Objective To evaluate the effects of chronic exposure to sub-anesthetic concentrations of sevoflurane on memory function and homeostasis of mice.Methods Thirty-six healthy male Kunming mice,aged 40 days,weighing 25-30 g,were randomly assigned into 3 groups (n =12 each):control group (group C),0.1％ sevoflurane group (group L) and 0.5 ％ sevoflurane group (group H).The mice inhaled 0.1％ (group L) or 0.5％ sevoflurane (group H) between 18:00-6:00 (the next day) every night for 30 days.Water maze test was performed at 27-30 days of inhalation.Blood samples were collected from the left ventricle for blood gas analysis and for determination of blood electrolytes.Results There was no significant difference in swimming time in Water maze test,number of errors and blood gas analysis and blood electrolytes.Conclusion Chronic exposure to subanesthetic concentrations of sevoflurane has no significant effects on memory function and homeostasis of mice.

Objective To evaluate the role of cholinergic anti-inflammatory pathway in dexmedeto-midine pretreatment-induced reduction of acute lung injury in a rat model of intestinal ischemia-reperfusion ( I∕R) . Methods Twenty-four healthy male Sprague-Dawley rats, aged 2-3 months, weighing 200-250 g, were divided into 4 groups ( n=6) using a random number table method: sham operation group ( S group) , intestinal I∕R group ( II∕R group ) , dexmetomidine group ( DEX group) and α7 nicotinic acetyl-choline receptor antagonistα-bungarotoxin (α-BGT) group (α-BGT group) . Intestinal I∕R was produced by occlusion of the superior mesenteric artery ( SMA) for 60 min followed by 120 min of reperfusion in anesthe-tized rats. Dexmetomidine 5 μg·kg-1 ·h-1 was injected via the tail vein at 1 h before operation in DEX group andα-BGT group. α-BGT 1μg∕kg was intraperitoneally injected at 15 min before dexmetomidine in-jection in α-BGT group. Rats were sacrificed at 120 min of reperfusion, and lung tissues were obtained for microscopic examination of pathological changes ( with a light microscope) and for determination of wet∕dry weight ratio ( W∕D ratio) , tumor necrosis factor-alpha ( TNF-α) and interleukin-6 ( IL-6) contents ( using enzyme-linked immunosorbent assay) , malondialdehyde ( MDA) content ( using thiobarbital acid method) and superoxide dismutase ( SOD) activity ( by xanthine oxidase method) . Results Compared with group S, the W∕D ratio and contents of MDA, TNF-αand IL-6 were significantly increased, and the SOD activi-ty was decreased in II∕R and α-BGT groups, and TNF-α and IL-6 contents were significantly increased in group DEX ( P<0. 05) . Compared with group II∕R, the W∕D ratio and contents of MDA, TNF-αand IL-6 were significantly decreased, SOD activity was increased (P<0. 05), and the pathological changes were significantly attenuated in group DEX. Compared with group DEX, the W∕D ratio and contents of MDA, TNF-α and IL-6 were significantly increased, SOD activity was decreased ( P<0. 05) , and the pathological changes were accentuated in group α-BGT. Conclusion Activation of cholinergic anti-inflammatory path-way is involved in the mechanism by which dexmedetomidine pretreatment reduces acute lung injury in a rat model of intestinal I∕R.