STRUCTURAL MATURATION, CELL-PROLIFERATION AND BIOELECTRIC ACTIVITY INLONG-TERM SLICE-CULTURES OF IMMATURE RAT HIPPOCAMPUS

Explants of transverse slices of the 6-day-old rat hippocampus were gr own in a serum-free medium for 2-14 days. Histology performed after va rious culturing periods demonstrated that these slices maintain a high degree of 3-dimensional organotypy, while undergoing growth and diffe rentiation of the main cellular elements similar to that seen in vivo. Histological indications of continuing cell proliferation were verifi ed by autoradiography showing a labelling of neuroblasts in the dentat e gyrus and of glioblasts at the sites of gliogenesis observed in vivo . Spontaneous bioelectric activity and evoked potentials were recorded , both indicating the development of impulse generation and neuronal c onnectivity within the explant. Silver impregnation and electron micro scopic studies lent further support for the presence of neuronal netwo rks intrinsic to the hippocampus. These findings suggest that within t he period studied the hippocampal slice cultures mature in a fashion s imilar to that seen in situ.