title: Evidence in support of a photoreceptoral origin for the "light-peak substance".
abstract: The light peak of the DC ERG was recorded in in vitro preparations of chick neural retina-RPE-choroid. Either the pharmacological agents Co2+, Mg2+, and low Ca2+, known to block calcium-dependent synaptic transmission or 2-amino-4-phosphonobutyric acid (APB), which blocks transmission in the ON pathway, were added to the solution perfusing the retina. These agents suppressed the b-wave of the ERG, thus indicating a severe suppression of synaptic transmission in the neural retina. The retina was also perfused with the OFF pathway inhibitor cis-2,3-piperidine dicarboxylic acid (PDA). None of these agents, however, significantly depressed the light peak, supporting the hypothesis that the light peak is generated by a photoreceptor-RPE interaction.
authors.affiliation: Department of Physiology, University of California, San Francisco 94143-0444.
authors.forename: R P
authors.initials: RP
authors.lastname: Gallemore
authors.forename: E R
authors.initials: ER
authors.lastname: Griff
authors.forename: R H
authors.initials: RH
authors.lastname: Steinberg
mesh_terms: D000818:Animals; D002829:Choroid / Q000502:physiology; D004596:Electroretinography; D008027:Light; D009433:Neural Inhibition; D010786:Photoreceptor Cells / Q000502:physiology*; D010857:Pigment Epithelium of Eye / Q000502:physiology; D012016:Reference Values; D012160:Retina / Q000502:physiology; D013569:Synapses / Q000502:physiology; D009435:Synaptic Transmission