慢性酒精中毒大鼠学习记忆及Meynert基底核胆碱能神经元的变化

目的研究酒精致大鼠学习记忆障碍与Meynert基底核(NBM)胆碱能神经元变化的关系。方法将24只雄性Wister大鼠随机均分成对照组和酒精中毒组,酒精中毒组大鼠隔日胃内注入含酒精(2.5 g/kg)的蒸馏水2 ml共90d,对照组则注入不含酒精的蒸馏水2 ml。然后采用Morris水迷宫和免疫组织化学技术,分析大鼠Meynert基底核胆碱能神经元、额叶皮层星形胶质细胞数的变化和学习记忆能力的关系。结果酒精中毒组大鼠Morris水迷宫潜伏期明显延长,Meynert基底核胆碱能神经元数目明显减少,额叶皮层星形胶质细胞数目反应性增生。结论酒精致大鼠学习记忆能力障碍与Meynert基底核胆碱能神经元减少有关。     

去脑皮层血管对大鼠前脑大细胞基底核AChE、ChAT、BDNF、trkB及其mRNA表达的影响

本研究采用去除大鼠皮层血管建立的血管性痴呆模型。去除皮层血管后 ,发现大鼠前脑大细胞基底核胆碱能神经元的ACh E、Ch AT、BDNF、trk B及其 m RNA的表达明显降低。结果说明 ,去皮层血管后造成的大细胞基底核的损害是继发皮质损害的逆行性变性 ,大鼠去皮层血管后 ,皮质、海马等处神经元靶源性的 BDNF、trk B及其 m RNA的表达降低 ,逆行性运输到大细胞基底核的胆碱能神经元的 BDNF减少 ,导致大细胞基底核神经元的变性、坏死     

不同年龄大鼠斜角带核水平支神经元内TrkA和ChAT的表达——免疫组织化学研究

目的 了解大鼠基底前脑斜角带核水平支神经元内酪氨酸激酶Ａ（ｔｙｒｏｓｉｎｅ ｋｉｎａｓｅ,Ａ,ＴｒｋＡ）、胆碱乙酰化转移酶（ｃｈｏｌｉｎｅ ａｃｅｔｙｌｔｒａｎｓｆｅｒａｓｅ,ＣｈＡＴ）样阳性神经元的生后发育规律及两乾的相互关系。方法 用免疫组织化学方法结合图像分析仪检测大鼠基底前脑斜角带核水平支ＴｒｋＡ、ＣｈＡＴ样阳性神经元的数量、面积和灰度值。结果 ＴｒｋＡ、ＣｈＡＴ分布于基底前脑神经元。生后１ｄ可见ＴｒｋＡ表达,但生后５ｄ才出现ＣｈＡＴ表达。生后２０ｄＴｒｋＡ、ＣｈＡＴ表达至高峰;生后３０ｄ下调,成年时维持相对较高水平。老年鼠ＴｒｋＡ、ＣｈＡＴ样阳性神经元出现萎缩、数量也分别减少３９．７％、３３．３％;胞体平均面积分别减少１５．７％、１２．８％;平均灰度值分别减少２９．９％、９．９％。同时,不同年龄大鼠Ｔ     

神经干细胞移植对老年痴呆模型鼠基底前脑胆碱能神经元和学习记忆能力的影响

目的:探讨神经干细胞移植对老年性痴呆模型鼠基底前脑胆碱能神经元及学习记忆能力的影响.方法:利用无血清培养技术获得新生SD鼠的基底前脑神经干细胞,切断SD大鼠左侧穹隆海马伞,基底前脑注射神经干细胞.4周后行Y迷宫测试学习记忆能力,免疫组化结合图像分析技术观察各组大鼠基底前脑胆碱能神经元变化.结果:损伤组损伤侧的内侧隔核(MS)和斜角带核(VDB)的NGFR阳性神经元大量减少,分别减少59.7%和5 1.4%.NSC移植组损伤侧的NGFR阳性神经元得到补充和保护,MS和VDB细胞数分别下降22.0%和26.1%.同时,NSC移植组损伤侧MS的NGFR阳性神经元的面积、周长显著增大(P＜0.01),灰度显著增加(P＜0.01);损伤侧VDB的NGFR阳性神经元的面积明显增大且灰度明显增加(P＜0.05),周长显著增大(P＜0.01).Y迷宫测试结果显示,NSC移植组大鼠的空间学习能力得到明显改善(P＜0.05),记忆能力得到显著提高(P＜0.01),基底前脑NGFR阳性细胞数与大鼠的空间学习记忆能力呈正相关.结论:神经干细胞移植对老年性痴呆模型鼠基底前脑胆碱能神经元有明显的补充和保护作用,同时大鼠的学习记忆能力得到明显的改善.     

Alzheimer病模型大鼠海马生长抑素神经元变化

目的：检测早老型痴呆(Alzheimer，AD)模型大鼠海马内生长抑素(Somatostatin，SS)神经元变化。方法：模型组用D-半乳糖和鹅膏蕈氨酸(Ibotenic acid，IBO)损毁Meynert核联合造模。运用免疫组化ABC法结合图像分析，检测并统计2组大鼠海马SS阳性神经元数目、截面积和灰度值。结果：模型组大鼠海马生长抑素神经元数目减少明显，灰度值增加明显，组间差异显著；生长抑素神经元胞体截面积无明显变化。结论：D半乳糖合并IBO损毁双侧Meynert核所致AD大鼠海马生长抑素神经元衰退明显。     

大鼠脊髓全横断后TrkA和TrkB在前角运动神经元的表达

为了探讨脊髓全横断损伤后神经营养因子受体表达的变化 ,本研究取大鼠 C6 和 L5节段脊髓进行 Trk A和 Trk B的免疫组织化学反应。用 HPIAS-10 0 0高清晰度彩色图像细胞测量系统检测免疫阳性神经元的数量和平均灰度。结果显示 ,大鼠脊髓全横断后 ,两种受体 Trk A和 Trk B在运动神经元的表达均出现短暂上调 ,其中 Trk A在颈段的表达高峰出现在损伤后 14 d而腰段为损伤后 7d;与此不同 ,Trk B在颈段和腰段两个部位的表达高峰均出现在 3d。在高峰之后 ,两种受体的表达均下降 ,至术后2 8d已接近或低于正常水平。提示 ,大鼠脊髓全横断损伤后 ,神经营养因子特异性受体 Trk A和 Trk B的表达有一定的时空规律 ,即损伤后 Trk B的表达由短暂上调到表达下降 ,随之出现 Trk A的表达高峰 ,意味着 Trk B的表达下降可能促进 Trk A的表达     

秋水仙碱对基底前脑巢蛋白阳性和阴性胆碱能神经元的影响

目的:通过研究侧脑室注射秋水仙碱前后基底前脑巢蛋白阳性和阴性胆碱能神经元变化,探讨巢蛋白表达对基底前脑神经元机能的影响及其可能机制。方法:成年健康雌性SD大鼠随机分为正常对照组和侧脑室注射秋水仙碱组,术后分别于24 h、48 h、3 d、7 d、14 d和28 d取脑行冷冻切片与免疫组织化学显色,比较秋水仙碱注射后不同时间点基底前脑巢蛋白~+和巢蛋白~-胆碱能神经元的数目变化。结果:大鼠侧脑室秋水仙碱注射后24 h,基底前脑的内侧隔核(MS)、斜角带核垂直支(vDB)和水平支(hDB)的巢蛋白~+和巢蛋白的胆碱能神经元数目都急骤下降。随着时间的推移巢蛋白~+神经元数目逐渐恢复,术后14 d,巢蛋白~+神经元数目基本恢复至正常水平,但巢蛋白~-胆碱能神经元数目一直维持较低水平。结论:侧脑室注射秋水仙碱后,基底前脑巢蛋白~+和巢蛋白~-的胆碱能神经元都急骤减少,但巢蛋白~+神经元在减少后可逐渐恢复,而巢蛋白~-神经元则不能恢复。     

七氟醚处理对老龄小鼠基底前脑胆碱能系统和认知功能的影响

目的:探讨七氟醚对基底前脑胆碱能系统和认知功能的影响。方法:老年C57小鼠吸入七氟醚建立全身麻醉动物模型,利用Morris水迷宫检测认知功能,免疫荧光检测Meynert基底核中胆碱能神经元计数,Western Blot检测额叶皮层胆碱乙酰转移酶及高亲和力胆碱转运体的蛋白水平,ELISA测定额叶皮层胆碱乙酰转移酶的活性。结果:与对照组相比,七氟醚组小鼠平台潜伏期延长,平台穿越次数减少(2.1±0.4 vs 5.6±0.5,P0.05),原平台所在象限停留时间缩短[(21.5±2.4)%vs(48.6±2.8)%,P0.05]。此外,七氟醚组小鼠Meynert基底核胆碱能神经元计数减少(3748±248 vs 5942±315,P0.05),额叶皮层胆碱乙酰转移酶及高亲和力胆碱转运体表达下降,伴有胆碱乙酰转移酶活性降低[(31.4±1.1)μmol/(g.h)vs(55.8±1.3)μmol/(g.h),P0.05]。结论:七氟醚可损害老龄鼠基底前脑胆碱能系统并诱导认知功能损害。     

神经生长因子受体TrkA在新生鼠、幼鼠及成鼠脊髓表达差异的研究

为了探讨神经生长因子 ( NGF)受体 Trk A在新生鼠、幼鼠及成鼠脊髓的分布状况、进而分析 NGF的作用机制 ,用免疫组化技术检测了新生鼠、幼鼠及成鼠脊髓 NGF受体 Trk A的表达。结果显示 ,新生鼠脊髓前角运动神经元只有胞核 Trk A表达明显 ,胞浆及胞膜无表达 ,中间带、背角均无表达。幼鼠前角运动神经元胞浆 Trk A表达明显 ,胞核少量表达 ,胞膜无表达 ;部分中间带、背角神经元胞浆有表达。成鼠前角运动神经元胞浆及部分胞膜都有 Trk A表达 ,胞核无表达 ,中间带、背角神经元胞浆以及胶质细胞也明显表达。推论 ,新生鼠时胞核中 Trk A可与配体结合引起神经元的生物效应 ;成鼠 Trk A则主要作为一种膜受体与配体结合而发挥生物效应     

植物雌激素对去卵巢大鼠基底前脑胆碱能神经元的影响

目的：观察植物雌激素对去卵巢大鼠基底前脑胆碱能神经元表达的影响，探讨植物雌激素在中枢神经系统的保护作用及机制。方法：采用乙酰胆碱转移酶(ChAT)免疫组织化学ABC法，观察去卵巢大鼠5w后各组基底前脑内侧隔核(MS)，斜角带垂直支(VDB)胆碱能神经元的数目。结果：与去卵巢对照组相比，植物雌激素用药组、雌激素用药组的内侧隔核，斜角带垂直支胆碱能神经元数目明显升高(P＜0．05)，与假手术组差别不明显。结论：本研究提示植物雌激素能明显增加去卵巢大鼠基底前脑胆碱能神经元的表达，从而对中枢神经系统退行性病变起保护作用，并有望预防和治疗老年性痴呆。     

雌激素受体α和TrkA在基底前脑的分布与共存

基底前脑为神经营养因子和雌激素作用的靶区之一。为了在受体水平探讨这些配体是否作用于正在发育和成年大鼠的基底前脑同一神经元 ,本文采用免疫组织化学双重反应方法观察了雌性大鼠雌激素受体α和酪氨酸激酶 A在基底前脑的分布与共存。用小鼠抗雌激素受体和兔抗酪氨酸激酶 A分别孵育切片 ,ABC法显示前者的反应产物主要位于胞核内 ,蓝黑色 ,呈点状 ;后者位于胞质和突起内 ,呈棕色。结果表明 :两者都分布于基底前脑神经元。在双重免疫组织化学反应条件下可见三种细胞 :雌激素受体阳性细胞 ,酪氨酸激酶 A阳性细胞和双重反应阳性细胞 ,双重反应阳性细胞所占的比例因部位而不同。雌激素受体和酪氨酸激酶 A共存提示它们的配体可通过共存于基底前脑同一神经细胞上的相应受体而作用于同一神经元 ,协同地调节特异的基因或者基因网络的表达 ,从而影响神经元的存活、分化、成熟、再生和可塑性     

成人基底前脑巢蛋白免疫阳性神经细胞的细胞化学观察

目的 探讨巢蛋白(nestin)免疫阳性细胞在人基底前脑内的分布规律及化学特性。方法 采用nestin331B、10C2、Rat 401抗体显示人基底前脑的nestin免疫阳性细胞，并应用NSE、p75NGFR、ChAT、GFAP抗体分别对nestin免疫阳性细胞进行了双标免疫细胞化学研究，同时还应用NADPH-d进行组织化学染色。结果 在成人基底前脑有一个连续的nestin免疫阳性细胞带，胞体较大，呈卵圆形或梭形，有1～3个突起，分布于隔核、斜角带核、Meynert核、无名质及杏仁核群。双标染色显示，nestin阳性细胞被NSE抗体标记，并与ChAT、NGFR、NOS阳性神经元间杂分布，多数不呈交叉反应。约28％nestin免疫阳性细胞为ChAT阳性神经元，15％为NGFR阳性神经元，6％为NOS阳性神经元。此外，透明隔及隔区靠近软膜处有少量nestin免疫阳性细胞，其形态与星形胶质细胞相似，不与GFAP有交叉免疫阳性反应。结论 成人基底前脑存在一个有别于ChAT、NGFR、NOS神经元的nestin免疫阳性神经元簇，其生物学意义值得进一步研究。     

Age-related changes in rostral basal forebrain cholinergic and GABAergic projection neurons: relationship with spatial impairment

Both cholinergic and GABAergic projections from the rostral basal forebrain contribute to hippocampal function and mnemonic abilities. While dysfunction of cholinergic neurons has been heavily implicated in age-related memory decline, significantly less is known regarding how age-related changes in codistributed GABAergic projection neurons contribute to a decline in hippocampal-dependent spatial learning. In the current study, confocal stereology was used to quantify cholinergic (choline acetyltransferase [ChAT] immunopositive) neurons, GABAergic projection (glutamic decarboxylase 67 [GAD67] immunopositive) neurons, and total (neuronal nuclei [NeuN] immunopositive) neurons in the rostral basal forebrain of young and aged rats that were first characterized on a spatial learning task. ChAT immunopositive neurons were significantly but modestly reduced in aged rats. Although ChAT immunopositive neuron number was strongly correlated with spatial learning abilities among young rats, the reduction of ChAT immunopositive neurons was not associated with impaired spatial learning in aged rats. In contrast, the number of GAD67 immunopositive neurons was robustly and selectively elevated in aged rats that exhibited impaired spatial learning. Interestingly, the total number of rostral basal forebrain neurons was comparable in young and aged rats, regardless of their cognitive status. These data demonstrate differential effects of age on phenotypically distinct rostral basal forebrain projection neurons, and implicate dysregulated cholinergic and GABAergic septohippocampal circuitry in age-related mnemonic decline.     

衰老大鼠禁水时视上核加压素能神经元超微结构变化

电镜观察不同禁水时间衰老大鼠下丘脑视上核加压素能神经元的超微结构变化。结果发现：禁水６、１２ｈ后，视上核加压素能神经元胞体增大，胞质中粗面内质网排列紧密且增多，高尔基复合体成熟面未成熟分泌颗粒及神经分泌颗粒增多；轴突中神经分泌颗粒增多不明显。而禁水２４ｈ后，神经元胞质内的神经分泌颗粒减少，轴突中的神经分泌颗粒聚集成膨大区域。禁水后，神经胶质细胞减少，突起回缩，使相邻的两神经元直接接触，突触结构重建增多。上述研究结果提示，衰老大鼠下丘脑视上核加压素能神经元在禁水时，其功能活动是增强的，胶质细胞突起回缩，有利于神经元之间的突触结构重建。     

p75 mediates death of cholinergic neurons during postnatal development of the neostriatum in mice

We have previously shown that p75 nerve growth factor receptor (p75^NGFR) mediates apoptosis of 25% of the cholinergic basal forebrain neurons in normal control mice between postnatal day 6 and 15, but only of cholinergic neurons that lacked the nerve growth factor receptor TrkA. Here, we investigated whether and when the cholinergic neurons of the neostriatum, which express TrkA and p75^NGFR during early postnatal times, undergo p75^NGFR-mediated death. The cholinergic neurons in the lateral neostriatal regions expressed choline acetyltransferase (ChAT) earlier (postnatal day 3–6) than those of the medial regions and TrkA appeared before ChAT in all regions. Between postnatal day 6 and 10, 40% of the ChAT-positive neurons in the most lateral regions disappeared in control mice but not in p75^NGFR-deficient mice. During this time, the neostriatum of control, but not p75^NGFR-deficient, mice contained many apoptotic cells. This suggests that, similar to the cholinergic neurons of the basal forebrain, the neostriatal cholinergic neurons of control mice die and that this process is mediated by p75^NGFR. However, the roles of p75^NGFR and TrkA appear to be more complicated in the neostriatum where relatively few neurons express p75^NGFR during the death phase (and predominantly in the lateral neostriatum where the neuronal loss is greatest), and TrkA-positive as well as TrkA-negative neurons may be lost.     

基底前脑神经元移植到海马后ChAT、NGFR和NOS的表达变化

为了比较基底前脑神经元移植至海马后胆碱乙酰转移酶、神经生长因子受体和一氧化氮合酶神经元的变化规律。选用雄性 SD大鼠 35只 ,在单侧穹隆海马伞损伤后一周 ,将胚胎基底前脑神经元植入损伤侧海马。在移植术后存活 5 d,7d,14 d,30d,6 0 d,90 d,和 180 d共分为 7个时间组灌注取材 ,进行 Ch AT和 NGFR的免疫组织化学反应及 NOS反应 ,观察其神经元的变化。结果证明 ,Ch AT神经元在移植后 30 d方出现阳性反应 ;NGFR神经元在移植后 7d可见淡染的胞体 ,随后逐渐增强 ;NOS神经元在移植后 7d时呈明显的阳性反应 ,而且数量多。三种神经元直到 180 d时均尚呈阳性反应。提示移植物内 NOS神经元出现早且数量多 ,NGFR神经元出现的也较早 ,Ch AT神经元出现最晚。这三种物质在细胞内出现的时间和数量差异与它们在细胞内发挥的功能有关     

老龄大鼠和年轻大鼠大脑皮层胆碱能系统功能的比较研究

用脑内微透析技术结合 HPL C-柱后固定化酶反应器 -电化学检测器方法分析比较了老龄大鼠和年轻成年大鼠额叶皮层乙酰胆碱的释放 ,并探讨了它和学习记忆功能减退的相关性。老龄大鼠额叶皮层乙酰胆碱的基础水平为 ( 0 .15 5 9± 0 .18)pmol/5μl,远较年轻大鼠的 ( 0 .2 93 9± 0 .14 ) pmol/5μl为低。老龄大鼠额叶胆碱能神经元对高 [K+ ]溶液的反应较弱 ,乙酰胆碱的释放量仅增加 3 0 .18% ,而年轻大鼠可增加 96%。老龄大鼠对新异环境刺激的反应也较年轻大鼠为弱 ,但电刺激 Meynert基底核仍能明显提高老龄大鼠额叶皮层乙酰胆碱的释放。实验结果还表明 ,老龄大鼠额叶皮层的乙酰胆碱水平有较大的个体差异 ,9只老龄大鼠额叶皮层乙酰胆碱释放量的变化范围为 0 .0 0 67pmol/5 μl～ 0 .41pmol/5 μl。这种差异也反映在老龄大鼠对被动回避反应的记忆保持能力上 ,2 4h步下潜伏期和乙酰胆碱释放量有较好的相关性 ,相关系数为 0 .86。本研究所获得的实验结果对进一步阐明老龄大鼠认知性功能缺损的机制具有重要意义     

Experimental approaches to age-related cognitive impairments

Rats exhibit morphological, biochemical, and metabolic changes in their brains, as well as cognitive deficits, with aging. Aged rats were found to be significantly impaired compared to young rats in a water maze task and test of motor coordination, and show reduced locomotor activity and exploration. Although aged rats did exhibit deficits as a group, not all aged rats were impaired. Additionally, the subgroup that was impaired on one task was not necessarily the subgroup that was impaired on another task. The cholinergic projection neurons in the basal forebrain region were significantly atrophied in the aged rodent. The degree of atrophy was highly correlated with the cognitive impairment exhibited on the Morris water maze task. Swollen choline acetyltransferase (ChAT)-positive "plaque-like" structures were observed in the neocortex of the aged but not the young rats. Declines in cholinergic activity in the brain has also been observed during aging. Biochemical measurements of ChAT in the basal forebrain region of aged rats revealed small but consistent decreases in ChAT activity compared to young rats. General metabolic activity, measured by the 2-deoxyglucose method, was also decreased in the hippocampal CA1 and CA3 fields, the dentate gyrus, the medial septal-diagonal band area, and the prefrontal cortex of aged rats. There was a significant correlation between the decrease in glucose utilization and deficits on the Morris water maze. Most aged rats exhibit pathological EEG patterns as reflected by frequent long-duration high voltage neocortical spindles (HVS) during immobility. Bilateral lesions of the nucleus basalis and scopolamine treatment increased the incidence of HVS, thereby mimicking changes in the aged brain. We attempted to ameliorate the cognitive deficits observed in subgroups or impaired rats by either: (1) implanting fetal cells of basal forebrain origin into the hippocampus, or (2) infusing nerve growth factor (NGF) chronically into the lateral ventricle. The grafts appeared to facilitate an improvement in the ability of the impaired aged rats to perform in the Morris water maze. This improved performance was reversed by injections of atropine at doses that did not affect the behavior of young animals that performed well in the same task. These results suggest that enhancement of the cholinergic system could have an effect on the performance of the impaired aged animals. The study of the effects of infusions of NGF clearly demonstrate that the ability of impaired aged rats to remember what they had previously learned was increased after NGF treatment.(ABSTRACT TRUNCATED AT 400 WORDS)