Table 3.

Cell-type composition, location, and degree of BrdU labeling in clusters containing β-gal+ glial cells

  • Data from 36 cortical hemispheres of 2-week-old rats given injections of retrovirus and BrdU at E16 are reported here.

  • Cells were studied either in double-immunostained cryostat sections orain adjacent semithin sections. Glial clusters are defined as groups of β-gal+ cells located within 540 μm in both rostrocaudal and mediolateral dimensions, which are composed exclusively of, or contain, glial cells. A cluster extending for >540 μm is marked with an asterisk.

  • F3-b Clusters that include cells located in different layers.

  • F3-c Clusters that include cells with different phenotype. Cortical areas were defined according to Paxinos and Watson (1986); laminar location was assigned according to Krieg (1946). Cells were classified as pyramidal neurons (Py), astrocytes (A), or oligodendrocytes (O) according to morphological features, which included size and shape of the cell body and cellular processes, axonal morphology when applicable, and nuclear size and shape (Peters and Jones, 1984; Peters et al., 1991). For the level of BrdU-immunoreactive nuclear area: ✺ = 25–50%;   = 12–25%;   = <12%; ○ = unlabeled; ? = unknown.