Fig. 3.

Neurogenesis in adult rat cultures: pulse labeling with [³H]thymidine. A, The increase in NST+ OSNs was a result of neurogenesis. After a 24 hr pulse of [³H]thymidine in ANM-alone cultures at 5 DIV, NST+ OSNs with silver grain labeling were found at 9 DIV (arrow).B, The increase in OMP+ OSNs was also a result of neurogenesis in vitro. After a 24 hr pulse of [³H]thymidine in ANM-alone cultures at 5 DIV, OMP+ OSNs with silver grain labeling were not detectable at 9 DIV, but they were at 12 DIV (C, arrow). This suggests that newly generated OSNs express NST before expression of OMP. Scale bar, 20 μm.