动物性成熟启动基因网络和神经内分泌调节研究进展

 动物性成熟启动是一个复杂的生物学过程,其决定性事件是下丘脑GnRH脉冲式释放增加。GnRH脉冲式释放增加是由跨突触改变和神经胶质输入两个方面共同引起的,其中,跨突触改变由谷氨酸能神经元、Kisspeptin神经元、γ 氨基丁酸能神经元、阿片能神经元及RFRP神经元提供,而神经胶质输入主要由生长因子家族提供。诸多功能基因参与了性成熟启动过程,组成了复杂的基因调控网络,这些基因并不是按照严格的等级顺序排列,而是在功能上有所重叠。转录调节因子的抑制性作用使得性成熟启动不会提早发生。论文还介绍了表观机制在性成熟启动调控中的重要作用。     

突触素研究进展

本文综述了突触素在神经组织及神经元和其它吸细胞中的分布。突触素参与钙离子依赖性神经递质的调节，对神经递质的快速释放和突触小泡的胞吐作用具有重要生理作用。突触素不仅可作为研究神经系统的发育，损伤及再生的标记物，而且可作为神经内分泌细胞的标记物。同时，为一些肿瘤及神经系统疾病诊断提供可靠依据。     

能量代谢调节中AMPK作用的研究进展

AMPK是一种细胞能量传感器,能准确应对代谢的动态变化和营养的过度消耗或不足。下丘脑AMPK通过作用于刺鼠相关蛋白(AgRP)和前阿片黑素细胞皮质激素(POMC)神经元来调节能量平衡和食欲。下丘脑在不同代谢状态下突触可塑性调节食欲和体重。激素的反馈机制影响AgRP和POMC神经元的突触可塑性。AMPK活性受损制约POMC神经元的主要功能是可预防肥胖。当前的研究表明,内分泌通过许多不同的代谢机制确保下丘脑AMPK从负能量平衡到能量平衡,表明了下丘脑AMPK维持基本能量平衡的重要性。文章就生长素、瘦素、胰岛素等激素对下丘脑AMPK活性的控制及对食欲和能量代谢影响的最新研究情况进行了综述。     

鸡中脑中央灰质的光、电镜结构研究

采用尼氏小体染色、髓鞘染色、高尔基技术和透射电镜观察等多种方法,对30只成龄母鸡的中脑中央灰质结构进行了较详细的研究。结果表明:鸡的中脑中央灰质仅位于三角形导水管的两侧,由形状、大小及染色深度不一的小神经元按非均一分布方式组成。神经元可分为卵圆形、梭形、三角形及四边形四种类型。从中脑导水管壁向外侧推移,中脑中央灰质神经元的密度、大小、染色深度、神经纤维的直径和有髓化程度均逐渐增加,无内、外侧亚核的区分。神经元胞体的核质比值很高,神经网主要由无髓神经纤维和树突组成。有轴—树、轴—轴、树—树和轴—体四种突触类型。突触小泡包括清亮圆形小泡、扁平小泡及腰粒性小泡三种。同时还发现有突触小球、轴—轴—树、树—轴—树、轴—树—轴等突触串及神经元胞体间的直接连接。     

鸡小脑突触素的表达与发育研究

应用免疫组织化学SP法，研究了突触素在15、20胚龄、10日龄鸡小脑中的表达。结果表明：突触素免疫反应产物以颗粒、小点、阳性神经元和阳性纤维形式出现；突触素免疫反应产物密度在15、20胚龄、10日龄有3种变化趋势：①分子层、颗粒层、中间核、外侧上核、外侧下核中随胚(日)龄增加保持不变；②蒲肯野氏层随胚(日)龄增加先升高后降低；③小脑内侧核则随胚(日)龄增加逐渐升高。结果揭示：突触素最终合成部位可能在高尔基复合体；20胚龄左右是蒲肯野氏层突触形成的高峰期；小脑各部突触在出壳前后发育具有不均衡性。     

山羊黄体弥散性神经内分泌细胞的分布

为了探查山羊卵巢黄体中是否存在弥散性神经内分泌细胞,采用免疫组化链霉素抗生物素蛋白-过氧化物酶法对12~18月龄妊娠奶山羊卵巢中弥散性神经内分泌细胞标志物的分布进行了研究。结果显示:黄体组织中各区均含有催产素、神经元特异性烯醇化酶、S-100蛋白、突触素和5-羟色胺样免疫反应阳性细胞。这些细胞散在或成团分布,多呈圆形、卵圆形和三角形,一些细胞具有明显的突起。阳性细胞数由多至少顺序为:催产素、突触素、S-100蛋白、神经元特异性烯醇化酶、5-羟色胺。鉴于神经元特异性烯醇化酶、S-100蛋白、突触素和5-羟色胺是弥散性神经内分泌系统广谱的、共同的细胞标记物,结果提示山羊卵巢黄体中存在弥散性神经内分泌细胞。     

伪狂犬病病毒感染动物神经系统的分子机制研究进展

伪狂犬病病毒(PRV)是猪伪狂犬病的病原体,在世界范围内造成了毁灭性的疾病和经济损失。由于该病毒的嗜神经性,因此引起病毒学家和神经生物学家的高度兴趣。当前,PRV已经成为研究疱疹病毒生物学的一种模式病毒。此外,由于该病毒具有感染突触连接神经元的显著倾向,被用作神经通路的示踪剂。我国虽然在根除PRV上取得了很大进展,但在许多国家仍然是一个地方性问题。现从PRV的最新研究技术、感染动物神经系统的致病机制以及功能应用3个方面进行综述。     

虫克星在兽医临床上的应用

虫克星的有效成分为阿维菌素 (ＡＶＭ ) ,是经微生物发酵、提炼和化学还原等工艺生产出的杀虫药 ,属一组大环内酯类化合物。作用机理是药物与靶虫细胞上的特异性高亲和力的结合位点结合 ,影响了细胞膜对氯离子的通透性 ,进而引起线虫的神经细胞与节肢动物的肌细胞抑制神经递质γ -氨基丁酸 (ＧＡＢＡ)的释放增加 ,ＧＡＢＡ作用于突触前神经末梢 ,减少兴奋性递质的释放 ,使突触后膜产生兴奋性突触后电位减少 ,突触后神经元因膜电位的去极化程度达不到阈值而不能进入兴奋状态 ,从而引起抑制 ,虫体麻痹、死亡。该制剂是一种新型、广谱、高效、…     

牛中枢神经兴奋伴有其他症状疾病的鉴别与诊断

神经兴奋是指神经系统处于亢奋状态。神经系统由和周围神经系统构成，通常指脑、脊髓、周围神经三部分。按照组成神经的形态来说，神经系统又主要是由神经元和神经胶质组成的。中枢神经系统是神经组织最集中的部位。人的中枢神经系统包括脑和脊髓，脑有大脑、小脑、间脑、中脑、脑桥、延髓。人体的反射活动表现在中枢神经系统，把不同空间和时间的传人冲动进行整合，神经元之间在机能上发生突触联系，使中枢神经系统的活动表现为兴奋的扩散、抑制和反馈。突触在结构和机能上的特性，决定了兴奋传递的单向性，从而使机体对内外界刺激的反应更加协调准确。     

蛋白翻译后泛素化修饰在精子发生中作用机制的研究进展

泛素-蛋白酶体系统（Ubiquitin-Proteasome System,UPS）是真核细胞内蛋白质降解的2种主要机制之一。在精子发生过程中许多蛋白质和细胞器被降解，UPS在促进精子形成的过程中起着关键作用。在精子发生的减数分裂、顶体生物发生和精子成熟等关键阶段，泛素相关成分（包括去泛素化酶）发挥着积极作用。一般来说，UPS功能障碍会阻止精子发生，这可能会在不同程度上诱发不育。许多UPS成分可以在不同水平上调节精子发生。本文综述了精子发生过程中泛素化修饰研究进展，为后续研究提供新的见解。     

New Insights into the Neural Differentiation Potential of Canine Adipose Tissue‐Derived Mesenchymal Stem Cells

Adipose tissue‐derived stem cells (ASCs) can be obtained from different adipose tissue sources within the body. It is an abundant cell pool, easily accessible, suitable for cultivation and expansion in vitro and preparation for therapeutic approaches. Amongst these therapeutic approaches are tissue engineering and nervous system disorders such as spinal cord injuries. For such treatment, ASCs have to be reliably differentiated in to the neuronal direction. Therefore, we investigated the neural differentiation potential of ASCs using protocols with neurogenic inductors such as valproic acid and forskolin, while dog brain tissue served as control. Morphological changes could already be noticed 1 h after neuronal induction. Gene expression analysis revealed that the neuronal markers nestin and βIII‐tubulin as well as MAP2 were expressed after induction of neuronal differentiation. Additionally, the expression of the neurotrophic factors NGF, BDNF and GDNF was determined. Some of the neuronal markers and neurotrophic factors were already expressed in undifferentiated cells. Our findings point out that ASCs can reliably be differentiated into the neuronal lineage; therefore, these cells are a suitable cell source for cell transplantation in disorders of the central nervous system. Follow‐up studies would show the clinical benefit of these cells after transplantation.     

CCL2 induces neural stem cell proliferation and neuronal differentiation in Niemann-Pick type C mice

Niemann-Pick type C disease (NP-C) is a rare and ultimately fatal lysosomal storage disorder with variable neurologic symptoms. Loss of neuronal function and neuronal cell death occur in the NP-C brain, similar to the findings for other neurodegenerative diseases. Targeting of neuronal cells in the brain therefore represents a potential clinical intervention strategy to reduce the rate of disease progression and improve the quality of life. We previously reported that bone marrow stem cells show a neurogenic effect through CCL2 (also known as monocyte chemoattractant protein-1, MCP-1) secretion in the brains of NP-C mice. However, the direct effect of CCL2 on neurogenesis has not been ascertained. Here, to define neurogenic effects of CCL2 in NP-C, we applied human recombinant CCL2 to neural stem cells (NSCs) derived from NP-C mice. CCL2-treated NSCs showed significantly increased capacity for self-renewal, proliferation and neuronal differentiation. Similar results were observed in the subventricular zone of NP-C mice after CCL2 treatment. Furthermore, infusion of CCL2 into the NP-C mouse brain resulted in reduction of neuroinflammation. Taken together, our results demonstrate that CCL2 is a potential new therapeutic agent for NP-C.     

牛奶中唾液酸的生物学功能研究

牛奶中含有丰富的唾液酸,尤其是在初乳中,它在各种生命活动中起着重要的作用,特别是在细胞与细胞之间的相互作用、神经生长、突触联系、记忆形成等方面.近年来,唾液酸及其衍生物在治疗流感、神经性疾病、炎症、肿瘤等方面有很重要的应用价值.     

Peripheral nerve pathology in two rottweilers with neuronal vacuolation and spinocerebellar degeneration

Neuronal vacuolation and spinocerebellar degeneration in young Rottweiler dogs is a neurodegenerative condition characterized by neuronal vacuolation of several nuclei in the central nervous system and degeneration of the spinal cord white matter. Here, we describe the morphologic and ultrastructural findings in laryngeal muscles and peripheral nerves of a 16-week-old female and a 32-week-old female Rottweiler dog affected by progressive ataxia and tetraparesis associated with laryngeal paralysis. Lesions were characterized by neurogenic muscle atrophy of the intrinsic laryngeal muscles, and a loss of large myelinated fibers in the recurrent laryngeal nerve, accompanied by demyelinating/remyelinating features affecting the small myelinated fibers. No significant changes were detected in the cranial laryngeal, vagus, phrenic, ulnar, or peroneal nerves. These findings were indicative of a selective distal neuropathy of the recurrent laryngeal nerve with early severe axonal degeneration, mainly of the large myelinated fibers.     

Pseudorabies virus induces a rapid up-regulation of nitric oxide synthases in the nervous system of swine

Nitric oxide (NO) is a free radical gas with important roles in the host's immune response against viral infections. In this study, we examined the kinetics and distribution of nitric oxide synthase (NOS) expression during the early steps of infection of the porcine nervous system by the alphaherpesvirus pseudorabies virus (PRV). To this end, we examined changes in the expression of the three major NOS isoforms, neuronal NOS (nNOS), endothelial NOS (eNOS) and inducible NOS (iNOS), by immunohistochemistry in the trigeminal ganglia and brain of pigs inoculated intranasally with a virulent PRV strain. The results obtained show that infection of the porcine nervous system by PRV induced a rapid and progressive increment in NOS expression that coincided in timing, location, and magnitude with those of virus propagation in the nervous tissue. A major finding of this study was that PRV caused not only nNOS and iNOS induction in a variety of cell types, but also eNOS up-regulation in endothelial cells and neurons; therefore, all possible sources of NO are activated and probably contribute to the overproduction of NO during infection with the neurotropic alphaherpesvirus PRV in its natural host.     

The reproductive system at the neuroendocrine-immune interface: focus on LHRH,estrogens and growth factors in LHRH neuron-glial interactions

Bidirectional communication between the neuroendocrine and immune systems plays a pivotal role in health and disease. Signals generated by the hypothalamic-pituitary-gonadal (HPG) axis (i.e. luteinizing hormone-releasing hormone, LHRH, and sex steroids) are major players coordinating the development immune system function. Conversely, products generated by immune system activation exert powerful and longlasting effects on HPG axis activity. In the central nervous system (CNS), one chief neuroendocrine-immune (NEI) compartment is represented by the astroglial cell population and its mediators. Of special interest, the major supporting cells of the brain and the thymus, astrocytes and thymic epithelial cells, share a similar origin and a similar set of peptides, transmitters, hormones and cytokines functioning as paracrine/autocrine regulators. This may explain some fundamental analogies in LHRH regulation of both cell types during ontogeny and in adult life. Hence, the neuropeptide LHRH significantly modulates astrocyte and thymic cell development and function. Here we focus this work on LHRH neuron-glial signaling cascades which dictate major changes during LHRH neuronal differentiation and growth as well as in response to hormonal manipulations and pro-inflammatory challenges. The interplay between LHRH, growth factors, estrogens and pro-inflammatory mediators will be discussed, and the potential physiopathological implications of these findings summarized. The overall study highlights the plasticity of this intersystem cross-talk and emphasize neuron-glial interactions as a key regulatory level of neuroendocrine axes activity.     

Development of Deep and Upper Neuronal Layers in the Domestic Cat,Sheep and Pig Neocortex

The neocortex plays a key role in cognition, volitional motor control and sensory perception and has undergone tremendous expansion during evolution. The mature neocortex consists of radially aligned neurons that are arranged in six layers. Layers II–VI are often split into two groups: deep and upper layers, both building up the so‐called cortical plate during embryonic and foetal development. So far cortical neurogenesis, including the generation of deep and upper layers, has mostly been studied in laboratory rodents and primates. However, precise data for most companion animals are lacking. This study determined the main period of neurogenesis, specifically the timing of deep and upper layer generation, in the developing domestic cat, pig and sheep neocortex using immunohistochemistry for specific neuronal markers, that is Tbr1 and Brn2. We found that the general sequence of neural events is preserved among cat, pig, sheep and other mammalian species. However, we observed differences in the timing of the overall cortical neurogenic period and occurrence of distinct neural events when these three species were compared. Moreover, our data provide further evidence that the cortical neurogenic period and gestation length might be tightly related. Together, these data expand our current understanding of neocortex development and are important for future studies investigating neocortex development and expansion especially in companion animals.     

Axogenesis in the central and peripheral nervous system of the amphipod crustacean Orchestia cavimana

We describe the formation of the major axon pathways in the embryonic central and peripheral nervous systems of the amphipod crustacean Orchestia cavimana Heller, 1865 by means of antibody staining against acetylated alpha‐tubulin. The data add to a long list of previous studies of various other aspects of development in Orchestia and provide a basis for future studies of neurogenesis on a deeper cellular and molecular level. Orchestia exhibits a tripartite dorsal brain, which is a characteristic feature of euarthropods. Its anlagen are the first detectable structures in the developing nervous system and can be traced back to distinct neuronal cell clusters in the early embryo. The development of the ventral nervous system proceeds with an anteroposterior gradient of development. In each trunk segment, the longitudinal connectives and the anterior commissure form first, followed by the intersegmental nerve, the posterior commissure and segmental nerves, respectively. A single commissure of a vestigial seventh pleonal segment is found. In the peripheral nervous system we observe a spatial and temporal pattern of leg innervation, which is strikingly similar in both limb types, the uniramous pereopods and the biramous pleopods. A proximal leg nerve splitting distally into two separated nerves probably reflects a general feature of crustaceans.     

Central nervous system trauma

Traumatic injury to the central nervous system causes immediate damage and sets in motion a complex series of pathophysiologic events that result in further neuronal injury. This secondary damage seems to be related to changes in blood flow and pressure on a systemic, regional, and microvascular level. Currently, there is evidence that these changes are, in part, mediated by endogenous opioids and arachidonic acid metabolites, namely thromboxane A2. Medical management is generally designed to intervene at one or more stages in this secondary cascade of events. Further research should lead us to better understanding of the mechanisms involved in trauma to the central nervous system and, subsequently, more specific and effective treatments.     

Multiple congenital malformations of the face, nervous system and musculoskeletal system of pigs

Multiple congenital malformations occurred in 21 of 26 pigs (81%) in 3 litters from 2 piggeries. Two of 26 pigs (7%) were mummified while 3 of 26 (11%) were normal. Cheiloschisis was seen in all malformed pigs and was accompanied by various combinations of palatoschisis, arhinencephaly, hypoplasia of the spinal cord, arthrogryposis of the pelvic limbs, polydactyly, renal lesions and cauliflower ears. Histological examination suggested that arthrogryposis was due to neurogenic muscular atrophy. The teratogen was not identified.