Figure 3.

Anxiety and stress response. No genotype differences were observed in basic anxiety tests, such as (A) the light dark test (LDT) and (B) the elevated plus maze (EPM). (C) Increased aversive environment in the novelty suppressed feeding (NSF) test induced anxiety-like behavior in TPH2-CB1^−/− mice. Although no genotype differences were observed in the time required for the first contact, mutants showed a delayed time to start eating. (D) While the frequency of interactions with the food pellet was not altered, a significant increase in the percentage of time spent digging was observed. (E) Mutants displayed a decreased floating behavior in the forced swim test (FST) as compared with control littermates. (F) No genotype differences were observed in plasma corticosterone concentrations, neither in basal conditions (non-stressed) nor 5 min after the FST (stressed). Risk asses = risk assessment; LC = lit compartment; n_[EPM+LD] = 41 WT + 49 KO; n_[NSF] = 32 WT + 33 KO; n_[FST] = 20 WT + 22 KO; *p < 0.05.