Selective suppression of rod signal transmission by cobalt ions of low levels in carp retina

  • Lilian Yuan
  • Xiongli Yang


Selective suppression of rod signal transmission by cobalt ions was reported in carp retina. Using 10 μnol/L Co2+, rod-driven horizontal cells were hyperpolarized and light responses were completely suppressed in superfused, isolated retina, while cone-driven horizontal cells were almost unaffected. Similarly, scotopic electroretinographic bwave was suppressed by 10 μnol/L Co2+, while the photopic b-wave remained unaffected. Furthermore, the glutamate-isolated receptor potential (PIII) was not altered by low Co2+ under dark-adapted conditions. Other divalent ions with high affinity to calcium channels, such as cadmium and manganese ions, did not show similar suppressive effect on the rod horizontal cells. When rod horizontal cells were hyperpolarized by 10 μnol/L Co2+, the use of 3 mmol/L glutamate caused a significant depolarization of the cells, indicating that Co2+ application did not impair the ability of these cells to respond to glutamate. On the other hand, application of 200 μnol/L β-hydroxyaspartate, a glutamate transport blocker, mimicked the effect of low Co2+, suggesting a possibility that the low Co2+ effect might be related to a blockade of glutamate uptake by rods.


rod system cone system electroretinogram horizontal cell cobalt ion 


  1. 1.
    Cervetto, L., Piccolino, M., Synaptic transmission between photoreceptors and horizontal cells in the turtle retina,Science, 1984, 183: 417.CrossRefGoogle Scholar
  2. 2.
    Dowling, J. E., Ripps, H., Effect of magnesium on horizontal cell activity in skate retina,Nature, 1973, 242: 101.PubMedCrossRefGoogle Scholar
  3. 3.
    Yang, X. L., Wu, S. M., Coexistence and functions of multiple types of glutamate receptor in the horizontal cells of the tiger salamander retina,Vision Neurosci., 1991, 7: 377.CrossRefGoogle Scholar
  4. 4.
    Yang, X. L., Fan, T. X., Shen, W., Effects of prolonged darkness on light responsiveness and spectral sensitivity of cone horizontal cells in carp retina in vivoJ. Neurosci., 1994, 14: 326.PubMedGoogle Scholar
  5. 5.
    Yang, X. L., Fan, T. X., Li, J. D., Electroretinographic b-wave merely reflects the activity of the rod system in the darkadapted carp retina,Vision Res., 1990, 30: 993.PubMedCrossRefGoogle Scholar
  6. 6.
    Grant, G. B., Eliasof, S., Werblin, F., Sodium glutamate cotransporter in rod terminals is essential for rod input to horizontal cells in tiger salamander,Invest Ophthalmol Vis. Sci. (Suppl), 1992, 33: 1327.Google Scholar
  7. 7.
    Evans, J. A., Hood, D. C., Holtzman, E., Differential effects of cobalt ions on rod and cone synaptic activity in the isolated frog retina,Vision Res., 1978, 18: 145.PubMedCrossRefGoogle Scholar
  8. 8.
    Dacheux, M., Miller, R., Photoreceptor-bipolar cell transmission in the perfused eye cup of the mudpuppy.Science. 1976. 191: 963.PubMedCrossRefGoogle Scholar
  9. 9.
    Mayer, M. L.. Vyklicky, L. Jr., Westbrook, G. L., Modulation of excitatory amino acid receptor by group IIB metal cations in cultured mouse hippocampal neurons,J. Physiol., 1989, 415: 329.PubMedGoogle Scholar
  10. 10.
    Marc, R. E., Lam, D. M. L. K., Uptake of aspartic and glutamic acid by photoreceptor in goldfish retina,Proc. Natl. Acad. Sci. USA, 1981, 78: 7185.PubMedCrossRefGoogle Scholar
  11. 11.
    Tachibana, M., Kaneko, A., L-glutamate-induced depolarization in solitary photoreceptor: a process that may contribute to the interaction between photoreceptor in situ,Proc. Natl. Acad. Sci. USA, 1988, 85: 5315.PubMedCrossRefGoogle Scholar
  12. 12.
    Eliasof, S., Werblin, F., Characterization of the glutamate transporter in retinal cones of the tiger salamander,J. Neurosci., 1993, 18: 402.Google Scholar

Copyright information

© Science in China Press 1997

Authors and Affiliations

  • Lilian Yuan
    • 1
  • Xiongli Yang
    • 1
  1. 1.Shanghai Institute of Physiology and Joint Laboratory of Life Natural ScienceChinese Academy of SciencesShanghaiChina

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