[RNA synthesis in cells of the cerebral cortex of mice according to electron-microscopic autoradiography findings].

An electron microscopy autoratiographic study of the RNA synthesis in the neurons of the mouse cerebral cortex revealed the highest label concentration in the nucleoli. A considerable amount of silver grains was concentrated over the nucleoplasm. The content of the radioactive substance in the cytoplasm of the neurons 2 1/2 hours after the animal was injected with 3H-5-uridine was lower than in the other kinds of cells at the same period of their contact with the labeled precursor. A considerable difference in the amount of silver grains was observed over the serial sections of the same nucleolus and in the way of the label distribution in the neurons located nearby.