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Connexin 36 and rod bipolar cell independent rod pathways drive retinal ganglion cells and optokinetic reflexes.

Publication ,  Journal Article
Cowan, CS; Abd-El-Barr, M; van der Heijden, M; Lo, EM; Paul, D; Bramblett, DE; Lem, J; Simons, DL; Wu, SM
Published in: Vision Res
February 2016

Rod pathways are a parallel set of synaptic connections which enable night vision by relaying and processing rod photoreceptor light responses. We use dim light stimuli to isolate rod pathway contributions to downstream light responses then characterize these contributions in knockout mice lacking rod transducin-α (Trα), or certain pathway components associated with subsets of rod pathways. These comparisons reveal that rod pathway driven light sensitivity in retinal ganglion cells (RGCs) is entirely dependent on Trα, but partially independent of connexin 36 (Cx36) and rod bipolar cells. Pharmacological experiments show that rod pathway-driven and Cx36-independent RGC ON responses are also metabotropic glutamate receptor 6-dependent. To validate the RGC findings in awake, behaving animals we measured optokinetic reflexes (OKRs), which are sensitive to changes in ON pathways. Scotopic OKR contrast sensitivity was lost in Trα(-/-) mice, but indistinguishable from controls in Cx36(-/-) and rod bipolar cell knockout mice. Mesopic OKRs were also altered in mutant mice: Trα(-/-) mice had decreased spatial acuity, rod BC knockouts had decreased sensitivity, and Cx36(-/-) mice had increased sensitivity. These results provide compelling evidence against the complete Cx36 or rod BC dependence of night vision's ON component. Further, the findings suggest the parallel nature of rod pathways provides considerable redundancy to scotopic light sensitivity but distinct contributions to mesopic responses through complicated interactions with cone pathways.

Duke Scholars

Published In

Vision Res

DOI

EISSN

1878-5646

Publication Date

February 2016

Volume

119

Start / End Page

99 / 109

Location

England

Related Subject Headings

  • Visual Pathways
  • Retinal Rod Photoreceptor Cells
  • Retinal Ganglion Cells
  • Retinal Bipolar Cells
  • Photic Stimulation
  • Nystagmus, Optokinetic
  • Models, Animal
  • Mice, Knockout
  • Mice
  • Gap Junction delta-2 Protein
 

Citation

APA
Chicago
ICMJE
MLA
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Cowan, C. S., Abd-El-Barr, M., van der Heijden, M., Lo, E. M., Paul, D., Bramblett, D. E., … Wu, S. M. (2016). Connexin 36 and rod bipolar cell independent rod pathways drive retinal ganglion cells and optokinetic reflexes. Vision Res, 119, 99–109. https://doi.org/10.1016/j.visres.2015.11.006
Cowan, Cameron S., Muhammad Abd-El-Barr, Meike van der Heijden, Eric M. Lo, David Paul, Debra E. Bramblett, Janis Lem, David L. Simons, and Samuel M. Wu. “Connexin 36 and rod bipolar cell independent rod pathways drive retinal ganglion cells and optokinetic reflexes.Vision Res 119 (February 2016): 99–109. https://doi.org/10.1016/j.visres.2015.11.006.
Cowan CS, Abd-El-Barr M, van der Heijden M, Lo EM, Paul D, Bramblett DE, et al. Connexin 36 and rod bipolar cell independent rod pathways drive retinal ganglion cells and optokinetic reflexes. Vision Res. 2016 Feb;119:99–109.
Cowan, Cameron S., et al. “Connexin 36 and rod bipolar cell independent rod pathways drive retinal ganglion cells and optokinetic reflexes.Vision Res, vol. 119, Feb. 2016, pp. 99–109. Pubmed, doi:10.1016/j.visres.2015.11.006.
Cowan CS, Abd-El-Barr M, van der Heijden M, Lo EM, Paul D, Bramblett DE, Lem J, Simons DL, Wu SM. Connexin 36 and rod bipolar cell independent rod pathways drive retinal ganglion cells and optokinetic reflexes. Vision Res. 2016 Feb;119:99–109.
Journal cover image

Published In

Vision Res

DOI

EISSN

1878-5646

Publication Date

February 2016

Volume

119

Start / End Page

99 / 109

Location

England

Related Subject Headings

  • Visual Pathways
  • Retinal Rod Photoreceptor Cells
  • Retinal Ganglion Cells
  • Retinal Bipolar Cells
  • Photic Stimulation
  • Nystagmus, Optokinetic
  • Models, Animal
  • Mice, Knockout
  • Mice
  • Gap Junction delta-2 Protein