Skip to main content
NCBI home page
The Journal of General Physiology logoLink to The Journal of General Physiology
. 1980 Apr 1;75(4):353–379. doi: 10.1085/jgp.75.4.353

Heterogenic components of a fast electrical potential in Drosophila compound eye and their relation to visual pigment photoconversion

PMCID: PMC2215748  PMID: 7381424

Abstract

The electroretinogram of the dipteran compound eye in response to an intense flash contains an early, diphasic potential that has been termed the M potential. Both phases of the M potential arise from the photostimulation of metarhodopsin. The early, corneal-negative component, the M1, can be recorded intracellularly in the photoreceptors and has properties similar to the classical early receptor potential (ERP). The M1 is resistant to cold, anaesthesia, and anoxia and has no detectable latency. It depends on flash intensity and metarhodopsin fraction in the manner predicted for a closed, two-state pigment system, and its saturation is shown to correspond to the establishment of a photoequilibrium in the visual pigment. On the other hand, the dominant, corneal-positive component, the M2, does not behave like an ERP. It arises, not in the photoreceptors, but deeper in the retina at the level of the lamina, and resembles the on-transient of the electroretinogram in its reversal depth and sensitivity to cooling or CO2. The on-transient, which is present over a much wider range of stimulus intensity than the M potential, has been shown to arise from neurons in the lamina ganglionaris. Visual mutants in which the on- transient is absent or late are also defective in the M2. It is proposed that the M2 and the on-transient arise from the same or similar groups of second-order neurons, and that the M2 is a fast laminar response to the depolarizing M1 in the photoreceptors, just as the on-transient is a fast laminar response to the depolarizing late receptor potential. Unlike the M1, the M2 is not generally proportional to the amount of metarhodopsin photoconverted, and the M2 amplitude is influenced by factors, such as a steady depolarization of the photoreceptor, which do not affect the M1.

Full Text

The Full Text of this article is available as a PDF (1.4 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Alawi A. A., Jennings V., Grossfield J., Pak W. L. Phototransduction mutants of Drosophila melanogaster. Adv Exp Med Biol. 1972;24(0):1–21. doi: 10.1007/978-1-4684-8231-7_1. [DOI] [PubMed] [Google Scholar]
  2. Alawi A. A., Pak W. L. On-transient of insect electroretinogram: its cellular origin. Science. 1971 Jun 4;172(3987):1055–1057. doi: 10.1126/science.172.3987.1055. [DOI] [PubMed] [Google Scholar]
  3. BROWN K. T., MURAKAMI M. A NEW RECEPTOR POTENTIAL OF THE MONKEY RETINA WITH NO DETECTABLE LATENCY. Nature. 1964 Feb 8;201:626–628. doi: 10.1038/201626a0. [DOI] [PubMed] [Google Scholar]
  4. CONE R. A. EARLY RECEPTOR POTENTIAL OF THE VERTEBRATE RETINA. Nature. 1964 Nov 21;204:736–739. doi: 10.1038/204736a0. [DOI] [PubMed] [Google Scholar]
  5. Cone R. A. Early receptor potential: photoreversible charge displacement in rhodopsin. Science. 1967 Mar 3;155(3766):1128–1131. doi: 10.1126/science.155.3766.1128. [DOI] [PubMed] [Google Scholar]
  6. HOYLE G. The effects of some common cations on neuromuscular transmission in insects. J Physiol. 1955 Jan 28;127(1):90–103. doi: 10.1113/jphysiol.1955.sp005240. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Harris W. A., Ready D. F., Lipson E. D., Hudspeth A. J., Stark W. S. Vitamin A deprivation and Drosophila photopigments. Nature. 1977 Apr 14;266(5603):648–650. doi: 10.1038/266648a0. [DOI] [PubMed] [Google Scholar]
  8. Heisenberg M. Separation of receptor and lamina potentials in the electroretinogram of normal and mutant Drosophila. J Exp Biol. 1971 Aug;55(1):85–100. doi: 10.1242/jeb.55.1.85. [DOI] [PubMed] [Google Scholar]
  9. Hillman P., Dodge F. A., Hochstein S., Knight B. W., Minke B. Rapid dark recovery of the invertebrate early receptor potential. J Gen Physiol. 1973 Jul;62(1):77–86. doi: 10.1085/jgp.62.1.77. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Hochstein S., Minke B., Hillman P., Knight B. W. The kinetics of visual pigment systems. I. Mathematical analysis. Biol Cybern. 1978 Jul 14;30(1):23–32. doi: 10.1007/BF00365480. [DOI] [PubMed] [Google Scholar]
  11. Kirschfeld K., Feiler R., Minke B. The kinetics of formation of metarhodopsin in intact photoreceptors of the fly. Z Naturforsch C. 1978 Nov-Dec;33(11-12):1009–1010. doi: 10.1515/znc-1978-11-1234. [DOI] [PubMed] [Google Scholar]
  12. Lisman J. E., Bering H. Electrophysiological measurement of the number of rhodopsin molecules in single Limulus photoreceptors. J Gen Physiol. 1977 Nov;70(5):621–633. doi: 10.1085/jgp.70.5.621. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Lisman J. E., Sheline Y. Analysis of the rhodopsin cycle in limulus ventral photoreceptors using the early receptor potential. J Gen Physiol. 1976 Nov;68(5):487–501. doi: 10.1085/jgp.68.5.487. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Lo M. V., Pak W. L. Desensitisation of peripheral photoreceptors shown by blue-induced decrease in transmittance of Drosophila rhabdomeres. Nature. 1978 Jun 29;273(5665):772–774. doi: 10.1038/273772a0. [DOI] [PubMed] [Google Scholar]
  15. Minke B., Kirschfeld K. The contribution of a sensitizing pigment to the photosensitivity spectra of fly rhodopsin and metarhodopsin. J Gen Physiol. 1979 May;73(5):517–540. doi: 10.1085/jgp.73.5.517. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Pak W. L., Boes R. J. Rhodopsin: responses from transient intermediates formed during its bleaching. Science. 1967 Mar 3;155(3766):1131–1133. doi: 10.1126/science.155.3766.1131. [DOI] [PubMed] [Google Scholar]
  17. Pak W. L., Lidington K. J. Fast electrical potential from a long-lived, long-wavelength photoproduct of fly visual pigment. J Gen Physiol. 1974 Jun;63(6):740–756. doi: 10.1085/jgp.63.6.740. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Pak W. L. Rapid photoresponses in the retina and their relevance to vision research. Photochem Photobiol. 1968 Nov;8(5):495–503. doi: 10.1111/j.1751-1097.1968.tb05893.x. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of General Physiology are provided here courtesy of The Rockefeller University Press

RESOURCES