培养的海马神经元致痫模型中钙离子的动力学研究

以往的研究证实，癫痫发作中存在神经元内钙离子(Ca^2 )超载现象，这种异常的Ca^2 内流是神经元同步化放电的先决条件，同时也能触发神经元一系列病理生理改变，导致神经元损伤和可塑性的改变。我们利用培养的海马神经元致痫模型，对神经元内游离钙离子([Ca^2 ]i)的时空分布和动力学进行研究，以探讨[Ca^2 ]i在痫性活动中的作用。     

凝血酶对原代培养海马神经元游离钙浓度的影响

目的研究凝血酶对原代培养海马神经元内游离Ca^2 水平的影响。方法采用原代培养大鼠海马神经元方法，用钙离子指示剂Fura-2双波长荧光检测凝血酶对海马神经元内游离钙浓度的影响。结果(1～40)U／ml凝血酶可使海马神经元内游离Ca^2 水平显著升高，且呈剂量依赖性。凝血酶受体激活肽可明显升高细胞内游离[Ca^2 ]i。当胞外Ca^2 为1．3mmol／L时，40U／ml凝血酶可使海马神经元游离[Ca^2 ]i明显增加；而当胞外Ca^2 为0．0mmol／L时，40U／ml凝血酶不影响海马神经元游离[Ca^2 ]i。预先加入MK-801可显著降低凝血酶的升钙作用。结论凝血酶使神经细胞内游离Ca^2 浓度异常升高的作用机制可能是通过激活凝血酶受体，继而激活NMDA受体门控的Ca^2 通道介导胞外Ca^2 大量内流。     

颞叶癫痫与学习、记忆障碍

颞叶癫痫的发作与海马等边缘系统的病变密切相关,而海马等结构又参与了学习、记忆等认知功能的形成。最近有关颞叶癫痫发作后引起的学习、记忆功能障碍逐渐得到人们的认识和重视。学习记忆的神经生物学机制是十分复杂的,本文从学习、记忆的解剖基础、突触修饰理论、长时程增强、神经细胞内钙离子等方面,对颞叶癫痫发作后引起的学习记忆障碍的机制进行了综述。     

红藻氨酸所致癫痫大鼠海马阿片受体表达的动态观察

目的研究红藻氨酸癫痫大鼠海马神经元阿片受体表达动态变化。方法利用红藻氨酸颈部皮下注射,诱发大鼠癫痫发作,用Westernblotting方法,检测不同时间段大鼠海马神经元阿片受体表达情况。结果在诱发4,5级癫痫发作后1周后海马mu型阿片肽受体（MORs）表达开始上调,至4周时达到高峰。结论红藻氨酸诱导的癫痫发作促进海马MORs表达,这种变化对进一步深入了解海马mu型阿片肽受体介导大鼠癫痫发作敏感性形成具有一定的意义。     

NO-cGMP-Glu-[Ca~(2 )]i途径在隔-海马通路损伤的大鼠学习功能障碍中的作用

为探讨海马中一氧化氮影响大鼠学习能力的机制，观察海马中一氧化氮（NO）降低后海马cGMP、谷氨酸（Glu）、胞内游离钙离子（[Ca2 ]i）含量的变化。结果表明海马中NO降低的同时cGMP、Glu和[Ca2 ]i也降低。提示海马中NO可能是通过NO－cGMP－Gin-[Ca2 ]i途径影响大鼠的学习能力。     

立体定向技术建立大鼠颞叶癫痫模型

目的 探讨立体定向技术在建立大鼠颞叶癫痫模型的实用性及模型长久癫痫敏感性的病理学基础。方法 按公斤体重计算的红藻氨酸剂量，应用立体定向手术一次性注入大鼠的海马组织，于手术后不同的时间段观察大鼠的癫痫发作情况和海马组织的形态学变化。结果 手术后的大鼠在经历“湿狗样抖动”、口唇和头的自运动症、前肢抽搐、后肢抽搐后，进入强直一阵挛性全身发作。以后，每周均有自行发作，发作表现与人类颞叶癫痫发作基本一致。海马神经元的缺失、胶质细胞增生是模型长期癫痫敏感性的基础。结论 立体定向手术建立的大鼠颞叶癫痫模型发作形式、病理学基础与人类的颞叶癫痫基本一致，并且具有长期的癫痫敏感性。同时，应用立体定向技术局部注药，用药量较系统给药明显减少，耗资大大降低，是临床科研中既可靠又经济实用的方法。     

凝血酶对原代培养海马神经元游离钙浓度的影响

目的研究原代培养的海马神经元内游离Ca2 水平及凝血酶的影响.方法大鼠海马神经元进行体外原代培养,用钙离子指示剂Fura-2双波长法测定海马神经元内游离[Ca2 ]i及不同浓度的凝血酶作用后细胞内[Ca2 ]i.结果原代培养的海马神经元生长旺盛,密度高,符合实验要求.在胞外Ca2 浓度为0.0 mmol/L时,静息状态下海马神经元游离[Ca2 ]i为(79.83±18.78)nmol/L.当胞外Ca2 浓度为1.3 mmol/L时,海马神经元游离[Ca2 ]i为(106.41±22.53)nmo1/L.(1～40)U/ml凝血酶可使海马神经元内游离Ca2 水平显著升高,与对照组相比均有显著性差异(P＜0.01).随凝血酶浓度的增加,胞内游离[Ca2 ]i之呈剂量依赖性增加.结论凝血酶可使原代培养的海马神经元内游离Ca2 浓度明显升高.     

血管性痴呆大鼠认知功能及nNOS的表达

目的 探讨血管性痴呆(VD)大鼠认知功能、海马神经元结构及nNOS的表达.方法 采用双侧颈总动脉结扎法制备慢性前脑缺血动物模型,40只老龄大鼠随机分为假手术组(S)、模型组(M).应用水迷宫、透射电镜及免疫组化方法对2组大鼠学习记忆、神经元结构、nNOS表达进行观察.结果 与假手术组比较,大鼠水迷宫学习记忆能力在造模2个月后差异有统计学意义(P＜0.05),大鼠海马神经元在造模后变性水肿明显,大鼠海马及颞叶皮层nNOS在造模2个月后表达增加 (P＜0.05).结论 海马及颞叶皮层nNOS表达增加,神经元变性,可能导致血管性痴呆大鼠学习记忆障碍.     

血管性痴呆大鼠学习记忆障碍及脑组织生长抑素的变化

目的探讨生长抑素（SS）参与血管性痴呆（VD）大鼠学习记忆障碍的作用机制。方法采用双侧颈总动脉结扎法制备慢性前脑缺血动物模型，随机分为假手术组（S）、模型组（M）。造模2月后进行水迷宫试验，观察2组大鼠空间学习记忆能力的差异，应用免疫组化方法检测造模2月后VD大鼠海马及颞叶皮层生长抑素表达变化。结果与假手术组比较，大鼠水迷宫学习记忆能力在造模2月后差异有显著性意义（P〈0．05），大鼠海马及颞叶皮层SS表达在造模2月后降低（P〈0．05）。结论脑组织SS表达降低，导致血管性痴呆大鼠学习记忆障碍。     

APETX2对氯化锂-匹鲁卡品诱导痫性发作大鼠的影响及机制探究

目的 探索APETX2对氯化锂-匹鲁卡品诱导痫性发作大鼠的行为学影响及可能的机制。方法 成年雄性SPF级SD大鼠18只,侧脑室置管后随机分为:癫痫组(9只)、APETx2组(9只),癫痫造模后观察2组癫痫大发作潜伏期及发作强度; APETx2处理原代培养海马神经元,动态观察其对钙成像的影响。结果 APETx2组的SD大鼠癫痫潜伏期延长,大发作程度减轻; APETx2处理原代培养海马神经元钙内流下降。结论 APETx2可抑制氯化锂-匹鲁卡品诱导SD大鼠痫性发作,减少酸诱导海马神经元钙离子浓度增加可能为机制之一。     

Genetic findings in obsessive-compulsive disorder in childhood and adolescence and in adulthood

Obsessive-compulsive disorders (OCD) are on the rise, and affected children, 1-2% of the general population, often are seriously impaired in their development. OCD is characterized by recurrent, intrusive and disturbing thoughts as well as by repetitive stereotypic behaviours. Depending on their age and developmental status, patients usually try unsuccessfully to suppress the obsessive thoughts and compulsive behaviours. The current state of genetic research on OCD and early-onset OCD is presented and discussed. OCD, especially early-onset OCD, has been shown to be familial. Convincing evidence indicates that both environmental and genetic factors substantially influence OCD. Various approaches, including linkage and association studies, yielded conflicting results as well as the notion that multiple genes of modest effect sizes, in interaction with environmental factors, cause vulnerability to the disorder. The phenotypic and genetic heterogeneity of OCD complicate the identification of specific genetic factors. Further studies have to be designed in consideration of subtypes, e.g. age at onset, symptom dimensions, or comorbid disorders.     

Changes in extra- and intracellular pH in the brain during and following ischemia in hyperglycemic and in moderately hypoglycemic rats

Incomplete forebrain ischemia of 15-min duration was induced in rats made hyperglycemic or moderately hypoglycemic prior to ischemia. Tissue CO2 tension, CO2 content, labile tissue metabolites, and extracellular pH (pHe) were measured, and intracellular pH (pHi) was derived by calculation on the assumption that cerebral intracellular fluids can be lumped into one space. In hypoglycemic animals, mean tissue lactate content increased from 2 to 10 mumol g-1. Tissue CO2 content was virtually unchanged and the CO2 tension increased from approximately 50 to approximately 145 mm Hg. In hyperglycemic animals, tissue lactate content rose to 20 mumol g-1, and the CO2 content decreased by 25%, demonstrating that some CO2 was lost to the blood supplied by the remaining perfusion. Accordingly, tissue CO2 tension did not rise above 200 mm Hg. pHe was reduced in proportion to the amount of lactate accumulated, the values obtained in hypo- and hyperglycemic animals showing relatively little scatter (6.76 +/- 0.03 and 6.25 +/- 0.04, respectively). In hypoglycemic animals the extracellular HCO-3 concentration was virtually unchanged, demonstrating that any influx of lactic acid from the cells must have been accompanied by H+ efflux and/or HCO-3 influx via independent routes. In hyperglycemic animals [HCO-3]e fell by greater than 10 mumol ml-1. In both groups [HCO-3]e was reduced during the first 5 min of recovery. Recovery of pHe was slower in hyper- than in hypoglycemic animals. During ischemia calculated pHi fell to 6.37 +/- 0.04 and 5.95 +/- 0.06 in hypo- and hyperglycemic animals, respectively. Differences in pHi were maintained for the first 15 min of recovery, but in both hypo- and hyperglycemic animals pHi had normalized after 30 min. It is concluded that preischemic hyperglycemia leads to a more pronounced intra- and extracellular acidosis than normo- and hypoglycemia, an acidosis that also resolves more slowly during recirculation.     

Dopamine-derived alkaloids in alcoholism and in Parkinson's and Huntington's diseases

Summary Tetrahydroisoquinoline (TIQ) alkaloids and 1-carboxy TIQ derivatives have been found in human fluids and/or tissues. The possible biosynthetic pathways of salsolinol (Sal), taken as an example of TIQs, are discussed, and the possibility that biosynthesis occurs through a stereospecific enzymatic reaction is considered. In this respect, it is reported that the R enantiomer of Sal predominates in urines of healthy volunteers, whereas the S enantiomer predominates in port wine and possibly in other beverages and foods, suggesting that Sal present in humans could have, at least partially, and endogenous enzymatic origin.TIQs and other dopamine-derived alkaloids are weak MAO inhibitors, the R enantiomer of Sal and salsolidine being more potent than the S form.The changes in monoamine oxidase activity and the nigrostriatal concentrations of dopamine and homovanillic acid in Parkinson's and Huntington's diseases and in alcoholism are reviewed. In these pathological situations, changes in the levels of dopamine-derived alkaloid levels may occur. The possibility that the modifications found might cause or contribute to changes in mental and/or neurophysiological states in these pathological situations is considered.