State-dependent retention produced with estrus in rats.

State-dependent retention (SDR) has frequently been demonstrated with drug-induced physiological changes which apparently serve as contextual cues for memory. These support the assumption that commonly occurring endogenous dispositions play a role in memory, yet there are few reports showing SDR with states that are likely to be part of an organism's natural experiences. To determine if behavioral estrus could produce SDR, ovariectomized female rats were rendered estrus via hormone injections or remained anestrus via placebo injections, trained with quinine-laced apple juice, and later tested while in the same or different state for reactions towards pure juice. SDR was not evident in the amount of juice consumed; however, those tested in the same state as the initial experience were slower to initiate drinking than those tested in a different state revealing a state-dependent influence on memory related to phases of the ovarian cycle.