September 2016
Volume 57, Issue 12
Open Access
ARVO Annual Meeting Abstract  |   September 2016
The Rod Connexin is Connexin36
Author Affiliations & Notes
  • Nange Jin
    Ophthalmology & Visual Science, University of Texas McGovern Medical School, Houston, Texas, United States
  • Friso Postma
    Neurobiology, Harvard University Medical School, Boston, Massachusetts, United States
  • Sean Youn
    Undergraduate Program, Rice University, Houston, Texas, United States
  • Eduardo Silveyra
    Ophthalmology & Visual Science, University of Texas McGovern Medical School, Houston, Texas, United States
  • David Paul
    Neurobiology, Harvard University Medical School, Boston, Massachusetts, United States
  • Stephen C Massey
    Ophthalmology & Visual Science, University of Texas McGovern Medical School, Houston, Texas, United States
  • Christophe P. Ribelayga
    Ophthalmology & Visual Science, University of Texas McGovern Medical School, Houston, Texas, United States
  • Footnotes
    Commercial Relationships   Nange Jin, None; Friso Postma, None; Sean Youn, None; Eduardo Silveyra, None; David Paul, None; Stephen Massey, None; Christophe Ribelayga, None
  • Footnotes
    Support  National Institutes of Health (grants EY018640, EY06515, EY010608, OD010768), the University of Texas System (seed grant #362469), the University of Texas Health Science Center at Houston (BRAIN Initiative and CTSA grant UL1 TR000371), the Hermann Eye Fund and an Unrestricted Challenge Grant from Research to Prevent Blindness.
Investigative Ophthalmology & Visual Science September 2016, Vol.57, 583. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to Subscribers Only
      Sign In or Create an Account ×
    • Get Citation

      Nange Jin, Friso Postma, Sean Youn, Eduardo Silveyra, David Paul, Stephen C Massey, Christophe P. Ribelayga; The Rod Connexin is Connexin36. Invest. Ophthalmol. Vis. Sci. 2016;57(12):583.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Purpose : Photoreceptors are electrically coupled via gap junctions. Rod/rod and cone/cone coupling are both present while rod/cone coupling provides an alternative pathway for rod signaling. In mammals, the gap junction expressed in cones has been identified as connexin36 (Cx36). However the identity of the rod connexin is unknown. To assess the role of Cx36, we compared wild type mice with a pan-Cx36 knockout and both rod and cone specific Cx36 knockouts.

Methods : The junctional conductance between pairs of adjacent rods was estimated using a perforated-patch clamp technique in the dark. The distribution of Cx36 in the outer plexiform layer (OPL) was assessed by confocal microscopy.

Results : The junctional conductance between pairs of adjacent rods was ~ 150 pS in wild type mice (appropriate littermates) and close to 0 pS in pan-Cx36-/- or rod-Cx36-/- mice. In addition, the rod junctional conductance was ~ 75 pS in cone-Cx36-/- retinas. In the wild-type retina, most of the Cx36 in the OPL was found around the periphery of cone pedicles. A large fraction of this labeling was observed at points of contact between telodendritic processes and rod spherules. Cx36 labeling in the OPL was reduced by more than 90% in both the rod-Cx36-/- and the cone-Cx36-/- lines, except in small clusters underneath the cone pedicles where Cx36 is known to be associated with bipolar cell dendrites. In the rod-Cx36-/- line, a few remaining Cx36 plaques were found at contacts between cone telodendria.

Conclusions : Direct measurements of the rod junctional conductance demonstrate that Cx36 is required for rod electrical coupling. Intervening cones apparently account for ~ 50% of rod coupling. The distribution of Cx36 expression in the conditional lines indicates that rod-cone gap junctions require Cx36 on both sides (rod and cone) as the absence of Cx36 on either side prevents the formation of a plaque. This implies that 1) most of the Cx36 plaques observed in the OPL are rod-cone gap junctions. Thus, the rod/cone coupling provides an important pathway. 2) Cx36 is expressed in rods and required to form rod-cone gap junctions. 3) Altogether, the data strongly indicate that Cx36 is the rod connexin.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×