The late positive retinal potential in dogs.
The late positive potential of the mammalian electroretinogram has been called the 'PI' or the 'c-wave' potential. It is unusual among retinal potentials because its peak implicit time increases in response to increasing stimulus intensity and because it cannot be demonstrated consistently in small samples of normal humans or normal dogs. We recorded wideband (DC-1 kHz) responses from 34 normal Beagles or dogs of similar size. Of the 34, 11 produced a late positive potential set that satisfied the criteria for c-waves. Multiple aspartate injections always increased c-wave amplitude and stimulus-response linearity in all 'producers'. Non-producers were never converted to producer status by aspartate blocking of the inner retina. Interaction of late positive and negative potentials and the possible influence of normal individual variations in the trans-epithelial potential are discussed. Individual mammal c-wave production is controlled by outer retinal phenomena which vary between individuals.
Dawson
W W
WW
Department of Ophthalmology, College of Medicine, University of Florida, Gainesville 32610-0284, USA.
Kommonen
B
B
D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D004285:Dogs / Q000502:physiology*; D004307:Dose-Response Relationship, Radiation; D004596:Electroretinography; D005074:Evoked Potentials, Visual / Q000187:drug effects / Q000502:physiology*; D010775:Photic Stimulation; D010857:Pigment Epithelium of Eye / Q000502:physiology*
D001224:Aspartic Acid