Reinnervation of transplanted hypothalamic neurons by host aminergic fibers in rats

Fetal mediobasal hypothalamic tissue which receives an extensive noradrenergic innervation in the adult brain, was implanted into the vicinity of the medial forebrain bundle of adult rats to determine whether host noradrenergic fibers would innervate the ectopically placed tissue in an organotypic manner. Tissue from the site of implantation was prepared for light and ultrastructural immunocytochemistry at 6, 12, or 20 weeks postsurgery. Putative host catecholamine fibers formed dense plexuses in localized portions of the grafts and made synaptic contacts with dendrites and somata of transplanted neurons. This suggests that a mature host central nervous system is capable of a region-specific integration of transplanted neurons.