The effects of target tissues on the outgrowth of chick cutaneous and muscle sensory neurons.
The effects of target tissues on the outgrowth of chick cutaneous and muscle sensory neurons.
复制标题
靶组织对鸡皮肤和肌肉感觉神经元生长的影响。
DOI：
10.1006/dbio.1995.1048
复制
发表时间：
1995
影响因子：
2.7
通讯作者：
Zou,JY
中科院分区：
文献类型：
--
作者：
Honig,MG;Zou,JY
在一些发育系统中，生长中的轴突被靶组织释放的可扩散分子吸引到它们的靶部位。在小鸡的后肢中，这种机制可以解释轴突在到达神经丛区域后如何生长为肌肉或皮肤。为了开始测试这种可能性的肢体神经支配的感觉神经元，我们共培养背根神经节外植体和潜在的靶组织在三维胶原凝胶。特别是，我们想知道在发育的早期阶段，靶组织是否只特异性地吸引适当类型的感觉神经元的轴突。为了识别每种类型的感觉神经元，我们使用DiI逆行标记胚胎中的皮肤或肌肉感觉神经元，然后进行培养。结果表明，皮肤和肌肉外植体都可以促进皮肤和肌肉感觉轴突的生长。相比之下，与发育中的肌肉相关的表皮和结缔组织似乎抑制皮肤和肌肉感觉轴突的生长。这些结果表明，在胚胎中，真皮和肌肉细胞都释放扩散因子，导致感觉轴突从神经丛分叉，向这些因子的来源延伸，从而形成离散的外周神经。表皮和肌肉相关结缔组织的抑制作用可用于限制感觉轴突向结构的生长，即，真皮和肌肉细胞，最终接受感觉神经支配。然而，由于对于每种不同类型的肢体组织，皮肤和肌肉感觉神经元的反应总是彼此相似，因此感觉轴突在决定是生长到皮肤还是肌肉时，一定不会对靶源性因子产生反应。
In some developing systems, growing axons are attracted to their target site by a diffusible molecule released by the target tissue. In the chick hindlimb, this mechanism could explain how axons, after having reached the plexus region, grow to muscle or to skin. To begin to test this possibility for limb-innervating sensory neurons, we cocultured dorsal root ganglion explants and potential target tissues in three-dimensional collagen gels. In particular, we wanted to know if target tissues, at early stages of development, specifically attract axons of only the appropriate type of sensory neuron. To identify each type of sensory neuron, we used DiI to retrogradely label either cutaneous or muscle sensory neurons in the embryo, prior to culturing. The results showed that dermal and muscle explants could each enhance the outgrowth of both cutaneous and muscle sensory axons. In contrast, the epidermis and the connective tissue associated with developing muscle appeared to inhibit the outgrowth of both cutaneous and muscle sensory axons. These results suggest that, in the embryo, the dermis and muscle cells both release diffusible factors that cause sensory axons to diverge from the plexus, extend toward the sources of these factors, and thereby form discrete peripheral nerves. The inhibitory effects of epidermis and muscle-associated connective tissue may serve to limit the growth of sensory axons to the structures, i.e., dermis and muscle cells, that ultimately receive sensory innervation. However, since for each of the different types of limb tissue, the responses of cutaneous and muscle sensory neurons were always similar to one another, sensory axons must not be responding to target-derived factors when they decide whether to grow to skin or to muscle.