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. 2013 Jan 21;8(1):e54463. doi: 10.1371/journal.pone.0054463

Figure 2. Garcinol impairs retrieval-related acetylation of histone H3 in the LA and fear memory reconsolidation.

Figure 2

(a) Schematic of the behavioral protocol. Rats were fear conditioned with three tone-shock pairings. Twenty four hrs following training rats were given a memory reactivation session consisting of a single tone CS presentation followed 1 hr later by intra-LA infusions of vehicle (n = 8) or garcinol (500 ng/side; n = 7). All rats were sacrificed 30 min following infusion. A third group did not receive conditioning or retrieval testing and was infused with vehicle prior to sacrifice (n = 7). Separate groups of rats were fear conditioned followed 24 hr later by a memory reactivation session consisting of a single tone CS presentation followed 1 hr later by intra-LA infusion of vehicle (n = 9) or garcinol (500 ng/side; n = 8). Two additional groups of rats were given a ‘no-reactivation’ session followed by infusion of vehicle (n = 7) or garcinol (500 ng/side; n = 5). All rats were then tested for PR-STM and PR-LTM 3 and 21 hrs later, respectively. (b) Cannula placements for rats infused with either vehicle (black circles) or garcinol (gray circles). (c) Memory retrieval data for the Reactivated (R)-Garcinol and R-Vehicle groups used in the Western blotting experiments. *p<0.05 relative to the pre-CS period. (d) Western blot analysis of acetylated and total histone H3 from LA homogenates taken from Naïve (N)-vehicle, R-Vehicle and R-Garcinol groups. * p<0.05 relative to R-Vehicle and N-Vehicle groups. Representative Western blots are depicted in the inset. (e) Memory retrieval data for the Reactivated (R)-Garcinol and R-Vehicle groups in the behavioral experiments. *p<0.05 relative to the pre-CS period. (f) Mean (± SEM) percent freezing during the PR-STM and PR-LTM tests in R-Vehicle and R-Garcinol groups. A third group is depicted that received infusion of either vehicle (n = 9) or garcinol (n = 6) 6 hrs following retrieval (‘delayed infusion’) followed by a PR-LTM test 21 hrs later. *p<0.05 relative to vehicle-infused controls. (g) Memory retrieval data for the Non-reactivated (NR)-Garcinol and NR-Vehicle groups. (h) Mean (± SEM) percent freezing during the ‘PR’-STM and ‘PR’-LTM tests in NR-Vehicle and NR-Garcinol groups.