Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1963 Jul;46(6):1249-65.
doi: 10.1085/jgp.46.6.1249.

PHOTOSENSITIVITY OF THE FROG IRIS

L BARR, M ALPERN

PHOTOSENSITIVITY OF THE FROG IRIS

L BARR et al. J Gen Physiol. 1963 Jul.

Abstract

The absorption of quanta by rhodopsin leads to the contraction of frog iris muscle. The contractions reach a maximum after about 8 sec. in the light. When the light is turned off the irises relax exponentially with a half-time of about 6 sec. Membrane polarization is not necessary for the response but calcium movement and membrane permeability changes probably are. The response is not mediated by acetylcholine or epinephrine. The curves of log It vs. log t for constant response amplitude bend progressively upward away from a unit slope line at short times as larger response criteria are used because (a) light influences tension development over longer times and (b) the higher intensity, shorter duration flashes are less effective.

PubMed Disclaimer

References

    1. J Physiol. 1955 Jan 28;127(1):81-9 - PubMed
    1. J Physiol. 1956 Jul 27;133(1):101-17 - PubMed
    1. J Gen Physiol. 1957 May 20;40(5):703-13 - PubMed
    1. J Physiol. 1958 Oct 31;143(3):474-85 - PubMed
    1. J Physiol. 1959 Dec;149:303-17 - PubMed