Developmental Neurobiology of Diffused Nervous System in Hydra

用间接免疫荧光法对水螅头部再生和出芽过程中神经网络的形成进行了研究。用神经肽RFamide的抗血清观察神经网。神经网络的形成分两步：第一步是神经节细胞在再生尖端的出现，第二步是感觉细胞在尖端的出现和神经节细胞从尖端的同时消失。上皮细胞在头部再生过程中的行为，如单克隆抗体TS 19所定义的，与神经网络形成相对应。我们研究了三种形态发生突变体的神经网络形成：头部再生缺陷突变体reg-16，出芽缺陷突变体L4和多头突变体mh-1。此外，我们还研究了由野生型上皮细胞和突变型神经细胞组成的嵌合菌株，反之亦然，我们获得了明确的证据，即神经网络的形成是由上皮细胞提供的环境控制的。

Nerve net formation was examined during head-regeneration and budding of hydra using indirect immunofluorescence on whole mounts. The nerve net was visualized with an antiserum to a neuropeptide, RFamide. The nerve net forms in two steps : the first is the appearance of ganglion cells at the regenerating tip, and the second is the appearance of sensory cells at the apex and the simultaneous disappearance of ganglion cells from the apex. The behavior of epithelial cells during head- regeneration, as defined by a monoclonal antibody TS19, corresponded with nerve net formation.We examined nerve net formation in three morphogenetic mutants : a head-regeneration deficient mutant, reg-16, a budding deficient mutant, L4, and a multi-headed mutant, mh-1. In addition, we also examined chimeric strains which consist of the epithelial cells from the wild type and nerve cells from a mutant, and vice versa.We obtained clear evidence that nerve net formation is controlled by the environment provided by the epithelial cells.