A) Paw withdrawal thresholds to mechanical stimuli were measured in conscious animals using the Dynamic Plantar Aesthesiometer 20 min after intraperitoneal administration of dexmedetomidine (DEX, 0.01 to 10 μg/kg, n = 13). Dexmedetomidine significantly increased the withdrawal threshold at doses of 1 μg/kg (*p < 0.05) and 10 μg/kg (**p < 0.01) compared control prior to drug administration (n = 13, one-way ANOVA and Dunnett’s post hoc test).
B) The sedation rating scores were assessed 20 minutes after intraperitoneal dexmedetomidine (DEX, 0.01 to 10 μg/kg, n = 6). Median scores were significantly decreased at 1 μg/kg (*p < 0.05) and 10 μg/kg (**p < 0.01) compared with pre-administration control (Kruskal-Wallis test followed by the Stell-Dwass test) although most of the animals were considered to be still awake or only mildly sedated in this dose range. Only those animals receiving 30 μg/kg showed evidence of moderate to heavy sedation which was a significantly greater degree of sedation than that produced by either 1 or 10 μg/kg (p < 0.05).