Figure 1.

Slow reversal of ketamine effects on PV-interneurons in vivo. C57BL/6 mice (3 month-old males) were treated with ketamine (30 mg/kg i.p.) on 1 or 2 consecutive days as described previously (Behrens et al., 2007). Animals were killed either 24 h after a single injection (1 injection), 24 h after the second injection (2 injections), or 3 and 10 d after withdrawal of the second ketamine injection. Coronal brain sections comprising the prelimbic region were analyzed by fluorescence immunohistochemistry for PV and GAD67, and expressed as percentage of the 1 d saline-treated controls. A slow increase in fluorescence intensity for both proteins is observed at 3 d after the second ketamine injection. *p < 0.05 by two-way ANOVA followed by Tukey's post hoc multiple comparisons. Each time point consisted of five animals treated with saline and five animals treated with ketamine. Data are means ± SD. Mean fluorescence intensity for 1 d of saline: PV = 160.6 ± 13.3; GAD67 = 110.4 ± 8.6.