Gap junction blocking agents can inhibit spontaneous discharge frequency in cells. We established a rat model of posttraumatic epilepsy induced using ferric ions. Rats were intraperitoneally injected with carbenoxolon...Gap junction blocking agents can inhibit spontaneous discharge frequency in cells. We established a rat model of posttraumatic epilepsy induced using ferric ions. Rats were intraperitoneally injected with carbenoxolone, 20 mg/kg, prior to and 30 minutes after model establishment, once a day for 14 consecutive days. Immunohistochemistry showed glial cell proliferation around a cortical focus and significantly increased connexin expression in posttraumatic epilepsy. However, carbenoxolone pretreatment or treatment significantly reduced connexin expression in the cortex, inhibited glial fibdllary acidic protein expression and ameliorated seizure degree in rats. These findings indicate that large amounts of glial cell proliferation and abnormal gap junction generation play a role in posttraumatic epilepsy, and that carbenoxolone may prevent and treat this disease.展开更多
Pectin is a biopolymer that has numerous useful purposes in food and beverage industry, cosmetic products and pharmaceutical fields. One of the important properties of pectin is its bioadhesive properties. Native pect...Pectin is a biopolymer that has numerous useful purposes in food and beverage industry, cosmetic products and pharmaceutical fields. One of the important properties of pectin is its bioadhesive properties. Native pectin provides fair bioadhesive properties that can be improved by modification of pectin structure. The immobilization of thiol groups on polymer can significantly improve the bioadhesive properties due to in situ cross-linking between thiol groups of polymer and mucin [1].展开更多
Objective To investigate whether hypertonic saline （HS） can induce the synthesis and release of glutamate in cultured hypothalamic astrocytes or C6 cell line. Methods Astrocytes were isolated, cultured, purified and...Objective To investigate whether hypertonic saline （HS） can induce the synthesis and release of glutamate in cultured hypothalamic astrocytes or C6 cell line. Methods Astrocytes were isolated, cultured, purified and identified from the hypothalamus of newborn rat （1 day）. The astrocytes were randomly divided into five groups： isotonic （IS） and HS groups, astrocytes were incubated by IS and HS （320 mosM NaCl） medium, respectively, for 1, 3, 5, 10 or 15 rain; carbenoxolone （CBX） ＋IS and CBX＋HS groups, astrocytes were pre-treated with CBX （100 mmol/L） for 1 h at 37℃ in a 5% CO2 / 95% atmosphere, then removed to IS and HS medium, respectively, for 1, 3, 5, 10 or 15 min; Ca2＋＋HS group, astrocytes were pre-incubated with Ca2＋ （1 000 μmol/L） for 1 h at 37℃ in a 5% CO2 / 95% atmosphere, followed by a wash with isotonic FBS/DMEM, and then removed to hypertonic saline for 1, 3, 5, 10 or 15 min. The media of five groups were collected to analyze the medium glutamate concentration with high performance liquid chromatography. The astrocytes were fixed and double immunofluorescent stained with anti-glial fibrillary acidic protein （GFAP） and anti-glutamate. The C6 cells were divided into four groups： IS, HS, CBX＋IS and CBX＋HS groups, and used for quantitative measurement of glutamate in cells by flow cytometry （FCM）. Results （1） Anti-GFAP immunofluorescent signal revealed no significant difference among various time points in each group, or among the five groups. （2） The anti-glutamate immunofluorescent signal was increased in HS group and peaked at 5 min, and decreased and returned to the level of IS group at 15 rain （P 〈 0.01 vs the 5 min of HS group）. In CBX＋HS group, the glutamate intensity was higher than that in CBX＋IS and HS groups. （3） The medium glutamate concentration had no change after treatment with HS for 1 and 3 min, while increased markedly after treatment for 5 min to 15 min （P 〈 0.01 vs 1 min and 3 min）. On the contrary, the medium glutamate concentrations in the CBX＋HS or Ca2＋＋HS group were significant lower than that in the HS group （P 〈 0.01）. （4） FCM showed HS and CBX＋HS induced glutamate increase in C6 cells. Conclusion HS induced cultured rat hypothalamic astrocytes or C6 cells to synthesize and release glutamate; CBX could block glutamate release, but could not disrupt glutamate synthesis.展开更多
Neuronal oscillations in the hippocampus are critical for many brain functions including learning and memory.The underlying mechanism of oscillation generation has been extensively investigated in terms of chemical sy...Neuronal oscillations in the hippocampus are critical for many brain functions including learning and memory.The underlying mechanism of oscillation generation has been extensively investigated in terms of chemical synapses and ion channels.Recently,electrical synapses have also been indicated to play important roles,as reported in various brain areas in vivo and in brain slices.However,this issue remains to be further clarified,including in hippocampal networks.Here,using the completely isolated hippocampus,we investigated in vitro the effect of electrical synapses on slow CA1 oscillations(0.5 Hz-1.5 Hz)generated intrinsically by the hippocampus.We found that these oscillations were totally abolished by bath application of a general blocker of gap junctions(carbenoxolone)or a specific blocker of electrical synapses(mefloquine),as determined by whole-cell recordings in both CA1 pyramidal cells and fast-spiking cells.Our findings indicate that electrical synapses are required for the hippocampal generation of slow CA1 oscillations.展开更多
基金supported by the Social Development Program of Nantong, No. S2009035
文摘Gap junction blocking agents can inhibit spontaneous discharge frequency in cells. We established a rat model of posttraumatic epilepsy induced using ferric ions. Rats were intraperitoneally injected with carbenoxolone, 20 mg/kg, prior to and 30 minutes after model establishment, once a day for 14 consecutive days. Immunohistochemistry showed glial cell proliferation around a cortical focus and significantly increased connexin expression in posttraumatic epilepsy. However, carbenoxolone pretreatment or treatment significantly reduced connexin expression in the cortex, inhibited glial fibdllary acidic protein expression and ameliorated seizure degree in rats. These findings indicate that large amounts of glial cell proliferation and abnormal gap junction generation play a role in posttraumatic epilepsy, and that carbenoxolone may prevent and treat this disease.
文摘Pectin is a biopolymer that has numerous useful purposes in food and beverage industry, cosmetic products and pharmaceutical fields. One of the important properties of pectin is its bioadhesive properties. Native pectin provides fair bioadhesive properties that can be improved by modification of pectin structure. The immobilization of thiol groups on polymer can significantly improve the bioadhesive properties due to in situ cross-linking between thiol groups of polymer and mucin [1].
基金supported by the National Nature Science Foundation of China(No.39770251)the Medical Foundation of the People's Liberation Army,China(No.01Z082,06MA234)the Foundation of the Fourth Military Medical University(No.05ZXJM001)
文摘Objective To investigate whether hypertonic saline （HS） can induce the synthesis and release of glutamate in cultured hypothalamic astrocytes or C6 cell line. Methods Astrocytes were isolated, cultured, purified and identified from the hypothalamus of newborn rat （1 day）. The astrocytes were randomly divided into five groups： isotonic （IS） and HS groups, astrocytes were incubated by IS and HS （320 mosM NaCl） medium, respectively, for 1, 3, 5, 10 or 15 rain; carbenoxolone （CBX） ＋IS and CBX＋HS groups, astrocytes were pre-treated with CBX （100 mmol/L） for 1 h at 37℃ in a 5% CO2 / 95% atmosphere, then removed to IS and HS medium, respectively, for 1, 3, 5, 10 or 15 min; Ca2＋＋HS group, astrocytes were pre-incubated with Ca2＋ （1 000 μmol/L） for 1 h at 37℃ in a 5% CO2 / 95% atmosphere, followed by a wash with isotonic FBS/DMEM, and then removed to hypertonic saline for 1, 3, 5, 10 or 15 min. The media of five groups were collected to analyze the medium glutamate concentration with high performance liquid chromatography. The astrocytes were fixed and double immunofluorescent stained with anti-glial fibrillary acidic protein （GFAP） and anti-glutamate. The C6 cells were divided into four groups： IS, HS, CBX＋IS and CBX＋HS groups, and used for quantitative measurement of glutamate in cells by flow cytometry （FCM）. Results （1） Anti-GFAP immunofluorescent signal revealed no significant difference among various time points in each group, or among the five groups. （2） The anti-glutamate immunofluorescent signal was increased in HS group and peaked at 5 min, and decreased and returned to the level of IS group at 15 rain （P 〈 0.01 vs the 5 min of HS group）. In CBX＋HS group, the glutamate intensity was higher than that in CBX＋IS and HS groups. （3） The medium glutamate concentration had no change after treatment with HS for 1 and 3 min, while increased markedly after treatment for 5 min to 15 min （P 〈 0.01 vs 1 min and 3 min）. On the contrary, the medium glutamate concentrations in the CBX＋HS or Ca2＋＋HS group were significant lower than that in the HS group （P 〈 0.01）. （4） FCM showed HS and CBX＋HS induced glutamate increase in C6 cells. Conclusion HS induced cultured rat hypothalamic astrocytes or C6 cells to synthesize and release glutamate; CBX could block glutamate release, but could not disrupt glutamate synthesis.
基金This work was supported by grants from the National Natural Science Foundation of China(3147107,91132711,30970960)a Key Project of Shanghai Science and Technology Commission(15JC1400102,19ZR1416600).
文摘Neuronal oscillations in the hippocampus are critical for many brain functions including learning and memory.The underlying mechanism of oscillation generation has been extensively investigated in terms of chemical synapses and ion channels.Recently,electrical synapses have also been indicated to play important roles,as reported in various brain areas in vivo and in brain slices.However,this issue remains to be further clarified,including in hippocampal networks.Here,using the completely isolated hippocampus,we investigated in vitro the effect of electrical synapses on slow CA1 oscillations(0.5 Hz-1.5 Hz)generated intrinsically by the hippocampus.We found that these oscillations were totally abolished by bath application of a general blocker of gap junctions(carbenoxolone)or a specific blocker of electrical synapses(mefloquine),as determined by whole-cell recordings in both CA1 pyramidal cells and fast-spiking cells.Our findings indicate that electrical synapses are required for the hippocampal generation of slow CA1 oscillations.
