Feedforward lateral inhibition in retinal bipolar cells: input-output relation of the horizontal cell-depolarizing bipolar cell synapse.
Lateral inhibition is the ubiquitous strategy used by visual neurons for spatial resolution throughout the animal kingdom. It has been a puzzle whether lateral inputs in retinal bipolar cells are mediated by the horizontal cell (HC)-cone feedback synapse, by the HC-bipolar cell feedforward synapse, or by both. By blocking the central inputs of the depolarizing bipolar cells (DBCs) with L-2-amino-4-phosphonobutyrate, we were able to eliminate the contribution of the feedback synapse and to demonstrate the postsynaptic light response in DBCs mediated by the HC-DBC feedforward synapse. The HC-DBC feedforward synapse contributes roughly one-third of the surround response whereas the HC-cone-DBC feedback synapse probably contributes the rest.
Yang
X L
XL
Cullen Eye Institute, Baylor College of Medicine, Houston, TX 77030.
Wu
S M
SM
D000557:Ambystoma; D000613:Aminobutyrates / Q000494:pharmacology; D000818:Animals; D066298:In Vitro Techniques; D008027:Light; D008564:Membrane Potentials / Q000187:drug effects; D009433:Neural Inhibition; D012160:Retina / Q000166:cytology / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects
D000613:Aminobutyrates; C012729:2-amino-4-phosphonobutyric acid