CYCLOHEXIMIDE DOWNSYNTHESIZES INHIBITORY MOLECULES FOR NEURITE OUTGROWTH IN NEURAL TRANSPLANTATION

Rat fetal substantia nigra treated with cycloheximide, a protein synth esis inhibitor, were implanted to adult rat striatum. After 4 weeks, t yrosine hydroxylase (TH)-like immunoreactive (-LI) fibers of host stri atum penetrated grafts, and TH-LI neurites in the grafts elongated and mingled with the host striatal neurites. Astrocytes proliferated in t he grafts without glial scar between the graft-host border. A few chon droitin sulfate- or tenascin-LI glial cells were found in the grafts, while in transplants without cycloheximide, glial scar expressed stron g immunoreactivity for these molecules. Downsynthesis of these inhibit ory molecules may alter the glial character and permit neurites traver sing the border.