We have compared changes in mRNA of three genes, zif268, raf B, and syntaxin 1 B, following the unilateral induction of long-term potentiation (LTP) in rats previously trained in a water maze, and in behaviourally naive animals. mRNA of all three genes was enhanced in the potentiated dentate gyrus of naive animals 3 h after the induction of LTP. Training did not affect expression of mRNA for zif268 or for syntaxin 1 B. Expression of raf B was enhanced by training, and in trained animals the LTP-associated increase in expression of raf B was occluded. These results suggest that LTP and spatial training engage a common pathway utilizing an increase in mRNA for raf B, and demonstrate a dissociation between LTP and spatial learning with respect to expression of zif268 and syntaxin 1B.