Rod light response augmented by active phosphodiesterase
- Creators
- Shimoda, Y.
- Hurley, J. B.
- Miller, W. H.
Abstract
Light activates rod outer segment (ROS) phosphodiesterase (PDEase), as shown by previous biochemical and physiological studies. We have further investigated the role of PDEase in this system by injecting trypsin-activated PDEase, purified from bovine ROS, into single ROS of the isolated retina of the toad Bufo marinus. Injection of about 300 molecules of activated PDEase in darkness is without immediate detectable effect, as measured by intracellular membrane-voltage recording. The effect of the activated PDEase injections only becomes evident after illumination. The light response is augmented; kinetics of repolarization are slowed. We conclude that this augmentation of the light-dependent hyperpolarization results from the hydrolysis of endogenous cyclic GMP caused by injected PDEase. These results provide evidence that PDEase affects light-dependent channels of the vertebrate scotopic photoreceptors but do not specify whether the effects are exercised for the initial hyperpolarizing phase of the receptor potential and for the recovery phase or only for the recovery phase.
Additional Information
© 1984 by the National Academy of Sciences. Communicated by Floyd Ratliff, September 19, 1983. We are indebted to Professor Lubert Stryer (Stanford University School of Medicine) and Professor E.N. Pugh, Jr. (University of Pennsylvania) for painstaking reviews, to Professor Melvin Simon (California Institute of Technology) for his support, and to Rosemary Hopkins for technical assistance. This work was supported in part by Public Health Service Grants AI-19296 (M.I. Simon, California Institute of Technology) and EY-03196 (W.H.M.) and by fellowships from Fight for Sight, Inc., New York City (Y.S.) and the Alexander B. Cox Memorial Fund, Yale Medical School (Y.S.). The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.Attached Files
Published - SHIpnas84.pdf
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Additional details
- PMCID
- PMC344730
- Eprint ID
- 11312
- Resolver ID
- CaltechAUTHORS:SHIpnas84
- AI-19296
- NIH
- EY-03196
- NIH
- Fight for Sight
- Alexander B. Cox Memorial Fund
- Created
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2008-08-06Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field