Molecular Mechanism of Adaptation in Vertebrate Rods
Steady background light and bright bleaching illumination produce changes in rod photoreceptor sensitivity and response waveform that are collectively known as adaptation. In this chapter, we review the phenomenology of both background and bleaching adaptation. We then describe the evidence for our present understanding of the molecular mechanisms of adaptation in vertebrate rods to both background light and bleaching, including the role of Ca2+ as a second messenger and modulation of guanylyl cyclase and phosphodiesterase. We also describe continuing areas of uncertainty awaiting resolution from future experimentation.
KeywordsAdaptation Calcium Retina Rod Transduction Vision
Work in our laboratory would not have been possible without the assistance of many able (and congenial) collaborators, including (in alphabetical order) Jason Chen, Jeannie Chen, Carter Cornwall, Alex Dizhoor, Hugh Matthews, Dan Tranchina, and Steve Tsang. We are also grateful to Margery J. Fain for drawing Fig. 4.1. Our research has been generously supported during the last 37 years by NIH R01 EY01844.
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