The Effects of Intracellular Ca2+ on the Light Response and on Light Adaptation in Limulus Ventral Photoreceptors

  • J. E. Lisman
  • J. E. Brown
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 24)


The photoreceptors of the horseshoe crab, Limulus, respond to light with a positive-going change in membrane voltage, (i.e. a depolarizing receptor potential). A dark-adapted photoreceptor responds to very dim illumination by producing a series of unitary events, called “quantum bumps”, each about 100 msec. in duration and 10 my in amplitude. Each quantum bump is thought to arise from the absorption of a single photon. In this low intensity range, the frequency of quantum bumps has been measured directly and was found to be nearly proportional to the number of incident photons. (Fuortes and Yeandle, 1964). At higher levels of illumination, individual bumps can no longer be resolved. The light response is characterized by an initial large depolarization, called the “transient”, followed by a smaller “plateau” phase which is maintained for the duration of the stimulus. The amplitude of this plateau phase increases roughly as the logarithm of the stimulus intensity over a very wide range of intensities.


Light Response Horseshoe Crab Plateau Phase Transient Phase Test Flash 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. BAKER, P.F. 1970. Calcium and Cellular Function. Cuthbert, A.W. McMillan, pp. 96–107.Google Scholar
  2. BROWN, H.M., S. HAGIWARA, H. KOIKE, and R. M MEECH. 1970. J. Physiol, 208, 385.PubMedGoogle Scholar
  3. BROWN, J.E. and M. MOTE. 1971. Bio. Bull., 141, 395.Google Scholar
  4. DODGE, F.A., B.W. KNIGHT, and J. TOYODA. 1968. Science (Washington), 160, 88.CrossRefGoogle Scholar
  5. FUORTES, M.G.F. and S. YEANDLE. 1964. J. Gen. Physiol., 47, 443.PubMedCrossRefGoogle Scholar
  6. LISMAN, J.E. and J.E. BROWN. 1971. J. Gen. Physiol., 58, 544.PubMedCrossRefGoogle Scholar
  7. MILLECCHIA, R. and A. MAURO. 1969a. J. Gen. Physiol., 54, 310.PubMedCrossRefGoogle Scholar
  8. MILLECCHIA, R. and A. MAURO. 1969b. J. Gen. Physiol., 54, 331.PubMedCrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1972

Authors and Affiliations

  • J. E. Lisman
    • 1
  • J. E. Brown
    • 2
    • 3
  1. 1.Harvard Biological LaboratoriesCambridgeUSA
  2. 2.Department of AnatomyVanderbilt UniversityNashvilleUSA
  3. 3.Marine Biological LaboratoryWoods HoleUSA

Personalised recommendations