min post convulsion in adrenalectomized rats.     

Opioid receptors in the brain of the rat following chronic treatment with desipramine and electroconvulsive shock

The effect of chronic administration of electroconvulsive shock and the antidepressant drug desipramine on binding to opioid receptors was studied in the cerebral cortex, the basal ganglia and the hippocampus of the forebrain of the rat. In vitro, desipramine inhibited the binding of enkephalinamide to opioid receptors through a reduction in the number of binding sites, whereas the affinity was unchanged or only slightly decreased. In vivo desipramine, injected daily (10 mg/kg) for three weeks, did not change the number of opioid binding sites in the forebrain of the rat. Chronic electroconvulsive shock, given twice a week for three weeks, had no effect on the number of opioid binding sites in the forebrain of the rat. The data do not support the hypothesis of shared effects of lithium, tricyclic antidepressants and electroconvulsive shock on the opiod peptide-opioid receptor systems.     

人参皂苷Rg1对铅所致大鼠海马CA1区长时程增强损伤的影响(英文)

目的研究人参皂苷Rg1对铅引起的大鼠海马CA1区长时程增强(LTP)的损伤是否有修复作用。方法 Wistar大鼠从出生至断奶通过母乳摄入铅(母鼠每天饮用0.2%醋酸铅溶液20 mL),在出生后的20 ～25 d记录其海马CA1区兴奋性突触后电位并诱导长时程增强。结果人参皂苷Rg1 (50μmo.lL-1)灌流对照组和铅暴露组大鼠海马脑片20min均能诱导出LTP,铅暴露组大鼠的LTP幅度较对照组低。在铅暴露组大鼠的海马脑片上,高频刺激(HFS,1 s, 100 Hz)诱导的LTP较对照组显著降低, 50μmol.L-1人参皂苷Rg1灌流20 min,HFS诱导的LTP幅度提高47.1%。结论人参皂苷Rg1能够提高基础的突触传递,并能部分修复铅损伤的HFS-LTP。