Glutamatergic separation of ON and OFF retinal channels: possible modulation by glycine and acetylcholine.
When intravitreally injected into the frog in vivo, 2-amino-4-phosphonobutyrate (APB) and cis-2,3-piperidine dicarboxylic acid (PDA) showed opposite effects on ON and OFF retinal channels: APB abolished the ON responses in the electroretinogram and in ganglion cell activity, and increased OFF responses. At the same time the receptive field area was enlarged, and the inhibition exerted by the surround was suppressed. A cholinergic/glycinergic loop involving amacrine cells was suggested to be the pathway of the inhibitory ON input upon the OFF channel. PDA abolished the OFF responses in the ERG and in ganglion cell activity, while increasing the ON response in the ERG and decreasing the ganglion cell sensitivity at ON. The receptive field area was not modified, but the inhibition exerted by the surround was suppressed, probably by a blockade of horizontal cell glutamate receptors.
Jardon
B
B
D.N.B.C., Centre de Neurochimie du CNRS, Strasbourg, France.
Yücel
H
H
Bonaventure
N
N
D000109:Acetylcholine / Q000502:physiology*; D000613:Aminobutyrates / Q000494:pharmacology; D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology; D004596:Electroretinography; D005724:Ganglia / Q000166:cytology / Q000187:drug effects; D005971:Glutamates / Q000502:physiology*; D005998:Glycine / Q000502:physiology*; D066298:In Vitro Techniques; D007267:Injections; D008839:Microelectrodes; D009434:Neural Pathways / Q000502:physiology; D010875:Pipecolic Acids / Q000494:pharmacology; D011893:Rana esculenta; D012160:Retina / Q000502:physiology*; D014822:Vitreous Body / Q000187:drug effects / Q000502:physiology
D000613:Aminobutyrates; D000927:Anticonvulsants; D005971:Glutamates; D010875:Pipecolic Acids; C029262:2,3-piperidinedicarboxylic acid; C012729:2-amino-4-phosphonobutyric acid; D000109:Acetylcholine; D005998:Glycine