title: Fluoxetine enhances memory processing in mice.
abstract: Fluoxetine (FLU) increases brain concentrations of serotonin by blocking its uptake, without appreciably affecting the dopamine or norepinephrine systems. The present experiments provide evidence that a subcutaneous injection of FLU enhanced post-memory processing ("consolidation") and retrieval, but not acquisition in young adult mice. FLU (15 mg/kg) enhanced 1-week memory retention when injected 2 min post-training. Similar enhancement was obtained with intracerebroventricular injection (20 micrograms per mouse). FLU enhanced retention when administered prior to training (1-5 mg/kg). FLU (2.5 mg/kg) enhanced recall scores when injected 1 h before the 1-week retention test, indicating an enhancing effect on memory retrieval. Neither the pre-training nor pre-testing effects depended on improved acquisition, since FLU did not improve acquisition of T-maze foot-shock avoidance over the dose range 0.5-35 mg/kg. The sensitive period for post-training enhancement by FLU (15 mg/kg) was less than 90 min, as shown by the temporal gradient typical of memory-enhancing drugs. The amnesia induced by a protein synthesis inhibitor anisomycin, or by an anticholinergic drug scopolamine, was blocked by FLU (15 mg/kg) injected post-training. Finally, FLU (15 mg/kg) injected after one-trial passive avoidance training enhanced 1-week retention, demonstrating effectiveness in this task as well as in the active avoidance task.
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D001921:Brain / Q000187:drug effects*; D004193:Discrimination Learning / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005473:Fluoxetine / Q000494:pharmacology*; D007276:Injections, Intraventricular; D008297:Male; D008568:Memory / Q000187:drug effects*; D011939:Mental Recall / Q000187:drug effects*; D051379:Mice; D008815:Mice, Inbred Strains; D009949:Orientation / Q000187:drug effects; D011437:Propylamines / Q000494:pharmacology*; D011985:Receptors, Serotonin / Q000187:drug effects; D012153:Retention, Psychology / Q000187:drug effects*
chemical_list: D011437:Propylamines; D011985:Receptors, Serotonin; D005473:Fluoxetine