Further ultrastructural data on the cytoplasmic nucleolus resembling bodies or nematosomes. Their relationship with the subsynaptic web and a cytoplasmic filamentous network

Summary An electron microscope study of the rat supraoptic nucleus, substantia nigra, neostriatum and periventricular preoptic area demonstrates that nematosomes are present within the perikaryon of neurons located in these structures. The latter structure may be found in close association with the subsynaptic web of axosomatic synapses. Numerous micro-filaments fan out from the nematosome and link the latter organelle to the ribosomes, the cytoplasmic membranes and the plasma membrane thus establishing an interwoven filamentous cytoplasmic network. A possible close relationship between the nematosomes and the neurofilaments and neurotubules is discussed.This work was supported by research grant MA-3448 from the Medical Research Council of Canada. The skillful technical assistance of Miss Marjolaine Thiffeault is gratefully acknowledged.