This study examined whether depletion of central serotonin produces an improved retrieval of aversive memories in the same way as pre-exposure to inescapable footshocks, in rats. Animals conditioned in a T-maze with appetitive (10% sucrose) and aversive (2.0 mA footshock) events were given i.c.v. 24 hr later a single dose of p-chlorophenylalanine (p-CPA). (100, 200, 400 micrograms/rat) or drug vehicle. The retention performance and activity were assessed 48 hr after treatment with this depletor. While lower doses of p-CPA selectively reduced serotonin levels in striatum and anterior cortex, higher doses reduced both serotonin and norepinephrine levels in hippocampus in a dose-dependent fashion. The depletor however, failed to produce a differential improvement of aversive memory retrieval. On the contrary, p-CPA reduced the latency to enter both, previously shocked and appetitively reinforced, goalboxes. The enhanced traversing behaviour in T-maze, together with an increased central entry in the open field that observed in depleted groups, might suggest an anxiolytic activity of p-CPA.