实验性自身免疫性脑脊髓炎脑内缝隙连接蛋白Cx43和Cx32的表达变化

目的 观察豚鼠实验性自身免疫性脑脊髓炎(EAE)模型脑内星形胶质细胞(AS)缝隙连接(GJ)蛋白Cx43与神经元缝隙连接蛋白Cx32表达变化及相互关系,以探讨胶质细胞和神经元表面缝隙连接与EAE模型损伤的关系.方法 采用免疫组化方法,显示EAE模型豚鼠脑内胶质细胞和神经元表面缝隙连接蛋白Cx43和Cx32的表达变化及分布规律.结果 EAE豚鼠模型建立成功后,脑内星形胶质细胞Cx43-Li细胞表达明显增加,呈斑点样或分枝样;神经元Cx32-Li细胞表达也增加,并存在一定时间相关性.结论 EAE豚鼠脑内Cx43和Cx32表达增加,提示EAE发生后星形胶质细胞与神经元间信息交流可能加强.     

Wistar大鼠实验性自身免疫性脑脊髓炎胶质纤维酸性蛋白变化的研究

目的通过建立实验性自身免疫性脑脊髓炎(EAE)模型研究Wistar大鼠脑内神经脱髓鞘后星形胶质细胞损伤随时间变化的规律。方法对Wistar大鼠经足垫注射豚鼠脊髓匀浆制作EAE模型,并于不同时间点将其处死,取脑组织进行免疫组化染色及图像分析检测脑组织中胶质纤维酸性蛋白(GFAP)水平并与健康对照组进行比较。结果GFAP阳性细胞随损伤时间呈先上升后下降的变化趋势,于发病后第7天表达最高,第21天恢复正常。其中发病后第7、14天GFAP阳性细胞突起增长、增粗,染色加深。结论EAE模型中星形胶质细胞可能参与了脑组织损伤后的修复过程,其标志性蛋白GFAP水平随损伤时间呈规律性改变。     

甘珀酸对癫痫大鼠前脑connexin-32和GFAP表达研究

目的研究大鼠在脑室埋管注射甘珀酸(CBX)预处理后戊四氮导致癫痫发作时前脑内胶质纤维酸性蛋白(GFAP)和连接蛋白-32(Cx32)表达及其相互关系. 方法动物分为生理盐水(NS)对照组(NS组)、CBX预处理对照组(CBX组)、戊四氮(PTZ)致痫组(PTZ组)、CBX预处理后再PTZ致痫组(CBX PTZ组),应用免疫荧光组织化学双重标记显示GFAP和Cx32在前脑的表达及其相互关系.结果 CBX PTZ组的大鼠癫痫发作的行为表现比PTZ组显著加重,星形胶质细胞GFAP的表达也比PTZ组明显升高,值得注意的是CBX组的星形胶质细胞GFAP的表达比NS组明显升高.Cx32在PTZ引起的癫痫大鼠的大脑皮层、海马和杏仁核内是增加的,而CBX预处理后的癫痫模型中Cx32却降低了.在Cx32与GFAP双标的切片上发现,Cx32与GFAP阳性的星形胶质细胞非常接近,在CBX预处理后的癫痫模型中GFAP阳性的星形胶质细胞显著增加的同时Cx32却明显降低. 结论在整体动物CBX预处理可以导致癫痫发作增强,这可能与星形胶质细胞增生及其Cx32表达降低有关.     

实验性变态反应性脑脊髓炎大鼠星形胶质细胞的变化

目的观察实验性变态反应性脑脊髓炎(EAE)大鼠脊髓中星形胶质细胞的变化,探讨EAE大鼠的发病相关生物学机制。方法采用免疫组化法,对豚鼠全脊髓匀浆诱导的Wistar大鼠EAE的过程中,脊髓内星形胶质细胞变化情况进行研究。结果EAE大鼠症状高峰期时星形胶质细胞开始激活,恢复期时激活达到高峰,而且活化的星形胶质细胞未见表达主要组织相容性抗原(MHC)。结论活化的星形胶质细胞可能与EAE大鼠的恢复有关。     

实验性自身免疫性脑脊髓炎神经元、胶质细胞及其细胞缝隙连接的超微结构改变

目的 探讨实验性自身免疫性脑脊髓炎(experimental autoimmune encephalomyelitis,EAE)豚鼠发病前、后脑内神经元、胶质细胞及其细胞间缝隙连接的超微结构变化.方法 采用髓鞘碱性蛋白经豚鼠足底注射制作EAE动物模型.将大鼠随机分为试验组(n=18)和对照组(n=6),采用抗Cx43和Cx32免疫电镜双标记的免疫组化方法观察EAE豚鼠脑白质内神经元、胶质细胞及其细胞之间连接部位超微结构改变.结果 胶质细胞之间和/或神经元之间形成大量的缝隙连接和半通道,同时除存在髓鞘破坏外神经元亦受到损伤.结论 (1)在EAE发展过程中,不仅存在髓鞘改变而且还存在轴索和突触的改变;(2)缝隙连接的增多提示EAE发生后星形胶质细胞与神经元间信息交流可能加强,缝隙连接很可能在神经元和髓鞘损伤中起关键作用.     

鞘内注射甘珀酸对大鼠热痛刺激反应的影响

目的:研究甘珀酸对大鼠热痛刺激反应的影响.方法:向实验组大鼠鞘内注射一种缝隙连接的阻断剂甘珀酸;对照组大鼠鞘内注射生理盐水,在注射前和注射后2 h测定热痛刺激大鼠缩足潜伏期(PWTL)的变化,并观察对脊髓背角胶质原纤维酸性蛋白(GFAP)和Fos蛋白表达的影响.结果:实验组阻断后PWTL测定值明显延长,与对照组差异具有统计学意义(P＜0.05);且阻断后Fos阳性神经元与对照组相比数量明显减少,GFAP阳性细胞则未见明显增加或减少.结论:本研究表明大鼠鞘内注射甘珀酸后①痛阈升高;②神经元对伤害性刺激信息的反应程度减弱,而AS的GFAP表达反应并未受影响.这提示,缝隙连接在疼痛的发生和维持中起着重要作用,AS有可能是通过缝隙连接参与对疼痛反应的过程.     

脑白质低灌注损伤后星形胶质细胞缝隙连接蛋白43的表达变化

目的研究慢性脑白质缺血后星形胶质细胞和缝隙连接蛋白Connexin43(Cx43)的变化。方法原代培养星形胶质细胞,建立体外慢性缺氧模型;双侧颈总动脉狭窄法,建立慢性低灌注脑白质损伤小鼠模型;免疫荧光共染观察星形胶质细胞活化与Cx43表达。Western蛋白定量分析髓鞘相关指标髓鞘相关糖蛋白MAG,星形胶质细胞标记物GFAP和Cx43的表达。结果与对照组相比,细胞慢性缺氧7d后,星形胶质细胞明显增生活化,伴随Cx43表达水平明显上调。Western blot发现,在慢性脑白质缺血过程中,MAG的表达逐渐降低,GFAP持续增高,Cx43表达明显上调。免疫荧光共标记可见,星形胶质细胞中Cx43表达上调,主要分布于胼胝体中央区。结论慢性脑白质缺血损伤过程伴随星形胶质细胞Cx43表达增加,Cx43可能成为临床治疗血管性认知障碍的新靶点。     

化疗性痛动物模型的建立及发病机制探讨

目的利用长春新碱(Vincristine)或紫杉醇(Paclitaxel)建立化疗性痛大鼠模型并探讨该模型的发病机制。方法利用微量释放泵连续给与SD大鼠一定量的长春新碱(Vincristine)或紫杉醇(Paclitaxel),而对照组给与相当量的溶剂。在注射前和注射后的连续时间点观察大鼠的痛觉行为学变化;当痛觉阈值降到最低点时,对处理组和对照组大鼠脊髓背角进行针对星形胶质细胞胶质纤维酸性蛋白(GFAP)和小胶质细胞OX42的免疫荧光染色,并鞘内给药抑制胶质细胞观察镇痛作用,同时取出两组大鼠的新鲜脊髓背角组织进行Western blot分析。结果长春新碱组注射后第6 d出现了明显的机械和热痛觉过敏,到注射后第8 d痛觉阈值降到最低点,以后基本维持在此水平;而紫杉醇组第4 d出现了明显的机械和热痛觉过敏,第12 d痛觉阈值降到最低点,以后基本维持在此水平。与对照组相比,处理组脊髓背角GFAP和OX42的染色密度出现了显著增强,鞘内给予针对星形胶质细胞的特异性抑制剂L-α-氨基己二酸(LAA)和小胶质细胞的特异性抑制剂米诺环素(minocycline)能起到有效镇痛作用。另外处理组脊髓细胞因子白介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)和磷酸化丝裂原活化蛋白激酶(MAPK)类分子磷酸化丝裂原活化蛋白激酶p38(p-p38)的表达显著上调。结论我们成功建立了化疗性痛模型,脊髓背角胶质细胞的激活有可能参与了化疗性痛的形成。     

实验性自身免疫性脑脊髓炎大鼠小胶质细胞的变化

目的　观察活化的小胶质细胞 (表达主要组织相容性抗原 )在实验性自身免疫性脑脊髓炎 ( EAE)大鼠脊髓中的变化 ,探讨 EAE大鼠发病相关生物学机制。方法　采用免疫组化法观察豚鼠全脊髓匀浆诱导的 Wistar大鼠 EAE过程中脊髓内表达 MHC 、MHC 类抗原的小胶质细胞的变化情况。结果　对照组脊髓内未发现表达 MHC抗原细胞 ,实验组脊髓内表达 MHC 抗原细胞与表达 MHC 抗原细胞的分布和形态一致 ,小胶质细胞变化与 EAE大鼠的病程一致。动物临床症状评分 2分和 3分 EAE大鼠脊髓表达 MHC抗原的小胶质细胞比评分 1分大鼠明显增高 ( P <0 .0 1 ) ,恢复期 EAE大鼠表达 MHC抗原的小胶质细胞明显减少 ( P <0 .0 1 )。结论　活化小胶质细胞与 EAE大鼠的病情相关 ,提示其可能通过表达 MHC抗原在 EAE大鼠的发病机制中具有作用     

载脂蛋白E对EAE星形胶质细胞的影响

目的探索载脂蛋白E(apolipoprotein E,apo E)对实验性自身免疫性脑脊髓炎(experimental autoimmune encephalomyelitis,EAE)模型小鼠病灶星形胶质细胞的影响。方法采用MOG35-55诱导apo E基因敲除的C57BL/6小鼠(apo E-/-EAE组)及野生型C57BL/6小鼠(普通EAE组),建立EAE模型。取免疫后35 d的EAE小鼠的大脑及脊髓切片,行HE染色,免疫组织化学染色法观察各组小鼠水通道蛋白4(AQP4)和胶质纤维酸性蛋白(GFAP)的表达。结果 apo E-/-EAE组和普通EAE组大脑和脊髓AQP4、GFAP的表达量均高于正常对照组,差异均有统计学意义(P<0.05);apo E-/-EAE组大脑和脊髓AQP4、GFAP表达量均高于普通EAE组,差异均有统计学意义(P<0.05)。结论 EAE中存在星形胶质细胞水肿、增生,apo E缺乏可以加重这一病变。     

Development of the projection from the nucleus of the brachium of the inferior colliculus to the superior colliculus in the ferret

Neurons in the deeper layers of the superior colliculus (SC) have spatially tuned receptive fields that are arranged to form a map of auditory space. The spatial tuning of these neurons emerges gradually in an experience-dependent manner after the onset of hearing, but the relative contributions of peripheral and central factors in this process of maturation are unknown. We have studied the postnatal development of the projection to the ferret SC from the nucleus of the brachium of the inferior colliculus (nBIC), its main source of auditory input, to determine whether the emergence of auditory map topography can be attributed to anatomical rewiring of this projection. The pattern of retrograde labeling produced by injections of fluorescent microspheres in the SC on postnatal day (P) 0 and just after the age of hearing onset (P29), showed that the nBIC-SC projection is topographically organized in the rostrocaudal axis, along which sound azimuth is represented, from birth. Injections of biotinylated dextran amine-fluorescein into the nBIC at different ages (P30, 60, and 90) labeled axons with numerous terminals and en passant boutons throughout the deeper layers of the SC. This labeling covered the entire mediolateral extent of the SC, but, in keeping with the pattern of retrograde labeling following microsphere injections in the SC, was more restricted rostrocaudally. No systematic changes were observed with age. The stability of the nBIC-SC projection over this period suggests that developmental changes in auditory spatial tuning involve other processes, rather than a gross refinement of the projection from the nBIC.     

Mechanisms of the suppression of the nociceptive reflex of the opening of the mouth during stimulation of the structures of the limbic brain

The comparative effectiveness of the inhibitory influence of tetanic stimulation of hypothalamus, amygdala and limbic cortex on EMG-response of m. digastricus evoked by electrical stimulation of tooth pulp nociceptive afferents was studied in cats anesthetized with a mixture of chloralose and nembutal. It was found that inhibition of the EMG-component of the jaw-opening reflex is most pronounced in case of stimulation of medial and lateral region of the hypothalamus, the inhibitory effect of central and medial nuclei of the amygdala is less pronounced and the effect of the limbic cortex is the weakest. It was shown that the mechanism of the antinociceptive effect of tetanic stimulation of the hypothalamus is not related to the concomitant increase of the blood pressure. After stabilization of the blood pressure the suppressive effect of the hypothalamus remains without changes, that points out to a direct, primary, not baro-afferent mechanism of the inhibition of the activity of nociceptive neurons of the trigeminal sensory nuclei. Noradrenaline, injected intravenously, induced a large increase of the blood pressure accompanied by a pronounced inhibition of the pain reflex. Angiotensin causes the same degree of blood pressure elevation without changes in the amplitude of the EMG-response of the pain reflex. Hypothalamic and noradrenergic mechanisms for control of pain sensitivity are discussed.     

The organization of the connections between the cortex and the claustrum in the monkey

The distribution of labelled cells and of extracellular granules in the claustrum has been studied after injections of horseradish peroxidase in several areas of the neocortex. The frontal and parietal lobes are related to the anterior and posterior halves respectively of the claustrum, and the occipital and temporal cortex to the posterior and inferior margins. Parts of the claustrum related to areas of the cortex in the frontal lobe overlap considerably in the antero-posterior dimension with parts related to widely separated but interconnected areas of the parieto-temporal cortex. Areas of cortex within one lobe which are interconnected are related to parts of the claustrum which overlap in the dorsoventral dimension.     

Sexual pheromones and the evolution of the reward system of the brain: the chemosensory function of the amygdala

The amygdala of all tetrapod vertebrates receives direct projections from the main and accessory olfactory bulbs, and the strong similarities in the organization of these projections suggest that they have undergone a very conservative evolution. However, current ideas about the function of the amygdala do not pay sufficient attention to its chemosensory role, but only view it as the core of the emotional brain. In this study, we propose that both roles of the amygdala are intimately linked since the amygdala is actually involved in mediating emotional responses to chemical signals. The amygdala is the only structure in the brain receiving pheromonal information directly from the accessory olfactory bulbs and we have shown in mice that males emit sexual pheromones that are innately attractive for females. In fact, sexual pheromones can be used as unconditioned stimuli to induce a conditioned attraction to previously neutral odorants as well as a conditioned place preference. Therefore, sexual pheromones should be regarded as natural reinforcers. Behavioural and pharmacological studies (reviewed here) have shown that the females' innate preference for sexual pheromones is not affected by lesions of the dopaminergic cells of the ventral tegmental area, and that the systemic administration of dopamine antagonists do not alter neither the attraction nor the reinforcing effects of these pheromones. Anatomical studies have shown that the vomeronasal amygdala gives rise to important projections to the olfactory tubercle and the islands of Calleja, suggesting that these amygdalo-striatal pathways might be involved in the reinforcing value of sexual pheromones.