Figure 2

HDAC3 inhibition re-establishes synaptic tagging and capture.

(A) Schematic representation of a hippocampal slice depicting the location of electrodes in CA1 region for the synaptic tagging and capture experiments. S1 and S2 are two stimulating electrodes positioned in the stratum radiatum to stimulate two independent synaptic inputs to the same neuronal population. The recording electrode is placed midway between S1 and S2 to record fEPSP from the distal apical dendrites. (B) “Weak before strong” paradigm was used to study STC. STET in S2 (filled circles) resulted in a significant potentiation that maintained till the end of recording but the WTET in S1 (open circles) resulted in early-LTP that was not reinforced (n = 6). (C) Inhibition of HDAC3 restored the synaptic tagging and capture. STET in the presence of RGFP966 (10 μM) induced a significant potentiation in S2 (filled circles) and the early-LTP in S1 (open circles) is transformed into a long-lasting LTP (n = 7). (D) RGFP966 (10 μM) applied 30 minutes after the WTET could not reinforce early-LTP to late-LTP. The potentiation was significant till 45 minutes (P < 0.05) but gradually declined to baseline (P > 0.05, n = 7). Single arrow represents the time of induction of eary-LTP by weak tetanization (WTET). All other symbols and traces are similar to Fig. 1 except in 2D, which is similar to Fig. 1G. Scale bars for all the traces vertical: 3mV; horizontal: 5ms. Error bars indicate ± SEM.