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本研究在离体大鼠肠系膜血管床灌流模型上,采用特异放免法测定灌流液中的降钙素基因相关肽(CGRP),观察几种常见炎症介质在内毒素引起CGRP释放中的作用。结果显示:前列腺素合成酶抑制剂地塞米松、布洛芬与消炎痛,缓激肽受体B2拮抗剂HOE140,血小板激活因子拮抗剂WEB2086,组胺H1受体拮抗剂苯海拉明以及和组胺H2受体拮抗剂西咪替丁,均能明显抑剂制内毒素引起的CGRP释放,5羟色胺受体拮抗剂ICS205930却无明显作用。从而提示:内毒素引起CGRP释放是通过炎症介质前列腺素、缓激肽、血小板激活因子和组胺介导的,阻断或减少炎症介质的产生可望减轻内毒素血症时CGRP的过量释放。 相似文献
2.
Intermolecular failure of L-type Ca2+ channel and ryanodine receptor signaling in hypertrophy
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Xu M Zhou P Xu SM Liu Y Feng X Bai SH Bai Y Hao XM Han Q Zhang Y Wang SQ 《PLoS biology》2007,5(2):e21
Pressure overload–induced hypertrophy is a key step leading to heart failure. The Ca2+-induced Ca2+ release (CICR) process that governs cardiac contractility is defective in hypertrophy/heart failure, but the molecular mechanisms remain elusive. To examine the intermolecular aspects of CICR during hypertrophy, we utilized loose-patch confocal imaging to visualize the signaling between a single L-type Ca2+ channel (LCC) and ryanodine receptors (RyRs) in aortic stenosis rat models of compensated (CHT) and decompensated (DHT) hypertrophy. We found that the LCC-RyR intermolecular coupling showed a 49% prolongation in coupling latency, a 47% decrease in chance of hit, and a 72% increase in chance of miss in DHT, demonstrating a state of “intermolecular failure.” Unexpectedly, these modifications also occurred robustly in CHT due at least partially to decreased expression of junctophilin, indicating that intermolecular failure occurs prior to cellular manifestations. As a result, cell-wide Ca2+ release, visualized as “Ca2+ spikes,” became desynchronized, which contrasted sharply with unaltered spike integrals and whole-cell Ca2+ transients in CHT. These data suggested that, within a certain limit, termed the “stability margin,” mild intermolecular failure does not damage the cellular integrity of excitation-contraction coupling. Only when the modification steps beyond the stability margin does global failure occur. The discovery of “hidden” intermolecular failure in CHT has important clinical implications. 相似文献
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To determine which subtype of α1-adrenergic receptors plays a role in the regulation of blood pressure, with α1--adrenergic receptor-mediated vasoconstriction in perfused hindlimb as a control, we compared the inhibitory effects of various
aradrenergic receptor selective antagonists on the vasopressure responses to phenylephrine between the mean arterial pressure
and hindlimb perfusion pressure in anesthetized rats. In Normotensive Wistar rats, the results showed that the inhibitory
effects (dose ratios of ED50, Dr) of α-1adrenoceptor selective antagonist (prazosin, Dr 13.5 ± 3.6 vs. 15.1 ± 4.3, n = 11), /ga1A-adrenoceptor selective antagonist (5-methyl-urapidil, Dr 2.4 ± 0.9 vs. 3.7 ± 2.3, n = 12; RS-17053, Dr 3.2 ± 1.6 vs. 4.4 ± 3.3, n =12) and α1D- adrenoceptor selective antagonist (BMY7378, Dr 1.9 ±0.9 vs. 2.2 ± 0.8, n = 8) on phenylephrineinduced increases of perfusion pressure in the autoperfused femoral beds were the same as that in the
mean arterial blood pressure in normotensive Wistar rats. The inhibitory effects of antagonists (RS-17053, Dr 3.4 ± 0.6 vs.
4.3 ± 0.9, n = 5; BMY7378, Dr 1.7 ± 0.5 vs. 1.7 ± 0.5, n = 8) in spontaneous hypertensive rats were similar with the Wistar rats. These results suggest that the mean arterial pressure
induced by phenylephrine was mainly mediated by α1A-adrenergic receptor in both the anesthetized Wistar rats and spontaneous hypertensive rats. 相似文献
4.
Photosynthetic characteristics and tolerance to photo-oxidation of transgenic rice expressing C4 photosynthesis enzymes 总被引:16,自引:0,他引:16
The photosynthetic characteristics of four transgenic rice lines over-expressing rice NADP-malic enzyme (ME), and maize phosphoenolpyruvate carboxylase (PC), pyruvate,orthophosphate dikinase (PK), and PC+PK (CK) were investigated using outdoor-grown plants.
Relative to untransformed wild-type (WT) rice, PC transgenic rice exhibited high PC activity (25-fold increase) and enhanced
activity of carbonic anhydrase (more than two-fold increase), while the activity of ribulose-bisphosphate carboxylase/oxygenase
(Rubisco) and its kinetic property were not significantly altered. The PC transgenic plants also showed a higher light intensity
for saturation of photosynthesis, higher photosynthetic CO2 uptake rate and carboxylation efficiency, and slightly reduced CO2 compensation point. In addition, chlorophyll a fluorescence analysis indicates that PC transgenic plants are more tolerant to photo-oxidative stress, due to a higher capacity
to quench excess light energy via photochemical and non-photochemical means. Furthermore, PC and CK transgenic rice produced
22–24% more grains than WT plants. Taken together, these results suggest that expression of maize C4 photosynthesis enzymes in rice, a C3 plant, can improve its photosynthetic capacity with enhanced tolerance to photo-oxidation.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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ZHANG Dian YUAN Bingxiang DENG Xiuling YANG Guangde HE Langchong ZHANG Youyi & HAN Qide . School of Medicine Xi''''an Jiaotong University Xi''''an China . College of pharmacy Xi''''an Jiaotong University Xi''''an China . Third Hospital Beijing University Beijing China 《中国科学:生命科学英文版》2004,(4)
Copyright by Science in China Press 2004 The a1-AR is present in many tissues including heart, blood vessels, liver, brain, kidney, prostate and spleen. In these tissues, the a1-AR mediates a variety of physiological effects such as neurotransmission, vasoconstriction, cardiacinotropy, chronotropy and glycogenolysis[1]. In 1986, Morrow and Greese pro-posed that a1-AR should be subclassified into two subtypes. Later this hypothesis was proved by Q.D Han in 1987. He not only verified a1-A… 相似文献
6.
Ping Zhang Qide Han Youyi Zhang Kaiming Xu Bin Tian Zhizhen Lü Jingxuan Guo Mingzhe Chen 《中国科学C辑(英文版)》1997,40(2):113-121
The alterations of cardiac and lymphocyte β-adrenoceptors were observed in the rats with chronic heart failure produced by constriction of both abdominal aorta and renal artery. The results showed that β1-adrenoceptor density and mRNA levels were increased, whereas these levels remained unchanged for β2. The concentrationcontractile response curve for isoproterenol was shifted m the right in cardiac atrium, whereas the concentration-CAMP accumulation response curve for isoproterenol in myocardium was not changed. The number of β-adrenoceptom in blood lymphocyte was markedly reduced. Thus in the heart-failure rats the density of cardiac β-adrenoceptor was increased accompanying reduced β-adrenoceptormediated positive inotropic response, suggesting a post adenylate cyclase dysfunction or impaired contractile components. In contrast, the alteration of β-adrenoceptor in lymphocyte is consistent with the reduced β-adrenoceptor-mediated inotropic response in heart. 相似文献
7.
Insufficient peroxiredoxin-2 expression in uterine NK cells obtained from a murine model of abortion
Yin G Li C Shan B Wang W Chen H Zhong Y Di J Lin Q Lin Y 《Journal of cellular biochemistry》2011,112(3):773-781
The CBA/J × DBA/2 mouse mating combination is prone to spontaneous embryo loss, in contrast to the MHC-identical CBA/J × BALB/c mating combination, which yields successful pregnancies. The underlying mechanisms for these observations are unclear. In this study, multi-vision immunohistochemical staining (IHC), flow cytometry and Western blot analysis were used to detect peroxiredoxin-2 (PRX-2) expression in the uterine natural killer (uNK) cells from CBA/J × DBA/2 and CBA/J × BALB/c mice. In IHC analysis, co-localization of PRX-2 and lectin from Dolichos biflorus agglutinin (DBA-lectin) was confirmed and the frequency of PRX-2(+) DBA-lectin(+) cells was significantly lower in CBA/J × DBA/2 than CBA/J × BALB/c. In flow cytometry and Western blotting, PRX-2 was found expressed at a significantly lower level in CBA/J × DBA/2 mice. PRX-2 inhibition with a neutralizing antibody significantly decreased PRX-2 expression, increased the cytotoxicity of uNK cells, and increased the percentage of embryo loss in CBA/J × DBA/2J mice. Our data suggest that PRX-2 may be involved in the modulation of maternal-fetal tolerance and that insufficient expression of this protein may correlate with increased embryo loss in CBA/J × DBA/2J mice. 相似文献
8.
NaCl胁迫对PSII光能利用和耗散的影响 总被引:13,自引:1,他引:13
用荧光动力学的方法研究了不同浓度的NaCl 处理对PSII光能利用和耗散的影响。结果表明,在较低的光强下,与对照、100m mol/L 和200m mol/L NaCl 处理相比,经300m mol/L 和400m mol/L NaCl 处理的小麦,其荧光光化学淬灭效率较低,荧光非光化学淬灭效率较高,Fo 淬灭系数较大,QB - 非还原性PSII反应中心含量较大; 而在较高光强下, 其荧光非光化学淬灭效率和Fo 淬灭系数则相对较低。 相似文献
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