Ketamine exposure can lead to selective neuroapoptosis in the developing brain.p66ShcA,the cellular adapter protein expressed selectively in immature neurons,is a known pro-apoptotic molecule that triggers neuroapopto...Ketamine exposure can lead to selective neuroapoptosis in the developing brain.p66ShcA,the cellular adapter protein expressed selectively in immature neurons,is a known pro-apoptotic molecule that triggers neuroapoptosis when activated.Sprague-Dawley rats at postnatal day 7 were subcutaneously injected in the neck with ketamine 20 mg/kg,six times at 2-hour intervals.At 0,1,3,and 6 hours after final injection,western blot assay was used to detect the expression of cleaved caspase-3,p66ShcA,and phosphorylated p66ShcA.We found that the expression of activated p66ShcA and caspase-3 increased after ketamine exposure and peaked at 3 hours.The same procedure was performed on a different group of rats.At the age of 4 weeks,spatial learning and memory abilities were tested with the Morris water maze.Latency to find the hidden platform for these rats was longer than it was for control rats,although the residence time in the target quadrant was similar.These findings indicate that ketamine exposure resulted in p66ShcA being activated in the course of an apoptotic cascade during the neonatal period.This may have contributed to the deficit in spatial learning and memory that persisted into adulthood.The experimental protocol was approved by the Institutional Animal Care and Use Committee at the University of Texas at Arlington,USA (approval No.A13.008) on January 22,2013.展开更多
The aim was to investigate how the PI3K/Akt pathway is involved in the protection of dexmedetomidine against propofol. The hippocampal neurons from fetal rats were separated and cultured in a neurobasal medium. Cell v...The aim was to investigate how the PI3K/Akt pathway is involved in the protection of dexmedetomidine against propofol. The hippocampal neurons from fetal rats were separated and cultured in a neurobasal medium. Cell viability was assayed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay. Then neurons were pretreated with different concentrations of dexmedetomidine before 100 μmol/L propofol was added. Akt, phospho-Akt(p-Akt), Bad, phospho-Bad(p-Bad), and Bcl-x L were detected by Western blot. Also, neurons were pretreated with dexmedetomidine alone or given the inhibitor LY294002 before dexmedetomidine pretreatment, and then propofol was added for 3h. The results demonstrated that propofol decreased the cell viability and the expression of p-Akt and p-Bad proteins, increased the level of Bad, and reduced the ratio of Bcl-x L/Bad. Dexmedetomidine pretreatment could reverse these effects. The enhancement of p-Akt and p-Bad induced by dexmedetomidine was prevented by LY294002. These results showed that dexmedetomidine potently protected the developing neuron and this protection may be partly mediated by the PI3K/Akt pathway.展开更多
基金supported by the National Natural Science Foundation of China,No.81200851(to DL)the National Institutes of Health of the USA,No.NS 040723(to QL)
文摘Ketamine exposure can lead to selective neuroapoptosis in the developing brain.p66ShcA,the cellular adapter protein expressed selectively in immature neurons,is a known pro-apoptotic molecule that triggers neuroapoptosis when activated.Sprague-Dawley rats at postnatal day 7 were subcutaneously injected in the neck with ketamine 20 mg/kg,six times at 2-hour intervals.At 0,1,3,and 6 hours after final injection,western blot assay was used to detect the expression of cleaved caspase-3,p66ShcA,and phosphorylated p66ShcA.We found that the expression of activated p66ShcA and caspase-3 increased after ketamine exposure and peaked at 3 hours.The same procedure was performed on a different group of rats.At the age of 4 weeks,spatial learning and memory abilities were tested with the Morris water maze.Latency to find the hidden platform for these rats was longer than it was for control rats,although the residence time in the target quadrant was similar.These findings indicate that ketamine exposure resulted in p66ShcA being activated in the course of an apoptotic cascade during the neonatal period.This may have contributed to the deficit in spatial learning and memory that persisted into adulthood.The experimental protocol was approved by the Institutional Animal Care and Use Committee at the University of Texas at Arlington,USA (approval No.A13.008) on January 22,2013.
基金supported by the Medical and Health Technology Development Program in Shandong Province(No.2015WSA13033)the National Natural Science Foundation of China(No.81301114)
文摘The aim was to investigate how the PI3K/Akt pathway is involved in the protection of dexmedetomidine against propofol. The hippocampal neurons from fetal rats were separated and cultured in a neurobasal medium. Cell viability was assayed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay. Then neurons were pretreated with different concentrations of dexmedetomidine before 100 μmol/L propofol was added. Akt, phospho-Akt(p-Akt), Bad, phospho-Bad(p-Bad), and Bcl-x L were detected by Western blot. Also, neurons were pretreated with dexmedetomidine alone or given the inhibitor LY294002 before dexmedetomidine pretreatment, and then propofol was added for 3h. The results demonstrated that propofol decreased the cell viability and the expression of p-Akt and p-Bad proteins, increased the level of Bad, and reduced the ratio of Bcl-x L/Bad. Dexmedetomidine pretreatment could reverse these effects. The enhancement of p-Akt and p-Bad induced by dexmedetomidine was prevented by LY294002. These results showed that dexmedetomidine potently protected the developing neuron and this protection may be partly mediated by the PI3K/Akt pathway.
