OBJECTIVETo investigate the effects of gestational isoflurane exposure on postnatal memory and learning and growth-associated protein-43 (GAP-43), neuropeptide Y(NPY) expression in the hippocampus of pups.

METHODSTwelve maternal Sprague-Dawley rats at gestation d 18(E18) were randomly divided into isoflurane group (n=6) and control group (n=6). Rats in isoflurane group were exposed to 1.3 % isoflurane for 6 h. For control group, animals breathed in 30 % oxygen and air mixed gas at the same condition. Spatial learning and memory of the offspring were determined with the Morris Water Maze(MWM) after postnatal 4 weeks. The changes of GAP-43 and NPY expression in the hippocampal CA1 region of the pups were determined by immunohistochemistry.

RESULTSIn MWM training, the escape latency to platform of the pups in isoflurane group was significantly longer, and the time spent in the third quadrant and times of original platform crossing were less than those of control animals (P<0.05). The number and optical density of GAP-43 and NPY positive neurons in the hippocampus of pups decreased significantly in the isoflurane group compared with the controls (P <0.01).

CONCLUSIONIsoflurane exposure in pregnant rats significantly impairs the spatial memory and learning of their pups at a juvenile age, which may be associated with the down-regulation of GAP-43 and NPY in the hippocampus.