Memory-dependent novelty-related location preferences: sex-related attenuation of forgetting by D-glucose and tacrine.

Following confinement to one chamber of a two-chamber exploration box (acquisition trial), male and female rats were intraperitoneally injected with saline, glucose (50, 100 mg/kg) or tacrine (1, 3 mg/kg). Twenty-four hours later they were given free access to this chamber and an identical novel one (retention trial). Tendencies to occupy the novel chamber (novelty-related location preferences) were increased by both doses of glucose for females and by the higher dose for males. While neither dose of tacrine affected this response for females, increased preferences occurred for males following the higher dose. However, when the higher doses of both agents were administered 2 h after acquisition, there were no significant effects for either sex. In view of the rats' lack of significant preferences for the novel chamber when treated with saline both immediately and 2 h after acquisition, the results were interpreted as sex-dependent attenuation of forgetting by post-acquisition treatment with both agents.