Figure 3
From: Histamine N-methyltransferase regulates aggression and the sleep-wake cycle
Increased aggression in Hnmt-deficient mice is driven by H2R activation. (A) Images of wild type (WT, left) and knockout (KO, right) mice in their home cages. Most KO mice had skin injures. (B) Ratios of wounded mice (n = 26–28). (C) Intensity of biting behaviours on the aggressive response meter (n = 8) (Student’s t-test, *p < 0.05). (D) Serum testosterone concentrations (pg/mL). (E) The number of attacks over 5 min in the resident-intruder test with histamine receptor antagonist pretreatment. White bar, saline; red bar, 10 mg/kg pyrilamine (H1R antagonist); blue bar, 10 mg/kg zolantidine (H2R antagonist) (two-way ANOVA with Bonferroni correction; *p < 0.05; n.s.: not significant).
