Figure 1.

Norepinephrine but not serotonin activates a precursor cell population from the adult hippocampus. A–C, Treatment of adult hippocampal cells with NE but not serotonin (5-HT) in the presence of EGF and bFGF significantly enhanced neurosphere formation with up to a twofold increase observed at 10 μm (mean ± SEM; ***p < 0.001) (A). In addition, norepinephrine treatment generated a number of very large neurospheres, an example of which is shown in C, compared with smaller neurospheres generated in the control (B). Scale bars, 100 μm. D, Neurospheres obtained in the presence of 10 μm norepinephrine were significantly larger than the control neurospheres. Note an increase in the percentage of norepinephrine-derived neurospheres measuring 100–150 μm, 150–200 μm, and >200 μm, but a reduction in the smaller neurospheres measuring <100 μm compared with the control neurospheres (mean ± SEM; *p < 0.05, **p < 0.01***p < 0.001).