The animal protocol was approved by Standing Committee on Animals at Massachusetts General Hospital (Boston, Massachusetts). Naïve mice [C57BL/6J mice (The Jackson Laboratory, Bar Harbor, ME)] and AD transgenic mice [B6.Cg-Tg(APPswe, PSEN1dE9)85Dbo/J, (The Jackson Laboratory, Bar Harbor, ME)] were distinguished by genotyping. All animals (3 to 12 mice per experiment) were six days of age at the time of anesthesia and were randomized by weight and gender into experimental groups that received either 3% or 2.1% sevoflurane plus 60% oxygen for either six or two hours, and control groups that received 60% oxygen for six or two hours at identical flow rates in identical anesthetizing chambers. We chose this sevoflurane anesthesia because the recent study by Satomoto et al. 6 (link) indicated that anesthesia with 3% sevoflurane plus 60% oxygen for six hours does not significantly alter blood gas and brain blood flow, which is consistent with our pilot studies. The mortality rate of the mice following the anesthesia with 3% sevoflurane plus 60% oxygen for six hours in the current studies was about 10-15%, which could be due to the higher than clinically relevant concentration of sevoflurane. We used this high concentration of sevoflurane anesthesia to illustrate the difference of sevoflurane-induced neurotoxicity between neonatal naïve and AD transgenic mice. Moreover, we also assessed the effects of anesthesia with 2.1% sevoflurane, a more clinically relevant concentration of sevoflurane (which did not cause the death of the mice), on the effects of caspase-3 activation and Aβ levels in the brain tissues of neonatal mice. Anesthetic and oxygen concentrations were measured continuously (Datex, Tewksbury, MA), and the temperature of the anesthetizing chamber was controlled to maintain the rectal temperature of the mice at 37 ± 0.5°C. In the interaction studies, Inositol triphosphate receptor (IP3R) antagonist 2-aminoethoxydiphenyl borate (2-APB) (5 and 10 mg/kg) was administered to the mice via intraperitoneal injection 10 minutes before the anesthetic was administered. 2-APB was first dissolved in dimethyl sulfoxide to 20 μg/μl, and then diluted with saline to 0.25 μg/μl (1:80 dilution) to 0.5 μg/μl (1:40 dilution).