Excitation of neuronal function in rabbit caudal ventrolateral medulla elevates plasma vasopressin

Injection of L-glutamate into the caudal ventrolateral medulla of the rabbit caused a dose-dependent increase in plasma vasopressin. Activity of the A1 noradrenergic cells within the caudal ventrolateral medulla appears to excite the vasopressin-secreting neuroendocrine cells within the hypothalamus.     

脱氢表雄酮对人脐静脉内皮细胞CD40/CD40L表达的影响

目的:探讨脱氢表雄酮(DHEA)对干扰素-γ(I NF-γ)刺激下的人脐静脉内皮细胞(HUVECs)CD40/CD40L表达的影响。方法:原代培养人脐静脉内皮细胞,给予I NF-γ刺激和不同浓度DHEA干预。采用流式细胞术检测CD40/CD40L在细胞表面的表达,通过反转录-聚合酶链反应(RT-PCR)检测CD40/CD40L mRNA的表达。结果:I NF-γ刺激HUVECs表达CD40/CD40L,DHEA下调I NF-γ诱导的HUVECs表面CD40/CD40L的表达,同时对I NF-γ刺激下的CD40/CD40L mRNA的表达有抑制作用,并且呈剂量依赖性。结论:DHEA能减轻I NF-γ刺激下的人脐静脉内皮细胞CD40/CD40L的表达。     

脊髓损伤后神经修复过程中的细胞微环境北大核心

背景:以往的研究显示单一改变脊髓损伤区域某一基因表达或者某一细胞的状态,对脊髓损伤后功能恢复无显著影响,而大量证据表明调控脊髓损伤后紊乱的细胞微环境是神经功能恢复的关键因素。目的:对脊髓损伤前后细胞微环境的生物学特性,包括多种细胞之间的相互调控以及细胞外组分对损伤神经修复的作用和机制进行综述。方法:由第一作者检索PubMed及Web of Science数据库,英文检索词为“spinal cord injury,glial cell,neuron,immune cell,neural stem cell,extracellular matrix,cytokine,extracellular vesicle,regeneration”。文献检索的时间范围为2000年1月至2021年12月,最终筛选出64篇文献进行分析。结果与结论:①脊髓损伤后,在细胞微环境的细胞组分中,占比最高的胶质细胞间的相互作用,以及与神经元的相互调控作用最为关键。②在脊髓损伤后的细胞外组分中,利用生物相容性良好的水凝胶模仿天然细胞外基质,可有效模拟和重建损伤区域内的细胞微环境,促进轴突伸长。③在脊髓损伤后的细胞外调节因子中,促炎因子如肿瘤坏死因子α和白细胞介素1β等加剧了细胞微环境的炎症反应,应用受体抑制剂或阻断相关通路抑制上述促炎因子的表达是一种有效的治疗方法,同时在脊髓微环境中增加白细胞介素10等抗炎因子的表达,抑制损伤区域炎症发展的研究也陆续出现。④最近被重视起来的细胞外囊泡作为传递信息的载体在细胞微环境中也发挥了重要作用。⑤文章揭示了脊髓损伤后细胞微环境中的包括细胞组分和细胞外组分之间的多组相互调控关系,证实了细胞微环境中各组分之间所发挥的神经修复作用并不是孤立的。     

Cord blood contains cells secreting antibodies to nervous system components.

Umbilical cord blood of newborns and peripheral blood of healthy adults were investigated by an immunospot assay for cells secreting IgG, IgA and IgM antibodies against myelin basic protein (MBP), proteolipid protein (PLP), myelin-associated glycoprotein (MAG) and myelin oligodendrocyte glycoprotein (MOG) which represent putative antigens for an autoimmune attack in multiple sclerosis (MS) and against acetylcholine receptor (AChR) which is considered an important autoantigen in myasthenia gravis. Cells secreting antibodies against one or more of these autoantigens were detected in 18 out of 24 newborns, and in eight out of 20 adults. Eight of the cord blood samples contained cells secreting antibodies of IgG, IgA and/or IgM isotypes to one antigen, five to two antigens, two to three antigens, two to four antigens, and one to five antigens. Most prominent were anti-MBP IgG antibody secreting cells which were detected in 13 newborns at a mean number of 1/20,000 cord blood cells, and in six adults at a mean number of 1/10(5) peripheral blood cells. Anti-AChR IgG antibody secreting cells were detected in four out of 12 newborns versus four out of 14 peripheral blood specimens, at mean values of 1/10(5) cells in both instances. Cells secreting autoantibodies of IgA and IgM isotypes were less frequent both in cord blood and peripheral blood. The occurrence of nervous tissue autoantibody secreting cells in newborns must be related to a possible primary role of such autoantibodies in MS and myasthenia gravis.     

The relationship between the lumbosacral enlargement and the conus medullaris during the period of fetal development and adulthood

The spinal cord is situated within the vertebral canal by the third month of intrauterine life. The spinal cord possesses two symmetrical enlargements, which constitute the segments of the plexuses the cervical enlargement for the brachial plexus and the lumbosacral enlargement for the lumbar and sacral plexus. In our study, we aimed to investigate the relationship between the termination level of the lumbosacral enlargement (TLLE) and that of the conus medullaris (TLCM) during the period of fetal development and adulthood. We used a total of 75 cases 25 fetuses (male 16, female 9) whose crown-rump length ranged between 90–190 mm, 25 premature and full-term neonates (male 17, female 8) whose post-menstrual ages ranged between 33–55 weeks, and 25 adults (male 12, female 13) aged between 22–72 years. The dissection technique for fetuses, ultrasonography for premature and full-term newborns, and magnetic resonance imaging (MRI) for adults were used to determine lumbosacral enlargement and TLCM. The differences between the TLCM and the termination level of the largest part of the transverse diameter of the lumbosacral enlargement were investigated. The differences between the TLLE and TLCM were found in different ratios from the period of fetal development to adulthood. Therefore, during medical treatment and surgical procedures this should be taken into account to avoid complications.     

Supraspinal effects on the fractal correlation in human H-reflex

In our previous study, -type power spectrum with the spectral exponent significantly greater than zero was found in the variability of soleus H-reflex amplitudes. This result indicated that the H-reflex variability was time-correlated owing to fractal characteristics. Furthermore, it was also suggested that the fractal characteristics were generated at the spinal level. The purpose of the present study was to investigate whether the fractal nature of the H-reflex variability was influenced by the loss of supraspinal input. Six healthy normal subjects and seven patients with spinal cord injury participated in this study. Soleus H-reflexes were evoked every l s from both legs simultaneously (stimulation intensity: motor threshold) and 1050 successive amplitudes of the H-reflex were recorded. The H-reflex sequence evoked from each leg was analyzed by coarse graining spectral analysis to calculate the spectral exponent . The value of was used to evaluate the level of time-correlation (fractal correlation). Cross-spectral analysis was used to evaluate the degree of synchronization between the H-reflex sequences evoked from both legs. The values for normal subjects (0.84±0.33, left leg; 0.88±0.34, right leg) were significantly greater (P<0.001) than those for patients (0.31±0.18, left leg; 0.32±0.14, right leg), suggesting that the H-reflex sequences for normal subjects were more time-correlated than for patients. In the frequency range less than 0.2 Hz, the coherence of both legs was high (0.41±0.14) for normal subjects as compared to 0.20±0.12 for patients (P<0.005). In this frequency range, the phase was almost 0 rad for normal subjects, indicating that the H-reflex variabilities of both legs were synchronized. These results suggested that (1) the strong fractal correlation observed in the H-reflex sequences for normal subjects was associated with supraspinal input, and (2) such supraspinal input had equal influence on the reflex arcs of the soleus of both legs.     

Somatotopic termination of the spino-olivary fibers in the cat,studied with the wheat germ agglutinin-horseradish peroxidase technique

Summary Terminal sites of the spino-olivary fibers (SOFs) were examined by the anterograde transport of wheat germ agglutinin-horseradish peroxidase in the cat. The tracer was injected at various spinal cord levels from the first cervical to the caudal segments. The SOFs derived from the C1-T1 segments terminated medially in the caudal half (levels II–VIII of Brodal) of the medial accessory olive (MAO), which projects to the A zone of the cerebellar cortex, whereas the SOFs derived from the L6-S1 segments terminated laterally in the caudal half (levels I–VIII) of the MAO. No projections were found from the T2-L5 segments to the MAO. In the dorsal accessory olive (DAO), the SOFs terminated at levels III–XIV; the DAO projects to the B zone and the C1 and C3 zones of the cerebellar cortex. The SOFs derived from the C1-C4 segments terminated in the most medial part of the DAO (levels III–XIV), followed laterally by those from the C5-T1 segments. Further laterally, the SOFs derived from the T2-L5 and the L6-S1 segments terminated in the mediolateral order at levels V–XIV. The SOFs from the L6-S1 segments occupied the most lateral part of the DAO. The present study demonstrates that there is a distinct somatotopic termination of the SOFs in the mediolateral order in the caudal MAO and the DAO.     

小胶质细胞极化介导炎症反应在脊髓损伤中的作用

背景:小胶质细胞极化参与脊髓损伤后的炎症反应,并在其中发挥关键作用。相关研究表明,有效诱导小胶质细胞从M1促炎表型向M2抗炎表型极化,可以减轻脊髓损伤后的炎症反应,促进组织的修复再生和神经功能的恢复。目的:文章对小胶质细胞的功能和极化、小胶质细胞极化对脊髓损伤的影响及其潜在调控策略以及脊髓损伤后炎症反应进行综述。方法:检索PubMed、Web of Science和中国知网数据库,英文检索词为“microglia,polarization,spinal cord injury,inflammation”,中文检索词为“小胶质细胞、极化、脊髓损伤、炎症”,按纳入和排除标准共纳入80篇文献进行总结。结果与结论:①由小胶质细胞介导的稳定而持续的炎症反应,对脊髓损伤的预后至关重要。②在生理条件下,小胶质细胞处于M0静止表型,但在脊髓损伤后,小胶质细胞活化,进而极化成M1促炎表型,导致神经组织修复能力降低和出现持续性神经炎症。③在脊髓损伤的炎症反应过程中,调控小胶质细胞向M2表型极化或至少向M2表型倾斜,有利于抑制氧化应激反应、调节突触重塑、促进轴突再生和血管生成,是一种有效的调控策略。④截止到目前的研究表明,间充质干细胞、外泌体、临床药物、天然产物、miRNAs和靶点分子可调控小胶质细胞在M1和M2表型之间的转换,这为脊髓损伤后神经组织的修复提供了一种新的思路,未来需进一步研究小胶质细胞在脊髓损伤过程中调控极化的详细机制。     

实验性哮喘豚鼠初级传入系统和中枢内NKB的变化(英文)

本文应用放射免疫分析方法，测定了16只哮喘豚鼠初级传入系统和中枢内神经激肽β（NKB）的水平。结果表明，与正常对照组（结状神经书3228±11．89，C7～C8段脊神经节23．63±13．26，T1～T2段脊神经节24．25±1819，T3～T5段脊神经节25．53±12．34，C7～T5段脊髓后角28．65±16．59，孤束核26．34±18．36Pg／gwettissue）相比较，哮喘豚鼠初级传入系统和中枢内（结状神经节43．26±12．35，C7～C段脊神经节32．53±17．63，T1～T2段神经书32.25±20．65，T3～T5段脊神经节34．36±15．33，C7～T5段脊髓后角39．53±2028，孤束核3662±17．85Pg／gwettissue）NKB的含量明显高于对照组（P＜0．05）。结合NKB在呼吸道的作用，这些结果提示，初级传入系统和中枢内的NKB可能参与哮喘发病的病理生理机制。     

疼痛模型大鼠下丘脑和脊髓P物质的含量变化

目的疼痛模型大鼠下丘脑和脊髓P物质（substance P，SP）的含量变化。方法左足跖皮下注射5％甲醛50μl建立大鼠疼痛模型，将动物随机分成空白对照组，生理盐水对照组和疼痛模型组，采用放射免疫分析法测定股动脉血、下丘脑和脊髓中SP的含量。结果疼痛模型组雄性S-D大鼠血浆中及下丘脑和脊髓SP含量分别与空白对照组、生理盐水对照组差别有统计学意义（P〈0．05）；而空白对照组与生理盐水对照组差别无统计学意义（P〉0．05）。结论皮下注射5％甲醛可致疼痛症状产生；提示皮下注射甲醛所致疼痛可通过下丘脑和脊髓组织中的SP释放增加，所致无菌性炎症反应而引起疼痛症状。