Photoreceptor coupling in turtle retina

Photoreceptors in the isolated turtle retina of two species of turtle, Chelydra serpentina and Pseudemus scripta elegans, were penetrated with double-barrel electrodes. Physiological responses were recorded through one barrel and Neurobiotin tracer was injected from the other. Intracellular injectio...

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Bibliographic Details
Published in:Visual neuroscience 1998-07, Vol.15 (4), p.755-764
Main Authors: FIRSOV, M.L., GREEN, D.G.
Format: Article
Language:English
Subjects:
Animals
Biological and medical sciences
Biotin - analogs & derivatives
Cell coupling
Cone
Eye and associated structures. Visual pathways and centers. Vision
Fluorescent Dyes
Fundamental and applied biological sciences. Psychology
Gap Junctions - physiology
Isoquinolines
Neurobiotin
Neurons - cytology
Neurons - physiology
Retina - anatomy & histology
Retina - physiology
Retinal Cone Photoreceptor Cells - cytology
Retinal Cone Photoreceptor Cells - physiology
Retinal Rod Photoreceptor Cells - cytology
Retinal Rod Photoreceptor Cells - physiology
Rod
Telodendria
Turtles
Vertebrates: nervous system and sense organs
Visual Pathways
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Summary:Photoreceptors in the isolated turtle retina of two species of turtle, Chelydra serpentina and Pseudemus scripta elegans, were penetrated with double-barrel electrodes. Physiological responses were recorded through one barrel and Neurobiotin tracer was injected from the other. Intracellular injection of Neurobiotin revealed patterns of tracer-coupled photoreceptors. Both the patterns of tracer coupling and the electrophysiology suggest a high degree of specificity of connections. Rods seem to be coupled only to rods and green and red cones seem to be coupled to cones of the same spectral type. Receptive-field profiles, measured with a thin, sharply focused slit of light, often had well-defined peaks and troughs in sensitivity. We have taken advantage of this observation and used the position of a peak in sensitivity to locate the position on the retina of a coupled cell. In one rod, it was possible to correlate physiological and morphological data and to show that the peaks in the physiological receptive field occurred at positions on the retina where there were dye-coupled cells. This provides direct evidence that gap junctions produce the physiological coupling between rods.
ISSN:0952-5238
1469-8714
DOI:10.1017/S0952523898154147