Effects of different concentrations of sevoflurane on cognitive function in gerontal rats

Objective To investigate the changes in cognitive function and glutarnatergie N-methyl-D-aspartate receptor-2B subunit (NR2B) expression in hippocarnpus after sevoflurane anesthesia in gerontal rats.Methods Forty 18 month old male SD rats weighing 500-650 g were randomly divided into 3 groups: group control (C n=8);group Ⅱ and Ⅲ inhaled 1.5% and 3.0% sevoflurane for 2 h respectively (S1, S2 n=16each). Y-maze was used to assess the cognitive function at 1 and 7 day after 2 h sovoflurane inhalation respectively (n=8 at each time point). The animals were killed at 12 h after the test and bilateral hippocarnpi were isolated for determination of expression of NR2B mRNA and protein using RT-PCR and immuno-histochemistry respectively. Results 3.0% sevoflurane inhalation induced cognitive decline and increased expression of NR2B mRNA and protein at 1 d in group S2 as compared with group C. There was no significant change in cognitive function after 2 h 1.5 % sevoflurane inhalation. Conclusion Anesthesia with high concentration of sevoflurane can induce cognitive decline in gerontal rats possibly through up-regulation of NMDA receptor expression in hippocampus. Key words: Anesthetics, inhalation; Cognition disorders; Aged; Receptors, N-methy-D-aspartate