The early receptor potential (ERP), membrane potential, membrane resistance, and sensitivity were measured during light and/or dark adaptation in the ventral eye of Limulus. After a bright flash, the ERP amplitude recovered with a time constant of 100 ms, whereas the sensitivity recovered with an initial time constant of 20 s. When a strong adapting light was turned off, the recovery of membrane potential and of membrane resistance had time-courses similar to each other, and both recovered more rapidly than the sensitivity. The receptor depolarization was compared during dark adaptation after strong illumination and during light adaptation with weaker illumination; at equal sensitivities the cell was more depolarized during light adaptation than during dark adaptation. Finally, the waveforms of responses to flashes were compared during dark adaptation after strong illumination and during light adaptation with weaker illumination. At equal sensitivities (equal amplitude responses for identical flashes), the responses during light adaptation had faster time-courses than the responses during dark adaptation. Thus neither the photochemical cycle nor the membrane potential nor the membrane resistance is related to sensitivity changes during dark adaptation in the photoreceptors of the ventral eye. By elimination, these results imply that there are (unknown) intermediate process(es) responsible for adaptation interposed between the photochemical cycle and the electrical properties of the photoreceptor.
Article|
March 01 1973
Adaptation in the Ventral Eye of Limulus is Functionally Independent of the Photochemical Cycle, Membrane Potential, and Membrane Resistance
A. Fein,
A. Fein
From the Department of Biomedical Engineering and Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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R. D. DeVoe
R. D. DeVoe
From the Department of Biomedical Engineering and Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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A. Fein
From the Department of Biomedical Engineering and Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
R. D. DeVoe
From the Department of Biomedical Engineering and Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
Received:
July 13 1972
Online ISSN: 1540-7748
Print ISSN: 0022-1295
Copyright © 1973 by The Rockefeller University Press
1973
J Gen Physiol (1973) 61 (3): 273–289.
Article history
Received:
July 13 1972
Citation
A. Fein, R. D. DeVoe; Adaptation in the Ventral Eye of Limulus is Functionally Independent of the Photochemical Cycle, Membrane Potential, and Membrane Resistance . J Gen Physiol 1 March 1973; 61 (3): 273–289. doi: https://doi.org/10.1085/jgp.61.3.273
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