Figure 2.

The small, vitreous-derived factor stimulates rat RGCs to regenerate their axons. a-d, Dissociated cultures of the mature rat retina were exposed to either defined media containing 15 μm forskolin (a, b) or the same conditions plus VE <3. c, d, RGCs are distinguished by retrograde FG-labeling. a, c, Axon outgrowth visualized by staining with antibodies to GAP-43 (b, d). e, Quantitative results. The effects of VE <3 are potentiated by either forskolin (forsk, 15 μm) or Sp-cAMPs (100 μm). Results for all rat RGC experiments are normalized to the level of growth in defined media alone. f, None of the agents tested altered RGC survival. g, VE <3 gives a near-maximal response at a concentration of 5%. ^**p < 0.01 compared with negative control; ^[***]p < 0.001 compared with either negative controls or cells treated with PKA agonists alone.