鞭角华扁叶蜂预蛹神经内分泌系统的解剖

通过对鞭角华扁叶蜂预肾的解剖,明确屯其神经内分泌系统的构造及其分布。其中枢神经系统由脑、食管下神经节、腹神经索组成,前、中、后脑分化明显。腹神经索包括三对胸神经节、八对腹神经节及纵贯各神经节的神经索,其中各了的分布与叶蜂预肾体节相一致,位于各体节腹板的前缘中部。口道交感神经系统由位于脑前方食道背面的额神经节和位于脑后方的后头神经节组成的神经连锁构成。腹交感神经系统由位于腹神经索各神经节上的横神经组     

蓝斑背肛海兔神经连索外表层超微量多肽组成的研究

蓝斑背肛海兔(NotarcusleachiicirrosusStimpson,NLCS)中枢神经系统缺少腹神经节.选用基质辅助激光解吸电离化飞行时间(Matrix assistedlaserdesorptionionization/timeofflight,MALDI TOF)质谱技术研究NLCS中枢神经系统连索外表层的超微量的多肽组成和分布时,发现该连索外表层含有丰富的酸性多肽(Aicdicpeptide,AP)的酶解片段和其他多肽组分.不同NLCS个体的中枢神经连索外表层多肽分布与组分有些差异,推测这些神经多肽可能参与中枢神经系统的信息传导和行为的可塑性.在不同的神经连索之间发现相同一级结构和聚合体的多肽组成,认为这些组份以不同的形式分泌到神经节或连索外表层参与信息传导活动,起到相似或相同的生理功能.     

Increased levels of myelin basic protein transcripts in virus-induced demyelination

In multiple sclerosis, a demyelinating disease of young adults, there is a paucity of myelin repair in the central nervous system (CNS) which is necessary for the restoration of fast saltatory conduction in axons. Consequently, this relapsing disease often causes marked disability. In similar diseases of small rodents, however, remyelination can be quite extensive, as in the demyelinating disease caused by the A59 strain of mouse hepatitis virus (MHV-A59), a coronavirus of mice. To investigate when and where oligodendrocytes are first triggered to repair CNS myelin in such disease, we have used a complementary DNA probe specific for one major myelin protein gene, myelin basic protein (MBP), which hybridizes with the four forms of MBP messenger RNA in rodents. Using Northern blot and in situ hybridization techniques, we previously found that MBP mRNA is first detected at about 5 days after birth, peaks at 18 days and progressively decreases to 25% of the peak levels in the adult. We now report that in spinal cord sections of adult animals with active demyelination and inflammatory cells, in situ hybridization reveals a dramatic increase in probe binding to MBP-specific mRNA at 2-3 weeks after virus inoculation and before remyelination can be detected by morphological methods. This increase of MBP-specific mRNA is found at the edge of the demyelinating area and extends into surrounding areas of normal-appearing white matter. Thus, in situ hybridization with myelin-specific probes appears to be a useful method for detecting the timing, intensity and location of myelin protein gene reactivation preceding remyelination. This method could be used to elucidate whether such a reactivation occurs in multiple sclerosis brain tissue. Our results suggest that in mice, glial cells react to a demyelinating process with widespread MBP mRNA synthesis which may be triggered by a diffusible factor released in the demyelinated areas.     

BDNF is a neurotrophic factor for dopaminergic neurons of the substantia nigra

Brain-derived neurotrophic factor (BDNF), present in minute amounts in the adult central nervous system, is a member of the nerve growth factor (NGF) family, which includes neurotrophin-3 (NT-3). NGF, BDNF and NT-3 all support survival of subpopulations of neural crest-derived sensory neurons; most sympathetic neurons are responsive to NGF, but not to BDNF; NT-3 and BDNF, but not NGF, promote survival of sensory neurons of the nodose ganglion. BDNF, but not NGF, supports the survival of cultured retinal ganglion cells but both NGF and BDNF promote the survival of septal cholinergic neurons in vitro. However, knowledge of their precise physiological role in development and maintenance of the nervous system neurons is still limited. The BDNF gene is expressed in many regions of the adult CNS, including the striatum. A protein partially purified from bovine striatum, a target of nigral dopaminergic neurons, with characteristics apparently similar to those of BDNF, can enhance the survival of dopaminergic neurons in mesencephalic cultures. BDNF seems to be a trophic factor for mesencephalic dopaminergic neurons, increasing their survival, including that of neuronal cells which degenerate in Parkinson's disease. Here we report the effects of BDNF on the survival of dopaminergic neurons of the developing substantia nigra.     

不同品级拟黑多刺蚁(Polyrhachis vicina)脑部雌激素相关受体基因的表达

采用原位杂交方法对不同品级拟黑多刺蚁(Polyrhachis vicina)脑部雌激素相关受体pvERRmRNA的表达进行了检测.结果表明,pvERRmRNA在不同品级的蕈形体、附叶、视叶、中脑、食道下神经节和球状细胞中都有表达.蚁后蕈形体和球状细胞中pvERRmRNA的阳性表达最为明显;工蚁中脑pvERR mRNA的阳性反应强度明显高于蚁后和雄蚁;pvERR mRNA在雄蚁视叶中有较强的表达.pvERR mRNA在不同品级的拟黑多刺蚁脑部的表达差异可能与它们各自在蚁群中的功能和行为有关.     

Ependymal cells of chordate larvae are stem-like cells that form the adult nervous system

In ascidian tunicates, the metamorphic transition from larva to adult is accompanied by dynamic changes in the body plan. For instance, the central nervous system (CNS) is subjected to extensive rearrangement because its regulating larval organs are lost and new adult organs are created. To understand how the adult CNS is reconstructed, we traced the fate of larval CNS cells during ascidian metamorphosis by using transgenic animals and imaging technologies with photoconvertible fluorescent proteins. Here we show that most parts of the ascidian larval CNS, except for the tail nerve cord, are maintained during metamorphosis and recruited to form the adult CNS. We also show that most of the larval neurons disappear and only a subset of cholinergic motor neurons and glutamatergic neurons are retained. Finally, we demonstrate that ependymal cells of the larval CNS contribute to the construction of the adult CNS and that some differentiate into neurons in the adult CNS. An unexpected role of ependymal cells highlighted by this study is that they serve as neural stem-like cells to reconstruct the adult nervous network during chordate metamorphosis. Consequently, the plasticity of non-neuronal ependymal cells and neuronal cells in chordates should be re-examined by future studies.     

黄脸油葫芦中枢神经系统的组织解剖学研究

应用解剖镜和光镜观察了黄脸油葫芦(Teleogryllus emma (Ohmachi and Matsuura))中枢神经系统的组织解剖学结构，并对脑和各体神经节的组织学结构进行了比较．结果表明，黄脸油葫芦的中枢神经系统由脑、食道下神经节和腹神经索组成；前、中、后脑分化明显，腹神经索包括三对胸神经节、五对腹神经节及纵贯各神经节的神经索；脑和各体神经节的组织学结构相似，由外向内依次是神经鞘、神经细胞层和髓质层；脑的髓质层复杂，其中含有四种由神经细胞球体和神经纤维束形成的脑体，一对蕈状体、一个脑桥体、一个中央体及一对脑腹体。     

Modification of retinal ganglion cell axon morphology by prenatal infusion of tetrodotoxin

The cellular mechanisms by which the axons of individual neurons achieve their precise terminal branching patterns are poorly understood. In the visual system of adult cats, retinal ganglion cell axons from each eye form narrow cylindrical terminal arborizations restricted to alternate non-overlapping layers within the lateral geniculate nucleus (LGN). During prenatal development, axon arborizations from the two eyes are initially simple in shape and are intermixed with each other; they then gradually segregate to form complex adult-like arborizations in separate eye-specific layers by birth. Here we report that ganglion cell axons exposed to tetrodotoxin (TTX) to block neuronal activity during fetal life fail to form the normal pattern of terminal arborization. Individual TTX-treated axon arborizations are not stunted in their growth, but instead produce abnormally widespread terminal arborizations which extend across the equivalent of approximately two eye-specific layers. These observations suggest that during fetal development of the central nervous system, the formation of morphologically appropriate and correctly located axon terminal arborizations within targets is brought about by an activity-dependent process.     

Spatial restriction in expression of a mouse homoeo box locus within the central nervous system

A common feature of Drosophila homoeo box genes appears to be their spatially restricted expression patterns during morphogenesis. Using Northern blot analysis and in situ hybridization to mouse tissue sections, the spatially restricted expression of a newly identified mouse homoeo box locus, Hox-3, within the central nervous system of newborn and adult mice has been demonstrated.     

阿片类物质的外周镇痛作用

就外周阿片受体的分布和阿片类物质的外周镇痛作用及机制的相关研究进展进行综述.阿片类物质的镇痛作用通过中枢和外周两种机制,研究表明:阿片类物质的外周镇痛作用是通过外周阿片受体起作用的.初级感觉神经元内及其外周末梢上存在着各类阿片受体,在炎症及神经损伤的情况下,阿片受体合成增加并转运到神经末梢或者受损部位,增加传导痛觉冲动...     

Expressions of cardiac sympathetic norepinephrine transporter and β1-adrenergic receptor decreased in aged rats

Evidence suggests that the deterioration of communication between the sympathetic nervous system and cardiovascular system always accompanies the aging of human and animals. Cardiac sympathetic norepinephrine (NE) transporter (NET) on presynaptic membrane is a predominant component to eliminate released NE in the synaptic cleft and maintains the sensitivity of the β-adrenergic receptor (β-AR). In the present study, we investigated NET and β₁-AR mRNA levels and sympathetic nerve density in cardiac sympathetic ganglion and left ventricular myocardium in 2- and 16-month-old rats with Northern blot analysis and immunohistochemistry. The expression levels of NET mRNA, NET protein and β₁-AR mRNA in the ganglia or myocardia of 16-month-old rats were markedly reduced by 67%, 26%, and 43%, respectively, in comparison with those in 2-month-old rats. Our results also show that aging induces a strong decrease of the catecholaminergic nerve fiber density.     

Transcript localization of four opsin genes in the three visual organs of Drosophila; RH2 is ocellus specific

Drosophila and other Dipteran flies have three different kinds of visual organs; in the adult a pair of compound eyes and three dorsal ocelli; and in the larva a pair of internal photoreceptor organs. They develop in distinct ways, yet have certain features in common. All three organs use retinal-derived chromophores, coupled to distinct opsins, to provide a diversity of spectral sensitivities. Four opsin genes have been identified thus far in Drosophila; Rh1, Rh2, Rh3 and Rh4 (refs 6-11). We have used in situ hybridization to study the messenger RNAs expressed by these four opsin genes in all three visual organs. Rh1, Rh3 and Rh4 are already known to be expressed in different subsets of cells in the compound eye. We found that, in contrast, opsin Rh2 is the predominant opsin expressed in the ocelli. Opsin Rh1 is known to be expressed in the larval photoreceptor. We found that Rh3 and Rh4 are as well, but not Rh2. The ocellar-specific gene expression of Rh2 is of particular interest for its possible bearing on the function of the ocellus.     

锯缘青蟹视神经节FSH和LH的免疫识别

甲壳动物的视神经节含有性腺抑制激素(Gonad inhibiting hormone, GIH),长期以来视神经节被理解为生殖抑制效应.本研究应用脊椎动物卵泡刺激素(Fllicle stimulating hormone,FSH)抗体和黄体生成素(Luteinizing hormone,LH)抗体,从锯缘青蟹(Scylla serrata)视神经节的视外髓、视内髓和视端髓检测到FSH和LH免疫细胞化学阳性反应.锯缘青蟹视神经节中的FSH和LH免疫阳性物质,可能参与了生殖神经内分泌调节.     

Neuroanatomy of sea spiders implies an appendicular origin of the protocerebral segment

Independent specialization of arthropod body segments has led to more than a century of debate on the homology of morphologically diverse segments, each defined by a lateral appendage and a ganglion of the central nervous system. The plesiomorphic composition of the arthropod head remains enigmatic because variation in segments and corresponding appendages is extreme. Within extant arthropod classes (Chelicerata, Myriapoda, Crustacea and Hexapoda--including the insects), correspondences between the appendage-bearing second (deutocerebral) and third (tritocerebral) cephalic neuromeres have been recently resolved on the basis of immunohistochemistry and Hox gene expression patterns. However, no appendage targets the first ganglion, the protocerebrum, and the corresponding segmental identity of this anterior region remains unclear. Reconstructions of stem-group arthropods indicate that the anteriormost region originally might have borne an ocular apparatus and a frontal appendage innervated by the protocerebrum. However, no study of the central nervous system in extant arthropods has been able to corroborate this idea directly, although recent analyses of cephalic gene expression patterns in insects suggest a segmental status for the protocerebral region. Here we investigate the developmental neuroanatomy of a putative basal arthropod, the pycnogonid sea spider, with immunohistochemical techniques. We show that the first pair of appendages, the chelifores, are innervated at an anterior position on the protocerebrum. This is the first true appendage shown to be innervated by the protocerebrum, and thus pycnogonid chelifores are not positionally homologous to appendages of extant arthropods but might, in fact, be homologous to the 'great appendages' of certain Cambrian stem-group arthropods.     

Motor neuron columnar fate imposed by sequential phases of Hox-c activity

The organization of neurons into columns is a prominent feature of central nervous system structure and function. In many regions of the central nervous system the grouping of neurons into columns links cell-body position to axonal trajectory, thus contributing to the establishment of topographic neural maps. This link is prominent in the developing spinal cord, where columnar sets of motor neurons innervate distinct targets in the periphery. We show here that sequential phases of Hox-c protein expression and activity control the columnar differentiation of spinal motor neurons. Hox expression in neural progenitors is established by graded fibroblast growth factor signalling and translated into a distinct motor neuron Hox pattern. Motor neuron columnar fate then emerges through cell autonomous repressor and activator functions of Hox proteins. Hox proteins also direct the expression of genes that establish motor topographic projections, thus implicating Hox proteins as critical determinants of spinal motor neuron identity and organization.     

Multiple forms of synaptic plasticity triggered by selective suppression of activity in individual neurons

The rules by which neuronal activity causes long-term modification of synapses in the central nervous system are not fully understood. Whereas competitive or correlation-based rules result in local modification of synapses, homeostatic modifications allow neuron-wide changes in synaptic strength, promoting stability. Experimental investigations of these rules at central nervous system synapses have relied generally on manipulating activity in populations of neurons. Here, we investigated the effect of suppressing excitability in single neurons within a network of active hippocampal neurons by overexpressing an inward-rectifier potassium channel. Reducing activity in a neuron before synapse formation leads to a reduction in functional synaptic inputs to that neuron; no such reduction was observed when activity of all neurons was uniformly suppressed. In contrast, suppressing activity in a single neuron after synapses are established results in a homeostatic increase in synaptic input, which restores the activity of the neuron to control levels. Our results highlight the differences between global and selective suppression of activity, as well as those between early and late manipulation of activity.     

Immunorecognition of estrogen and androgen receptors in the brain and thoracic ganglion mass of mud crab, Scylla paramamosain

The brain and the thoracic ganglion of crustacean can synthesize and secrete gonad-stimulating hormone (GSH) which stimulates the maturation of gonad. In the previous experiments, sex steroid hormones (estradiol, testosterone, progesterone, etc.) have been detected from crustacean. However, the feedback regulation of sex steroid hormones on the brain and thoracic ganglion of crustacean has not been reported so far. In the present experiment, monoclonal antibodies were applied to investigate the immunorecognition of estrogen receptor (ER) and androgen receptor (AR) in the brain and thoracic ganglion mass of Scylla paramamosain. The results showed that the distribution of the immunopositive substances of ER and AR was extremely similar. They distributed in the protocerebrum, deutocerebrum and tritocerebrum of the brain, and mainly in protocerebrum. In the thoracic ganglion mass, immunopositive substances distributed in the subesophageal ganglion, thoracic ganglion and abdomen ganglion, and mostly in subesophageal ganglion. Immunopositive substances of ER and AR mostly existed in the cytoplasm of neurons. The present study will provide morphological evidence for the origin and evolution of ER and AR. In addition, the immunoreactivities of ER and AR suggested that the estrogen and androgen may be involved in the feedback regulation of crustacean neuroendocrine.     

Molecular characterization of diapause hormone inHelicoverpa armigera

Diapause hormone (DH) is a neurohormone which is secreted from suboesophageal ganglion and responsible for induction of embryonic diapause in many insects. Using rapid amplification of the cDNA ends (RACE) method, the cDNA encoding diapause hormone inHelicoverpa armigera, a main kind of crops pest was cloned. The nucleotide sequence reveals that the mRNA encodes an open reading frame and the 25-aa DH peptide is localized at N-terminal region just after the signal peptide. A homology search showed thatH. armigera DH has high homology with the diapause hormone ofBombyx mori andHelicoverpa zea; and it also belongs to the FXPRL neuropeptide family. Thus,H. armigera DH seems to be a new type of diapause hormone molecule.