Acute exposure to isoflurane is documented to cause cognitive and behavioral impairment in both animals and human studies. Occupational exposure to trace concentrations of isoflurane occurs in operating rooms, recovery rooms, dental operatories and veterinary facilities. The purpose of this experimental work is to determine if chronic exposure to trace concentrations of isoflurane can result in effects resembling those of acute exposure in anesthetic concentrations or not. Methods: 56 male albino mice were divided into 4 groups (14 mice each). Control group (G1) received 3 L/min 100% O2 8 h daily for 8 weeks, then exposed to behavioral study (Morris water maze, T maze, open field and rotarod ) immediately 8 weeks after exposure and after another 8 weeks in an ordinary environment. Isoflurane groups (G2, G3, and G4), received 32ppm, 16ppm and 8ppm in 100% O2 8 h a daily for 8 weeks and then exposed to behavioral study as control group.
Results: Chronic exposure to trace isoflurane resulted in long-term/reference memory impairment and impairment in non-spatial working memory in a dose dependant manner. While anxiety and exploratory activity did not affect also motor learning and coordination did not affect. These effects were the same after 8 weeks in an ordinary environment. 
Conclusion: Chronic exposure to trace concentrations of isoflurane could affect some behaviors while leaving others intact. This provides an evidence of drawback effect of isoflurane on some brain functions in trace concentrations found in the operating rooms.



10 / Behavioral Effects of Chronic Exposure to Trace Concentrations of Isoflurane in Mice