title: Developmental loss of functional laminin receptors on retinal ganglion cells is regulated by their target tissue, the optic tectum.
abstract: The ability of chick retinal ganglion cells (RGCs) to extend neurites on tissue culture substrata of the extra-cellular matrix protein laminin is lost during embryonic development. In order to establish the mechanism responsible for the loss of response, the number of high affinity (KD 10(-9) M) laminin receptors on both the cell bodies and neurites of RGCs were determined throughout this period by a ligand binding assay using radio-labelled laminin. It was found that the loss of response paralleled a decrease in receptor numbers on both the cell bodies and the neurites of the RGCs. Bilateral tectal ablation at embryonic day 6 resulted in the subsequent maintenance of laminin-stimulated neurite outgrowth, together with a partial inhibition of the loss of laminin receptors. Thus, the loss of response of the RGCs to laminin reflects a decrease in the numbers of laminin receptors on these neurons, and furthermore, this down-regulation is in turn dependent on innervation of the target tissue.
authors.affiliation: Department of Anatomy, UMDS (Guy's Hospital), London, UK.
authors.forename: J
authors.initials: J
authors.lastname: Cohen
authors.forename: V
authors.initials: V
authors.lastname: Nurcombe
authors.forename: P
authors.initials: P
authors.lastname: Jeffrey
authors.forename: D
authors.initials: D
authors.lastname: Edgar
mesh_terms: D000818:Animals; D002478:Cells, Cultured / Q000502:physiology; D002642:Chick Embryo; D015536:Down-Regulation; D066298:In Vitro Techniques; D007797:Laminin / Q000378:metabolism; D009474:Neurons / Q000502:physiology; D011971:Receptors, Immunologic / Q000378:metabolism*; D017474:Receptors, Laminin; D012160:Retina / Q000378:metabolism*; D012165:Retinal Ganglion Cells / Q000378:metabolism*; D013477:Superior Colliculi / Q000502:physiology*
chemical_list: D007797:Laminin; D011971:Receptors, Immunologic; D017474:Receptors, Laminin