title: Straying phenomenon of migrating LHRH neurons and highly polysialylated NCAM in the chick embryo.
abstract: The present study on unilaterally incompletely placodectomized chick embryos revealed that arrival of migrating LHRH neurons into the forebrain area is dependent on the presence of a central projection of the olfactory nerve. When a fragment of the lateral and medial olfactory epithelium was spared the damage, a small number of LHRH-ir cells were found to migrate into the forebrain along a thin NCAM-H-expressing fiber bundle of the olfactory nerve. In embryos with large lesions which destroyed the lateral olfactory epithelium, the poorly developed NCAM-H-positive olfactory nerve fibers were arrested where they meet the NCAM-positive medial nasal branch of the ophthalmic nerve and frequently fused with this branch fiber bundle. In these embryos, no LHRH-ir cells were detected in the forebrain area. They were deviated from their regular migratory course to the NCAM-H-positive medial nasal branch fiber bundle. This straying phenomenon indicates that some structural support is apparently needed for the migration of LHRH-ir cells, but their migratory route is not completely programmed in their precursor cells in the olfactory placode. In cultures of placodal tissues, the coexistence of migrating LHRH-ir cells with NCAM-H-expressing neural elements was always confirmed. It is suggested therefore that not only the structural support for the migration but also the interaction between LHRH-ir cells and NCAM-H-expressing neural elements is a prerequisite for successful LHRH neuronal migration.
authors.affiliation: Department of Anatomy, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Murakami
authors.forename: M
authors.initials: M
authors.lastname: Kamiya
authors.forename: S
authors.initials: S
authors.lastname: Akutsu
authors.forename: T
authors.initials: T
authors.lastname: Seki
authors.forename: Y
authors.initials: Y
authors.lastname: Kuwabara
authors.forename: Y
authors.initials: Y
authors.lastname: Arai
mesh_terms: D000818:Animals; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism*; D002478:Cells, Cultured; D002642:Chick Embryo; D004567:Electrodes, Implanted; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007150:Immunohistochemistry; D009411:Nerve Endings / Q000378:metabolism; D009434:Neural Pathways / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D009474:Neurons / Q000378:metabolism* / Q000502:physiology; D009832:Olfactory Nerve / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D012794:Sialic Acids / Q000378:metabolism*
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; D012794:Sialic Acids; D007987:Gonadotropin-Releasing Hormone