MECHANISMS OF SENSORY NEURON AND GANGLION DEVELOPMENT

包括人类在内的所有脊椎动物的颅感觉神经节都是从 两个原基，神经源性安慰剂和神经脊。神经源性 胎盘是表面外胚层的增厚，神经母细胞来自于外胚层 形成了。这些细胞随后成为远端的传入神经元。 第VII、IX和X神经节，三叉神经远端(V)和 前庭-声学复合体()。神经脊细胞起源于 紧靠或之前的神经上皮的边缘(神经)皱褶 在大脑和脊髓关闭后。在头部区域的脊部 细胞产生近端感觉神经节的神经元；它们也形成 所有的副细胞和雪旺细胞、外周传出神经元和许多 头面部骨骼和结缔组织。这样做的目的是 研究是为了定义控制这些疾病发展的机制 颅感觉神经元，尤指起源于胎盘的感觉神经元。四 将检查发育过程：(1)胎盘的形成，(2) 神经母细胞产生，(3)感觉神经节发育，这涉及到 神经脊和胎盘细胞的共同参与，以及(4)规范 感觉神经元，其意思是建立适当的 中央和外周投射。分析的方法包括 神经源性安慰剂原基异位移植 位置，位于不同的胎盘位置或到非胎盘位置 地点。所有捐献组织都将包含一个标记，这样它们就可以 区别于宿主细胞。对宿主胚胎的检查将涉及到 细胞学、免疫组织化学(使用神经丝抗体)和 神经解剖学技术。后者包括修改后的HRP示踪 宿主胚胎和对照胚胎的传入投射。马尾松的辅助移植 神经峰将作为一个互补的系列来执行。这个系统 提供了一个独特的机会来研究两者之间的相互作用 两条不同的神经源性细胞线，以及这些细胞和 头部的其他非神经源性组织。在其他脊椎动物中 胚胎神经系统是既可识别又可接近的原基 在神经发生之前和早期阶段，在什么时候 细胞学和生化特性以及突起的模式 下定决心。

Cranial sensory ganglia in all vertebrates, including humans, develop from two primordia, neurogenic placodes and the neural crest. Neurogenic placodes are thickenings of the surface ectoderm from which neuroblasts are formed. These cells subsequently become afferent neurons in the distal ganglia of nerves VII, IX, and X, the distal part of the trigeminal (V) and the vestibulo-acoustic complex (VIII). Neural crest cells arise from the marginal (neural) folds of the neurepithelium immediately prior to or following closure of the brain and spinal cord. In the head region crest cells give rise to neurons of the proximal sensory ganglia; they also form all accessory and Schwann cells, peripheral efferent neurons, and many craniofacial skeletal and connective tissues. The objective of this research is to define the mechanisms controlling development of these cranial sensory neurons, particularly those of placodal origin. Four developmental processes will be examined: (1) placode formation, (2) neuroblast production, (3) sensory ganglion development, which involves the participation of both neural crest and placode cells, and (4) specification of sensory neurons, by which is meant the establishment of appropriate central and peripheral projections. The method of analysis involves transplantation of the primordia of neurogenic placodes to heterotopic sites, either in the place of a different placode or to a non-placodal site. All donor tissues will contain a marker so that they can be distinguished from host cells. Examination of host embryos will involve cytological, immunohistochemical (using antibodies to neurofilaments) and neuroanatomical techniques. The latter include modified HRP tracing of afferent projections in host and control embryos. Ancillary transplants of the neural crest will be performed as a complementary series. This system provides an unique opportunity to investigate the interactions both between two distinct lines of neurogenic cells and also between these cells and other, non-neurogenic tissues in the head. In no other vertebrate embryonic neural system are the primordia identifiable and accessible both prior to and during the early stages of neurogenesis, at which times the cytological and biochemical properties and patterns of projections are determined.