title: The growth-associated protein GAP-43 is specifically expressed in tyrosine hydroxylase-positive cells of the rat retina.
abstract: In the adult retina, the growth-associated protein GAP-43 is exclusively present in three distinct sublaminae of the inner plexiform layer. During postnatal development, it is transiently expressed in the optic nerve fibers. No conclusions about the GAP-43 expressing cells can be derived from immunohistochemical stainings because GAP-43 protein is rapidly transported into the distal neuronal processes. We have combined immunohistochemistry to study the protein expression of GAP-43 and non-radioactive in situ hybridization to study the cellular expression of GAP-43 in the rat retina. We have found that in the mature retina GAP-43 mRNA is present only in retinal ganglion cells and in a small subset of cells of the inner nuclear layer. During postnatal development, no cells besides retinal ganglion cells and a subpopulation of cells in the inner nuclear layer express GAP-43 mRNA. Double staining experiments with tyrosine hydroxylase (TH) immunohistochemistry and GAP-43 in situ hybridization showed that GAP-43 expressing cells in the inner nuclear layer are immunoreactive for TH. They are most probably dopaminergic amacrine cells. Our results show that GAP-43 expression in the retina is restricted to very few cell types. They suggest that TH-positive cells (probably dopaminergic amacrine cells) retain a higher degree of structural plasticity in the adult retina.
authors.affiliation: Brain Research Institute, University of Zurich, Switzerland. kapfhamj@uni-freiburg.de
authors.forename: J P
authors.initials: JP
authors.lastname: Kapfhammer
authors.forename: F
authors.initials: F
authors.lastname: Christ
authors.forename: M E
authors.initials: ME
authors.lastname: Schwab
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000502:physiology; D019922:GAP-43 Protein; D006133:Growth Substances / Q000096:biosynthesis*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008562:Membrane Glycoproteins / Q000096:biosynthesis*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D015347:RNA Probes; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011917:Rats, Inbred Lew; D012160:Retina / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D012165:Retinal Ganglion Cells / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
chemical_list: D019922:GAP-43 Protein; D006133:Growth Substances; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D015347:RNA Probes; D012333:RNA, Messenger; D014446:Tyrosine 3-Monooxygenase