Scorpion alpha and alpha-like toxins differentially interact with sodium channels in mammalian CNS and periphery

Scorpion alpha-toxins from Leiurus quinquestriatus hebraeus, LqhII and LqhIII, are similarly toxic to mice when administered by a subcutaneous route, but in mouse brain LqhII is 25-fold more toxic. Examination of the two toxins effects in central nervous system (CNS), peripheral preparations and expressed sodium channels revealed the basis for their differential toxicity. In rat brain synaptosomes, LqhII binds with high affinity, whereas LqhIII competes only at high concentration for LqhII-binding sites in a voltage-dependent manner. LqhII strongly inhibits sodium current inactivation of brain rBII subtype expressed in HEK293 cells, whereas LqhIII is weakly active at 2 microM, suggesting that LqhIII affects sodium channel subtypes other than rBII in the brain. In the periphery, both toxins inhibit tetrodotoxin-sensitive sodium current inactivation in dorsal root ganglion neurons, and are strongly active directly on the muscle and on expressed muI channels. Only LqhII, however, induced repetitive end-plate potentials in mouse phrenic nerve-hemidiaphragm muscle preparation by direct effect on the motor nerve. Thus, rBII and sodium channel subtypes expressed in peripheral nervous system (PNS) serve as the main targets for LqhII but are mostly not sensitive to LqhIII. Toxicity of both toxins in periphery may be attributed to the direct effect on muscle. Our data elucidate, for the first time, how different toxins affect mammalian central and peripheral excitable cells, and reveal unexpected subtype specificity of toxins that interact with receptor site 3.     

Light-adaptive effects of retinoic acid on receptive field properties of retinal horizontal cells

Besides its role in ocular development, retinoic acid (RA), which is a light-correlated byproduct of the phototransduction cycle, was recently shown to affect light-driven synaptic plasticity in the outer plexiform layer of the adult fish retina. Tuning by ambient light conditions of the retinal network properties is very prominent in outer plexiform layer circuits, and we therefore examined whether RA could affect cone horizontal cell physiology similar to ambient light. Performing intracellular recordings and dye injections in the dark-adapted inverted eyecup preparation of the carp, we found that RA reduced the receptive fields of horizontal cell somata and impaired gap junctional communication. This action was not observed among coupled axon terminals of horizontal cells and appeared to be stereospecific because it could only be attributed to all-trans and 13-cis RA but not to the 9-cis isomer and photoisomerized all-trans RA. Modulation of receptive field size occurred independently of the dopaminergic system. Furthermore, RA affected the light responsiveness of cone horizontal cells. Compared to the dark-adapted condition, responsiveness to intense light stimulation was enhanced but decreased when low intensities were used. Moreover, following RA treatment H2-type horizontal cells of dark-adapted retinae which do not give rise to colour-opponent light properties became colour-opponent and performed depolarizing responses to long-wavelength stimulation. In all these cases RA perfectly matched the effects of light adaptation, supporting the notion that RA acts as an endogenous neuromodulator.     

咽食管括约肌切开术在喉全切除术后发音重建中的作用

目的　探讨咽食管括约肌切开术对减少咽食管括约肌失弛缓对喉全切除术后安装Blom Singer发音管发音重建的影响。方法　喉全切除术后 ,咽食管括约肌收缩或是痉挛都会不同程度地影响食管的气流并阻碍发音。咽食管括约肌的解剖位置是环咽肌以及其上的下咽缩肌的一部分和颈段食管上段的一部分。手术操作是在喉全切除术中、术后于气管造瘘口外上方切除长 5cm ,宽 1cm的咽食管括约肌。结果　 3 3例喉全切除术的患者进行咽食管括约肌切开术后有 3 2例发音成功 ,发音重建的成功率是 97%。其中包括 12例喉全切除术中I期进行环咽肌切开术 ,2 1例是Ⅱ期进行咽食管括约肌切开术的 ,后者又有 9例是安装Blom Singer发音管后发音不能再行咽食管括约肌切开术的。患者 3年存活 2 5例 ,5年存活 18例。同期行喉全切除术和咽食管括约肌切开术的 12例患者 ,Kaplan Meier法统计 3年生存率 81 82 % ,5年生存率 42 86%。结论　咽食管括约肌切开术能提高Blom Singer发音管发音重建的成功率。     

Expression of connexin36 in the adult and developing rat brain

The distribution of connexin36 (Cx36) in the adult rat brain and retina has been analysed at the protein (immunofluorescence) and mRNA (in situ hybridization) level. Cx36 immunoreactivity, consisting primarily of round or elongated puncta, is highly enriched in specific brain regions (inferior olive and the olfactory bulb), in the retina, in the anterior pituitary and in the pineal gland, in agreement with the high levels of Cx36 mRNA in the same regions. A lower density of immunoreactive puncta can be observed in several brain regions, where only scattered subpopulations of cells express Cx36 mRNA. By combining in situ hybridization for Cx36 mRNA with immunohistochemistry for a general neuronal marker (NeuN), we found that neuronal cells are responsible for the expression of Cx36 mRNA in inferior olive, cerebellum, striatum, hippocampus and cerebral cortex. Cx36 mRNA was also demonstrated in parvalbumin-containing GABAergic interneurons of cerebral cortex, striatum, hippocampus and cerebellar cortex. Analysis of developing brain further revealed that Cx36 reaches a peak of expression in the first two weeks of postnatal life, and decreases sharply during the third week. Moreover, in these early stages of postnatal development Cx36 is detectable in neuronal populations that are devoid of Cx36 mRNA at the adult stage. The developmental changes of Cx36 expression suggest a participation of this connexin in the extensive interneuronal coupling which takes place in several regions of the early postnatal brain.     

黄芪注射液对蟾蜍和小鼠中枢、神经-肌接头和肌疲劳的影响

目的:利用已建立的蟾蜍和小鼠中枢、神经-肌接头和肌疲劳模型,比较不同剂量的黄芪注射液对蟾蜍和小鼠中枢、神经-肌接头和肌疲劳的影响.方法:分别记录蟾蜍和小鼠坐骨神经干动作电位和腓肠肌收缩曲线,测定中枢、神经-肌接头和肌疲劳的时间.结果:①0.8g·kg-1、1.2g·kg-1、1.6g·kg-1和2.0g·kg-1剂量的黄芪注射液均能延缓小鼠中枢、神经-肌接头和肌的疲劳,蟾蜍仅有0.8 g·kg-1和1.2 g·kg-1有此作用,1.6g·kg-1及以上剂量的黄芪注射液对蟾蜍有加速上述部位疲劳的作用.两种动物均以1.2g·kg-1剂量作用最显著;②最佳剂量1.2g·kg-1黄芪注射液延缓两种动物神经-肌接头和肌疲劳的作用与延缓中枢疲劳的作用比较差异具有统计学意义(P＜0.05);③最佳剂量1.2g·kg-1黄芪注射液对小鼠三个部位的作用同蟾蜍比较差异具有统计学意义(P＜0.05).结论:黄芪注射液对两栖动物和哺乳动物中枢、神经-肌接头和肌疲劳的影响具有差异性;其抗疲劳作用主要发生在神经-肌接头和肌等部位,即延缓外周疲劳;其抗疲劳效应,哺乳动物优于两栖动物.     

糖尿病氧化应激环境中α-Klotho对巨噬细胞-血管内皮细胞串扰的影响

目的：探讨糖尿病氧化应激环境中过表达α-Klotho(KL)的小鼠单核巨噬细胞白血病细胞(RAW264.7)对人脐静脉内皮细胞(HUVECs)增生、迁移、管腔形成以及紧密连接的影响。

方法：将RAW264.7细胞分为对照组、4-羟壬二酸酯(4HNE)组、4HNE+KL组,采用免疫荧光实验检测RAW264.7细胞F4/80的表达。制备3组细胞的条件培养基用于培养HUVECs,分为Mø-NC组、Mø-4HNE组和Mø-4HNE+KL组。采用CCK8实验检测血管内皮细胞增生,采用划痕实验和Transwell实验检测迁移,采用管腔形成实验检测管腔形成,采用Western blot实验检测闭合蛋白5(Claudin 5)、咬合蛋白(Occludin)、带状闭合蛋白1(ZO 1)表达水平。

结果：免疫荧光实验结果显示,4HNE组RAW264.7细胞F4/80荧光强度较对照组明显增强,而4HNE+KL组F4/80荧光强度较4HNE组明显减弱(均P<0.05)。CCK8实验结果显示,相比于Mø-NC组,Mø-4HNE组HUVECs增生显著增加,而Mø-4HNE+KL组HUVECs增生较Mø-4HNE组显著下降(均P<0.01)。划痕实验和Transwell实验结果显示,相比于Mø-NC组,Mø-4HNE组HUVECs迁移显著增强,而Mø-4HNE+KL组HUVECs迁移较Mø-4HNE组显著减弱(均P<0.01)。管腔形成实验结果显示,相比于Mø-NC组,Mø-4HNE组HUVECs管腔数显著增加,而Mø-4HNE+KL组管腔数较Mø-4HNE组显著下降(均P<0.01)。Western blot实验结果显示,相比于 Mø-NC组,Mø-4HNE组HUVECs中Claudin 5、Occludin、ZO 1蛋白的相对表达量明显减少,而Mø-4HNE+KL组Claudin 5、Occludin、ZO 1蛋白的相对表达量较Mø-4HNE组明显增加(均P<0.01)。

结论：KL通过改变糖尿病氧化应激环境中巨噬细胞激活状态抑制了HUVECs的增生、迁移、管腔形成,并增强了HUVECs的紧密连接。     

槟榔多酚对大鼠肺微血管内皮细胞低氧损伤的保护作用

目的：探究槟榔多酚对大鼠肺微血管内皮细胞（PMVEC）低氧损伤的保护作用。方法：采用氧化应激指标丙二醛和超氧化物歧化酶筛选肺部缺氧损伤细胞模型最适条件;采用细胞计数试剂盒法筛选槟榔多酚最适给药剂量。将PMVEC分为常氧对照组、模型对照组和槟榔多酚组,采用BCA法检测蛋白浓度并测定PMVEC中的氧化应激水平,蛋白质印迹法检测炎症和凋亡相关蛋白的表达,免疫荧光染色法检测闭合蛋白和闭锁小带1等紧密连接蛋白的表达,Transwell小室实验检测跨内皮细胞膜电阻,罗丹明荧光染料检测PMVEC屏障的通透性。结果：1%氧浓度培养PMVEC细胞48 h后成功构建肺部缺氧损伤细胞模型;20μg/mL的槟榔多酚可以显著逆转缺氧损伤细胞模型中PMVEC的存活率下降以及氧化应激水平的升高（均P<0.05）;槟榔多酚对于低氧诱导下PMVEC中炎症相关蛋白核因子κB(NF-κB)和核因子E2相关因子（Nrf）2的上调有显著抑制作用（均P<0.05）;槟榔多酚可以下调低氧诱导下PMVEC中凋亡相关蛋白胱天蛋白酶（caspase）3、Bcl-2相关X蛋白（Bax）的表达（均P<0.05）,从而减轻低...     

Causal role of the right temporoparietal junction in selfishness depends on the social partner

The right temporoparietal junction (rTPJ) is a hub of the mentalizing network, but its causal role in social decisions remains an area of active investigation. While prior studies using causal neurostimulation methods have confirmed the role of the rTPJ in mentalizing and strategic social interactions, most of the evidence for its role in resource-sharing decisions comes from correlational neuroimaging studies. Further, it remains unclear if the influence of the rTPJ on decisions about sharing resources depends on whether the other person is salient and identifiable. To clarify the causal role of the rTPJ in social decision making, we examined the effects of putatively inhibitory rTPJ transcranial magnetic stimulation (TMS) on Dictator Game behavior with one partner that was physically present and one that was only minimally identified. Under control conditions, participants tended to create more advantageous inequity toward the partner that was only minimally identified, selfishly keeping more resources themselves. rTPJ TMS reduced this differential treatment of the two partners. Clarifying prior mixed findings, results suggest that the rTPJ may play a role in differentiating between others when deciding how equitably to divide resources, but may not play a general role in reducing selfishness by promoting aversion to advantageous inequity.     

桃红四物汤抗癫痫作用机制研究

目的研究桃红四物汤的抗癫痫作用机制。方法建立戊四氮(PTZ)点燃大鼠癫痫模型,随机分为对照组、模型组和桃红四物汤低、中、高剂量组。桃红四物汤剂量分别为0.7、1.4、2.1 g/kg,给药体积为10 m L/kg,每日ig给药1次,连续给药2周。给药第0、14天观察大鼠癫痫发作程度。给药结束处死大鼠,伊文思蓝(EB)法测定血脑屏障通透性,Western blotting法和免疫荧光法测定脑组织及不同部位3种紧密连接蛋白:闭锁连接蛋白-1(ZO-1)、基质金属蛋白酶-9(MMP-9)、Occludin蛋白表达水平。结果高、中、低剂量桃红四物汤可显著降低大鼠癫痫发作程度和血脑屏障通透性(P0.01)。低剂量桃红四物汤可显著升高大鼠脑组织皮层、海马及纹状体的MMP-9表达水平(P0.05);中、高剂量桃红四物汤可显著升高大鼠脑组织ZO-1、MMP-9、Occludin表达水平(P0.05、0.01)。结论桃红四物汤可显著减轻癫痫发作程度,作用机制可能与降低血脑屏障通透性及升高脑组织紧密连接蛋白表达水平有关。     

维甲酸对人RPE细胞胞间通讯功能和Cx43表达的影响

目的观察培养的人视网膜色素上皮（RPE）细胞中连接蛋白Cx43的表达特点，以及维甲酸（RA）对人RPE细胞生长和细胞间缝隙连接功能、细胞间通道蛋白Cx43表达的影响及其相互关系。方法免疫组织化学方法观察缝隙连接蛋白（Cx43）在培养的人RPE细胞中的表达特点；不同浓度的RA作用于培养的第4代人的色素上皮细胞，用MTT方法观察RA对体外培养人RPE细胞生长的抑制；用LY染料传输方法测定细胞间隙连接功能，观察这三组不同浓度的RA对人RPE细胞缝隙连接功能的影响；免疫组织化学方法鉴别不同浓度RA影响后的缝隙连接蛋白Cx43的表达，用计算机灰度测量的方法评估表达的强度并作统计学分析。结果免疫组织化学染色显示体外培养的人RPE细胞表达缝隙连接蛋白Cx43，表达的部位主要在细胞浆和细胞膜上；RA对人RPE细胞的生长有明显的抑制作用，其抑制作用呈剂量依赖性；LY染料传输试验表明在RA的作用下RPE细胞间通讯功能明显增强；经计算机图像分析表明RA使连接蛋白Cx43表达增强，增强的程度与RA的浓度呈正相关。结论体外培养的人RPE细胞可以表达Cx43蛋白，RA抑制培养的色素上皮细胞的生长，提高细胞间隙连接通讯功能，上调Cx43蛋白在人RPE细胞中的表达。