Figure 3

Modulation of brain Trp and serotonin metabolism by tdo disruption. (A-F) Trp and serotonin (5-HT) metabolites of the hippocampus (A-C) and midbrain (D-F) in 18- to 20-week-old Tdo^+/+ (+/+) and Tdo^-/- (-/-) mice. Trp (A, D), 5-HT (B, E), and 5-HIAA (C, F) contents in the hippocampus (upper) and midbrain (middle) were determined using an HPLC-FD system (means ± S.E.). *, p < 0.01. **, p < 0.0001. (G) tryptophan hydroxylase (tph2) mRNA levels and enzymatic activity in the adult midbrain of Tdo^+/+ (+/+) and Tdo^-/- (-/-) mice. (left) tph2 mRNA expression in the midbrain. TaqMan RT-PCR analyses were performed using total RNA extracted from the midbrain of 14- to 16-week-old mice. After normalization to gapdh, data were expressed as % fluorescent units relative to those in Tdo^+/+ mice. Data represent means ± S.E. (right) Assay for TPH enzymatic activity. TPH enzyme activity was measured using midbrain homogenates obtained from 15-week-old mice of each genotype. Values represent means ± S.E. N.S., not significant.