Structural basis for on-and off-center responses in retinal bipolar cells.
Electron microscopy of Golgi preparations of goldfish retina shows that dendrites of type a (hyperpolarizing, off-center) bipolar cells make wide cleft junctions unassociated with synaptic ribbons, while those of type b (depolarizing, on-center) bioplar cells make narrow cleft junctions and synaptic ribbon contacts, with rods and cones. This suggests that wide cleft junctions are the site of sign-conserving, and narrow cleft junctions or ribbon contacts (or both) are the site of sign-inverting synaptic transmission from photoreceptors to bipolars.
D000818:Animals; D003712:Dendrites / Q000648:ultrastructure; D005724:Ganglia / Q000648:ultrastructure*; D006054:Goldfish / Q000033:anatomy & histology; D010786:Photoreceptor Cells / Q000648:ultrastructure; D012160:Retina / Q000502:physiology / Q000648:ultrastructure*; D013569:Synapses / Q000648:ultrastructure; D009435:Synaptic Transmission; D014795:Visual Pathways / Q000648:ultrastructure