Effects of sevoflurane on learning, memory, and expression of pERK1/2 in hippocampus in neonatal rats.

Abstract

Sevoflurane may be associated with neural toxicity in the developing brain, but the mechanism is still unclear. Phosphorylated extracellular signal-regulated kinases 1/2 (pERK1/2) are important for developing neurons. The aim of our study was to investigate the effects of sevoflurane on spatial learning and memory and on expression of pERK1/2 in hippocampus of neonatal rats. Sixty-three neonatal rats were randomly divided into three groups: control group, sevoflurane (sevo) group, and sham group. Rats in the control group were placed in a plastic chamber flushed continuously for 4 h with air alone, rats in the sevo group were exposed in 5% sevoflurane and air for 4 h, and rats in the sham group were exposed in 5% carbon dioxide and air for 4 h, with identical flow rates for all groups. All three groups were subjected to Morris water maze test 1 day after sevoflurane exposure. Moreover, expression of pERK1/2 was determined by immunochemistry and Western blot at 1, 3, and 6 weeks after exposure. Compared with the control group, the escape latency was longer in sevo group and the expression of pERK1/2 was significantly inhibited in the sevo group (P < 0.01); no differences between control and sham groups were observed. Our study demonstrated that neonatal rats exposed to sevoflurane had impaired spatial learning and memory, and this may be attributed to decreased pERK1/2 in the hippocampus.