OBJECTIVE Investigate the effects of diazepam(DZP) on γ2 subunit containing GABA type A receptor(GABA A R) trafficking.METHODS Immunofluorescence microscopy measured surface GABA A Rs and gephyrin in rat cortical neu...OBJECTIVE Investigate the effects of diazepam(DZP) on γ2 subunit containing GABA type A receptor(GABA A R) trafficking.METHODS Immunofluorescence microscopy measured surface GABA A Rs and gephyrin in rat cortical neurons after 24 h exposure of 1.0 μmol·L^(-1) DZP.Biochemical studies of mice injected with 10 mg·kg^(-1) DZP vs vehicle were assessed for γ2 subunit and total gephyrin cortical levels 12 h post-injection.Ubiquitination of the γ2 subunit was studied by immunoprecipitation after 12 h of 1.0 μmol·L^(-1) DZP exposure.A γ2 subunit encoding an N terminal fluorogen-activating peptide and pH-sensitive green fluorescent protein(γ2 pH FAP) measured lysosomal targeting of γ2 containing GABA A Rs.RFP-gephyrin and γ2 pH FAP synaptic diffusion rates were examined using fluorescence recovery after photobleaching(FRAP).RESULTS Extrasynaptic levels of γ2 GABA A Rs decreased by 12.2%,while synaptic gephyrin S270 phosphorylation increased by 18.3% in DZP-treated neurons after 24 h compared to control(P<0.05).Dendritic levels of gephyrin were also reduced to 74.1% of control,while S270 phosphorylation was elevated by 25.2%(P<0.05;P<0.01).Mice 12 h post-DZP injection demonstrated a 12.7% and 26.1% decrease in total γ2 and gephyrin levels,respectively(P<0.05;P<0.01).12 h DZP treatment enhanced γ2 subunit ubiquitination 1.13-fold relative to control(P<0.05).Internalized γ2 pH FAP GABA A Rs associated with lysosomes was 8.0% higher in neurons treated with 12-16 h DZP compared to control.Pilot FRAP experiments suggest gephyrin and γ2 have increased mobility and turnover at synapses following DZP.CONCLUSION DZP treatment decreases γ2 GABA A R levels and gephyrin scaffolding function after one day of exposure,which may contribute to the formation of DZP tolerance.展开更多
This article concentrates on the method of the determination of diazepam and chlorpromazine residue in meat and kidney,by using HPLC-MS/MS.The D6-chlorpromazine was added to sample as an internal standard.Then extract...This article concentrates on the method of the determination of diazepam and chlorpromazine residue in meat and kidney,by using HPLC-MS/MS.The D6-chlorpromazine was added to sample as an internal standard.Then extracted the sample with acetonitrile,cleaned up the extract through Oasis HLB cartridge.Determination and confirmation is made by means of liquid chromatography-tandem mass spectrometry,using internal standard method.The limit of quantitation of chlorpromazine and diazepam are all 1.0 μg/kg.展开更多
本研究建立了高效液相色谱-静电场轨道阱高分辨质谱法(ultra performance liquid chromatography-electrostatic field orbital high resolution mass spectrometry,UPLC-Q Exactive MS),研究了鳊鱼中地西泮的富集及代谢规律。通过开展...本研究建立了高效液相色谱-静电场轨道阱高分辨质谱法(ultra performance liquid chromatography-electrostatic field orbital high resolution mass spectrometry,UPLC-Q Exactive MS),研究了鳊鱼中地西泮的富集及代谢规律。通过开展鳊鱼组织中地西泮的分布情况试验,确定地西泮在鳊鱼体内的传导路径;通过鳊鱼中地西泮代谢规律研究试验,确定鳊鱼体内地西泮的最快检出时间、浓度及代谢规律。由于鳊鱼体内地西泮的代谢周期较长,在实际生产过程中,应尽量避免在水体和鱼内引入地西泮,不定期地对水体和产品进行监测,以保障食用者的安全与健康。展开更多
基金supported by National Institute of Health(T32GM008424)Whitehall Foundation+1 种基金William C DEGROAT Neuropharmacology Departmental FellowshipPharmacology and Chemical Biology Startup Funds
文摘OBJECTIVE Investigate the effects of diazepam(DZP) on γ2 subunit containing GABA type A receptor(GABA A R) trafficking.METHODS Immunofluorescence microscopy measured surface GABA A Rs and gephyrin in rat cortical neurons after 24 h exposure of 1.0 μmol·L^(-1) DZP.Biochemical studies of mice injected with 10 mg·kg^(-1) DZP vs vehicle were assessed for γ2 subunit and total gephyrin cortical levels 12 h post-injection.Ubiquitination of the γ2 subunit was studied by immunoprecipitation after 12 h of 1.0 μmol·L^(-1) DZP exposure.A γ2 subunit encoding an N terminal fluorogen-activating peptide and pH-sensitive green fluorescent protein(γ2 pH FAP) measured lysosomal targeting of γ2 containing GABA A Rs.RFP-gephyrin and γ2 pH FAP synaptic diffusion rates were examined using fluorescence recovery after photobleaching(FRAP).RESULTS Extrasynaptic levels of γ2 GABA A Rs decreased by 12.2%,while synaptic gephyrin S270 phosphorylation increased by 18.3% in DZP-treated neurons after 24 h compared to control(P<0.05).Dendritic levels of gephyrin were also reduced to 74.1% of control,while S270 phosphorylation was elevated by 25.2%(P<0.05;P<0.01).Mice 12 h post-DZP injection demonstrated a 12.7% and 26.1% decrease in total γ2 and gephyrin levels,respectively(P<0.05;P<0.01).12 h DZP treatment enhanced γ2 subunit ubiquitination 1.13-fold relative to control(P<0.05).Internalized γ2 pH FAP GABA A Rs associated with lysosomes was 8.0% higher in neurons treated with 12-16 h DZP compared to control.Pilot FRAP experiments suggest gephyrin and γ2 have increased mobility and turnover at synapses following DZP.CONCLUSION DZP treatment decreases γ2 GABA A R levels and gephyrin scaffolding function after one day of exposure,which may contribute to the formation of DZP tolerance.
文摘This article concentrates on the method of the determination of diazepam and chlorpromazine residue in meat and kidney,by using HPLC-MS/MS.The D6-chlorpromazine was added to sample as an internal standard.Then extracted the sample with acetonitrile,cleaned up the extract through Oasis HLB cartridge.Determination and confirmation is made by means of liquid chromatography-tandem mass spectrometry,using internal standard method.The limit of quantitation of chlorpromazine and diazepam are all 1.0 μg/kg.
文摘本研究建立了高效液相色谱-静电场轨道阱高分辨质谱法(ultra performance liquid chromatography-electrostatic field orbital high resolution mass spectrometry,UPLC-Q Exactive MS),研究了鳊鱼中地西泮的富集及代谢规律。通过开展鳊鱼组织中地西泮的分布情况试验,确定地西泮在鳊鱼体内的传导路径;通过鳊鱼中地西泮代谢规律研究试验,确定鳊鱼体内地西泮的最快检出时间、浓度及代谢规律。由于鳊鱼体内地西泮的代谢周期较长,在实际生产过程中,应尽量避免在水体和鱼内引入地西泮,不定期地对水体和产品进行监测,以保障食用者的安全与健康。
