Generation of the e-wave of the electroretinogram in the frog retina.
The e-wave and a delayed-OFF increase in extracellular K+ concentration are both maximum in the distal half of the inner plexiform layer. These responses also have similar latency, time-course, intensity-dependence, surround properties, and sensitivity to tetrodotoxin. Current source-density analysis of the e-wave reveals a current sink through the proximal retina, a source at the retinal surface, and, in some cases, a weaker source in the mid-retina. These results suggest a model for e-wave generation: delayed-OFF activity in proximal neurons releases K+, which enters Muller cells in the inner plexiform layer; a current exists Muller cells primarily via their endfeet, and the return flow through extracellular space produces the e-wave.
Karwoski
C J
CJ
Department of Psychology, University of Georgia, Athens 30602.
Newman
E A
EA
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D003623:Dark Adaptation; D004596:Electroretinography; D066298:In Vitro Techniques; D011188:Potassium / Q000494:pharmacology; D011892:Rana catesbeiana; D011894:Rana pipiens; D012160:Retina / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology
D013779:Tetrodotoxin; D011188:Potassium