Retinal degeneration in cats fed casein. IV. The early receptor potential.
Electroretinographic studies of casein-fed cats with retinal taurine deficiency revealed that the early receptor potential (ERP) was initially normal in amplitude at a time when the a-wave and b-wave of the electroretinogram were substantially reduced or even nondetectable. The preserved ERP's in these taurine-deficient cats could be correlated with the histologic finding that their outer segments were relatively intact over 90% of the retinal area subtended by the test flash. The sequence of electroretinographic changes in these taurine-deficient cats was also consistent with previous biochemical studies on the normal cat retina that have shown a relatively low concentration of taurine at the level of the outer segments and a higher concentration at the level of the inner segments. The responses in early stages from taurine-deficient cats differed from the responses obtained from vitamin A--deficient cats but resembled those from cats that received an intravitreal injection of ouabain. Similarities and a difference between the responses of taurine-deficient cats and those of patients with early retinitis pigmentosa are considered.
D000818:Animals; D002364:Caseins; D002415:Cats; D004032:Diet; D004596:Electroretinography; D005071:Evoked Potentials; D006801:Humans; D010042:Ouabain; D010775:Photic Stimulation; D010786:Photoreceptor Cells / Q000503:physiopathology*; D012162:Retinal Degeneration / Q000209:etiology / Q000503:physiopathology*; D012174:Retinitis Pigmentosa / Q000503:physiopathology; D012374:Rod Cell Outer Segment / Q000473:pathology / Q000503:physiopathology*; D013654:Taurine / Q000502:physiology; D014802:Vitamin A Deficiency / Q000503:physiopathology
D002364:Caseins; D013654:Taurine; D010042:Ouabain