Fig. 2. Analysis of the levels of sedation induced by subcutaneous administration of midazolam (10 mg/kg; 15 min postinjection) revealed a lack of sedative effect in the youngest (P3) group of animals. In older P10 and P21 rats, significant differences were seen between midazolam- and saline-treated animals. Comparisons among age groups illustrated significant differences in the sedative action of midazolam between P3 and both the P10 and P21 groups. Bars indicate mean ± SE. ***  P < 0.001, n = 6–12 in each group.