LATERAL VENTRICLE INJECTION OF THE PROTEIN-SYNTHESIS INHIBITOR ANISOMYCIN IMPAIRS LONG-TERM-MEMORY IN A SPATIAL MEMORY TASK

Although protein synthesis inhibition has been shown to affect long-te rm memory in a wide variety of animal species, cases have been reporte d in which protein synthesis inhibition failed to affect memory consol idation [S. Wittstock, R. Menzel, Color learning and memory in honey b ees are not affected by protein synthesis inhibition, Behav. Neural Bi ol., 62 (1994) 224-229.]. Most findings argue that the critical time f or protein synthesis is during or immediately after training. However, other reports show a second time window, hours after training, where protein synthesis inhibition can cause amnesia [F.M. Freeman, S.P.R, R ose, A.B. Scholey, Two time windows of anisomycin-induced amnesia for passive avoidance training in the day-old chick, Neurobiol. Learn.Mem. , 63 (1995) 291-295.][G. Grecksch, H. Matthies, Two sensitive periods for the amnesic effect of anisomycin, Pharmacol. Biochem. Behav., 12 ( 1980) 663-665.]. In this study, we addressed two questions: (1) Is pro tein synthesis essential for spatial memory? and (2) At what injection time window(s) will protein synthesis inhibition cause spatial memory amnesia? We report that bilateral intraventricular microinjection of anisomycin (Ani) impairs consolidation of long-term memory, in the hip pocampal-dependent Morris water maze spatial memory task. Memory was i mpaired in a dose-dependent manner without affecting short-term memory . Spatial memory was affected only if Ani was injected 20 min before p erforming the task and not in any other time window before or after th e behavioral test. The inhibition did not affect pre-existing memories or the capability to memorize once the effect of the inhibition dimin ished. (C) 1998 Elsevier Science B.V.