Activation of PKCε, an abundant and developmentally regulated PKC isoform in the brain, has been implicated in memory throughout life and across species. Yet, direct evidence for a mechanistic role for PKCε in memory is still lacking. Hence, we sought to evaluate this in rats, using short-term treatments with two PKCε-selective peptides, the inhibitory εV1-2 and the activating ψεRACK, and the novel object recognition task (NORT). Our results show that the PKCε-selective activator ψεRACK, did not have a significant effect on recognition memory. In the short time frames used, however, inhibition of PKCε activation with the peptide inhibitor εV1-2 significantly impaired recognition memory. Moreover, when we addressed at the molecular level the immediate proximal signalling events of PKCε activation in acutely dissected rat hippocampi, we found that ψεRACK increased in a time-dependent manner phosphorylation of MARCKS and activation of Src, Raf, and finally ERK1/2, whereas εV1-2 inhibited all basal activity of this pathway. Taken together, these findings present the first direct evidence that PKCε activation is an essential molecular component of recognition memory and point toward the use of systemically administered PKCε-regulating peptides as memory study tools and putative therapeutic agents. HIGHLIGHTS