Behavioral consequences of diazepam treatment during one- or two-week postnatal developmental temporal windows.

<p><b>a)</b> Schematic showing the schedule of DZP treatment and behavioral testing of the five cohorts of mice analyzed. DZP was administered during P10-16, P14-28, P22-28, P29-35 or P50-56, followed by behavioral testing between 8 and 11 weeks of age or, in the case of P29-35 and P50-56, between 4 and 9 weeks after the end of DZP treatment. <b>b–f)</b> In the EPMT, the percentage of open arm entries of P10-16 DZP- vs. vehicle-treated mice was reduced (b). Similarly, the percentage of open arm entries trended lower in P14-28 DZP-treated vs. vehicle treated mice (c). However, the number of closed arm entries was unaffected for both treatment periods, consistent with unaltered locomotion. By contrast, DZP treatment during P22-28, P29-35 and P50-56 was without long-term behavioral consequences in this test (d-f). <b>g–k)</b> When tested in the FST, the mice treated with DZP during P10-16, P14-28, P22-28 and P50-56 showed normal behavior compared to vehicle treated controls (g-i, k). By contrast, mice treated with DZP during P29-35 showed a reduced latency to immobility and increased immobility duration (j). <b>l)</b> Increased immobility of P29-35 DZP-treated mice observed in the FST was confirmed by increased immobility duration in the TST, although the latency to assume an immobile position was unchanged. <b>m–o)</b> The distance traveled of P10-16, P29-35 and P50-56 DZP-treated mice in a 15 min OFT was unaltered compared to controls, showing that locomotion was unaffected. *p<0.05, **p<0.01, ***p<0.001, t-tests.