Acute restraint stress impairs aversive memory retention but not memory formation

Stress can alter neurochemical signalling, affecting memory processing, but its underlying neurobiological mechanism remains unclear. Here, we investigate the effect of acute restraint stress (ARS) on long-term retention of aversive memory in rats. We exposed the animals to either handling or ARS protocol and tested the rats in the plus-maze discriminative avoidance task (PMDAT). Also, we performed immunohistochemistry assays to unveil the effect of stress on neuronal activity. We found that ARS immediately after training does not impair memory formation but hinders retention. Training triggers a peak of C-fos 1 hour later and a delayed 18-hour increase of Zif268 in the dorsal CA1. The same does not occur when ARS is experienced immediately after training. We demonstrate the crucial role of Zif268 and C-fos signalling in maintaining PMDAT LTM. ARS is more relevant for memory retention than for memory formation of discriminative aversive memory. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=129 SRC="FIGDIR/small/666772v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@1c6fa1org.highwire.dtl.DTLVardef@e4c693org.highwire.dtl.DTLVardef@1a8e79corg.highwire.dtl.DTLVardef@1fdcf50_HPS_FORMAT_FIGEXP M_FIG C_FIG