Effect of various stresses on the incorporation of ( 3 H)orotic acid into goldfish brain RNA.

A possible relationship of RNA metabolism to higher brain functions has been inferred from theoretical considerations 9, from experiments in which RNA-blocking antimetabolites affect behavior 2, and from reports that training affects either the rate of labeling of brain RNA by radioactive precursors 24, or changes the patterns of labeling la. An indication of such a qualitative change from injected labeled orotic acid has been reported in goldfish which were trained to swim upright following attachment of a styrofoam float to the lower jaw 20. The present experiments were undertaken for two reasons first, to establish whether there was a quantitative or qualitative alteration in the labeling of brain RNA as a result of training fish in a shock avoidance task studied extensively in this laboratory 1, and secondly, in the event that such an alteration were found, to determine whether this was a specific result of learning as distinct from more nonspecific stresses associated with training. We were also interested in whether altered labeling reflected a change in synthesis of RNA, or alternatively, in specific activities of RNA precursors. The present study reports the incorporation of intracranially (i.c.) injected [aH]orotic acid into total goldfish brain RNA as well as its relative incorporation into the uridylate and cytidylate moieties (U/C ratio) of the acid-soluble fraction, as influenced by a number of behavioral and physiological parameters.