Two distinct subpopulations of nestin-positive cells in adult mouse dentate gyrus.

Neurogenesis in the dentate gyrus of the adult mammalian hippocampus has been proven in a series of studies, but the differentiation process toward newborn neurons is still unclear. In addition to the immunohistochemical study, electrophysiological membrane recordings of precursor cells could provide an alternative view to address this differentiation process. In this study, we performed green fluorescent protein (GFP)-guided selective recordings of nestin-positive progenitor cells in adult dentate gyrus by means of nestin-promoter GFP transgenic mice, because nestin is a typical marker for precursor cells in the adult dentate gyrus. The patch-clamp recordings clearly demonstrated the presence of two distinct subpopulations (type I and type II) of nestin-positive cells. Type I cells had a lower input resistance value of 77.1 M(Omega) (geometric mean), and their radial processes were stained with anti-glial fibrillary acidic protein antibody. On the other hand, type II nestin-positive cells had a higher input resistance value of 2110 MOmega and expressed voltage-dependent sodium current. In most cases, type II cells were stained with anti-polysialylated neural cell adhesion molecule. Taken together with a bromodeoxyuridine pulse-chase analysis, our results may reflect a rapid and dynamic cell conversion of nestin-positive progenitor, from type I to type II, at an early stage of adult neurogenesis in the dentate gyrus.