Distribution of F-actin in bipolar and horizontal cells of bass retinas.
F-actin distribution was studied in bipolar and horizontal interneurons of white bass retina. Cryosections of intact retina and isolated cells in culture were labeled with the F-actin specific probe fluorescent phalloidin. In intact retina, labeling was heaviest in the photoreceptor-pigment epithelium region, outer limiting membrane, horizontal cell somata, and plexiform layers. In isolated bipolar and horizontal cells, labeling patterns specific to each cell type were obtained, as were patterns in distinct categories of neurites extending from cells maintained in culture for several days. Label was especially heavy where contacting horizontal cells apposed and were coupled via extensive gap junctions both in the intact retina and in culture. This observation led to the hypothesis that this F-actin domain might modulate junctional conductance. However, cytochalasin D-induced disruption of the F-actin cytoskeletons of coupled, cultured horizontal cells had no effect on normal coupling or on dopamine-induced uncoupling. The F-actin domain may instead mediate gap junction turnover.
Vaughan
D K
DK
Department of Physiology, University of Utah School of Medicine, Salt Lake City 84108.
Lasater
E M
EM
D000199:Actins / Q000032:analysis*; D000818:Animals; D001369:Axons / Q000502:physiology / Q000648:ultrastructure; D001492:Bass; D002478:Cells, Cultured; D007365:Intercellular Junctions / Q000648:ultrastructure*; D007395:Interneurons / Q000166:cytology*; D008854:Microscopy, Electron; D010857:Pigment Epithelium of Eye / Q000166:cytology; D012160:Retina / Q000166:cytology* / Q000648:ultrastructure; D012374:Rod Cell Outer Segment / Q000166:cytology
D000199:Actins