腺苷及其阻断剂茶碱对大鼠尾状核脑薄片神经元自发放电的影响

本实验采用脑薄片电活动胞外记录法，研究腺苷及其非特异性阻断剂茶碱对大鼠尾状核脑薄片神经元自发放电的影响，在记录的３１个细胞中，对２１个细胞灌流了腺苷，其中３个细胞自发放电频率无明显变化，占３／２１＝１４２８％；在另外１８个对腺苷有反应的细胞中，有６个细胞自发放电频率增加，占６／２１＝２８５７％；有１２个细胞自发放电频率减少，占１２／２１＝５７２２％。腺苷的兴奋和抑制效应都有量效关系。茶碱对大鼠尾状核神经元自发放电的效应与腺苷相反。结果提示，大鼠尾状核内存在两种类型的腺苷受体：Ａ１和Ａ２；腺苷对大鼠尾状核脑片神经元自发放电的抑制效应是通过激活Ａ１受体实现的，而其兴奋效应是由于激活了Ａ２受体。     

大鼠脑损伤后海马GAP-43 mRNA水平的变化

以DIG（Digoxigenin）标记的GAP-43 cDNA片段为探针,使用原位杂交方法,检测了大鼠皮层硬性脑挫伤后GAP-43 mRNA水平的变化。结果表明：海马CA3、CA1和DG区的GAP-43 mRNA水平在损伤后48h明显升高,其中CA3区变化最甚,而且伤侧比对侧显著。1周和2周后表达仍维持较高水平,但不如48h的高,这显示表达的峰值在1周之内。上述结果为研究脑损伤后生理及机能代偿的修复机制提供了有意义的信息。     

补肾醒脑方对血管性痴呆大鼠脑组织中信号传导转接蛋白MyD88的影响

观察补肾醒脑方对缺血再灌注造成损伤的血管性痴呆大鼠脑组织中My D88信号传导通路影响,探讨该方对缺血性脑损伤大鼠靶向性防治机理。成年雄性Wistar大鼠造模成功后随即等分为假手术组(A组)、模型组(B组)、吡拉西坦组(C组)、补肾醒脑方组(D组),每组12只灌胃给药。第3 d、7 d检查大鼠神经功能缺损情况,1周后检测大鼠脑组织中My D88的含量。D组神经功能缺损改善较B组改善明显(P0.05);D组脑组织中My D88表达减少程度虽与C组比较差异不显著(P0.05),但与B组比较差异显著(P0.05)。补肾醒脑方能有效改善缺血再灌注造成损伤的血管性痴呆大鼠的神经损伤的症状,降低大鼠模型脑组织中信号传导转接蛋白My D88,抑制炎性反应保护大脑组织。     

3H-baclofen and 3H-GABA bind to bicuculline-insensitive GABA B sites in rat brain

The presence of a novel receptor for the neurotransmitter gamma-aminobutyric acid (GABA) on peripheral autonomic nerve terminals and in mammalian brain slices has been described recently. This receptor differs from the classical GABA site as it is unaffected by recognized GABA antagonists such as bicuculline and is not sensitive to the majority of accepted GABA-mimetics such as 3-aminopropanesulphonic acid (3-APS) or isoguvacine. We propose to designate the classical site as the GABA A and the novel site as the GABA B receptor. The beta-p-chlorophenyl derivative of GABA, baclofen, is stereospecifically active at the GABA B site whereas it is devoid of activity at the classical GABA A3 site. We now report that high-affinity saturable binding of 3H-baclofen and 3H-GABA to the GABA B site can be detected in fragments of crude synaptic membranes prepared from rat brain. The results support the concept of a novel GABA receptor within the mammalian brain and show that GABA and baclofen can compete for the same recognition site.     

Release of somatostatin-28(1-12) from rat hypothalamus in vitro

Following the discovery of the growth hormone release-inhibiting factor somatostatin from extracts of ovine hypothalamus, an N-terminally extended somatostatin of 28 amino acids has been identified in mammalian tissue. The original peptide, somatostatin-14 (SS14), corresponds to the C-terminus of somatostatin-28 (SS28). Both SS28 and SS14 have biological activity, occur in several rat brain regions, are present in cell bodies and nerve terminals and can be released in vitro upon depolarization in a calcium-dependent manner. Further, high-affinity binding sites were described for SS14, which also bind SS28 (refs 20-23). Recently, a dodecapeptide which corresponds to the N-terminus of somatostatin-28, somatostatin-28(1-12), has been characterized in rat hypothalamus. Radioimmunological and immunohistochemical studies have indicated the presence of SS28(1-12)-like immunoreactivity in several cortical and subcortical regions of the rat brain. This peptide was found to be unevenly distributed with the highest concentration in the hypothalamus, and preferentially localized to dendritic and axonal processes and terminals. These observations suggest that SS28(1-12) may be a neurotransmitter. In this study, we describe a calcium-dependent release of a SS28(1-12)-like peptide from hypothalamic slices in vitro. This finding supports a neurotransmitter function for this peptide.     

纳洛酮对大鼠脑外伤后神经细胞凋亡的影响

目的：采用Feeney法自由落体撞击脑损伤动物模型，观察纳洛酮对脑外伤后神经细胞凋亡和脑水肿的影响。方法：90只大鼠分为实验组及对照组，在损伤后15、60min及24h分别予纳洛酮或生理盐水，损伤后第5d断头处死大鼠，TUNEL法测定神经细胞原位凋亡情况，测定损伤侧大脑半球含水理以及光镜下观察细胞形态学改变。结果：与对照组比较，大鼠脑外伤后15及60min静注纳洛酮可保护神经细胞，减少凋亡率，减轻脑水肿；而外伤后24h给药，神经细胞凋亡率以及脑水肿无显著性差异。结论；研究结果提示纳洛酮作为阿片受体的拮抗剂有保护大鼠脑外伤后神经细胞的作用，但应在外伤后尽早用药。     

Do human platelets have opiate receptors?

In their study of prostaglandin E1 (PGE1)-sensitive adenylate cyclase (AC) in rat brain homogenates, Collier and Roy claimed that the activity of this enzyme is inhibited by opiates. They also proposed that opiates exert their analgesic and allied effects by inhibiting AC of neurones that are normally stimulated by E prostaglandins. Studies using neuroblastoma x glioma hybrid cells supported this hypothesis. However, subsequent studies with mammalian brain and rat brain tissue slices yielded conflicting results. PGE1 also inhibits platelet aggregation, probably through activation of platelet AC. Gryglewski et al. showed that morphine inhibits the anti-aggregating effect of PGE1 on ADP- and adrenaline-induced platelet aggregation, and suggested that the inhibition by morphine is mediated through platelet AC activity. We report here our attempts to reproduce the results of Gryglewski et al. and our examination of the effect of morphine on PGE1-sensitive AC activity in platelet lysates and on PGE1-induced accumulation of cyclic AMP in intact platelets. The possible existence of opiate receptors in platelets was also assessed by direct binding studies with 3H-etorphine. In contrast to Gryglewski et al., we could not detect any effect of opiates on the aggregation of human platelets, nor did we find any other evidence supporting the presence of opiate receptors in these cells. Thus we conclude that the presence of opiate receptors in human platelets is unlikely.     

大鼠促红细胞生成素受体基因克隆及其在颅脑损伤模型中的表达分析

利用巢式PCR(nest PCR)的方法克隆大鼠促红细胞生成素受体基因.该基因ORF区全长1 524bp,编码507个氨基酸,推测其相对分子质量为55.48ku,等电点5.07.实时荧光定量PCR结果显示:大鼠早期颅脑损伤中,EPOR基因表达呈逐步上升趋势,颅脑损伤后24h表达量达到顶峰,为对照组的6倍.     

大鼠DAI特殊染色观察及NF-κB的表达

为了分析大鼠弥漫性轴索损伤(DAI)后病理学变化及核因子-κB(NF-κB)的表达,探讨了NF-κB在弥漫性轴索损伤中的作用,构建了大鼠DAI动物模型.运用Glees-Marsland染色法和Weil氏染色法观察伤后不同时间段的病理学改变,并运用免疫组化SABC法观察NF-κB的表达.实验结果表明,大鼠弥漫性轴索损伤后1h即可观察到部分轴索肿胀、断裂,髓鞘水肿、分层等现象,24h可见典型轴索收缩球形成,髓鞘崩解呈筛网状改变,72h轴索断裂数量、范围及髓鞘筛网状改变达到高峰;伤后1h,脑组织内可见NF-κB阳性细胞,伤后3h阳性细胞数增多,伤后24h达到高峰,持续到72h,伤后7d,仍可见阳性细胞表达,但数量减少.对照组细胞核未见阳性表达.大鼠弥漫性轴索损伤后NF-κB表达增加,可能与轴索继发性损伤有关.     

Glycogenolysis induced by serotonin in brain: identification of a new class of receptor

Serotonin-containing neurones in brain have been proposed to have a role in the control of physiological mechanisms such as sleep, thermoregulation, pain perception and endocrine secretions as well as in the physiopathology of migraine or depressive illness. One difficulty in testing these possibilities lies in the scarcity of pharmacological agents able to interact selectively with the probably multiple classes of serotonin receptors in the central nervous system. Development of such agents would be facilitated by simple in vitro models in which biological responses to serotonin in mammalian brain could be quantified. Thus a serotonin-sensitive adenylate cyclase has been characterized in rat brain, but the response to serotonin is weak in newborn and practically absent in adult animals. In addition, two pharmacologically distinct classes of serotoninergic binding site have been identified using 3H-serotonin and 3H-spiperone as ligands, but their identification as receptors remains to be established. More recently, serotonin has been shown to stimulate phosphorylation of a neuronal protein in slices from the facial motor nucleus, although the receptors mediating this action were not characterized. We now report that serotonin stimulates glycogen hydrolysis in slices of cerebral cortex, that this action is mediated by a novel class of receptors and that tricyclic antidepressants are among the best competitive antagonists of the indolamine.     

A new algorithm of brain volume contours segmentation

This paper explores brain CT slices segmentation technique and some related problems, including contours segmentation algorithms, edge detector, algorithm evaluation and experimental results. This article describes a method for contour-based segmentation of anatomical structures in 3D medical data sets. With this method, the user manually traces one or more 2D contours of an anatomical structure of interest on parallel planes arbitrarily cutting the data set. The experimental results showes the segmentation based on 3D brain volume and 2D CT slices. The main creative contributions in this paper are: (1) contours segmentation algorithm; (2) edge detector; (3) algorithm evaluation.     

大鼠急性颅脑损伤后脑肿胀及钙镁离子的变化

目的研究大鼠急性颅脑损伤后脑肿胀及钙镁离子的改变,以找出颅脑损伤后病情转化的规律,为临床治疗提供依据。方法大鼠40只随机分为4组,采用自由落体致大鼠脑挫裂伤,伤后122、44、8 h分别取材,观察脑肿胀及钙镁离子的变化。结果大鼠急性颅脑损伤后脑肿胀在24 h达到高峰,钙镁离子也有相应变化。结论急性颅脑损伤后脑肿胀的变化有一定的规律可循,产生外伤性脑肿胀的病理基础为脑血管扩张充血导致微循环障碍,救治急性颅脑损伤要重视预防微循环障碍,及时脱水,纠正缺血、缺氧。     

香菇多糖对依地酸钙钠治疗铅中毒的增效作用及机制

为研究香菇多糖对依地酸钙钠治疗铅中毒的增效作用及机制,用跳台实验检测小鼠学习记忆功能,用生物化学法检测血液与脑组织中总超氧化物歧化酶(SOD)、丙二醛(MDA)和谷胱甘肽过氧化物酶(GSH-Px)等指标,用HE染色观察海马组织形态学改变.结果表明,香菇多糖高剂量组能显著改善铅中毒所致的学习记忆功能,显著提高血液和脑组织中SOD和GSH-Px活性、降低MDA含量,并显著改善海马神经元的变性、脱落.由此可见,香菇多糖对依地酸钙钠治疗铅中毒有增效作用,其作用机制可能与香菇多糖提高SOD和GSH-Px活性、降低MDA含量有关.     

生物光子与藏药七十味珍珠丸的药理机制

采用高度敏感的生物光子检测(成像)系统(主要由电子倍增CCD和体视显微镜组成),研究了藏药七十味珍珠丸(RNSP)灌胃处理对健康成年雌性昆明小鼠脑片、肝和肾组织的生物光子活动调控的影响.实验结果表明:脑片、肝和肾均具有自发光现象(生物光子).在光刺激下,脑片、肝和肾具有不同程度的诱发光现象.RNSP处理后的脑组织诱发光的最大值高于对照组,并且衰减较慢.研究结果提示RNSP可能通过影响效应组织如脑组织的生物光子的活动来发挥其药理作用.其作用机制可能是通过影响生物光子信号传递对组织细胞功能产生调节作用,确切的作用机制值得进一步研究.     

大脑皮质微血管内皮细胞培养及其缺氧性损害模型

建立改良的体外培养大鼠脑皮质微血管内皮细胞缺氧模型．取1～5d Wistar乳鼠脑皮质获得的脑微血管内皮细胞（BMEC）进行体外培养，缺氧组置入一个经改造的保鲜盒内，密闭并通入混合气体（95％N2和5％CO2）12h，检测缺氧细胞的形态结构、细胞死亡率及培养液中乳酸脱氢酶漏出量．结果显示缺氧BMEC形态结构损伤，细胞死亡率增加，细胞乳酸脱氢酶漏出量显著增加（p〈0．01）．该模型可使脑血管内皮细胞受到损伤，证实该模型具有一定的可靠性、操作简便，可重复性强，为体外研究脑血管疾病提供帮助．     

CT对重型颅脑损伤后颅内压的估价

为探讨CT对重型颅脑损伤后颅内压的估价，CT扫描150例重型颅脑损伤患者，分析其脑室脑池形态、脑室/颅腔比率、中线结构移位等变化特征，从而估价颅内压，其结果与颅内压监测结果对照，分析颅内压和预后的关系．结果表明：(1)CT显示三脑室、基底池受压明显或消失，脑室/颅腔比率越小，中线结构移位越严重者，颅内压升高超明显；(2)颅内压越高，预后越差，生存质量越低；(3)CT能够估价颅内压，并由此指导治疗，判断预后．     

Possible association of alcohol tolerance with increased synaptic Ca2+ sensitivity

The inhibitory effect of ethanol on neurotransmitter release has been suggested to be due to either reduced Ca2+ entry or increased removal of free intracellular Ca2+ from the synapse. The use of the Ca2+ ionophore, A23187, to allow direct access of external Ca2+ to the presynaptic interior should help to determine which of these two factors is the more important, as ethanol should inhibit A23187-induced release of transmitter only if increased Ca2+ removal from the synapse is important. Here we show in rat striatal slices that, although 3H-dopamine release evoked by depolarization with 40 mM K+ is inhibited by 50 mM ethanol, the release evoked by A23187 is enhanced by the presence of ethanol in vitro. The results suggest that ethanol reduces depolarization-induced transmitter release by reducing Ca2+ entry to the presynaptic terminal. However, for brain slices taken from rats made tolerant to ethanol, 3H-dopamine release in the absence of ethanol showed altered characteristics; both K+ depolarization and A23187 released a significantly greater fraction of 3H-dopamine from these slices than from controls. Thus tolerance to the inhibitory effect of ethanol on release may develop by a mechanism involving increased sensitivity of the terminal to Ca2+ entry.     

A functional correlate for the dihydropyridine binding site in rat brain

Calcium channels, controlling the influx of extracellular Ca2+ and hence neurotransmitter release, exist in the brain. However, drugs classed as calcium antagonists and which inhibit Ca2+ entry through voltage-activated Ca2+ channels in heart and smooth muscle, seem not to affect any aspect of neuronal function in the brain at pharmacologically relevant concentrations. Yet the dihydropyridine calcium antagonists (for example, nitrendipine) bind stereospecifically with high affinity to a recognition site on brain-cell membranes thought to represent the Ca2+ channel and consequently, the physiological relevance of these sites has been questioned. However, activation of voltage-dependent Ca2+ channels can increase cytoplasmic Ca2+ and neurotransmitter release in neuronal tissue. We show here that Bay K8644, a dihydropyridine Ca2+-channel activator, can augment K+-stimulated release of serotonin from rat frontal cortex slices and that these effects can be antagonized by low concentrations of calcium antagonists. As 3H-dihydropyridine binding to cortical membrane preparations resembles the binding in heart and smooth muscle where there are good functional correlates we conclude that the dihydropyridine binding sites in the brain represent functional Ca2+ channels that can be unmasked under certain circumstances.     

神经元兴奋性群体峰电位信号的Renyi信息表达

应用时频分布级数分析方法，提取了单次诱发群体峰电位(PS)信号的Renyi信息，并用以表征神经元的兴奋性变化．采用液压打击大鼠脑损伤模型和细胞外记录技术，记录了离体海马脑片CA1区锥体神经元PS，发现损伤侧和非损伤侧PS的Renyi信息参数值差异显著，进而分析了神经元灌流大黄酸后损伤侧PS的Renyi信息参数值的变化，研究大黄酸对神经元的超兴奋性和突触传递的作用．研究结果表明，颅脑损伤可造成海马CA1区锥体神经元的迟发性过度兴奋，大黄酸对神经元的过度兴奋有抑制作用，Renyi信息可作为反映神经元兴奋性变化的一个特征参数．