nNOS deficiency-induced cell proliferation depletes the neurogenic reserve

► Consequences of NOS-knockout on neuronal precursors in the SGZ and SVZ were analyzed. ► Neonatal, adult and 18-month-old wild-type, nNOS-, eNOS-, and iNOS-minus mice were studied. ► Reduced NO supply, initially inducing cell proliferation in nNOS-minus mice, leads to exhausted cell division in age. ► Present study supports the idea of a finite proliferation capacity of neuronal stem cells.