Endogenous Electrical Current and Neural Crest Cell Migration in Chick Embryos

这项工作的目的是直接测试小鸡胚胎中的内源性电场引导腰骶神经嵴细胞到达后肠目标的假设。罗宾逊博士会在嵴细胞迁移期间通过控制内源性电场来达到这个目的。这个电场是离开后肠门静脉的大电流的结果，通过在被膜上形成的伤口将产生的电流分流，或通过电压箝住胚胎上皮电位，从而消除或逆转内源性电场，将会改变这个电场。荧光染料DiI将用于追踪神经嵴细胞的迁移过程。罗宾逊博士还将对小鸡的尾肠退化进行光镜和电子显微镜研究，以确定这一过程是他检测到的流出后肠门的电流的原因。外加电场对拟建的内源性电场靶细胞的体外效应也将进行研究。他将把他的振动探针观察扩展到小鼠胚胎，特别是一些可用的突变体，以确定是否有任何内源性电流参数的变化表明了特定的异常。从这些实验中获得的信息将大大增加我们对迁移细胞在发育过程中是如何被引导的认识。

The aim of the work described in this proposal is to test directly the hypothesis that an endogenous electrical field in the chick embryo acts to guide lumbo-sacral neural crest cells to their targets in the hind gut. Dr. Robinson will do this by manipulating the endogenous field during the period of crest cell migration. This field, which is the result of a large current that leaves the posterior intestinal portal, will be altered by shunting the current which generates it through wounds created in the integument, or by voltage clamping the embryonic transepithelial potential, thus eliminating or reversing the endogenous field. The fluorescent dye DiI will be used to trace the neural crest cells during their migration. Dr. Robinson will also do a light and electron microscopy study of tail gut degeneration in the chick in order to establish that this process is responsible for the currents he detects leaving the posterior intestinal portal. The in vitro effects of an applied electrical field on the proposed endogenous field target cells will also be examined. He will extend his vibrating probe observations to mouse embryos, particularly some of the mutants that are available, in order to determine if changes in any of the endogenous current parameters are indicative of specific abnormalities. The information gained from these experiments will add substantially to our knowledge of how migratory cells are guided during development.