ABSTRACT
Objective To compare the effects of propofol and ketamine on long-term memory and the expression of brain N-methylgroup-D-aspartate receptor 2B(NMDAR2B) and Gamma-aminobutyric acid receptor 1(GABAR1) in aged rats, and preliminary investigate the relation between the long-term memory and expression of neurotransmitter receptors in different cerebral areas. Methods The aged male rats were randomly divided into control group,propofol group and ketamine group. Morris water maze training was performed in all the rats of three groups for 5 days. On the 6th day, intraperitoneal injection of 50 mg?mL-1 propofol was administrated in propofol group,80 mg?mL-1 ketamine was intraperitoneally injected in ketamine group,and blank control group was given the same dose of saline.Seven days after the administration,space exploration experiment and navigation experiment test were performed to test the impact on the learning and memory ability of rats. After that, the expression levels of GABAR1 and NMDAR2B in temporal lobe and hippocampal CA1 region of the rat brain were detected by immunofluorescence and FISH technique. Results The results of Morris water maze showed there was no significant difference between propofol group (9.49±1.24) s and blank control group (8.82±2.22) s.There was statistically significant difference between ketamine group (12.04±2.67) s and blank control group (P<0.05),with longer latency time and less number of times of passing through target as compared with blank control group.By using immunohistochemistry and FISH technique,the expression of GABAR1 in temporal lobe and hippocampal CA1 region of the rat brain was not significantly different between propofol group and blank control group,but it was significantly up-regulated in ketamine group as compared with blank control group ( P<0.05) . The expression of NMDAR2B in temporal lobe and hippocampal CA1 region of the rat brain was not significantly different between propofol group and blank control group,but it was significantly down-regulated in ketamine group as compared with blank control group (P<0.05). Conclusion Propofol anesthesia alone had no effect on long-term learning and memory,but ketamine anesthesia can result in long-term learning and memory impairment. The mechanism may be related with down-regulation of the expression of NMDAR2B receptor and up-regulation of GABAR1 not only in CA1 region hippocampus,but also in temporal lobe.