Figure 2

Bipolar cell morphology observed using retroviral lineage analysis in vivo. The retroviral vector Ely expresses the human placental alkaline phosphatase as a histochemical reporter. Neonatal rat pups were injected in vivo during development at PO, P4, and P6 and sacrificed at P21 after retinal differentiation is complete. Cryosections were made and the type of cell in each clone was assessed using morphological criteria. (a-h) Cone bipolar cells wherein the process ends prior to the innermost aspect of the IPL. (i, j) Rod bipolar cells whereby processes extend to the innermost aspect of the IPL and display narrow endings and characteristic dendrites.