Fig. 1. Subcutaneous administration of midazolam significantly decreased mechanical withdrawal thresholds in P3 rats at all doses tested ( A ). Conversely, no significant effects of the drug were seen in P10 rats ( B ). No significant effects of midazolam were observed in older (P21) neonates ( C ). Comparisons of data from the 15-min postinjection time point reveals significant differences between the responses at P3 and the other three ages (Friedman’s test) ( D ). Bars indicate mean ± SE. *** P < 0.001, n = 6–12 in each group.