Objective To test the ability of isoflurane-induced preconditioning against oxygen and glucose dep- rivation （OGD） injury in vitro. Methods Rat hippocampal slices were exposed to 1 volume percentage （vol%）, 2vo1%...Objective To test the ability of isoflurane-induced preconditioning against oxygen and glucose dep- rivation （OGD） injury in vitro. Methods Rat hippocampal slices were exposed to 1 volume percentage （vol%）, 2vo1% or 3vo1% isoflurane respectively for 20 minutes under normoxic conditions （95% O2/5% CO2） once or twice （12 slices in each group） before OGD, with 15-minute washout after each exposure. During OGD experiments, hippocampus slices were bathed with artificial cerebrospinal fluid （ACSF） lacking glucose and perfused with 95% N2 and 5% CO2 for 14 minutes, followed by a 30-minute reperfusion in normal ACSF. The CA1 population spike （PS） was measured and used to quantify the degree of neuronal function recovery after OGD. To assess the role of mitogen-activated protein kinases （MAPKs） in isoflurane preconditioning, U0126, an inhibitor of extracellular signal-regulated protein kinase （ERK1/2）, and SB203580, an inhibitor of p38 MAPK, were used before two periods of 3vol% isoflurane exposure. Results The degree of neuronal function recovery of hippocampal slices exposed to 1 vol%, 2vol%, or 3vol% isoflurane once was 41.88%±9.23%, 55.05%±11.02%, or 63.18%±10.82% respectively. Moreover, neuronal function recovery of hippocampal slices exposed to 1 vol%, 2vo1%, or 3vo1% isoflurane twice was 53.75%±12.04%, 63.50%±11.06%, or 76.25%±12.25%, respectively. Isoflurane preconditioning increased the neuronal function recovery in a dose-dependent manner. U0126 blocked the preconditioning induced by dual exposure to 3vo1% isoflurane （6.13%±1.56%, P〈0.01） and ERK1/2 activities. Conclusions Isoflurane is capable of inducing preconditioning in hippocampal slices in vitro in a dose-dependent manner, and dual exposure to isoflurane with a lower concentration is more effective in triggering preconditioning than a single exposure. Isoflurane-induced neuroprotection might be involved with ERK 1/2 activities.展开更多
Ephrin ligands interact with Eph receptors to regulate a wide variety of biological and pathological processes. Recent studies have identified several downstream pathways that mediate the functions of these receptors....Ephrin ligands interact with Eph receptors to regulate a wide variety of biological and pathological processes. Recent studies have identified several downstream pathways that mediate the functions of these receptors. Activation of the receptors by ephrin binding results in the phosphorylation of the receptor tyrosine residues. These phospho- rylated residues serve as docking sites for many of the downstream signaling pathways. However, the relative contributions of different phosphotyrosine residues remain undefined. In the present study, we mutated each individual tyrosine residues in the cytoplasmic domain of EphA3 receptor and studied the effects using cell migration, process retraction, and growth cone collapse assays. Stimulation of the EphA3 receptor with ephrin-A5 inhibits 293A cell mi- gration, reduces NG108-15 cell neurite outgrowth, and induces growth cone collapse in hippocampal neurons. Muta- tion of either Y602 or Y779 alone partially decreases EphA3-induced responses. Full abrogation can only be achieved with mutations of both Y602 and Y779. These observations suggest a collaborative model of different downstream pathways.展开更多
OBJECTIVE: We wished to study the impact of Chaihushugan San(CSS) on the behavior of perimenopausal rats with liver-Qi stagnation(LQS) and to investigate the effect of CSS on signal transduction of the Raf/mitogen-act...OBJECTIVE: We wished to study the impact of Chaihushugan San(CSS) on the behavior of perimenopausal rats with liver-Qi stagnation(LQS) and to investigate the effect of CSS on signal transduction of the Raf/mitogen-activated protein kinase(MEK)/extracellular signal-regulated kinase(ERK) cascade in the hippocampi of rats induced by immobilization.METHODS: Twenty 52-week-old female rats were divided into two groups by the random number table method: model control group(MCG) and CSS group(CSSG), with 10 rats in each group.Ten-week-old female rats were used as the normal control group(NCG). CSS effects were assessed using rats exposed to immobilization stress by measuring body weight and sucrose consumption, serum hormone levels, and observing performance in the open field test(OFT). Molecular mechanisms were examined by measuring the effect of CSS on expression of Raf1, MEK1/2 and ERK1/2 m RNA in hippocampi using quantitative real-time polymerase chain reaction and by measuring levels of these proteins and related phospho-proteins using Western blotting.RESULTS: Perimenopausal rats with LQS had decreased locomotor activity; reduced sucrose consumption; and increased serum levels of corticotropin releasing hormone(CRH) and corticosterone(CORT). Activation of hippocampal Raf/MEK/ERK cascade was suppressed significantly in the MCG,and activation was increased after 21 days of CSS treatment.CONCLUSION: CSS has significant effects upon relief of the symptoms of LQS in immobilization-induced rats. The mechanism underlying this action might(at least in part) be mediated by reversal of disruption of the Raf/MEK/ERK pathway.展开更多
基金Supported by Foundation of Shihezi University of Xinjiang Province (RCZX200688)
文摘Objective To test the ability of isoflurane-induced preconditioning against oxygen and glucose dep- rivation （OGD） injury in vitro. Methods Rat hippocampal slices were exposed to 1 volume percentage （vol%）, 2vo1% or 3vo1% isoflurane respectively for 20 minutes under normoxic conditions （95% O2/5% CO2） once or twice （12 slices in each group） before OGD, with 15-minute washout after each exposure. During OGD experiments, hippocampus slices were bathed with artificial cerebrospinal fluid （ACSF） lacking glucose and perfused with 95% N2 and 5% CO2 for 14 minutes, followed by a 30-minute reperfusion in normal ACSF. The CA1 population spike （PS） was measured and used to quantify the degree of neuronal function recovery after OGD. To assess the role of mitogen-activated protein kinases （MAPKs） in isoflurane preconditioning, U0126, an inhibitor of extracellular signal-regulated protein kinase （ERK1/2）, and SB203580, an inhibitor of p38 MAPK, were used before two periods of 3vol% isoflurane exposure. Results The degree of neuronal function recovery of hippocampal slices exposed to 1 vol%, 2vol%, or 3vol% isoflurane once was 41.88%±9.23%, 55.05%±11.02%, or 63.18%±10.82% respectively. Moreover, neuronal function recovery of hippocampal slices exposed to 1 vol%, 2vo1%, or 3vo1% isoflurane twice was 53.75%±12.04%, 63.50%±11.06%, or 76.25%±12.25%, respectively. Isoflurane preconditioning increased the neuronal function recovery in a dose-dependent manner. U0126 blocked the preconditioning induced by dual exposure to 3vo1% isoflurane （6.13%±1.56%, P〈0.01） and ERK1/2 activities. Conclusions Isoflurane is capable of inducing preconditioning in hippocampal slices in vitro in a dose-dependent manner, and dual exposure to isoflurane with a lower concentration is more effective in triggering preconditioning than a single exposure. Isoflurane-induced neuroprotection might be involved with ERK 1/2 activities.
文摘Ephrin ligands interact with Eph receptors to regulate a wide variety of biological and pathological processes. Recent studies have identified several downstream pathways that mediate the functions of these receptors. Activation of the receptors by ephrin binding results in the phosphorylation of the receptor tyrosine residues. These phospho- rylated residues serve as docking sites for many of the downstream signaling pathways. However, the relative contributions of different phosphotyrosine residues remain undefined. In the present study, we mutated each individual tyrosine residues in the cytoplasmic domain of EphA3 receptor and studied the effects using cell migration, process retraction, and growth cone collapse assays. Stimulation of the EphA3 receptor with ephrin-A5 inhibits 293A cell mi- gration, reduces NG108-15 cell neurite outgrowth, and induces growth cone collapse in hippocampal neurons. Muta- tion of either Y602 or Y779 alone partially decreases EphA3-induced responses. Full abrogation can only be achieved with mutations of both Y602 and Y779. These observations suggest a collaborative model of different downstream pathways.
基金Supported by the National Natural Sciences Foundations of China(Study on the Molecular Mechanism of Formation of Liver-Qi Stagnation in Perimenopausal Syndrome Based on the Neuroendocrine Axis and Ras/Raf/MEK/ERK Pathway,No.81302889Study on the Mechanism of Liver-Qi Stagnation in Perimenopausal Syndrome Based on "Women Easily Qi-Stagnated" and Ca2+/Camp Pathway Mediated by the Estrogen Receptor,No.81173203)
文摘OBJECTIVE: We wished to study the impact of Chaihushugan San(CSS) on the behavior of perimenopausal rats with liver-Qi stagnation(LQS) and to investigate the effect of CSS on signal transduction of the Raf/mitogen-activated protein kinase(MEK)/extracellular signal-regulated kinase(ERK) cascade in the hippocampi of rats induced by immobilization.METHODS: Twenty 52-week-old female rats were divided into two groups by the random number table method: model control group(MCG) and CSS group(CSSG), with 10 rats in each group.Ten-week-old female rats were used as the normal control group(NCG). CSS effects were assessed using rats exposed to immobilization stress by measuring body weight and sucrose consumption, serum hormone levels, and observing performance in the open field test(OFT). Molecular mechanisms were examined by measuring the effect of CSS on expression of Raf1, MEK1/2 and ERK1/2 m RNA in hippocampi using quantitative real-time polymerase chain reaction and by measuring levels of these proteins and related phospho-proteins using Western blotting.RESULTS: Perimenopausal rats with LQS had decreased locomotor activity; reduced sucrose consumption; and increased serum levels of corticotropin releasing hormone(CRH) and corticosterone(CORT). Activation of hippocampal Raf/MEK/ERK cascade was suppressed significantly in the MCG,and activation was increased after 21 days of CSS treatment.CONCLUSION: CSS has significant effects upon relief of the symptoms of LQS in immobilization-induced rats. The mechanism underlying this action might(at least in part) be mediated by reversal of disruption of the Raf/MEK/ERK pathway.
