Comparative morphology of distal neurons in larval and adult zebrafish retinas.
Distal retinal cells from larval (7-10 days postfertilization) and adult zebrafish retinas were cultured in 70% L-15 medium for 4-5 d and comparable cell types identified. Four photoreceptor types were observed in adult retinal cultures, whereas only single cones were isolated from larval retinas. Horizontal cells in both larval and adult cultures were distinguished by their large size and stellate morphology and two subtypes, A and B, were recognized. Bipolar cells were readily identified in adult cultures, but rare in larval cultures. Two bipolar cell types, large and small, were distinguished. Measurements of the various cell types are provided.