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S. C. Massey, J. J. O'Brien, X. Chen, P. R. MacLeish; Photoreceptor coupling in the primate retina. Journal of Vision 2004;4(11):21. doi: https://doi.org/10.1167/4.11.21.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: There are many examples of neuronal coupling via gap junctions in the primate retina. In the outer retina, cone to cone coupling may provide a mechanism to reduce uncorrelated noise (DeVries et al., 2002). Here we report the distribution of connexin36 (Cx36) in the outer plexiform layer of the primate retina.
Methods: Macaque retina was immunostained with antibodies against Cx36, cone arrestin (7G6) and blue cone opsin and labeling was viewed by confocal microscopy.
Results: The monoclonal antibody to cone arrestin (7G6) labels cones from their outer segments to their pedicles (Zhang et al., 2003). In addition, high-resolution confocal images in the plane of the cone pedicles also show a network of fine telodendria connecting adjacent cones. These contact points between adjacent cones have previously been identified as gap junctions sites by electron microscopy (Tsukamoto et al., 1992). Double labeling of this material with an antibody to connexin36 showed a light distribution of fine Cx36 plaques at the level of the telodendria. Individual Cx36 plaques occurred at contacts between neighboring cone telodendria. Connexin36 plaques also occurred at presumed postsynaptic processes beneath the cone pedicle. Blue cones were visualized within the photoreceptor matrix with an antibody against blue cone opsin. Animating through a confocal stack enabled us to identify blue cone pedicles, which are smaller and bear fewer telodendria. We are currently evaluating the Cx36 contacts of blue cone pedicles.
Conclusion: By visualizing the matrix of cone telodendria in the outer plexiform layer of the primate retina, we conclude that Cx36 is responsible for cone-to-cone coupling in the primate retina.
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