Effects of different doses of ketamine on cognitive function in aged rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effects of different doses of ketamine on spatial cognitive function and the expression of mRNA and protein of N-methyl-D-uspartate (NMDA) receptor subunits NR1 and NR2B in the hippocampus of aged rats.Methods Forty SD rats of both sexes aged 15 months weighing 470-570 g were randomly divided into 4 groups (n=10 each) one control group (C) and three ketomine groups (K1 ,K2 ,K3).The animals in group K1 ,K2 and K3 received intraperiteneal(IP) ketaminc 10,20 and 100 mg/kg respectively once a day for 3 days,whereas the animals in control group received IP normal saline instead of ketamine.One day after the last drug administration,the animals underwent Morris water maze test 4 times a day for 3 consecutive days.The animals were killed within 1 h after the last test for determination of the expression of NR1 mRNA and NR2B mRNA (using RT-PCR) and protein (using immuno-histochemistry) in the hippocampus.Results The latency period and swimming distance of water maze test were significantly longer on the 2nd and 3rd days in group K3 than in control group.The NR2B mRNA and protein expression was significantly lower in group K3 than in control group.Conclusion Anesthetic dose of ketamine decreases spatial cognitive function and the expression of NR2B mRNA and protein in aged rats whereas subanesthetic doses of ketamine do not.