Dendritic stratification differs among retinal OFF bipolar cell types in the absence of rod photoreceptors

PLoS One. 2017 Mar 3;12(3):e0173455. doi: 10.1371/journal.pone.0173455. eCollection 2017.

Abstract

Retinal OFF bipolar cells show distinct connectivity patterns with photoreceptors in the wild-type mouse retina. Some types are cone-specific while others penetrate further through the outer plexiform layer (OPL) to contact rods in addition to cones. To explore dendritic stratification of OFF bipolar cells in the absence of rods, we made use of the 'cone-full' Nrl-/- mouse retina in which all photoreceptor precursor cells commit to a cone fate including those which would have become rods in wild-type retinas. The dendritic distribution of OFF bipolar cell types was investigated by confocal and electron microscopic imaging of immunolabeled tissue sections. The cells' dendrites formed basal contacts with cone terminals and expressed the corresponding glutamate receptor subunits at those sites, indicating putative synapses. All of the four analyzed cell populations showed distinctive patterns of vertical dendritic invasion through the OPL. This disparate behavior of dendritic extension in an environment containing only cone terminals demonstrates type-dependent specificity for dendritic outgrowth in OFF bipolar cells: rod terminals are not required for inducing dendritic extension into distal areas of the OPL.

MeSH terms

  • Animals
  • Basic-Leucine Zipper Transcription Factors / genetics*
  • Dendritic Cells / metabolism
  • Dendritic Cells / ultrastructure*
  • Disease Models, Animal
  • Eye Proteins / genetics*
  • Glutamic Acid / genetics
  • Glutamic Acid / metabolism
  • Humans
  • Mice
  • Mice, Knockout
  • Microscopy, Electron
  • Retinal Bipolar Cells / metabolism
  • Retinal Bipolar Cells / ultrastructure*
  • Retinal Photoreceptor Cell Outer Segment / ultrastructure
  • Retinal Rod Photoreceptor Cells / metabolism
  • Retinal Rod Photoreceptor Cells / ultrastructure*
  • Synapses / genetics
  • Synapses / metabolism
  • Synapses / ultrastructure*

Substances

  • Basic-Leucine Zipper Transcription Factors
  • Eye Proteins
  • Nrl protein, mouse
  • Glutamic Acid