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 diss ociated cell cultures of human spinal cords from 6-10-week-old fetuses using immunohistochemistry with anti-GABA antibodies. Light microscop y 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 extend ing far from the cell body (large neuritic tree neurons). Both types w ere studied at different ages in vitro, in control and in thienyl phen cyclidine (TCP)-treated cultures by means of computer reconstructions and morphometric parameters. A discriminant analysis permitted the rec ognition of three populations: whatever the age, the control and TCP-t reated neurons with small neuritic trees were not discriminated from e ach 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 neurit ic trees were clearly separated from each other and from the small cel l population. In all models, an astrocytic labeling, weaker than that of the neurons, was observed. The nature of these neurons (probably in terneurons) intrinsic to the spinal cord is discussed in view of previ ous findings concerning the anatomical distribution and organization o f the GABAergic system in the spinal cord.