5-HT responses to stress are altered in efferent brain regions of CRFR2-null mice. 5-HIAA and 5-HT levels as well as 5-HIAA/5-HT ratios are shown in the (A) subiculum (S), (B) intermediate part of the lateral septum (LSI), (C) medial septum (MS), (D) basolateral amygdala (BLA) and (E) central amygdala (CeA). CRFR2-null mice showed differences in basal levels of 5-HT and or 5-HIAA:5-HT ratio in the S and LSI, and a differential response to stress in the LSI and BLA. Data expressed as mean ± SEM. N = 8 for LCMRglu, ANOVA critical F(1,28) value = 4.196 for P ≤ 0.05, 7.636 for P ≤ 0.01, 13.500 for P ≤ 0.001. N = 6 or 7 for 5-HIAA and 5-HT content, ANOVA critical F(1,22) values = 4.301 for P ≤ 0.05, 7.945 for P ≤ 0.01, 14.380 for P ≤ 0.001. * P < 0.05, ** P < 0.01, *** P < 0.001 in post-hoc analysis.