Effect Of REM Sleep Deprivation And FK506 Intervention On Spatial Memory And Hippocampal Calcineurin In Rats

PARTâ… Effect of REM Sleep Deprivation and Recovery on Spatial Memory and Hippocampal Calcineurin in RatsObjective: To investigate effects of different durations of rapid eye movement (REM) sleep deprivation and recovery on spatial memory, hippocampal calcineurin(CaN) enzyme activity and its expression in rats. To discuss the connection between cognition disorder and hippocampal calcineurin activity changes caused by REM sleep deprivation. To reveal the effect of sleep recovery on cognition.Methods: Adult male Sprague-Dawley rats were randomly divided into cage control group (CC), tank contral group (TC), REM sleep deprivation group (SD) and sleep recovery group (SR). Each group were divided into three duration groups: 1d, 3d and 5d. SD group was divided into 1d group(SD1), 3d group (SD3) and 5d group (SD5).SR group was divided into SR1 (1d REM sleep deprivation followed by 6h sleep recovery), SR3 (3d REM sleep deprivation followed by 18h sleep recovery) and SR5 (5d REM sleep deprivation followed by 30h sleep recovery). All the rats were trained for spatial learning in Morris water maze place navigation test for 5 days. Then the rats were deprived of REM sleep for different durations by the modified multiple platform method (MMPM). Morris water maze spatial probe test was performed to test spatial memory of rats after sleep deprivation. Colorimetric method was used to test hippocampal CaN enzyme activity. Hippocampal CaN quantity was analyzed by Western-blot. Results: 1. There were no significant differences among latency and swimming path length of all the groups during spatial learning (p>0.05). 2. Time in goal quadrant of spatial probe test: There was no significant difference between CC and TC (p>0.05). CC1, TC1, SD1 and SR1 were not significantly different (p>0.05). SD3 and SD5 were significantly lower than CC and TC (p<0.01). SR3 was not different from CC3, TC3 and SD3 (p>0.05). SR5 was significantly lower than CC5 (p<0.01) and TC5 (p<0.05) while it was not different from SD5 (p>0.05). SD1 was significantly higher than SD3 (p<0.05) and SD5 (p<0.01). 3. Hippocampal CaN enzyme activity: There was no significant difference between CC and TC (p>0.05). CC1, TC1, SD1 and SR1 were not significantly different (p>0.05). SD3 was significantly higher than CC3, TC3 and SR3 (p<0.01). SR3 was not different from CC3 and TC3 (p>0.05). SD5 and SR5 were significantly higher than CC5 and TC5 (p<0.01) but they are not different from each other (p>0.05). SD3 and SD5 were significantly higher than SD1 (p<0.01). 4. Hippocampal CaN quantity: There were no differences among all the groups (p>0.05).Conclusion: One-day REM sleep deprivation did not significantly affect spatial memory, hippocampal CaN activity or quantity. As the rats were deprived of REM sleep for more time, their spatial memory declined with the increase of hippocampal CaN activity while there were no changes in hippocampal CaN quantity. Sleep recovery following 3 days of REM sleep deprivation improved spatial memory and lowered hippocampal CaN activity in rats. But sleep recovery following 5 days of REM sleep deprivation did not have the effect. There may be a connection between hippocampal CaN activity rise and spatial memory deficits after REM sleep deprivation.PARTâ…¡Effect of REM Sleep Deprivation and FK506 Intervention on Spatial Memory and Hippocampal Calcineurin in RatsObjective: To investigate effects of different durations of rapid eye movement (REM) sleep deprivation plus calcineurin (CaN) inhibitor FK506 intervention on spatial memory, hippocampal CaN enzyme activity and quantity in rats. To discuss the role of CaN in cognition deficits caused by REM sleep deprivation. To reveal the possible mechanism of FK506 intervention.Methods: Adult male Sprague-Dawley rats were randomly divided into cage control group (CC), tank contral group (TC), REM sleep deprivation group (SD), sleep recovery group(SR), high dose (10mg/kg, intraperitoneal injection) FK506 intervention group (FH), low dose (1mg.kg, ip.) FK506 intervention group (FL), vehicle control group (SV) and Rapamycin control group (RA). Each group was divided into three duration groups: 1d, 3d and 5d. CC for 1d was divided into normal control group(CC), normal plus high dose FK506 group (CFH), normal plus low dose FK506 group (CFL), normal plus vehicle group (CV). SD group was divided into 1d group(SD1), 3d group (SD3) and 5d group (SD5).SR group was divided into SR1 (1d REM sleep deprivation followed by 6h sleep recovery), SR3 (3d REM sleep deprivation followed by 18h sleep recovery) and SR5 (5d REM sleep deprivation followed by 30h sleep recovery). All the rats were trained for spatial learning in Morris water maze place navigation test for 5 days. Then the rats were deprived of REM sleep for different durations by the modified multiple platform method (MMPM) while FK506, Rapamycin or vehicle was injected intraperitoneally every day. Morris water maze spatial probe test was performed to test spatial memory of rats after sleep deprivation. Colorimetric method was used to test hippocampal CaN enzyme activity. Hippocampal CaN quantity was analyzed by Western-blot.Results: 1. There were no significant differences among latency and swimming path length of all the groups during spatial learning (p>0.05). 2. There were no significant differences in spatial memory, hippocampal CaN activity and quantity among CC, CFH, CFL and CV(p>0.05). 3. Time in goal quadrant of spatial probe test: There was no significant difference between CC and TC (p>0.05). All the 1d groups were not significantly different from one another (p>0.05). There were no significant differences among CC3, TC3, FH3, FL3 and SR3 (p>0.05). No significant differences were seen among SR3, SD3, SV3 and RA3 (p>0.05). SD3, SV3 and RA3 were significantly lower than CC3, TC3 (p<0.01) and FH3 (p<0.05). FL3 was significantly higher than SD3 and SV3 (p<0.05) while it was not different from RA3 (p>0.05). No significant differences were seen among CC5, TC5, FH5 and among SD5, SR5, FL5, SV5, RA5 (p>0.05). SD5, SV5 and RA5 were significantly lower than CC5, TC5 (p<0.01) and FH5 (p<0.05). SR5 and FL5 were significantly lower than CC5 (p<0.01) and TC5 (p<0.05) while they were not different from FH5 (p>0.05). 4. Hippocampal CaN enzyme activity: There was no significant difference between CC and TC (p>0.05). All the 1d groups were not significantly different from one another (p>0.05). There were no differences among CC3, TC3, FL3 and SR3 (p>0.05). SD3, SV3 and RA3 were significantly higher than CC3, TC3, FH3, FL3 and SR3 (p<0.01) while they were not different from one another (p>0.05). FH3 was significantly lower than SR3 (p<0.01) but was not different from FL3 (p>0.05). No significant differences were seen among CC5, TC5, FH5 and among SD5, SV5, RA5, SR5, FL5 (p>0.05). SD5, SV5, RA5, SR5 and FL5 were significantly higher than CC5 and TC5 (p<0.01). FH5 was significantly lower than SD5, SV5 (p<0.01), RA5 and SR5 (p<0.05) while it was not different from FL5 (p>0.05). 5. Hippocampal CaN quantity: There were no differences among all the groups (p>0.05).Conclusion: FK506 intervention did not significantly affect spatial memory, hippocampal CaN activity or quantity in normal rats or rats deprived of 1d REM sleep. As the rats were deprived of REM sleep for more time, FK506 intervention improved their spatial memory and decreased hippocampal CaN activity leaving CaN quantity unchanged. Two kinds of dose were both effective when rats were deprived of REM sleep for 3 days while only the high dose was effective when the deprivation duration prolonged for another 2 days. FK506 may improve spatial memory of REM sleep deprived rats by decreasing hippocampal CaN activity.PARTâ…¢Effect of REM Sleep Deprivation and Sleep Recovery on Hippocampal Striatal Enriched Protein Tyrosine Phosphatase and Extracellular Signal-Regulated Kinase in Rats and FK506 Intervention EffectObjective: To investigate effects of different durations of rapid eye movement (REM) sleep deprivation and sleep recovery on hippocampal striatal enriched protein tyrosine phosphatase (STEP) and extracellular signal-regulated kinase (ERK) phosphorylation level and quantity in rats. To investigate the effect of FK506 intervention on these indices. To discuss the mechanism of cognition deficits caused by REM sleep deprivation and hippocampal CaN activity rise. To reveal the more detailed mechanism of FK506 intervention.Methods: Adult male Sprague-Dawley rats were randomly divided into cage control group (CC), tank contral group (TC), REM sleep deprivation group (SD), sleep recovery group(SR), high dose (10mg/kg, intraperitoneal injection) FK506 intervention group (FH), vehicle control group (SV) and Rapamycin control group (RA). Each group was divided into three duration groups: 3d and 5d. SD group was divided into 3d group (SD3) and 5d group (SD5). SR group was divided into SR3 (3d REM sleep deprivation followed by 18h sleep recovery) and SR5 (5d REM sleep deprivation followed by 30h sleep recovery). Rats were deprived of REM sleep for different durations by the modified multiple platform method (MMPM) while FK506, Rapamycin or vehicle was injected intraperitoneally every day. After certain duration of REM sleep deprivation or sleep recovery, hippocampal STEP and ERK2 phosphorylation level and quantity were analyzed by Western-blot.Results: 1. Hippocampus STEP phosphorylation level: There were no significant differences among CC, TC and FH (p>0.05). SD3, SV3 and RA3 were significantly lower than CC3, TC3, SR3 and FH3 (p<0.01) while they were not different from one another (p>0.05). SR3 was significantly lower than CC3 (p<0.01) and FH3 (p<0.05) and was not different from TC3 (p>0.05). SD5, SV5, RA5 and SR5 were significantly lower than CC5, TC5 and FH5 (p<0.01) while they were not different from one another (p>0.05). 2. There were no significant differences in hippocampal total ERK2 quantity among all the groups (p>0.05). 3. Hippocampus ERK2 phosphorylation level: There were no significant differences among CC, TC and FH (p>0.05) and among SD, SV, RA (p>0.05). SD, SV and RA were significantly lower than CC, TC and FH (p<0.01). SR3 was significantly higher than SD3, SV3 and RA3 (p<0.01) while it was not different from FH3 (p>0.05). SR5 was significantly higher than SD5, SV5 (p<0.01) and RA5 (p<0.05) while it was lower than CC5, TC5 (p<0.01) and FH5 (p<0.05).Conclusion: REM sleep deprivation elevated hippocampal STEP activity and decreasd hippocampal ERK2 activity by lowering their phosphorylation level, but had no effect on hippocampal total ERK2 quantity. FK506 intervention and sleep recovery after 3d REM sleep deprivation both decreased hippocampal STEP activity and elevated ERK2 activity. FK506 may improve spatial memory of REM sleep deprived rats by modulating hippocampal STEP and ERK2 activity.