GABAergic neurons in human spinal cord cultures: a computer-aided analysis of normal and thienyl-phencyclidine-treated cells.

gamma-Aminobutyric acid (GABA)-containing neurons were studied in dissociated cell cultures of human spinal cords from 6-10-week-old fetuses using immunohistochemistry with anti-GABA antibodies. Light microscopy showed two types of immunoreactive (IR) neurons: (1) IR neurons with short neuritic processes remaining near the cell body (small neuritic tree neurons); and (2) IR neurons with long neuritic processes extending far from the cell body (large neuritic tree neurons). Both types were studied at different ages in vitro, in control and in thienyl phencyclidine (TCP)-treated cultures by means of computer reconstructions and morphometric parameters. A discriminant analysis permitted the recognition of three populations: whatever the age, the control and TCP-treated neurons with small neuritic trees were not discriminated from each other and were considered to be one population whereas the 98 DIV control and both 21 DIV and 98 DIV TCP-treated cells with large neuritic trees were clearly separated from each other and from the small cell population. In all models, an astrocytic labeling, weaker than that of the neurons, was observed. The nature of these neurons (probably interneurons) intrinsic to the spinal cord is discussed in view of previous findings concerning the anatomical distribution and organization of the GABAergic system in the spinal cord.