Figure 4.

Fear memory does not modify p-ERK signaling in the dorsal hippocampus. Mice trained for tone fear conditioning and injected with saline before the reactivation trial did not show any significant difference in total ERK levels (A), p-ERK levels (B) and in p-ERK/total ERK ratio (C) in the CA1 dorsal hippocampus upon fear memory testing in comparison with pseudo-trained mice. Pre-reactivation injections of propranolol did not modify p-ERK, total ERK, and the p-ERK/total ERK ratio in this region. Data are expressed as mean ± s.e.m. (D) Representative immuno-blotting and densitometry of p-ERK, total ERK, and tubulin expression in CA1 dorsal hippocampus.