Figure 3.

Propranolol prevents the increase in p-ERK signaling observed in basolateral amygdala upon fear memory testing. (A) Total ERK levels did not vary across experimental conditions. Mice trained for tone fear conditioning and injected with saline before the reactivation trial showed an increase in p-ERK levels (B) and a higher p-ERK/total ERK ratio (C) in the basolateral amygdala upon fear memory testing in comparison with saline-injected pseudo-trained mice. Injections of propranolol blocked the increase in p-ERK and p-ERK/total ERK ratio in this region. Data are expressed as mean ± s.e.m. ^*p < 0.05; ^***p < 0.005. (D) Representative immuno-blotting and densitometry of p-ERK, total ERK, and tubulin expression in basolateral amygdala.