Work by both Miao-Fang Lin Altshuller and Keow Thavaradhara Essig demonstrated that NO was present in larval brains during development. Because NO controls neurogenesis by suppressing DNA synthesis in other invertebrates, we hypothesized that NO might have this same role in larval Tritia. Thus, Brian Burrows – MS degree 2005 investigated this idea, that larval neurogenesis might be controlled by NO. To determine how rates of neurogenesis change during larval development, Brian incubated larvae at a number of ages in 5-bromo-2’-deoxyuridine (BrdU) for 3 hours, to label cells that were undergoing replication, and presumably, mitosis. He then localized BrdU labelling by immunocytochemistry. He stained all nuclei in these specimens with 4’,6-diamidino-2-phenylindole (DAPI) to facilitate counting all neuronal nuclei and compared that number to BrdU-labelled nuclei in 9 major ganglia. As indicated in the graph (Below), Brian determined that levels of neurogenesis drop as development progresses, which may be correlated with changes in NO levels (Hens et al., 2005, Soc. Neurosci. Abstr. Viewer & Itinerary Planner CD-ROM. Program 30.11). Supported by NSF grants IBN-0130677 and DBI-0319021.
Above: The birth of new neurons in the central nervous system declines during planktonic larval development.
