title: Amacrine cell subtypes differ in their intrinsic neurite growth capacity.
abstract: OBJECTIVE
  Amacrine cell neurite patterning has been extensively studied in vivo, and more than 30 subpopulations with varied morphologies have been identified in the mammalian retina. It is not known, however, whether the complex amacrine cell morphology is determined intrinsically, is signaled by extrinsic cues, or both.
  
  
  METHODS
  Here we purified rat amacrine cell subpopulations away from their retinal neighbors and glial-derived factors to ask questions about their intrinsic neurite growth ability. In defined medium strongly trophic for amacrine cells in vitro, we characterized survival and neurite growth of amacrine cell subpopulations defined by expression of specific markers.
  
  
  RESULTS
  We found that a series of amacrine cell subtype markers are developmentally regulated, turning on through early postnatal development. Subtype marker expression was observed in similar fractions of cultured amacrine cells as was observed in vivo, and was maintained with time in culture. Overall, amacrine cell neurite growth followed principles very similar to those in postnatal retinal ganglion cells, but embryonic retinal ganglion cells demonstrated different features, relating to their rapid axon growth. Surprisingly, the three subpopulations of amacrine cells studied in vitro recapitulated quantitatively and qualitatively the varied morphologies they have in vivo.
  
  
  CONCLUSIONS
  Our data suggest that cultured amacrine cells maintain intrinsic fidelity to their identified in vivo subtypes, and furthermore, that cell-autonomous, intrinsic factors contribute to the regulation of neurite patterning.
authors.affiliation: Shiley Eye Center, University of California-San Diego, La Jolla, California.
authors.forename: Noelia J
authors.initials: NJ
authors.lastname: Kunzevitzky
authors.forename: Kevin T
authors.initials: KT
authors.lastname: Willeford
authors.forename: William J
authors.initials: WJ
authors.lastname: Feuer
authors.forename: Monica V
authors.initials: MV
authors.lastname: Almeida
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Goldberg
mesh_terms: D025042:Amacrine Cells / Q000166:cytology* / Q000502:physiology; D027322:Amino Acid Transport System X-AG / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D015415:Biomarkers / Q000378:metabolism; D064032:Calbindin 2 / Q000378:metabolism; D019070:Cell Lineage; D002469:Cell Separation; D002470:Cell Survival; D002478:Cells, Cultured; D020916:Conotoxins / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D008856:Microscopy, Fluorescence; D016501:Neurites / Q000502:physiology*; D055495:Neurogenesis / Q000502:physiology*; D010320:Parvalbumins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000196:embryology; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000378:metabolism; D050827:Syntaxin 1 / Q000378:metabolism
chemical_list: D027322:Amino Acid Transport System X-AG; D015415:Biomarkers; C576512:Calb2 protein, rat; D064032:Calbindin 2; D020916:Conotoxins; D010320:Parvalbumins; C494213:Stx1a protein, rat; D050827:Syntaxin 1; C507383:alpha-conotoxin Vc1.1
keywords: amacrine cells; intrinsic neurite growth; neurite patterning; retinal development