Increase in aggressive behavior and 5-HT reduction by the 5-HT
synthesis inhibitor pCPA. (A and B)
Aggressive behavior as measured by the resident–intruder test 72
h after 0.9% saline solution (single injection, n
= 5 for each genotype; three daily injections, n =
4 each genotype; group collectively named as saline because no
differences are detected), single dose of 300 mg/kg pCPA (1 ×
300, n = 10 each genotype) or three doses of 300
mg/kg pCPA (72, 48, and 24 h before tests, 3 × 300,
n = 7 each genotype) i.p. injections in WT and
nNOS−/− mice. (C) Locomotor activity in an
open field 74 h after first i.p. injection (n
= 6–10 in each group). *, P < 0.05; †,
P < 0.01 in relation to saline in the same
genotype; and #, P < 0.05; and ##,
P < 0.01 in relation to WT same treatment. Data
are means ± SEM and were analyzed by using two-way ANOVA
(genotype × treatment) with post hoc Tukey test.
(D and E) HPLC determinations of 5-HT (S)
and its metabolite 5-HIAA (M) in the cerebral cortex (Cor),
hypothalamus (Hyp), hippocampus (Hipp), amygdala (Amy), midbrain (Mid),
and cerebellum (Cer) of WT and nNOS−/− mice 75 h
after single i.p. injection of 300 mg/kg pCPA (D) and
3 × 300 mg/kg pCPA (E). Data are percent
decrease from saline group in each genotype (means ± SEM,
n = 5–6 mice each group). *,
P < 0.05; and †, P < 0.01 in
relation to saline in the same genotype. In E, all data
are P < 0.05 or P < 0.01 in
relation to saline controls (two-way ANOVA with post hoc Tukey test).