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Document Type:Latin Dissertation
Language of Document:English
Record Number:55626
Doc. No:TL25580
Call number:‭3226283‬
Main Entry:Gary A. Williams
Title & Author:Rodent photopigments, photoreceptors, and vision: Examination of an ultraviolet -sensitive cone photopigment in the Syrian hamster, Mesocricetus auratus and vision in the aging mouseGary A. Williams
College:University of California, Santa Barbara
Date:2006
Degree:Ph.D.
student score:2006
Page No:154
Abstract:This thesis reports results from two research projects that deal with interrelationships between pigment genes, photopigments, ocular structure, and vision in rodents. The first of these is an investigation of cone photopigments in the Syrian hamster, while the second examines the effects of age on cone photoreceptors and visual function in the house mouse. Most mammals have two cone photopigments segregated into separate cone photoreceptors. Studies examining photopigments in the Syrian hamster have clearly demonstrated the presence of an MWS cone photopigment but there are conflicting results regarding the presence of a SWS/UVS cone in this species. Reports of the SWS/UVS cone opsin gene sequence suggest that the gene contains a mutation resulting in a premature stop codon which would result in a truncated non-functional opsin protein. Polymerase chain reaction (PCR) was performed to see if the hamster SWS/UVS opsin gene is transcribed. Also, a sensitive electroretinogram (ERG) flicker photometric procedure was performed in order to investigate separate MWS and SWS/UVS cone mechanisms in the Syrian hamster retina. Results from the PCR experiments show that the hamster SWS/UVS opsin gene is transcribed. In addition to the MWS cone mechanism the ERG experiments show the presence of a second distinct cone-based mechanism that is maximally sensitive to short/ultraviolet wavelengths. The data presented here provide evidence for the presence of a functional SWS/UVS cone photopigment in the Syrian hamster. However, the data suggest that the SWS/UVS cone photopigment must comprise a very small part of the total cone photopigment complement in the species. Mice are frequently used as models of human visual pathologies involving aging. However, previous studies examining mouse vision in the have been limited to relatively young subjects. The present experiments examined the effects of age on cone opsin gene transcription, retinal histology, retinal electrophysiology, and visual behavior in mice well over the 50% survival age without visual pathologies. Results show age-related declines in measures of retinal electrophysiology while opsin gene transcription, retinal histology, and behavioral measures were unchanged even in extremely old mice.
Subject:Psychology; Biological sciences; Aging; Cone; Photopigments; Photoreceptors; Ultraviolet-sensitive; Vision; Neurology; Psychobiology; 0317:Neurology; 0349:Psychobiology
Added Entry:G. H. Jacobs
Added Entry:University of California, Santa Barbara