Rod and cone components in the compound ERG of the beagle dog (original) (raw)

Abstract

In the dog ERG flash-induced activation of the rod receptors can be selectively investigated due to relatively poor photic excitability of the cone component.

The ERG was produced in immobilized dogs using the method of Ganzfeld stimulation with white light flashes of 10 μsec duration. Relatively dim flashes ranging to about 100-fold above ERG threshold lead in the dark-adapted dog to selective activation of the rod receptors. This scotopic rod ERG consists of ERG positivity including a_b_ wave with superimposed oscillations followed by a protracted potential, presumably the_c_ wave.

Light flashes exceeding 100-fold threshold luminance cause simultaneous activation of rod and cone receptors. ERG characteristics include appearance of an early negativity, the_a_ wave, followed by_b_ and_c_ waves of reduced amplitudes.

In the presence of a bright background luminance of 33 ftL bright light flashes cause an ERG resulting from selective cone activation. This photopic cone ERG consists of a small_a_ wave followed by a small_b_ wave with oscillatory potentials and by marked subsequent late negativity. With increase in background luminance the late negativity increases in amplitude and occurs progressively earlier.

The characteristics of the dog ERG allow selective assessment of functional changes in rod and cone receptors.

Access this article

Log in via an institution

Subscribe and save

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  1. R. Granit,The Components of the Retinal Action Potential in Mammals and their Relation to the Discharge in the Optic Nerve, J. Physiol., Lond.77, 207–239 (1933).
    Google Scholar
  2. R.W. Rodieck,Components of the Electroretinogram — a Reappraisal, Vision Res.12, 773–780 (1972).
    PubMed Google Scholar
  3. K.T. Brown andK. Watanabe,Isolation and Identification of a Receptor Potential from the Pure Cone Fovea of the Monkey Retina, Nature, Lond.193, 958–960 (1962).
    Google Scholar
  4. R.F. Miller andJ.E. Dowling,Intracellular Responses of the Müller (Glial) Cells of Mudpuppy Retina: Their Relation to the b Wave of the Electroretinogram, J. Neurophysiol.33, 323–341 (1970).
    PubMed Google Scholar
  5. J.E. Dowling,Organization of Vertebrate Retinas, Invest. Ophthalmol.9, 655–680 (1970).
    PubMed Google Scholar
  6. J.C. Armington,The Electroretinogram, (Academic Press, N.Y., 1974).
    Google Scholar
  7. R.H. Steinberg, R. Schmidt andK.T. Brown,Intracellular Responses to Light from Cat Pigment Epithelium: Origin of the Electroretinogram c Wave, Nature, Lond.227, 728–730 (1970).
    Google Scholar
  8. V. Hrachovina,Schwellendichte elektronisch gemittelter Elektroretinogramme dunkel adaptierter Augen, Albrecht v. Graefes Arch. Ophthal.173, 192–198 (1967).
    Google Scholar
  9. V. Hrachovina andB. Schmidt,Electroretinogram Fusion Frequency and Illumination of some Vertebrate Eyes, 6 ISCERG Symposium, 1967 (Georg Thieme, Leipzig, 1968), pp. 279–282.
    Google Scholar
  10. U. Schaeppi andF. Liverani,Procedures for Routime Clinical Electroretinography (ERG) in Dogs, Agents and Actions_7_, 347–351 (1977).
    PubMed Google Scholar
  11. U. Schaeppi andF. Liverani,Electroretinography as an Indicator of Toxic Retinopathy in Dogs. International Workshop on Pharmacological Methods in Preclinical Safety-Evaluation of New Drugs (Pergamon Press Oxford, in print).
  12. D. Finkelstein, P. Gouras andM. Hoff,Human Electroretinogram Near the Absolute Threshold of Vision, Invest. Ophthalmol.7, 214–218 (1968).
    PubMed Google Scholar
  13. P. Gouras,Electroretinography: Some Basic Principles, Invest. Ophthalmol.9, 557–569 (1970).
    PubMed Google Scholar
  14. G. Niemeyer,Stäbchen und Zapfenktivität im klinischen Elektroretinogramm, Ophthalmologica, Basel_172_, 175–180 (1976).
    Google Scholar
  15. G.D. Aguirre andL.F. Rubin,The Electroretinogram in Dogs with Inherited Cone Degeneration, Invest. Ophthalmol.14, 840–847 (1975).
    PubMed Google Scholar
  16. H.B. Parry, K. Tansley andL.C. Thomson,The Electroretinogram of the Dog, J. Physiol., Lond.120, 28–40 (1953).
    Google Scholar
  17. A.A. Genest,Oscillatory Potentials in the Electroretionogram of the Normal Human Eye, Vision Res.4, 595–604 (1964).
    PubMed Google Scholar
  18. R. Granit andH.A. Riddell,The Electrical Responses of Light and Dark-Adapted Frogs' Eyes to Rhythmic and Continuous Stimuli, J. Physiol., Lond.81, 1–28 (1934).
    Google Scholar

Download references

Author information

Authors and Affiliations

  1. CIBA-GEIGY Limited, CH-4002, Basle, Switzerland
    U. Schaeppi & F. Liverani

Authors

  1. U. Schaeppi
  2. F. Liverani

Rights and permissions

About this article

Cite this article

Schaeppi, U., Liverani, F. Rod and cone components in the compound ERG of the beagle dog.Agents and Actions 9, 294–300 (1979). https://doi.org/10.1007/BF01966704

Download citation

Keywords