Light and electron microscope study of mouse cerebral neocortex in tissue culture

Abstract

The morphological development of neurons in newborn mouse cerebral neocortex cultured in vitro was studied by silver staining methods and electron microscopy. In Bodian and Holmes' preparations, two principal types of neurons, large pyramidal cells and small pyramidal cells, were identified. The developmental history of the large pyramidal cell was described in four sequential developmental phases (unipolar stage, bipolar stage, multipolar stage and the stage of maturation). Synaptic boutons were observed on somas and dendrites of large pyramidal cells. In electron micrographs, large pyramidal cells with well-developed Nissl substance, Golgi apparatus, subsurface cisternae, synapses terminating on perikarya and occasional perikaryal spines were demonstrated. Small pyramidal cells contain large oval nuclei and only a thin rim of cytoplasm in which the Nissl substance is not well-developed. Two types of synaptic membrane specializations were observed in synaptic structures corresponding closely to Gray's type 1 and type 2 synapses. In many respects, morphological features observed in silver preparations and electron micrographs of mouse cerebral neocortex cultured in vitro correspond faithfully to those seen in noncultured tissue in situ.