MOLECULAR ASPECTS OF PHOTORECEPTOR ADAPTATION IN VERTEBRATE RETINA

This chapter discusses the molecular aspects of photoreceptor adaptation in vertebrate retina. Study of the light reception mechanism in vertebrates, that is, the vertebrate phototransduction mechanism, is studied. The study of the phototransduction mechanism is progressed in the fields of both biochemistry and electrophysiology. The two fields have stimulated each other and have brought about almost full understanding of the mechanism. In the study of phototransduction, there are several advantages. First, in biochemical work, a preparation containing rod photoreceptors with little contamination from other cells or tissues can be obtained in large quantities. Second, in electrophysiological work, isolation of a single functioning photoreceptor is rather easy and the size of a photoreceptor in some animals is large enough for successful penetration or access of electrodes. The third advantage is the capability to control the stimulus precisely, in which, intensity and on/off of the light stimulus can be strictly controlled. These advantages makes experimentation in each field easy and reliable and direct comparison is possible between the results obtained in each field. It seems that the phototransduction mechanism is designed based on multiple, or at least dual regulation. © 1993, Academic Press Inc.