Effects of different post-encoding stress intensities on short-term recognition memory in rats: The endocannabinoid buffering

Stress-induced changes in corticosterone affect memory. The endocannabinoid system appears as an emotional buffer in stress regulation. We evaluated how different stress intensities after encoding influence rat short-term memory in an object recognition task, whether the effects depend on circadian variation of corticosterone and if exogenous augmentation of anandamide levels could restore any observed impairment. Both mild and strong forced swimming stresses impaired memory in rats tested in the morning, while only the stronger stress caused memory impairments in the afternoon tested rats. The anandamide hydrolysis inhibitor URB597 counteracted the observed impairments, leaving memory unaltered in the non-impaired groups.