Effect of various stresses on the incorporation of [3H]orotic acid into goldfish brain RNA

Abstract

The effect of a number of stresses on the incorporation of [5-3H]orotic acid into total goldfish brain RNA and its pyrimidine precursors is reported. The ratio of labeling of the uridylate and cytidylate moieties of the RNA (U/C) varied as a function of the temperature and duration of the experiment. The ratio was elevated when fish were subjected to pentylenetetrazol-induced convulsions or to mild electrical shock, with or without training of an avoidance conditioning task. The increase in ratio in all cases resulted from a decrease in cytidylate labeling. In experiments where this decrease was marked, a substantial decrease in the labeling of total RNA was seen as well. The observation that the increase in U/C was greater when increased numbers of fish were shocked per tank eventually led to the finding that addition of carbon dioxide to tank water results in a decrease in labeling of cytidylate isolated from RNA hydrolysates, as well as decreased labeling of cytidine precursors of RNA.