Fig. 5.
Spontaneous locomotor activity and amphetamine-induced locomotor activity in Tbx1 heterozygous (HT) mice. (A) Time course of locomotor activity in Tbx1 HT mice and WT littermates. Data are presented at every 5 min for each 30-min session. Both HT and WT mice showed a daily habituation (F6,150 = 6.14, P < 0.01), but locomotor activity did not differ between the two groups (F1,25 = 1.30, n.s.). Error bars represent ±SEM. WT, n = 14; HT, n = 13. (B) Effects of d-amphetamine on spontaneous locomotor activity in WT littermates (filled bars) and Tbx1 heterozygous mice (open bars). Mice were tested in the open field for 3 days and received acute injections of d-amphetamine (0, 0.5, or 1.0 mg/kg, s.c.) immediately before testing on day 4. Horizontal locomotor activity was recorded for 30 min. Data are presented for each 30-min session. Although the drug significantly increased locomotor activity in a dose-dependent manner (F2,56 = 8.69, P < 0.01), HT and WT mice did not differ (F1,56 = 0.58, n.s.). Asterisks indicate a statistically significant difference from respective vehicle controls at 5% (*) and 1% (**) levels, as determined by Newman-Keuls tests. Error bars represent ±SEM. n = 6-16 mice per group.