小脑性共济失调大鼠模型的行为学和病理学研究

目的：评价海人酸（KA）损毁单侧小脑顶核制备的小脑性共济失调大鼠模型。方法：实验大鼠分为小脑性共济失调模型组（KA模型组）和假手术组。KA模型组采用经立体定向仪定位大鼠左侧小脑顶核注射KA毁损制备单侧小脑性共济失调模型;假手术组在相同部位注入等量生理盐水。用平衡木实验及旋转杠实验检测两组大鼠的行为学改变,并在光学显微镜下观察两组大鼠小脑顶核及小脑的病理改变。结果：KA模型组模型大鼠在平衡木上的得分减少、通过平衡木的时间延长、在旋转杠上持续运动的时间减少,与假手术组相比,差异有统计学意义（P〈0.05）。光学显微镜下病理学观察KA注射位置准确,大鼠小脑左侧顶核神经元细胞破坏,其他周围组织未受影响。在1个月的检测期内,大鼠生存能力好。结论：用KA制备的大鼠小脑性共济失调模型适用于后续的治疗研究。     

胚胎小脑悬液移植治疗小脑共济失调的实验研究

应用立体定位仪将兴奋性神经毒素海人藻酸(Kainic acid,KA)直接注入 S-D 大鼠小脑半球后内侧部,造成小脑共济失调的动物模型。用胚胎大鼠小脑制成的细胞悬液移植至模型的大鼠小脑内,用四种功能标准半定量评分观察小脑平衡行为。3个月的观察结果显示:该小脑共济失调模型能较长期保持平衡障碍的体征,而经过移植,平衡障碍得到纠正。3个月后处死动物,发现:KA 模型组γ-氨基丁酸(GABA)升高,胚胎移植后使其下降。门冬氨酸等氨基酸无明显改变。KA 组的 cGMP 下降,移植后回升至对照水平。     

食蟹猴脊髓小脑性共济失调模型的制作研究

目的 探讨食蟹猴脊髓小脑性共济失调(SCAs)模型的制作. 方法选取2只成年雄性食蟹猴,在不同的时间段内分别采用腹腔注射3-乙酰吡啶(3-AP)、静脉注射3-AP及立体定向注射3-AP损毁小脑中央核群(顶核、齿状核、栓状核)的方法制作食蟹猴SCAs模型,并建立行为学评价体系(行为学评定、取食实验、水平旋转实验等)用于食蟹猴共济运动的评估. 结果首先采用腹腔注射3-AP 8倍有效剂量并观察12周,行为学评价体系结果未出现有关共济失调的症状;再次采用静脉注射3-AP6倍的有效剂量并观察12周,行为学评价体系结果未出现有关共济失调的症状;最后立体定向注射3-AP损毁小脑中央核群,行为学评价体系结果统计分析显示造模后8周内均较造模前差异有统计学意义(P<0.05),而造模后12周起又逐步恢复至造模前状态. 结论立体定向注射3-AP损毁小脑中央核群方法可以制作食蟹猴SCAs的急性模型,行为学评定、取食实验、水平旋转实验适用于该模型的评价.     

食蟹猴脊髓小脑性共济失调模型的制作研究

目的 探讨食蟹猴脊髓小脑性共济失调(SCAs)模型的制作. 方法选取2只成年雄性食蟹猴,在不同的时间段内分别采用腹腔注射3-乙酰吡啶(3-AP)、静脉注射3-AP及立体定向注射3-AP损毁小脑中央核群(顶核、齿状核、栓状核)的方法制作食蟹猴SCAs模型,并建立行为学评价体系(行为学评定、取食实验、水平旋转实验等)用于食蟹猴共济运动的评估. 结果首先采用腹腔注射3-AP 8倍有效剂量并观察12周,行为学评价体系结果未出现有关共济失调的症状;再次采用静脉注射3-AP6倍的有效剂量并观察12周,行为学评价体系结果未出现有关共济失调的症状;最后立体定向注射3-AP损毁小脑中央核群,行为学评价体系结果统计分析显示造模后8周内均较造模前差异有统计学意义(P<0.05),而造模后12周起又逐步恢复至造模前状态. 结论立体定向注射3-AP损毁小脑中央核群方法可以制作食蟹猴SCAs的急性模型,行为学评定、取食实验、水平旋转实验适用于该模型的评价.     

小脑共济失调大鼠模型中ATM及p53的表达水平变化

目的 探讨小脑共济失调大鼠模型中共济失调毛细血管扩张突变(Ataxia telangiectasia-mutated,ATM)蛋白和p53的表达水平变化。方法 采用3-乙酰吡啶(3-acetylpyridine,3-AP)和烟酸诱导SD大鼠小脑共济失调,观察大鼠行为学变化; HE染色观察大鼠小脑组织中神经元的形态学变化; 尼氏染色观察小脑组织中神经元的缺失; 免疫组化观察小脑神经元中ATM、p53的表达水平。结果 模型组大鼠厌食,体重减轻,步态异常,平衡障碍,表型观察符合小脑共济失调模型特征; 模型组小脑组织中神经元细胞核固缩深染,且存在炎性细胞浸润分子,颗粒细胞减少,浦肯野细胞形态异常甚至缺失,神经元中ATM及p53表达水平升高,且呈现出一定的时间依赖性。结论 小脑共济失调大鼠模型小脑组织出现神经元退行性病变,可能是通过激活ATM/p53信号通路来修复细胞损伤。     

海马内注射内皮素-1导致大鼠痫性发作和海马硬化的初步研究

目的 观察大鼠海马内注射内皮素(endothelin,ET)-1是否导致大鼠痫性发作和海马硬化.方法 立体定位在成年大鼠海马CA3区内分别注射1 μL ET-1(200 pmol,15只)、海人酸(kainate,KA 5 pmol,15只)或磷酸盐缓冲液(PBS,0.01 mol,8只),观察大鼠行为学、脑电及对侧海马病理学改变.结果 海马注射PBS后大鼠未见痫性发作,脑电图呈10～15 Hz、150-200μV基本节律.注射ET-1或KA 2 h内大鼠出现不同程度的痫性发作和脑电图异常改变(尖波或尖慢波),KA组3-5级发作率高于ET-1组(86.67% vs 16.67%,P<0.05).部分ET-1和KA组大鼠在给药后2～3周可见癫痫样发作行为学改变.与PBS组比较,El-1和KA组给药后48 h对侧海马各区Nissl染色细胞数明显减少,GFAP表达增强(P<0.05);给药后30 d,对侧CA3区和门齿区苔藓纤维出芽评分高于PBS组(P<0.05).结论 海马注射ET-1可以导致大鼠癫痫样行为改变和海马硬化.     

海人酸致痫大鼠海马IL-1β、TNF-α的表达

目的 立体定向手术建立海人酸(KA)颞叶癫痫大鼠模型,检测海马内IL-1β、TNF-α蛋白及其mRNA的表达.方法 大鼠随机分为空白对照组、生理盐水对照组和模型组.模型组大鼠一侧海马CA3区注射KA (生理盐水组注射生理盐水),观察其行为学特征,HE染色和Nissl染色以及电镜观察其病理学改变,免疫组化法检测大鼠海马内IL-1β、TNF-α蛋白的表达,原位杂交法检测TNF-α mRNA的动态表达.结果 大鼠注射KA后出现湿狗样抖动、头面部肌阵挛、肢体阵挛及全面强直阵挛发作等,病理结果显示海马神经元变性、缺失及胶质细胞增生,模型组IL-1β在致痫后3 、6 h表达水平明显增加并于12 h达高峰,之后逐渐下降,7 d后与对照组相比差异无统计学意义(P＞0.05);TNF-α蛋白与mRNA表达时程基本一致,3 h出现,12 h达高峰,而后逐渐下降,7 d后回归至对照组表达水平,15 、30 d又高于对照组(P＜0.05).结论 (1)大鼠一侧海马注射KA是人类颞叶癫痫理想的动物模型;(2)内源性IL-1β、TNF-α参与了癫痫发病机制.     

红藻氨酸致痫大鼠海马突触素的表达变化及辛醇的干预作用

目的 观察红藻氨酸(kainic acid,KA)致痫大鼠海马突触素(synaptophysin,SYP)表达的动态变化及辛醇的干预作用.方法 将65只健康雄性SD大鼠随机分为空白对照组、模型组、辛醇干预组、二甲基亚砜(DMSO)组,空白对照组5只,余各组20只.采用KA注射于大鼠右侧杏仁核方法制备癫痫模型.造模前30 min给予大鼠腹腔注射辛醇进行干预,并观察辛醇干预前后大鼠行为学改变,采用免疫组化检测造模后不同时间点海马区SYP的表达水平.结果 辛醇干预组大鼠出现湿狗样摇动(WDS)的潜伏期明显长于模型组(P＜0.01),Patel评分显著低于模型组(P＜0.01);模型组大鼠海马区SYP的表达于造模后1周逐渐升高,3周时达高峰,4周后开始下降;辛醇组大鼠海马区SYP的表达在各时间点均明显低于模型组(P＜0.01).结论 辛醇可抑制KA致痫后大鼠海马区SYP表达的增高,具有明显的抗痫效应,提示辛醇抗痫机制可能与抑制SYP表达有关.     

Noggin参与海人酸损伤后成年大鼠海马颗粒下区颗粒细胞增殖

目的 探讨侧脑室注射海人酸(KA)致大鼠海马损伤后Noggin的表达变化及其与颗粒细胞增殖的关系.方法 健康雄性SD大鼠32只采用随机数字表法分为实验组(16只)及对照组(16只).对照组又分为生理盐水对照组和空白对照组,各8只.实验组大鼠侧脑室注射KA,生理盐水对照组注射等剂量生理盐水.空白对照组不作处理.侧脑室注射KA 1周内,尼氏染色检测海马神经元的丢失.免疫荧光染色与原位杂交的方法检测海马齿状回BrdU标记细胞与Noggin mRNA阳性细胞的变化.结果 在侧脑室注射KA致海马损伤后1周,海马CA3、CA4区神经元丢失明显.与生理盐水对照组比较,实验组海马齿状回BrdU阳性细胞升高,差异有统计学意义(P=0.006),其中注射侧较对侧更为明显.海马Noggin mRNA阳性细胞在第3天时升高,第7天时下降.结论 侧脑室注射KA致海马损伤后.成年大鼠海马齿状回颗粒细胞异常增殖可能与Noggin表达波动有关.     

α-细辛醚对KA癫痫大鼠海马组织中Bax、Bcl-2的影响

目的 探讨不同浓度的α-细辛醚对KA癫痫大鼠海马组织中细胞凋亡调节基因Bax、Bcl-2的mRNA及其蛋白表达的影响.方法 红藻氨酸(kainic acid,KA)侧脑室注入SD大鼠制备癫痫模型,随机分为模型对照组(KA组)、α-细辛醚低浓度组(6mg/kg)、中浓度组(12mg/kg)和高浓度组(24mg/kg),另设假手术组为正常对照组,每组10只.α-细辛醚组经腹腔注射连续给药10d后检测大鼠海马组织中Bax、Bcl-2的mRNA及其蛋白的表达.结果 α-细辛醚用药后,大鼠表现为明显的镇静、抗惊厥作用;与正常对照组相比,KA组、α-细辛醚低、中浓度组大鼠海马区Bax的mRNA及蛋白表达升高,差异有统计学意义(P均＜0.05),α-细辛醚高浓度组Bax的mRNA及蛋白表达下降(P＜0.05);与正常对照组相比,Bcl-2的mRNA及蛋白表达KA组显著降低,α-田辛醚中、高浓度组升高(P均＜0.05),低浓度组与对照组相比差异不明显(P＞0.05).结论 KA诱导的SD癫痫大鼠神经元存在Bax、Bcl-2的异常表达,α-细辛醚可能通过降低Bax和提升Bcl-2基因的表达从而减少SD癫痫大鼠神经元凋亡.     

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.     

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.