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Objective To investigate the effects of different concentration and inhalation duration time of isoflurane on cognitive performance and the expression of GABAR1 and NMDAR2B in aged SD rat cerebral temporal lopes.Methods Aged male SD rats (9 months) were randomly divided into control group (n=10) and test group (n=80).The control group received air at room tempreture.Test groups were divided into four groups: group S1 (1.5%-2 h),group S2 (2.5%-2 h),group S3 (1.5%-4 h),group S4 (2.5%-4 h)according to isoflurane concentration and inhalation duration time.Every group was equally divided into two groups and Morris water maze test was performed day 1 and day 7 after isoflurane inhalation.Then the right temporal lobe was gathered and the mRNA transcription and protein expression of GABAR1 and NMDAR2B were detected by RT-PCR and Immunofluorescence technique.Results One day after isoflurane inhalation, accompanied with increased isoflurane concentration and inhalation duration, the spatial memory ability of every test group decreased continually, and the mRNA transcription and protein expression of GABAR1 increased and the mRNA transcription and protein expression of NMDAR2B decreased compared with control group (P<0.01).Seven days after isoflurane inhalation, the spatial memory ability of group S4 decreased, the mRNA transcription and protein expression of both GABAR1 increased, the mRNA transcription and protein expression of NMDAR2B decreased compared with control group and the other test groups (P<0.01).There was no significant difference between the control group and groups S1, S2, S3.Conclusion Continuous inhalation of isoflurane has great effects on spatial memory ability.And impaired spatial memory by isoflurane inhalation of high concentration with long duration is present in a long time.Thoses are related with the mRNA transcription and protein expressions of GABAR1 and NMDAR2B in cerebral temporal lope.
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Objective To observe the changes of learning and memory ability and the expression of GRP8,ATF4 and CHOP in the frontal lobe neurons of rats after isoflurane anesthesia.Methods Male SD aged rats were randomly divided into 4 groups with 15 in each group.Rats in ISO group received 1.5% isoflurane 2 h,SAL group received intraperitoneal injection Salubrinal(1 mg/kg),ISO+SAL group received 1.5% 2 h after intraperitoneal injection Salubrinal(1 mg/kg),C group only inhaled 30% air and oxygen mixture.Morris water maze (MWM) test was performed 24 hours after isoflurane anesthesia,and then the left frontal lobe of rats was collected,gene transcription and protein expression changes of 78-kDa glucose-regulated protein(GRP78),activating transcription factor 4(ATF4),C/EBP homologous protein(CHOP) were evaluated by real-time fluorescence quantitative PCR and immunofluorescence.Results Compared with the C group,the latent time of ISO group was significantly prolonged(ISO group(19.10±2.98)s vs C group (10.54±2.05)s,P<0.05);the number of times passing through the target platform of ISO group was decreased significantly(ISO group (6.78±1.47) vs Cgroup (9.03±1.69),P<0.05);protein expression level of GRP78 was significantly increased in group ISO (ISO group (965.8±86.5) vs C group(247.5±46.3),P<0.05);protein expression level of ATF4 was significantly increased in group ISO(ISO group (470±69.4) vs C group (275.4±56.3),P<0.05) protein expression level of CHOP was significantly increased in group ISO(ISO group (618.7±83.3) vs C group(174.5±71.2),P<0.05).The transcription trends of GRP78,ATF4,CHOP were consistent with their protein expression.Conclusion The decrease of short-term memory ability after isoflurane anesthesia may be related to the activation of endoplasmic reticulum stress pathway in frontal lobe neurons.