Yip J W, Yip Y P
Department of Physiology, School of Medicine, University of Pittsburgh, PA 15261.
Brain Res Dev Brain Res. 1992 Jul 24;68(1):23-33. doi: 10.1016/0165-3806(92)90244-q.
The possible role of laminin on axon outgrowth and guidance in vivo was examined by: (1) determining its developmental expression, and relationship to outgrowth of sensory, motor and sympathetic axons in the chick embryo; and (2) evaluating the changes in the pattern of sympathetic preganglionic projections subsequent to injections of laminin, antilaminin and other laminin function blockers (JG22, INO) into their pathways during axon outgrowth. Double immunofluorescent staining for laminin and neurofilaments in peripheral nerves prior to and during initial outgrowth showed no obvious relationship between laminin and potential nerve pathways. Even though weak laminin immunostaining is apparent throughout the mesenchyme through which axons grow, the most prominent laminin immunostaining is on basement membranes of the neural tube, notochord and dermamyotome. However, as peripheral nerves mature, laminin becomes localized to nerve fascicles throughout the peripheral nervous system, beginning with the dorsal and ventral roots, and progressing later to more distal spinal nerves. Microinjections of antilaminin, JG22 (a monoclonal antibody against laminin/fibronectin receptors) and INO (a monoclonal antibody against a laminin-heparan sulfate proteoglycan complex) into the pathway of sympathetic preganglionic axons prior to and during outgrowth had no effect on the spatio-temporal patterns of sympathetic preganglionic projections. An alternate laminin-rich pathway produced by injecting laminin into the region of the sympathetic trunk immediately adjacent but caudal to the T1 spinal level also did not alter the projection of T1 preganglionic axons. These results suggest that laminin may not be crucial to the initial of peripheral axons. The localization of laminin in nerve fascicles in later stages of development suggests instead that laminin may be important in the maintenance of these structures.
（1）确定其发育表达以及与鸡胚中感觉、运动和交感神经轴突生长的关系；（2）评估在轴突生长过程中向交感神经节前投射路径注射层粘连蛋白、抗层粘连蛋白和其他层粘连蛋白功能阻断剂（JG22、INO）后，交感神经节前投射模式的变化。在轴突开始生长之前和期间，对周围神经中的层粘连蛋白和神经丝进行双重免疫荧光染色，结果显示层粘连蛋白与潜在神经通路之间没有明显关系。尽管在轴突生长穿过的整个间充质中都有明显的弱阳性层粘连蛋白免疫染色，但最显著的层粘连蛋白免疫染色出现在神经管、脊索和皮肌节的基底膜上。然而，随着周围神经成熟，层粘连蛋白开始定位于整个周围神经系统的神经束，首先是背根和腹根，随后逐渐定位于更远端的脊神经。在交感神经节前轴突生长之前和期间，向其路径中显微注射抗层粘连蛋白、JG22（一种抗层粘连蛋白/纤连蛋白受体的单克隆抗体）和INO（一种抗层粘连蛋白-硫酸乙酰肝素蛋白聚糖复合物的单克隆抗体），对交感神经节前投射的时空模式没有影响。通过在紧邻T1脊髓水平但在其尾侧的交感干区域注射层粘连蛋白产生的另一条富含层粘连蛋白的路径，也没有改变T1节前轴突的投射。这些结果表明，层粘连蛋白可能对周围轴突的起始并不关键。相反，层粘连蛋白在发育后期定位于神经束，这表明它可能在维持这些结构方面很重要。
