
AbstractSome mammalian rod bipolar cells (RBCs) can receive excitatory chemical synaptic inputs from both rods and cones (DBCR2), but anatomical evidence for mammalian cone‐RBC contacts has been sparse. We examined anatomical cone‐RBC contacts using neurobiotin (NB) to visualize individual mouse cones and standard immuno‐markers to identify RBCs, cone pedicles and synapses in mouse and baboon retinas. Peanut agglutinin (PNA) stained the basal membrane of all cone pedicles, and mouse cones were positive for red/green (R/G)‐opsin, whereas baboon cones were positive for calbindin D‐28k. All synapses in the outer plexiform layer were labeled for synaptic vesicle protein 2 (SV2) and PSD (postsynaptic density)‐95, and those that coincided with PNA resided closest to bipolar cell somas. Cone‐RBC synaptic contacts were identified by: (a) RBC dendrites deeply invaginating into the center of cone pedicles (invaginating synapses), (b) RBC dendritic spines intruding into the surface of cone pedicles (superficial synapses), and (c) PKCα immunoreactivity coinciding with synaptic marker SV2, PSD‐95, mGluR6, G protein beta 5 or PNA at cone pedicles. One RBC could form 0‐1 invaginating and 1‐3 superficial contacts with cones. 20.7% and 38.9% of mouse RBCs contacted cones in the peripheral and central retina (p < .05, n = 14 samples), respectively, while 34.4% (peripheral) and 48.5% (central) of cones contacted RBCs (p > .05). In baboon retinas (n = 4 samples), cone‐RBC contacts involved 12.2% of RBCs (n = 416 cells) and 22.5% of cones (n = 225 cells). This suggests that rod and cone signals in the ON pathway are integrated in some RBCs before reaching AII amacrine cells.
Male, Mice, Inbred C57BL, Mice, Retinal Bipolar Cells, Retinal Rod Photoreceptor Cells, Synapses, Retinal Cone Photoreceptor Cells, Animals, Female, Papio
Male, Mice, Inbred C57BL, Mice, Retinal Bipolar Cells, Retinal Rod Photoreceptor Cells, Synapses, Retinal Cone Photoreceptor Cells, Animals, Female, Papio
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 19 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Top 10% | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Average | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Top 10% |
