慢性脑缺血海马CA1区HCN1蛋白表达下调与学习记忆损伤研究

目的 探讨慢性脑缺血导致大鼠认知功能障碍与HCN1通道亚型蛋白表达变化的内在关系。方法 健康成年雄性SD大鼠20只,随机分为假手术组、缺血组,每组各10只。各组缺血4周后采用Morris水迷宫检测大鼠学习记忆功能,免疫组化检测HCN1表达水平,进一步用蛋白印迹检测HCN1蛋白表达水平。结果 与假手术组相比,缺血组大鼠逃避潜伏期明显延长(P<0.05); 缺血组大鼠海马CA1区HCN1蛋白表达水平明显降低,与模型组比较有明显差异(P<0.05)。结论 慢性脑缺血海马CA1区存在HCN1通道亚型表达下调且参与大鼠认知功能损伤,可能为治疗慢性脑缺血所致认知功能障碍的新靶点。     

p38MAPK在脑缺血后处理大鼠海马区的表达与意义

目的观察脑缺血后处理大鼠海马区神经元p38MAPK表达变化,探讨脑缺血后处理的脑保护机制。方法将96只雄性SD大鼠随机均分为假手术组(Sham组)、脑缺血组(IR组)、脑缺血后处理组(IpostC组)。Sham组只切开头部皮肤不电凝,分离颈总埋线不夹闭。IR组采用改良的Pulsinelli四血管闭塞(4-VO)法制作全脑缺血大鼠模型,缺血时间20min;IpostC组于IR组恢复再灌注前给予再灌注15s/缺血15s,重复3次处理。每组又按恢复再灌注后6h、24h、48h、72h分为4个亚组(每个亚组8只大鼠)。应用光镜观察各组大鼠海马区神经元形态变化;免疫组织化学染色和Western Blot检测海马区磷酸化p38MAPK表达情况。结果 IR组大鼠海马区神经元结构损伤严重,各时间点神经元坏死率增加,神经元磷酸化p38MAPK表达增多,差异有统计学意义(P0.05);与IR组比较,IpostC组大鼠海马区神经元结构损伤明显改善,各时间点神经元坏死率下降,神经元磷酸化p38MAPK表达明显增多,差异有统计学意义(P0.05)。结论脑缺血后处理对全脑缺血再灌注损伤具有保护作用,其机制可能与下调p38MAPK表达有关     

丁咯地尔对慢性脑缺血大鼠海马CA1区星形胶质细胞及认知障碍的影响

目的研究丁咯地尔对慢性脑缺血大鼠海马CA1区星形胶质细胞和认知障碍的影响。方法采用双侧颈总动脉永久性结扎制备慢性脑缺血模型,治疗组大鼠给与丁咯地尔灌胃,免疫组化法多克隆抗血清GFAP标记海马CA1区星形细胞,用Y-型迷宫测定大鼠的认知功能变化。实验研究为持久性2VO2个月。结果慢性脑缺血2个月后大鼠海马CA1区星形胶质细胞大量增生肥大,认知能力明显下降,丁咯地尔治疗后,星形胶质细胞的活动明显减少,认知功能明显提高。结论丁咯地尔能抑制慢性脑缺血大鼠海马CA1区星形胶质细胞反应,改善其认知功能障碍。     

慢性脑缺血海马CA1区微血管LRP-1的表达及其对认知功能的影响

目的探讨慢性脑缺血大鼠海马CA1区微血管LRP—1表达与认知功能改变的相关性。方法应用双侧颈动脉结扎的方法制作SD大鼠慢性缺血模型;Morris水迷宫对大鼠的认知功能进行测试;免疫组化技术测定海马CA1区微血管LRP-1,Ⅷ因子相关抗原及GFAP的表达;放免技术对脑脊液Aβ蛋白的浓度进行测定。采用 MIAS图像分析系统对免疫组化结果进行平均光密度测定及微血管计数。结果术后1个月手术组大鼠认知功能已明显下降,寻找平台所需游走的距离较假手术显著延长。术后6个月手术组大鼠海马CA1区微血管LRP-1的表达较假手术组大鼠显著降低;GFAP的表达显著增强;但VIII因子相关抗原的表达及微血管计数两组之间无显著差异。微血管LRP-1表达与水迷宫成绩呈负相关。手术组大鼠脑脊液Aβ蛋白含量较假手术组显著下降。结论慢性缺血过程中,大鼠认知功能下降与海马CA1区微血管LRP-1的表达下降有显著相关性。     

亚低温对大鼠全脑缺血再灌注损伤后海马CA1区c-Jun蛋白表达的影响

目的研究亚低温对大鼠全脑缺血再灌注损伤后海马CA1区神经元的保护作用,并探讨其可能的机制。方法采用四血管阻断法建立大鼠全脑缺血模型。SD大鼠,随机分为假手术组(SH组)、常温组(IR组)和亚低温组(HIR组)。各组在全脑缺血15min后分别再灌注6h、12h、1d、3d,采用苏木素-伊红(HE)染色观察各时间点海马CA1区细胞形态学变化和TUNEL法检测海马CA1区神经元凋亡,免疫印迹检测c-Jun蛋白表达。结果(1)HE染色结果 IR组和HIR组于全脑缺血再灌注后6h,HE染色未见明显改变,IR组缺血再灌注1d时CA1区出现严重改变,3d时损伤最严重,出现细胞数目减少,细胞胞体缩小、胞核固缩深染,损伤严重,排列紊乱,核膜不清,核仁消失。而HIR组海马存活的锥体细胞数较之IR组12h、1d、3d时间点均明显增加(P<0.05)。(2)TUNEL标记IR组于缺血再灌注后6h在海马CA1区阳性细胞开始增多,缺血再灌注1 d时阳性细胞数最多。而HIR组各时间点阳性细胞数均较IR组明显减少(P<0.01)。(3)免疫印迹结果全脑缺血再灌注后6h c-Jun蛋白在IR组海马CA1区表达开始增加,12h达高峰,持续到3d;HIR组在各时间点的表达均弱于IR组(P<0.01)。结论亚低温通过减少海马CA1区c-Jun的表达,抑制海马CA1区神经元的凋亡,可能是亚低温脑保护作用的机制之一。     

尼莫地平对慢性脑缺血大鼠认知和海马CA1区NOS亚型的影响

目的 探讨尼莫地平对慢性脑缺血大鼠海马CA1区三种一氧化氮合酶亚型(nNOS、iNOS、eNOS)的表达和认知的影响.方法 24只大鼠随机分为假手术组、模型组和治疗组,双侧颈总动脉永久结扎造模,治疗组于术后24h开始用尼莫地平(10mg/kg,2次/d)灌胃,连续60d,各组于60d后用Y型迷宫测试认知功能,测试结束后做免疫组化染色,观察计算海马CA1区每个高倍镜视野下的阳性细胞均数.结果 与假手术组相比,模型组认知能力下降,海马CA1区nNOS和eNOS表达下降,iNOS表达增强,治疗组的各项指标介于两者之间.结论 尼莫地平能改善慢性脑缺血大鼠的认知能力,其机制可能与提高海马CA1区nNOS和eNOS的表达及抑制iNOS的表达有关.     

小檗碱对大鼠脑缺血后MCP-1表达的影响

目的探讨小檗碱处理对大鼠脑缺血后单核细胞趋化蛋白-1（MCP-1）表达的影响及小檗碱对脑缺血的神经保护作用。方法建立大鼠短暂性全脑缺血模型，采用尼氏体亚甲蓝染色观察脑缺血后大鼠脑海马CA1区神经元存活情况；采用免疫荧光染色方法检测脑缺血后大鼠缺血脑组织中MCP-1的表达情况。结果（1）与假手术组比较，脑缺血组大鼠脑海马CA1区神经元明显缺失，而小檗碱处理组大鼠脑海马CA1区神经元存活数明显多于缺血对照组；（2）与假手术组比较，脑缺血组大鼠脑缺血区MCP-1表达显著增多，而小檗碱处理显著降低了大鼠脑缺血区MCP-1的阳性表达。结论脑缺血引起MCP-1表达上调，提示MCP-1可能参与脑缺血损伤。小檗碱可抑制缺血脑组织MCP-1的表达，推测其可能经此途径减轻脑缺血的炎症反应而发挥一定的神经保护作用。     

胰岛素对脑缺血后鼠海马CA1区神经元凋亡及记忆影响

目的　观察胰岛素对全脑缺血后海马CA1区神经元凋亡及大鼠学习记忆力改变的影响 ,探讨胰岛素对全脑缺血后海马CA1区神经元产生中枢直接保护作用的机理。方法　利用 4 VO法制作大鼠全脑缺血模型。造成脑缺血 15min后行再灌注 ,于再灌注后即刻经脑室注入 1U胰岛素 ,利用免疫组化及原位标记法分别于全脑缺血后 1、3d观察海马CA1区Bcl 2、Bcl xl蛋白表达及神经元凋亡的情况 ;缺血后 8周 ,利用“Y”型迷宫测试大鼠的学习记忆功能。结果　全脑缺血后 3d ,缺血组大鼠海马CA1区Bcl 2、Bcl xl蛋白的表达呈阴性 ,海马CA1区原位标记阳性细胞计数为 14 3.5± 11.6。治疗组大鼠海马CA1区Bcl 2、Bcl xl蛋白呈阳性表达 ,海马CA1区原位标记阳性细胞计数为 75 .6±6 .7。全脑缺血后 8周 ,治疗组大鼠学习记忆力明显好于缺血组。结论　全脑缺血后脑室内注入胰岛素可促进海马CA1区Bcl 2、Bcl xl蛋白表达 ,减少神经元的凋亡 ,进而减轻脑缺血后大鼠的学习记忆力损害 ,这可能是其对全脑缺血后海马CA1区神经元产生中枢直接保护作用主要机理之一     

慢性脑缺血老龄大鼠海马NMDA受体亚单位NR2B表达的特征

目的研究老龄大鼠慢性脑缺血后大脑海马中NR2B表达特征。方法应用免疫组化染色技术检测大鼠脑海马中CA1、CA3区和齿状回中NR2B的表达。结果缺血组海马CA1、CA3区和齿状回三处NR2B灰度值均低于对照组,差异具有统计学意义(P<0.05)。结论老龄大鼠海马结构内CA1、CA3区及齿状回内NR2B的表达明显减少。     

参芎化瘀胶囊对脑缺血-再灌注大鼠海马细胞凋亡机制的研究

目的探讨参芎化瘀胶囊对脑缺血-再灌注损伤的保护作用及机制。方法通过改良的Pulsineli 4血管阻断(4-VO)法制作全脑缺血-再灌注大鼠模型。72只雄性SD大鼠随机分成假手术组、模型组、参芎化瘀胶囊组。术后首先应用尼氏体和TUNEL染色研究缺血-再灌注后大鼠海马区神经元的形态学变化和凋亡情况,然后以免疫组织化学法检测海马区p38MARK的表达。结果假手术组相比,模型组可见大量的凋亡细胞,p38MARK蛋白表达增多,参芎化瘀胶囊组的凋亡细胞数量较模型组明显减少(p<0.05),p38MARK蛋白表达水平较低(p<0.05)。结论参芎化瘀胶囊对脑缺血-再灌注损伤的保护作用与调控p38MAPK信号通路抑制神经细胞凋亡有关。     

Denervation study of synapses of organ of corti of old world monkeys

Fine structural characteristics of synapses in the spiral organ of Corti were examined, with reference to differences between inner and outer haircell systems, and to location of neurons of origin of efferent axons. Surgical interruption of crossed olivocochlear bundle, of vestibular nerve, of facial nerve, and excision of superior cervical ganglia were used to determine the pathways of efferent axons. Interruption of the vestibular nerve near the brainstem results in degeneration of all efferent terminals on outer hair cells. Mid-line lesions at, and caudal to, the facial colliculus result in degeneration of about half of these efferent terminals. Efferent synaptic bulbs to the inner hair-cell system are small, of the order of one micron, and form type 2 junctions with afferent dendrites. They tend to have more large dense-core vesicles (about 80 nm) than the large efferent terminals of the outer hair-cell system, and appear to be the terminals of axons in the habenula perforata, which exhibit varicosities laden with large dense core vesicles. The varicosities are unaffected by excision of the superior cervical ganglia. So far as our material can reveal, it appears that the varicosities in the habenula perforata do not survive vestibular root interruption, nor do the efferent processes in the internal spiral bundle or at the base of inner hair cells. Most interestingly, the afferent processes of the inner hair-cell system, as identified for example by their relation to pre-synaptic bodies in the inner hair cells, are subject to a trans-synaptic reaction after severance of the vestibular root. They undergo a dramatic cytological transformation, characterized by increase of volume, engorgement with microtubules, microfilaments, microvesicles of various sizes, and clusters of lysosomes. Thus, both the efferent and afferent terminals of the inner hair-cell system show marked cytological differences from the corresponding terminals of the outer hair cell system.     

Mechanism of action of tubocurarine on nicotinic cholinoreceptors of neurons of the sympathetic ganglia of rats

Tubocurarine (Tc) effect on membrane currents elicited by acetylcholine (ACh) was studied in isolated superior cervical ganglion neurons of rat using patch-clamp method in the whole-cell recording mode. The "use-dependent" block of ACh current by Tc was revealed in the experiments with ACh applications, indicating that Tc blocked the channels opened by ACh. Mean lifetime of Tc-open channel complex, tau, was found to be 9.8 +/- 0.5 s (n = 7) at -50 mV and 20-24 degrees C. tau exponentially increased with membrane hyperpolarization (e-fold change in tau corresponded to the membrane potential shift by 61 mV). Inhibition of the ACh-induced current by Tc (3-30 microM/1) was completely abolished by membrane depolarization to the level of 80-100 mV. Inhibition of ACh-induced current was augmented at increased ACh doses. It is concluded that the open channel block produced by Tc is likely to be the only mechanism for Tc action on nicotinic acetylcholine receptors in superior cervical ganglion neurons of rat.     

The effect of age of onset of PD on risk of dementia

Background Dementia occurs in the majority of patients with Parkinson’s disease (PD). Late onset of PD has been reported to be associated with a higher risk for dementia. However, age at onset (AAO) and age at baseline assessment are often correlated. The aim of this study was to explore whether AAO of PD symptoms is a risk factor for dementia independent of the general effect of age. Methods Two community-based studies of PD in New York (n = 281) and Rogaland county, Norway (n = 227) and two population-based groups of healthy elderly from New York (n = 180) and Odense, Denmark (n = 2414) were followed prospectively for 3–4 years and assessed for dementia according to DSM-IIIR. All PD and control cases underwent neurological examination and were followed with neurological and neuropsychological assessments. We used Cox proportional hazards regression based on three different time scales to explore the effect of AAO of PD on risk of dementia, adjusting for age at baseline and other demographic and clinical variables. Findings In both PD groups and in the pooled analyses, there was a significant effect of age at baseline assessment on the time to develop dementia, but there was no effect of AAO independent of age itself. Consistent with these results, there was no increased relative effect of age on the time to develop dementia in PD cases compared with controls. Interpretation This study shows that it is the general effect of age, rather than AAO that is associated with incident dementia in subjects with PD. Received in revised form: 22 December 2005     

Limits of deinstitutionalization--perspectives of relatives of psychiatric patients

After a hopeful beginning, the social process of the reintegration of those with severe mental illness has come to a standstill. I am led to wonder whether "the community" really wants to live together with people suffering from severe mental illness, and if so, how closely? As long as the medical treatment of mental illness provided by the general practitioners is fundamentally deficient, as they are not able to prescribe the necessary interventions--such as out-patient psychiatric nursing, and service providers in the out-patient sector are content with offering increasingly intensive forms of care for the less seriously ill at the cost of the Social Welfare System--the reintegration of those with serious mental illness remains an illusion--which is mainly to the benefit of providers of residential care in homes and hostels.