共查询到20条相似文献,搜索用时 62 毫秒
1.
实验用Fluo-3负载细胞,在激光扫描共聚焦显微镜下直接监测缺氧后分散培养的大鼠海马CA1区神经元内游离Ca^2+浓度([Ca^2+]i)的变化,观察腺苷对这种变化的影响并初步探讨其作用机制。结果发现,急性缺氧使海马神经元[Ca^2+]i显著升高;腺苷(100μmol/L)明显抑制缺氧引起的[Ca^2+]i增高,腺苷A1受体拮抗剂CPT以及K^+通道阻断剂4-AP和ATP敏感性K^+通道阻断剂gl 相似文献
2.
使用Ca ̄(2+)敏感的荧光指示剂Fura-2/AM,对培养的心肌细胞测定细胞内Ca ̄(2+)的瞬间变化。结果为,在一个心搏周期中,经过大约180ms的时间,[Ca ̄(2+)]_i瞬间变化达到最大值,然后恢复到基线水平(最小值),经历了260ms。测得平均[Ca ̄(2+)]_i瞬间变化的最大值及最小值分别为346±38nmol/L和102±18nmol/L。血管紧张素Ⅱ100nmol/L引起[Ca ̄(2+)]_i瞬间变化最大值明显增加,但对[Ca ̄(2+)]_i瞬间变化的基线水平没有明显的影响。ryanodine3μmol/L使[Ca ̄(2+)]_i瞬间变化的幅度明显降低。KCl50mmol/L使[Ca ̄(2+)]_i瞬间变化完全停止,并明显增加[ca ̄(2+)]_i的基线水平。结果提示,本实验模型可用来观察[Ca ̄(2+)]_i的瞬间变化。 相似文献
3.
SNP抑制5-HT诱导的胞内游离钙浓度升高和内钙释放 总被引:2,自引:0,他引:2
用Fura - 2/AM 荧光测量技术研究了5 - 羟色胺(5- HT) 诱导的大鼠尾动脉平滑肌细胞胞内钙升高和一氧化氮(NO) 的抑制效应。实验表明, 胞外0m mol/ L Ca2 + 时胞内静息[Ca2 + ] i 为20 .2±8 .6nmol/L(n = 8) 。10μmol/L 5- HT 可诱导出胞内钙库释放引起的瞬态[Ca2 +]i 升高,其峰值达245 .7 ±71.6nmol/ L(n = 6) 。10 - 7 mol/L 硝普钠(SNP) 可抑制5- HT 诱导的[Ca2 +]i 升高,其峰值浓度降为75.1±35 .9nmol/L(n = 5) 。当细胞浴液含2.5m mol/L Ca2 + 时,静息[Ca2 +]i为112 .8 ±10 .3nmol/ L(n = 5) , 这时10μmol/ L 5 - HT 可诱导[Ca2 + ] i 的峰值为252 .3 ±80 .6nmol/L(n = 4) ,以及其后平台浓度为143 .0 ±37 .6nmol/L(n = 4) ,略大于[Ca2 +]i 为112.8 ±10 .3nmol/L 的静息浓度,为外钙内流引起。10 - 7 mol/L SNP 也可抑制5- HT 诱导[Ca2 + ]i 平台相浓度。平台浓度由143 ±47 相似文献
4.
缺氧时大鼠红细胞变形性损伤的机制研究 总被引:5,自引:0,他引:5
本实验通过测定平原和模拟高原减压缺氧30天大鼠红细胞滤过指数(IF)、红细胞内[pH]i、[K+]i/[Na+]i比值、[Ca2+]i、[Mg2+]i、平均红细胞体积(MCV)及平均红细胞血红蛋白浓度(MCHC),从而探讨缺氧条件下大鼠红细胞变形性损害的机制。结果发现:1.缺氧组大鼠红细胞[Ca2+]i明显升高,且与IF呈显著正相关,但[Mg2+]i无明显差异;2.缺氧组[K+]i/[Na+]i值较平原组明显降低,且与IF呈显著负相关;3.缺氧组MCHC与平原组无明显差异,但MCV显著升高;4.缺氧组红细胞内[pH]i较平原组明显升高。提示:缺氧时红细胞[Ca2+]i升高,[K+]i/[Na+]i值降低,MCV增大以及红细胞[pH]i值的改变在其变形性损伤中起重要作用。 相似文献
5.
氨对脑细胞胞浆游离钙含量的影响 总被引:3,自引:0,他引:3
李夏青 《中国应用生理学杂志》2000,16(2):114-116
目的与方法:采用Fura-2/AM探针技术观察NH4Cl对离体急性分离之Wistar乳鼠大脑细胞胞头游离钙「Ca^2+」i含量的影响。结果:NH4^+浓度为2.5mmol/L时脑细胞内「Ca^2+」i含量升高。在一定范围内,随着NH4^+浓度的加大,细胞内Ca^2+持续升高。NH4^+的升钙作用主要被Nicardipine所阴断,其变化特征类以KCl。结论:NH4^+主要通过影响电压依赖性钙离子通 相似文献
6.
糖皮质激素对肝细胞内游离钙的作用 总被引:2,自引:0,他引:2
应用钙离子荧光指示剂fura-2,对糖皮质激素(Glucocorticoid,GC)是否影响肝细胞内游离钙(Intracellualar free calcium,[Ca^2+]i作了初步探讨,结果发现,GC在短期内能升高肝细胞[Ca^2+]水入1.0μmol/L的Cortiso0.25min即可引起肝细胞[Ca^2+]的明显升高,到10分钟时效应达高峰。此时与静息状态的肝细胞水平相比胞浆内游离钙 相似文献
7.
为测定植物细胞质内[Ca^2+]i,对胡萝卜(Daucuscartavar.sativaDC.)原生质体制备介质做了改进,并在正常生理条件,用温和的、非损伤性的方法将Ca^2+荧光指示剂indo-1K^+和fura-2K^+地入该原生体,能很好地标记细胞质的游离Ca^2+。 相似文献
8.
在原代培养的大鼠肾上腺嗜铬细胞上,综合运用细胞内钙测定法和全细胞膜片钳法,以检测膜电容变化为手段测定单一肾上腺嗜铬细胞的胞吐过程。-70mV到+20mV去极化引起的钙电流和细胞膜电容的变化以及吹加60mmol/LKCl时,细胞内游离钙离子浓度[Ca2+]i和细胞膜电容变化的同时检测,表明了Ca2+对细胞胞吐的控制作用。而用微碳纤电极则能检测到吹加60mmol/LKCl导致嗜铬细胞胞吐时儿茶酚胺的量子化释放。细胞膜电容检测和微碳纤电极检测从不同侧面动态的反映了细胞胞吐过程与Ca2+的相关性 相似文献
9.
应用钙离子荧光指示剂fura-2,对糖皮质激素(Glucocorticoid,GC)是否影响肝细胞内游离钙(Intracellular free calcium,[Ca2+]i作了初步探讨。结果发现,GC在短期内能升高肝细胞[Ca2+]i,水平,并具有明显的量效关系。以1.0μmol/L的Cortisol和10.0μmol/L的Dexamethasone效果最好。加入1.0μmol/L的Cortisol0.25min即可引起肝细胞[Ca2+]i的明显升高,到10分钟时效应达高峰。此时与静息状态的肝细胞[Ca2+]i水平相比,胞浆内游离钙升高了近3倍;与相应对照组比较,胞浆内游离钙升高具有明显的统计学意义,P<0.01。RU486为一种人工合成的糖皮质激素受体(Glucocorticoid receptor,GR)的拮抗剂,它可以取消GC升高肝细胞[Ca2+]i的效应,提示GC升高肝细胞内[Ca2+]i可能与GR介导有一定关系。鉴于GC升高[Ca2+]i时间较短,推测与肝细胞膜GR的非基因快速调节作用影响钙离子通道有关。 相似文献
10.
降钙素基因相关肽对缺氧时海马细胞内游离Ca^2+的影响 总被引:21,自引:0,他引:21
本实验用Fura-2荧光测定技术直接监测了缺氧时大鼠海马细胞内游离Ca2+浓度([Ca2+]i)的变化,并观察了降钙素基因相关肽(CGRP)对这种变化的影响。结果发现,缺氧可使海马细胞[Ca2+]i显著增高;4或8nmol/LCGRP能明显地降低缺氧引起的[Ca2+]i增高,但在无胞外Ca2+的情况下,CGRP的作用消失。结果表明,CGRP的降钙作用是通过抑制缺氧时胞外Ca2+的内流来实现的。 相似文献
11.
12.
《Autophagy》2013,9(5):856-857
CISD2, an ER BCL2-associated autophagy regulator also known as NAF-1, is responsible for the human degenerative disorder Wolfram Syndrome 2. In order to interrogate the physiological role of CISD2 we generated and characterized the Cisd2 gene deletion in mice. Cisd2 null mice manifest significant degeneration in skeletal muscle tissues, which is accompanied with augmented autophagy, dysregulated Ca2+ homeostasis and elongated mitochondria. Our findings describe a novel role for BCL2-CISD2 in the homeostatic maintenance of skeletal muscle. It remains to be elucidated how and if the antagonism of the BECN1 autophagy-initiating complex and modulation of ER Ca2+ homeostasis by BCL2-CISD2 are interconnected. 相似文献
13.
A.P. Tulloch 《Chemistry and physics of lipids》1979,25(3):225-235
Deuterated oleates have been synthesized by semihydrogenation of acetylenic intermediates. [11-2H2]Oleate was prepared by two-carbon chain extension of the C16 alcohol obtained from [1-2H2]octyl bromide and 7-octyn-1-ol. [8-2H2] and [7-2H2]oleates were both prepared from dimethyl suberate, tetradeutero intermediate C16 alcohols were synthesized from [1,8-2H4] and [2,7-2H4]octane diols by monobromination, conversion to deuterated 9-decyn-1-ols and reaction with octyl bromide. Oxidation gave [8-2H2]-9-octadecynoate and [2,7-2H2]-9-octadecynoate, after semihydrogenation of the latter, deuterons at C-2 were removed by exchange with aqueous alkali. [6-2H2] and [5-2H2]oleates were obtained from methyl 5-tetradecynoate, semihydrogenation, deuterium exchange at C-2 and two malonate extensions gave [6-2H2]oleate; reduction with lithium aluminum deuteride, two malonate extensions and semihydrogenation gave the [5-2H2] ester. [4-2H2] and [3-2H2]oleates were both obtained from methyl 7-cis-hexadecenoate, exchange of the α protons and chain extension gave the [4-2H2] ester and reduction with lithium aluminum deuteride and chain extension gave the [3-2H2] ester. 相似文献
14.
We present procedures for nucleoside and oligonucleotide synthesis, binding affinity (Tm) and structural analysis (CD spectra) of 2'-deoxy-2',2'-difluoro-alpha-D-ribofuranosyl and 2'-deoxy-2',2'-difluoro-beta-D-ribofuranosyl oligothymidylates. Possible reasons for the thermal instability of duplexes formed between these compounds and RNA or DNA targets are discussed. 相似文献
15.
16.
17.
R J Suhadolnik S Pornbanlualap D C Baker K N Tiwari A K Hebbler 《Archives of biochemistry and biophysics》1989,270(1):374-382
2'-Amino-2'-deoxyadenosine and 2'-chloro-2'-deoxycoformycin (2'-CldCF) are two nucleoside antibiotics produced by Actinomadura. The biosynthesis of these two nucleoside antibiotics has been studied by the addition of [U-14C]adenosine with or without unlabeled adenine to cultures of Actinomadura. By this experimental approach, it is possible to demonstrate that adenosine is the direct precursor for the biosynthesis of 2'-amino-2'-deoxyadenosine and 2'-CldCF. These conclusions are based on the observation that the percentage distribution of 14C in the aglyconic and pentofuranosyl moieties of 2'-amino-2'-deoxyadenosine and 2'-CldCF were similar to the distribution of 14C in the adenine and ribosyl moieties of the [U-14C]adenosine (i.e., 48:52) added to cultures of Actinomadura. Experimentally, the percentage distribution of 14C in the (i) adenine:2-amino-2-deoxy-beta-D-ribofuranose of 2'-amino-2'-deoxyadenosine is 51:49; (ii) 8-(R)-3,6,7,8-tetrahydroimidazo[4,5-d]-[1,3-diazepin-8-o1]:2 -chloro-2- beta-D-ribofuranose of 2'-CldCF is 45:55; and (iii) adenine:ribose of the adenosine isolated from the RNA of Actinomadura is 42:58. Further proof that adenosine is the direct precursor for the biosynthesis 2'-amino-2'-deoxyadenosine and 2'-CldCF was demonstrated by the addition of 75 mumol of unlabeled adenine together with [U-14C]adenosine to nucleoside-producing cultures of Actinomadura. The percentage distribution of 14C in the aglycon and the sugar moieties of 2'-amino-2'-deoxyadenosine and 2'-CldCF were 46:54 and 47:53, respectively; the percentage distribution of 14C in the adenine and ribose moieties of the adenosine isolated from the RNA of Actinomadura was 51:49. These data show that the hydroxyl on C-2' of the ribosyl moiety of adenosine undergoes a replacement by a 2'-amino or a 2'-chloro group to form 2'-amino-2'-deoxyadenosine or 2'-CldCF with retention of stereconfiguration at C-2'. Finally, Actinomadura can utilize inorganic chloride from the medium as demonstrated by the isolation of [36Cl]2'-CldCF following the addition of [36Cl]chloride to the culture medium. Mechanisms for the regioselective modification of the C-2' hydroxyl group and stereospecific insertion of the amino and chloro groups are discussed. 相似文献
18.
4-nitrophenyl 3,4,6-tri-O-acetyl-2-azido-2-deoxy-alpha- and beta-D-mannopyranosides were prepared from methyl 4,6-O-benzylidene-alpha-D-glucopyranoside and 1,3,4,6-tetra-O-acetyl-alpha-D-glucopyranose, respectively. Chemoselective reduction of both azides with hydrogen sulfide readily afforded 4-nitrophenyl 2-acetamido-4,6-di-O-acetyl-2-deoxy-alpha-D- and -beta-D-mannopyranosides in higher yields than reduction with triphenylphosphine or a polymer-supported triarylphosphine. Subsequent de-O-acetylation yielded 4-nitrophenyl 2-acetamido-2-deoxy-alpha-D-mannopyranoside and 4-nitrophenyl 2-acetamido-2-deoxy-beta-D-mannopyranoside in 20% and 44% overall yields, respectively. 相似文献
20.
An overview of structurally characterized alpha-hydroxycarboxylatodioxo- and alpha-hydroxycarboxylatooxoperoxovanadates(V) is presented and the geometric parameters of the V2O2 bridging core are discussed. The first case of a stereospecific formation of oxoperoxovanadates(V) is reported: The crystal structures of the isomeric compounds (NBu4)2[V2O2(O2)2(L-lact)2] x 2H2O and (NBu4)2[V2O2(O2)2(D-lact)(L-lact)] x 2H2O (lact = C3H4O3(2-), the anion of the lactic acid) differ mainly in the arrangement of the V2O2 core and in mutual orientation of the V=O bonds. The complexes with achiral ligands adopt the same structural type as the complexes formed from a racemic mixture of a chiral ligand, while the structure obtained using an enantiopure L,L-hydroxycarboxylate is different. 相似文献