Accession Number : ADA192898

Title :   Regulatory Biochemical and Metabolic Responses in Photoreceptors.

Descriptive Note : Final rept. 1 Jul 84-30 Sep 87,

Corporate Author : YALE UNIV NEW HAVEN CT DEPT OF OPHTHALMOLOGY AND VISUAL SCIENCE

Personal Author(s) : Stein, Peter J

PDF Url : ADA192898

Report Date : Nov 1987

Pagination or Media Count : 41

Abstract : Studies of near infrared light scattering changes in disk membrane suspensions revealed three novel phenomena. The light induced scattering changes observed in the presence of Guanosine triphosphate and Cyclic guanosine monophosphate were produced by aggregation/disaggregation of the membrane vesicles. this aggregation/disaggregation process was correlated with activation of phosphodiesterase and a change in its apparent solubility. That is, PDE became more tightly bound to the membrane when it was activated. We have begun preliminary studies of near infrared scattering signals in the isolated retina. In this preliminary work, we have observed that IBMX, an inhibitor of phosphodiesterase activity, profoundly affects the infrared light scattering signal in the isolated retina. It seems likely that the in vitro and in vivo signals may share a common origin. In a separate series of experiments, we have purified opsin, the apoprotein of the visual pigment protein, and reconstituted it into phospholipid vesicles. We used patch clamp recording to demonstrate that the purified, reconstituted protein exhibits cGMP-activated single channel activity. These results suggest that opsin, in addition to performing its function as the receptor molecule, may be the light-sensitive pore in the plasma membrane of the rod outer segment.

Descriptors :   *METABOLISM, *PROTEINS, *MICROPHOTOMETERS, *SPECTROPHOTOMETERS, *PHOTORECEPTORS, *NUCLEOTIDES, *EYE PIGMENTS, ACTIVATION, BIOCHEMISTRY, GUANOSINE, IN VITRO ANALYSIS, IN VIVO ANALYSIS, INFRARED RADIATION, INHIBITORS, MOLECULES, NEAR INFRARED RADIATION, OPTICAL IMAGES, PHOSPHATES, PHOSPHODIESTERASE, RECORDING SYSTEMS, RETINA, SENSE ORGANS, SIGNALS, RESPONSE(BIOLOGY), RETINA, MEMBRANES(BIOLOGY)

Subject Categories : Biochemistry
      Anatomy and Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE