Fig. 5.

Mean (± SE) blood oxygen saturation (%) in Sprague Dawley rats (n=6/age group; 3, 6, 12, and 18 months old) following an intraperitoneal administration of 80 mg/kg of ketamine and 10 mg/kg xylazine. The SaO₂ was evaluated with a pulse oximeter at tentatively selected time points (5, 15, 30, 45, 60, 90, and 120 min), with evaluation ending when all animals had a positive withdrawal reflex. A significant difference (post hoc Dunnett’s test*) between groups was seen only at 5 min between 3- (P<0.002) and 6-month-old (P<0.02) animals compared with 12-month-old animals.