EFFECTS OF NERVE STIMULATION ON THE METABOLISM OF RIBONUCLEIC ACID IN A MOLLUSCAN GIANT NEURONE

—In vitro experiments were performed in order to determine whether nerve stimulation would affect the RNA metabolism of an identified giant neurone (R2) in the abdominal ganglion of Aplysia californica. The electrophysiological activity of the neurone was continuously monitored with an intra- or extracellular microelectrode. The mere presence of an intracellular microelectrode inside the neurone had no significant effect on the incorporation of tritiated nucleosides into the RNA of the giant neurone. Prolonged electrical stimulation of ganglionic nerves, strong enough to elicit post-synaptic spikes in the giant neurone, produced a marked increase in the amount of labelled RNA in the nucleus as well as in the cytoplasm. Electrophoresis studies suggested that this increase in labelling might concern RNA with molecular weights corresponding to ribosomal as well as to non-ribosomal RNA.