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1.
目的研究大鼠腺苷A1受体(A1R)和腺苷A2A(A2AR)受体的siRNA分别转染大鼠肝星状细胞(HSC)对乙醛诱导的HSC活化增殖的影响。方法采用乙醛诱导HSC-T6建立离体的大鼠酒精性肝纤维化HSC模型,设计并合成A1R和A2AR小干扰RNA(small interfering RNA,siRNA)序列,通过脂质体LipofectamineTM2000瞬时转染至HSC-T6细胞内,荧光倒置显微镜观察细胞的转染效率,用四甲基偶氮唑盐(MTT)法检测HSC-T6细胞增殖变化;利用Real-Time q PCR及Western blot法分别检测HSC-T6的A1R、A2AR、α-SMA、Collagen I mRNA及蛋白表达。结果将A1R和A2AR siRNA转染至HSC-T6细胞内,A1R和A2AR基因及蛋白的表达水平明显降低;同时α-SMA、Collagen I mRNA及蛋白表达水平亦明显降低;靶向封闭A1R或A2AR基因的表达可明显抑制HSC-T6细胞的活化增殖。结论靶向封闭A1R或A2AR基因的表达可明显抑制HSC-T6细胞的活化增殖,A1R和A2AR可能是潜在的酒精性肝纤维化的治疗靶点。  相似文献   

2.
目的:探讨夏枯草总三萜(TTP)对乙醛刺激的大鼠肝星状细胞(HSC)-T6增殖、凋亡的影响及部分作用机制.方法:用不同浓度的TTP(10、30、100、300、1000 μg/mL)对乙醛刺激的HSC-T6进行处理,四甲基偶氮唑蓝(MTF)法检测细胞增殖;流式细胞仪检测细胞凋亡;RT-PCR法检测HSC-T6中平滑肌肌动蛋白(α-SMA)、Ⅰ型前胶原(Procollagen Ⅰ)、TGF-β信号转导通路下游中介分子Smad2、Smad3、Smad7 mRNA表达.结果:TTP可抑制乙醛刺激的大鼠HSC-T6增殖,诱导其凋亡,下调HSC-T6中α-SMA、ProcollagenⅠ、Smad2、Smad3的mRNA表达,上调Smad7的mRNA表达.结论:TTP对乙醛刺激的HSC-T6增殖具有抑制作用,并能够促进其凋亡,下调α-SMA、Procollagen Ⅰ表达量,其机制可能与TTP能抑制Smad2、Smad3表达,升高Smad7的表达,从而对TGF-β/Smad信号通路发挥调控作用有关.  相似文献   

3.
龙翠珍  舒远辉  何萍  王豫萍   《天津医药》2020,48(7):606-610
目的 探究大麻素受体2激动剂AM1241对转化生长因子(TGF)-β1诱导的大鼠肝星状细胞(HSC-T6)增 殖、活化与凋亡的影响及其作用机制。方法 体外培养HSC-T6,采用CCK-8法检测AM1241对空白对照组(空白培 养基)、阴性对照组(未加药品)、TGF-β1 组(5 μg/L TGF-β1)及 20、40、80、160 μmol/L AM1241 组(5 μg/L TGF-β1+ 20、40、80、160 μmol/L AM1241)HSC-T6增殖的影响,计算半数抑制浓度(IC50)。采用流式细胞术检测阴性对照组、 TGF-β1组、30 μmol/L AM1241组、60 μmol/L AM1241组HSC-T6凋亡情况;采用Western blot检测阴性对照组、TGF- β1 组、27 μmol/L AM1241 组 α-平滑肌肌动蛋白(α-SMA)、碱性成纤维细胞生长因子(bFGF)、凋亡相关蛋白 Bax、 cleaved caspase-3、JNK及磷酸化c-Jun氨基末端激酶(p-JNK)蛋白表达水平。结果 与TGF-β1组比较,AM1241可 抑制HSC-T6增殖能力,且呈剂量依赖性(P<0.05)。AM1241的IC50为27 μmol/L。30、60 μmol/L AM1241组HSC-T6 凋亡率较TGF-β1组明显上升,且60 μmol/L AM1241组高于30 μmol/L AM1241组(P<0.05)。27 μmol/L AM1241组 α-SMA 和 bFGF 蛋白表达水平较 TGF-β1 组降低,Bax、cleaved caspase-3、p-JNK 蛋白表达水平较 TGF-β1 组升高 (P<0.05)。结论 大麻素受体2激动剂AM1241能抑制TGF-β1诱导的HSC-T6的增殖与活化,并促进其凋亡,其作 用机制可能与JNK通路有关。  相似文献   

4.
目的探讨瞬时感受器电位离子通道香草素受体亚家族4(transient receptor potential vanilloid receptor 4,TRPV4)对肝星状细胞(hepatic stelate cell,HSC)活化增殖的作用及可能的作用机制。方法以含50%CCl4的花生油溶液(1m L·kg-1)皮下注射,建立大鼠肝纤维化模型。应用蛋白印迹等方法在体观察TRPV4及肌动蛋白α(α-smooth muscle actin,α-SMA)的蛋白表达变化。以转化生长因子-β1(transforming growth factor-β1,TGF-β1)(10μg·L-1)刺激肝星状细胞株(HSC-T6),离体观察TRPV4及α-SMA的蛋白表达变化。应用TRPV4非特异性抑制剂钌红(ruthenium red,Ru)及TRPV4-siRNA特异性沉默TRPV4,观察HSC-T6增殖及α-SMA、蛋白激酶B(protein kinase B,Akt/PKB)蛋白表达变化。结果肝纤维化组织与TGF-β1活化的HSC中TRPV4及α-SMA蛋白表达明显增加。阻断TRPV4可明显抑制HSC增殖,且α-SMA、Akt蛋白表达明显降低。结论 TRPV4参与调控HSC的活化增殖,调控Akt蛋白磷酸化。  相似文献   

5.
目的探讨Zeste基因增强子同源物2(enhancer of zeste homolog 2,EZH2)表达沉默对大鼠肝星状细胞HSC-T6细胞增殖活化的影响,及其部分调控机制。方法应用EZH2的抑制剂DZNep(3-Deazaneplanocin A)作用于TGF-β1诱导活化的HSC-T6细胞,采用Western blot法检测蛋白EZH2、p-ERK、p-AKT和α-SMA的表达;根据EZH2的碱基序列设计并合成小干扰RNA(small interfering RNA,si RNA),通过脂质体LipofectamineTM2000转染到HSC-T6细胞内,应用四甲基偶氮唑盐(MTT)法检测HSC-T6细胞的增殖变化,Western blot法检测蛋白EZH2、p-ERK、p-AKT和α-SMA的表达。结果将DZNep加入TGF-β1诱导活化的HSC-T6细胞后,EZH2蛋白水平明显降低,同时p-ERK、pAKT和α-SMA蛋白水平亦明显降低;将EZH2-si RNA转染活化的HSC-T6细胞内,HSC-T6细胞的增殖可明显被抑制,同时EZH2、p-ERK、p-AKT和α-SMA蛋白水平亦明显降低。结论抑制EZH2的表达可明显抑制HSC-T6细胞的增殖活化,EZH2可能是潜在的治疗肝纤维化的靶点。  相似文献   

6.
目的:通过核因子-κB(NF-κB)抑制剂二硫代氨基甲酸吡咯烷(PDTC),观察NF-κB在转化生长因子(TGF-β1)诱导肺成纤维细胞表达结缔组织生长因子(CTGF)及向肌成纤维细胞(MF)分化中的作用。方法:一次性气管内滴注博莱霉素-A5复制肺纤维化模型,取肺组织培养肺成纤维细胞,细胞分为Sham组、TGF-β1组、PDTC TGF-β1组和PDTC组。采用免疫细胞化学技术、流式细胞术检测PDTC对TGF-β1诱导的成纤维细胞表达α-平滑肌肌动蛋白(α-SMA)和CTGF的影响。结果:TGF-β1组和Sham组比较,肺成纤维细胞表达CTGF和α-SMA明显增加,PDTC TGF-β1组肺成纤维细胞表达CTGF和α-SMA低于TGF-β1组,单独PDTC对肺成纤维细胞无影响。结论:NF-κB促进TGF-β1诱导肺纤维化模型大鼠肺成纤维细胞表达CTGF及肺成纤维细胞向MF分化。  相似文献   

7.
青蒿琥酯抗大鼠免疫性肝纤维化的作用及机制研究   总被引:7,自引:0,他引:7  
目的研究青蒿琥酯抗实验性肝纤维化的作用及其可能机制。方法制备牛血清白蛋白免疫性大鼠肝纤维化模型。动物随机分为6组:正常对照组、模型对照组、Art组(5、15、45 mg.kg-1)、阳性对照Col组(0.1 mg.kg-1)。Masson染色观察肝组织病理变化,Jamall法测定肝组织中羟脯氨酸(Hyp)的含量,RT-PCR技术检测肝组织转化生长因子β1(TGF-β1),α-肌动蛋白(α-SMA)mRNA的表达。体外培养大鼠肝星状细胞株(HSC-T6),用TGF-β1(5μg.L-1)刺激,与Art(终浓度6.25、25、50 mg.L-1)共培养后,检测HSC-T6中Ⅰ型前胶原(procollagenⅠ)mRNA及Ⅰ型胶原(collagenⅠ)蛋白的表达。结果与模型组相比,Art各组能减轻肝组织纤维增生的程度,降低肝组织Hyp含量,使肝组织α-SMA、TGF-β1 mRNA和HSC-T6中procollagenⅠmRNA和collagenⅠ蛋白的表达水平下降。结论 Art有明显的抗肝纤维化作用,其机制可能与抑制HSC活化,降低TGF-β1 mR-NA及collagenⅠ蛋白的表达有关。  相似文献   

8.
酒精对HBV转基因小鼠肝脏的损伤作用及其机制   总被引:4,自引:2,他引:2  
目的探讨在肝损伤早期酒精和HBV协同作用的分子机制。方法20只HBV转基因小鼠和20只普通小鼠随机分为4组:转基因小鼠酒精组(alcohol-fed Tg mice)和普通小鼠酒精组(alcohol-fed Wt mice),以白酒灌胃;转基因小鼠对照组(control Tg mice)和普通小鼠对照组(control Wtmice),以生理盐水灌胃。连续处理10wk后检测各组小鼠血清ALT、AST水平,肝组织转化生长因子-β1(TGF-β1)、Smad3、Smad7、结缔组织生长因子(CTGF)mRNA表达水平及TGF-β1、CTGF、α-平滑肌肌动蛋白(α-SMA)蛋白表达水平。结果酒精可升高转基因小鼠血清ALT、AST水平,诱发其肝脏病理损伤,但纤维化不明显;肝组织TGF-β1、Smad3、Smad7、CTGF mRNA及TGF-β1、CTGF、α-SMA蛋白表达增加。结论酒精和HBV对肝损伤协同作用的机制可能与TGF-β1、Smad3、CTGF、α-SMA表达增加以及TGF-β1/Smads通路信号分子表达比例失调有关。  相似文献   

9.
目的:观察银杏叶提取物(GBE)对转化生长因子-β1(TGF-β1)诱导的人Tenon's囊成纤维细胞(H TCFs)增殖的影响及可能机制.方法:体外培养HTCFs及鉴定;MTT法检测不同浓度的GBE(25、50、100、200 mg/L)对TGF-β1(2 ng/mL)诱导的HTCFs增殖的影响;流式细胞仪检测细胞周期;免疫细胞化学法观察α-平滑肌动蛋白(α-SMA)表达的情况.RT-PCR检测细胞结缔组织生长因子mRNA(CTGF mRNA)的表达.结果:TGF-β1可显著促进HTCFs的增殖,促进细胞由G0/G1期进入S期,上调α-SMA、CTGF在蛋白和mRNA水平的表达;GBE能够抑制TGF-β1的上述作用.结论:GBE具有抑制TGF-β1诱导的人Tenon's囊成纤维细胞增殖的作用,其机制可能是阻止细胞进入S期,下调α-SMA及CTGF的表达.  相似文献   

10.
吲哚-3-原醇对乙醛所致精密肝切片中星状细胞活化的影响   总被引:1,自引:0,他引:1  
目的利用精密肝切片(PCLS)技术,研究吲哚-3-原醇(I3C)对乙醛活化肝星状细胞(HSCs)的作用及其机制。方法将200~800μmol.L-1的I3C及700μmol.L-1乙醛与PCLS共同孵育6h,免疫组化法分析肝切片中α-平滑肌肌动蛋白(α-SMA)表达,并检测培养液中谷胱甘肽S-转移酶(GST)和乳酸脱氢酶(LDH)活性、转化生长因子-β1(TGF-β1)含量、基质金属蛋白酶-1(MMP-1)及基质金属蛋白酶抑制物-1(TIMP-1)表达量及组织丙二醛(MDA)和羟脯氨酸(Hyp)含量。结果200~800μmol.L-1I3C可不同程度的减少乙醛激活的HSCs,并可明显降低乙醛升高的培养液中GST、LDH活性和肝组织中MDA和Hyp含量(P<0.05或P<0.01),呈良好的浓度依赖性。I3C给药组与乙醛对照组比较,培养液中TGF-β1含量降低(P<0.01),MMP-1/TIMP-1蛋白表达比值升高(P<0.01)。结论I3C能有效拮抗乙醛所致的HSCs活化,其机制与降低细胞氧化应激和促进基质胶原降解有关。  相似文献   

11.
The acute motor effects elicited by drugs acting upon adenosine A(2A) receptors, namely the highly selective agonist CGS 21680 or the antagonists SCH 58261 and ZM 241385, were investigated in mice. CGS 21680 dose-dependently (0.1-2.5 mg/kg i.p.) decreased horizontal and vertical motor activities. The depressant effect of CGS 21680 (0. 5 mg/kg i.p.) was maintained in mice pretreated by the adenosine receptor antagonist 8-(p-sulfophenyl)-theophylline (10-30 mg/kg i.p. ), which poorly penetrates the blood-brain barrier, but was completely lost in adenosine A(2A) receptor knockout mice. Thus, the adenosine A(2A) receptor is critically involved in motor activity. SCH 58261 (1-10 mg/kg i.p.) increased locomotion and rearing with a quick onset, but for a shorter period in mice habituated to the environment than in mice unfamiliar to it. ZM 241385 (7.5-60 mg/kg i. p.) stimulated horizontal and vertical activities with a slow onset at the two highest tested doses, similarly in naive and in habituated mice. The increase in locomotion elicited by ZM 241385 (15-30 mg/kg i.p. and 10-20 nM i.c.v.) was retained in mice treated by CGS 21680 (0.5 mg/kg i.p.) but that elicited by SCH 58261 (1-3-10 mg/kg i.p. and 10-20 nM i.c.v.) partially subsided. In conclusion, both 'striatal-like'/'SCH 58261-sensitive' adenosine A(2A) receptors and 'ZM 241385-sensitive'/'atypical' CGS 21680 binding sites may mediate CGS 21680-induced motor effects. Moreover, our results suggest that 'atypical' CGS 21680 binding sites could be adenosine A(2A) receptors with a peculiar pharmacological profile.  相似文献   

12.
Selective A2A agonists (CGS 21680 and DPMA) produce a moderate neuroprotector effect with respect to the complete global cerebral ischemia (GCI). At the same time, selective A2A antagonists 8-(3-chlorostyrylcaffeine (CSC) and ZM 241385 somewhat reduce the brain resistance to complete GCI, completely prevent the neuroprotector effect of CGS 21680, partly suppress the neuroprotector activity of adenosine and 5'-N-ethylcarboxamidoadenosine (NECA), and do not affect (CSC) or potentiate (ZM 241385) the neuroprotector effect of N6-cyclopentyladenosine. The A2A-receptors are probably mediating in the neuroprotector activity of CGS 21680 and participating in the natural brain stability with respect to complete GCI, as well as in the effects of NECA and adenosine.  相似文献   

13.
1. In the present study we investigated the role of A2A adenosine receptors in hippocampal synaptic transmission under in vitro ischaemia-like conditions. 2. The effects of adenosine, of the selective A2A receptor agonist, CGS 21680 (2-[p-(2-carboxyethyl)-phenethylamino]-5'-N-ethylcarboxamidoade nos ine ), and of selective A2A receptor antagonists, ZM 241385 (4-(2-[7-amino-2-(2-furyl)-?1,2,4?-triazolo?2,3-a??1,3, 5?triazin-5-ylamino]ethyl)phenol) and SCH 58261 (7-(2-phenylethyl)-5-amino-2-(2-furyl)-pyrazolo-[4,3-e]-1,2, 4-triazolo[1,5-c]pyrimidine), have been evaluated on the depression of field e.p.s.ps induced by an in vitro ischaemic episode. 3. The application of 2 min of in vitro ischaemia brought about a rapid and reversible depression of field e.p.s.ps, which was completely prevented in the presence of the A1 receptor antagonist DPCPX (1, 3-dipropyl-8-cyclopentylxanthine) (100 nM). On the other hand both A2A receptor antagonists, ZM 241385 and SCH 58261, by themselves did not modify the field e.p.s.ps depression induced by in vitro ischaemia. 4. A prolonged application of either adenosine (100 micronM) or CGS 21680 (30, 100 nM) before the in vitro ischaemic episode, significantly reduced the synaptic depression. These effects were antagonized in the presence of ZM 241385 (100 nM). 5. SCH 58261 (1 and 50 nM) did not antagonize the effect of 30 nM CGS 21680 on the ischaemia-induced depression. 6. These results indicate that in the CA1 area of the hippocampus the stimulation of A2A adenosine receptors attenuates the A1-mediated depression of synaptic transmission induced by in vitro ischaemia.  相似文献   

14.
We have tested the existence of functional A2A adenosine receptor in porcine coronary artery using, for the first time, the new A2A antagonist ZM241385. Nonselective agonist NECA and A2A-selective agonist CGS21680 produced concentration-dependent relaxation of prostaglandin F2alpha (PGF2alpha)-precontracted endothelium intact (E+) and denuded (E-) rings. Relaxation was significantly greater in E+ rings than in E-rings. A2A adenosine receptor-selective antagonist, ZM241385 (10(-6) M), significantly attenuated the relaxation responses. The antagonism of ZM241385 was compared with that of SCH58261 (10(-6)M), another A2A adenosine receptor-selective antagonist, which also significantly attenuated the relaxation response to both agonists. However, ZM241385 produced a significantly greater shift of the relaxation-response curves to the right compared with SCH58261 both in E+ and E- rings. The data show for the first time that ZM241385 is a potent A2A-receptor antagonist in porcine coronary artery and a useful tool to study A2A-receptor function.  相似文献   

15.
目的:研究银杏叶提取物对肝星状细胞增殖及转化生长因子(TCF)-β1、结缔组织生长因子(CTCF) mRNA表达及细胞外基质分泌的影响。方法:用不同浓度(0,1,10,100,500 mg·L-1)的银杏叶提取物处理 HSC-T6 24 h及48 h后,用逆转录聚合酶链反应(RT—PCR)法检测各组细胞及空白对照组中TGF—β1,CTGF mRNA的表达;放射免疫法分析上清液中Ⅲ型前胶原、Ⅳ型胶原、透明质酸和层粘连蛋白的含量;MTT及流式细胞仪检测其对肝星状细胞增殖及细胞周期的影响。结果:银杏叶提取物10,100,500 mg·L-1能明显抑制 TGF-β1和CTGF mRNA的表达,降低上清液中Ⅲ型前胶原、Ⅳ型胶原、透明质酸和层粘连蛋白的含量 (P<0.01或P<0.05),在一定范围内呈随剂量增加及时间的延长,抑制效率增加;并可抑制肝星状细胞的增殖,影响HSC-T6的细胞周期,使细胞周期阻滞于G1期。结论:银杏叶提取物可明显抑制HSC-T6的增殖,降低其细胞因子基因表达及细胞外基质的分泌。  相似文献   

16.
We have investigated the effects of the adenosine A(2A) receptor agonist CGS 21680 (0.01 - 1 microM) on reactive oxidant production by, and elastase release from FMLP-activated human neutrophils, as well as on cytosolic Ca(2+) fluxes and intracellular concentrations of cyclic AMP. Oxidant production, elastase release and cyclic AMP were assayed using lucigenin-enhanced chemiluminescence, colourimetric and radioimmunoassay procedures respectively, while cytosolic Ca(2+) fluxes were measured by fura-2 spectrofluorimetry in combination with radiometric procedures which distinguish between net efflux and influx of the cation. Treatment of neutrophils with CGS 21680 did not affect the FMLP-activated release of Ca(2+) from intracellular stores, but resulted in dose-related acceleration of the rate of decline in fura-2 fluorescence, as well as decreases in both efflux and store-operated influx of Ca(2+), compatible with enhancement of resequestration of the cation by the endo-membrane Ca(2+)-ATPase. These effects on neutrophil Ca(2+) handling were associated with increased intracellular cyclic AMP and with inhibition of oxidant production and release of elastase. In contrast, treatment of neutrophils with the selective A(2A) receptor antagonist, ZM 241385 (2.5 microM), prevented the transient increase in cyclic AMP in FMLP-activated neutrophils which was associated with delayed sequestration of incoming Ca(2+) during store-operated influx. The CGS 21680-mediated reduction of Ca(2+) efflux from FMLP-activated neutrophils was also antagonized by pretreatment of the cells with ZM 241385 (2.5 microM), as well as by thapsigargin (1 microM), an inhibitor of the endo-membrane Ca(2+)-ATPase. ZM 241385 also neutralized the cyclic AMP-elevating and anti-inflammatory interactions of CGS 21680 with neutrophils. We conclude that A(2A) receptors regulate the pro-inflammatory activities of human neutrophils by promoting cyclic AMP-dependent sequestration of cytosolic Ca(2+).  相似文献   

17.
1. We have previously shown that ATP increased cyclic AMP in NG108-15 cells, which was inhibited by P(1) receptor antagonist methylxanthines. In the present study, we examined the effects of P(1) and P2 receptor antagonists on cyclic AMP formation induced by beta,gamma-methyleneATP (beta,gamma-MeATP) and CGS21680, an A(2A) adenosine receptor agonist, in NG108-15 cells. 2. beta,gamma-MeATP and CGS21680 increased intracellular cyclic AMP with EC(50) values of 8. 0+/-0.98 microM (n=4) and 42+/-7.5 nM (n=4), respectively. 3. Several P(1) receptor antagonists inhibited both beta,gamma-MeATP- and CGS21680-induced cyclic AMP increase with a similar rank order of potency; ZM241385>CGS15943>XAC>DPCPX. However, the pK(i) values of these antagonists for beta,gamma-MeATP were larger than those for CGS21680. 4. Alloxazine, a P(1) receptor antagonist, and several P2 receptor antagonists (PPADS, iPPADS, reactive blue-2) inhibited beta, gamma-MeATP-induced response, while these antagonists little affected CGS21680-induced one. Suramin was effective only for beta, gamma-MeATP-induced response at 1 mM. 5. 2-chloroadenosine (2CADO) and 2-chloroATP (2ClATP) increased cyclic AMP with similar potencies. The effects of these agonists were both inhibited by ZM241385, but only 2ClATP-induced response was inhibited by PPADS. 6. ATP- and beta, gamma-MeATP-induced responses were little affected by alpha, beta-methyleneADP, a 5'-nucleotidase inhibitor. 7. These results clearly demonstrate that ATP-stimulated cyclic AMP formation can be distinguished from the A(2A) receptor agonist-induced one by using the several P(1) and P2 receptor antagonists.  相似文献   

18.
In this research the role of adenosine A1 and A2A receptors of the entorhinal cortex on piriform cortex kindled seizures was investigated. In piriform cortex kindled rats, N6-cyclohexyladenosine (CHA), a selective A1 receptor agonist, 1,3-dimethyl-8 cyclopenthylxanthine (CPT), a selective A1 receptor antagonist, CGS21680 hydrochloride (CGS), a selective A2A receptor agonist and ZM241385 (ZM), a selective A2A receptor antagonist were injected into the entorhinal cortex bilaterally. Five minutes later, animals were stimulated and seizure parameters were recorded. CHA (10 and 100microM) decreased the afterdischarge duration (ADD), stage 5 seizure duration (S5D), and seizure duration (SD), and increased the latency to stage 4 of the seizure (S4L) significantly. Bilateral microinjection of CPT (100microM) increased ADD, S(5)D, and SD, and reduced S(4)L significantly. Pretreatment of animals with CPT (50microM) before CHA (100microM), reduced the effect of CHA on seizure parameters. On the other hand, CGS (1mM) increased only ADD. Bilateral microinjection of ZM had no effect on seizure parameters. However, pretreatment of animals with ZM (200microM) before CGS (1mM), eliminated the excitatory effect of CGS on seizure parameters. These results suggest that activation of A1 receptors of the entorhinal cortex has an anticonvulsant, but activation of A2A receptors of this region has a proconvulsive effect on piriform cortex kindled seizures.  相似文献   

19.
The hippocampal GABAergic system is assumed not to be a target for purine modulation. We have now confirmed that neither adenosine A(1) and A(3) receptor nor nucleotide P(2) or P(4) receptor activation modified the K(+)-evoked [(3)H]GABA release from hippocampal synaptosomes. However, activation of adenosine A(2A) receptors with CGS 21680 (10 nM) or HENECA (30 nM) facilitated GABA release by 32% and 21%, respectively. These effects were prevented by the A(2A) antagonist, ZM 241385 (20 nM). A(2A) receptors may activate adenylate cyclase and protein kinase A since CGS 21680 (10 nM) facilitation was partially prevented by 8-bromo-cAMP (1 mM), forskolin (10 microM) and HA-1004 (10 microM). Protein kinase C may also be recruited, since chelerythrine (6 microM) and phorbol-12, 13-didecanoate (250 nM) attenuated CGS 21680 (10 nM) facilitation of [(3)H]GABA release. Omega-agatoxin-IVA (200 nM) occluded CGS 21680 facilitation suggesting the involvement of P-type calcium channels. Thus, the adenosine A(2A) receptor system appears to be one of the first presynaptic neuromodulatory systems able to enhance the evoked release of GABA from hippocampal nerve terminals.  相似文献   

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