Spatially Restricted Increase in Polysialic Acid Enhances Corticospinal Axon Branching Related to Target Recognition and Innervation

摘要: The polysialic acid (PSA) modification of the neural cell adhesion molecule (NCAM) has been shown to alter responses developing axons their environment. We have studied potential role PSA in regulating innervation spinal cord by corticospinal axons, which occurs a delayed formation collateral branches from parent axons. Developmental changes distribution were examined immuno-histochemically using light and electron microscopy. Whereas NCAM is distributed along entire pathway rat as they grow cortex cord, PSA-modified does not become evident until later. When becomes evident, it restricted distal segment these caudal hindbrain through cord. increase on coincides with time that begin form This unique spatiotemporal suggests its involvement axon branching. To test this hypothesis, was selectively removed an vivo injection endoneuraminidase N. treatment did seem interfere pathfinding axons; however, removal onset branching within later diminished magnitude These findings indicate for regulation interstitial branching, crucial step process target recognition