Depletion of Cholinergic Amacrine Cells by a Novel Immunotoxin Does Not Perturb the Formation of Segregated On and Off Cone Bipolar Cell Projections

摘要: Cone bipolar cells are the first retinal neurons that respond in a differential manner to light onset and offset. In mature retina, terminal arbors of On Off cone terminate different sublaminas inner plexiform layer (IPL) where they form synapses with dendrites ganglion stratified processes cholinergic amacrine cells. Here we show within IPL present early development, being evident rat on day birth, ∼10 d before formation segregated cell axons. This temporal sequence, as well our previous finding segregation inputs occurs absence cells, suggested could provide scaffold for subsequent in-growth To test this hypothesis directly, new immunotoxin was constructed by conjugating saporin, ribosome-inactivating protein toxin, an antibody against vesicular acetylcholine transporter. A single intraocular injection caused rapid, complete, selective loss from developing retina. were visualized using recoverin, calcium-binding labels soma these interneurons. After complete depletion axon terminals still formed their two characteristic strata IPL. These findings demonstrate presence is not required recoverin-positive projections.