Spinal cord long-term potentiation is often studied as a model for cellular memory of nociceptive information. In the present report, extracellular single-unit recordings and quantitative real-time reverse transcriptase polymerase chain reaction were used to examine whether the induction of spinal cord long-term potentiation involves changes in expression of Zif, c-fos and cyclooxygenase-2. The data demonstrated that induction of spinal cord long-term potentiation was associated with a transient increase in the expression of Zif at 120 min (p < 0.05, long-term potentiation group vs. control group). In contrast, a decrease or no changes were observed in the expression of c-fos and cyclooxygenase-2. The transient increase of the expression of Zif is consistent with an involvement in the transition from the early to the late-phase of spinal cord long-term potentiation.