Expression of peptides and transmitters in neurons and expression of filament proteins in astrocytes in fetal cerebral cortical transplants to adult spinal cord

This chapter describes the studies demonstrating that the appropriate biochemically defined and morphologically identified neurons in the cerebral cortex arise in an ectopically located homograft, but do not elaborate the extensive dendritic trees seen in the normal adult cerebral cortex. Integration between the host and the graft has been established by finding vasoactive intestinal polypeptide (VIP) neurons in the ventral horn of the host, substance P (SP) and 5-hydroxytryptamine (5-HT) fibers in the graft, and astrocytes with processes that extend between host and graft. These findings suggest that the use of fetal cerebral cortical homografts to adult rat spinal cord should undergo further examination as a possible model in spinal cord regeneration studies. The series of experiments described in this chapter demonstrate that fetal rat cerebral cortical homografts to adult rat spinal cord develop as cerebral cortex but, unlike normal cerebral cortex, the transplanted cortical material receives fibers directly from the spinal cord of the host.