五味子酚对大鼠中性粒细胞呼吸爆发的影响

目的　研究五味子酚对大鼠中性粒细胞呼吸爆发时自由基生成和溶酶体酶释放的影响。方法　分别用紫外分光法、荧光分光法和同位素法测定该细胞自由基生成、溶酶体酶释放、胞浆钙离子和环磷酸腺苷(cAMP)含量。结果　五味子酚能抑制中性粒细胞超氧阴离子、过氧化氢、脂质过氧化产物丙二醛（MDA）以及一氧化氮的生成,减少溶菌酶和β-葡糖醛酸苷酶的释放,而且,还能拮抗FMLP引起的细胞胞浆钙离子的增加,进一步增强FMLP引起的胞浆cAMP的增加。结论　五味子酚可能通过降低细胞内钙离子浓度和/或升高胞浆cAMP的含量而抑制中性粒细胞呼吸爆发所导致的上述变化。     

粉防己碱的抗炎作用与炎症白细胞cAMP的关系

目的　研究粉防己碱 (tetrandrine,Tet)的抗炎作用与炎症白细胞cAMP的关系。方法　在大鼠胸膜腔内注射角叉菜胶 (1 0mg·kg- 1 )复制胸膜炎 ,并于致炎前 30min腹腔注射Tet。用常规方法测量胸膜腔渗出液量 ,用试管稀释法计数渗出液中白细胞数 ,用放射免疫分析法、间接法、酶放射化学分析法和荧光比色法 ,分别测定炎症白细胞cAMP浓度、腺苷酸环化酶 (AC)、磷酸二酯酶 (PDE)活性及胞质内游离钙浓度 ([Ca2 + ] i) ;体外观察细胞外钙对Tet调节炎症白细胞PDE活性的作用。结果　Tet(1 0～ 80mg·kg- 1 )腹腔注射 ,剂量依赖地降低胸膜腔渗出液量和白细胞游出数 ,同时增加白细胞cAMP浓度 ;Tet亦剂量依赖地降低炎症白细胞PDE活性及 [Ca2 + ] i,但对白细胞AC活性无明显影响。Tet抑制炎症渗出的作用与其增加白细胞cAMP浓度的作用呈线性相关 ;其增加白细胞cAMP浓度的作用则与其抑制PDE活性呈线性相关 ;后者与其降低 [Ca2 + ] i 呈线性相关。在体外 ,Tet抑制细胞外Ca2 + 和A2 31 87引起的PDE活性升高 ,其抑制作用可因细胞外钙浓度增加而逆转。结论　增加炎症白细胞cAMP浓度可能是Tet重要的抗炎作用机制之一 ;Tet主要通过降低炎症白细胞 [Ca2 + ] i从而抑制PDE活性并最终减少cAMP降解 ,Tet对AC活性无明显影响     

甘草次酸钠对大鼠化学性腹膜炎的影响(英文)

目的:研究甘草次酸钠(SG)的抗炎机制.方法: 制备大鼠腹膜炎模型,用放免法测PGE_2含量,Folin-酚试剂法测蛋白含量,邻苯三酚-NBT法测SOD活性,竞争性蛋白结合法测cAMP含量.结果:组胺致炎时,SG 10-20 mg·kg~(-1) im减少渗液量;角叉菜胶致炎时,SG 20 mg·kg~(-1) im使渗液量及其中PGF_2含量减少,SOD活性增加;花生四烯酸致炎时,SG 20 mg·kg~(-1)im抑制Neu中cAMP浓度下降,减少渗出液中PGE_2含量.SG也使三种腹膜炎渗出液中Neu计数和蛋白含量减少.结论:SG通过抑制Neu游走及PGE_2合成、降低毛细血管通透性、清除氧自由基而发挥抗炎作用.     

吗啡抑制嗜中性白细胞呼吸暴发并清除氧自由基(英文)

目的:研究吗啡对活性氧自由基的影响.方法:用化学发光法检测.(a)人血嗜中性白细胞受佛波醇刺激产生呼吸爆发的活性氧.(b)黄嘌呤-黄嘌呤氧化酶体系产生的O~(?)_2;(c)AA-Cu~(2 )-酵母多糖产生的·OH;(d)过氧化氢的释放反应.结果:吗啡清除(a),(b),(c),(d)所产生的氧自由基,其IC_(50)值(nmol L~(-1))分别为21.1(13.0—34.0),54.1(50.0—58.5),224.0(128.2—390.8),和66.9(62.9—71.0).结论:吗啡的氧自由基清除作用与吗啡的免疫抑制作用有关.     

眼镜蛇毒因子对大鼠血小板的激活作用(英文)

目的:研究补体激活剂眼镜蛇毒因子(CVF)对大鼠血小板的作用及其细胞机制。方法:比浊法测富血小板血浆内血小板聚集并同步记录ATP释放;生色底物法测血小板表面凝血酶原酶活性;用钙离子荧光指示剂Fura-2 AM负载血小板测细胞内游离钙;放免法测细胞内cAMP含量。结果:CVF在19.5-617nmol·L~(-1)范围内浓度依赖性地诱导血小板聚集和ATP释放,195nmol·L~(-1)诱导的ATP释放不依赖于聚集,且明显弱于凝血酶1U/ml的作用。CVF195nmol·L~(-1)时间依赖性地增加血小板表面凝血酶原酶活性。抗血小板膜糖蛋白Ⅰb/Ⅸ、Ⅲa、Ⅱb的单克隆抗体SZ-1、SZ-21、SZ-22抑制CVF诱导的血小板聚集。CVF 195nmol·L~(-1)使血小板内游离钙从静息态的(141±46)nmol·L~(-1)升高到(240±64)nmol·L~(-1),在61.7-617nmol·L~(-1)范围内轻度降低血小板内的cAMP。结论:补体激活剂CVF能诱导大鼠血小板聚集、ATP释放,增加血小板表面凝血酶原酶活性,其激活血小板的作用与血小板表面纤维蛋白原受体及血小板内游离钙升高、cAMP下降有关。     

Effect of rolipram and dibutyryl cyclic AMP on resequestration of cytosolic calcium in FMLP-activated human neutrophils

1. We have investigated the effects of the selective phosphodiesterase (PDE) type 4 inhibitor, rolipram (0.01–1 μM) on cytosolic Ca²⁺ fluxes in FMLP-activated human neutrophils, as well as on superoxide production by, and release of elastase from, these cells.
2. Cytosolic Ca²⁺ fluxes were measured by use of fura-2 spectrofluorimetry in combination with a radiometric procedure that enables distinction between net efflux and influx of the cation. Superoxide production and elastase release were measured by lucigenin-enhanced chemiluminescence and a colorimetric procedure, respectively.
3. Pretreatment of neutrophils with rolipram did not affect the FMLP-activated release of Ca²⁺ from intracellular stores, but was associated with dose-related acceleration of the rate of decline in fura-2 fluorescence and with decreased efflux, as well as store-operated influx of ⁴⁵Ca²⁺, indicative of enhancement of resequestration of the cation by the endo-membrane Ca²⁺-ATPase.
4. Inhibition of superoxide production and elastase release was observed at concentrations of rolipram which accelerated the clearance of Ca²⁺ from the cytosol of FMLP-activated neutrophils.
5. These effects of rolipram on FMLP-activated Ca²⁺ fluxes, superoxide generation and elastase release were mimicked by pretreatment of neutrophils with dibutyryl cyclic AMP (0.5–4 mM), while theophylline (10–150 μM), a non-specific PDE inhibitor, as well as the β₂-agonist, salbutamol, were less effective.
6. We conclude that rolipram deactivates FMLP-stimulated human neutrophils by enhancement of cyclic AMP-dependent resequestration of cytosolic Ca²⁺.

     

普罗托品对家兔血小板功能的影响

普罗托品(protopine,Pro)体外(1—1000μmol·L~(-1))和体内(10和20mg·kg~(-1))均抑制ADP,胶原,花生四烯酸(AA)和烙铁头蛇毒血小板聚集素(TMVA)诱导的兔血小板聚集及血小板5-HT释放。Pro不抑制AA诱导的免血小板TXA_2生成。也不升高血小板内cAMP水平,但升高cGMP水平。提示其抗血小板作用的机制与升高血小板内cGMP水平,抑制血小板释放活性物质有关。     

甘草次酸钠对乳鼠心肌细胞的影响(英文)

目的:研究甘草次酸钠(SG)对乳鼠心肌细胞的作用。方法:体外培养乳鼠心肌细胞,用放射免疫法和荧光法分别测定cAMP和[Ca~(2 )]_i。结果:SG 0.4mmol·L~(-1)于5,10和15min使心肌细胞搏动频率由73±9min~(-1)分别降至62±5,59±7和56±6min~(-1)。SG0.1和0.2mmol·L~(-1)分别在15和10,15min呈现以上相似的结果。SG0.2和0.4mmol·L~(-1)与心肌细胞37℃共孵10,15min,cAMP浓度和[Ca~(2 )]_i均被降低。SG 0.2mmol·L~(-1)处理组的cAMP含量低于对照组(1.09±0.18,1.12±0.35pmol per vial,P<0.05);[Ca~(2 )]_i的变化也类似(30±4nmol·L~(-1),P<0.01,28±6nmol·L~(-1)P<0.05)。SG 0.1和0.2mmol·L~(-1)提高心肌细胞悬液氧分压变化率(87％±5％,75％±4％,P<0.01),但SG0.4mmol·L~(-1)降低氧分压变化率(31％±2％,P<0.01)。结论:SG可保护心肌或治疗缺血性心脏病。     

Effect of PDE4 inhibitors on zymosan-induced IL-8 release from human neutrophils: synergism with prostanoids and salbutamol

1. The activation of neutrophils with particulate stimuli such as zymosan induces the generation of the C-X-C chemokine interleukin (IL)-8. There is evidence that neutrophil derived IL-8 plays an important role in human diseases such as the adult respiratory distress syndrome. In the present study, we examined the effects of cyclic AMP elevating agents on the ability of human neutrophils to generate IL-8 in response to zymosan particles.
2. The PDE4 inhibitor rolipram had limited effect on zymosan-induced IL-8 generation. In contrast, the PDE4 inhibitors RP 73401 and SB 207499 concentration-dependently suppressed IL-8 generation. The potency of these inhibitors was RP 73401 > SB 207499 > rolipram which is correlated with their rank order of potency at inhibiting the catalytic site of purified neutrophil PDE4. Pretreatment of neutrophils with the PDE3 inhibitor ORG 9935 or the PDE5 inhibitor zaprinast had no effect on IL-8 generation.
3. The prostanoids prostaglandin E₁ (PGE₁) and PGE₂ inhibited zymosan-induced IL-8 release from neutrophils in a dose-dependent manner, in response to 10^?5M PGE₁ and PGE₂ inhibiting IL-8 generation by 89% and 75%, respectively. Similarly, the β₂-adrenoceptor agonist salbutamol also inhibited IL-8 generation, but it was less effective than the prostanoids.
4. Significant synergism between prostanoids or salbutamol and the PDE4 inhibitors to inhibit IL-8 generation was observed. In contrast, there was no significant synergism between PGE₂ and the PDE3 inhibitor ORG 9935 or the PDE5 inhibitor zaprinast.
5. In order to evaluate the potential role of protein kinase A in mediating the inhibitory effects of cyclic AMP-elevating agents, we used the protein kinase A inhibitors, H 89 and KT 5720. Pretreatment of neutrophils with these drugs completely reversed the inhibitory effects of a combination treatment with rolipram and PGE₂ on zymosan-induced IL-8 release.
6. Microscopic examination revealed that most neutrophils contained one or more zymosan particles and that combination treatment with rolipram and PGE₂ noticeably reduced the number of ingested particles. Moreover, there was a significant reduction in the percentage of neutrophils which ingested three or more zymosan particles.
7. Thus, our results demonstrate that cyclic AMP-elevating agents modulate the ability of neutrophils to generate IL-8 in response to a particulate stimulus. However, these agents also modulate the ability of neutrophils to phagocytose zymosan particles. Whether this effect will translate into inhibition of the ability of neutrophils to deal with infectious agents needs to be investigated further.

     

Relationships between norepinephrine and cyclic nucleotides in brain and seizure activity

To characterize further the roles of norepinephrine (NE) and cyclic nucleotides in seizure mechanisms, an examination was made of the effects of several drugs purported to depress noradrenergic influence in the CNS on pentylenetetrazol-induced seizure activity and regulation of cyclic AMP levels in the cerebral cortex and hippocampus in mice. Depletion of brain stores of NE with reserpine or treatment of neonatal mice with 6-hydroxy-dopamine decreased seizure latency and/or threshold and diminished seizure-induced accumulation of cyclic AMP in brain. Propranolol, a β-adrenergic receptor antagonist, and yohimbine, an α₂-adrenergic receptor antagonist, had effects qualitatively similar to reserpine and 6-hydroxy-dopamine, but phentolamine, a mixed α-adrenergic antagonist, increased seizure threshold and latency and did not reduce the accumulation of cyclic AMP. None of the drugs tested had any consistent effect on the regulation of cyclic GMP levels in brain during seizures. These data are consistent with the hypothesis that cyclic AMP in brain may be mediating an inhibitory influence of NE on seizure activity.     

Electrophysiological analysis of exogenous and endogenous adenosine actions in the rat and human hippocampus in vitro

Adenosine acts in at least three different ways at A₁ receptors in order to reduce excitability and signal transfer. In the hippocampus, it causes in a steady state outward (potassium) current which is blocked by barium ions and not sensitive to voltage; (ii) an increase in the calcium and cyclic AMP-dependent current 1AHP which is responsible for a long lasting afterhyperpolarization and the accommodation of action potential firing; (iii) a presynaptic reduction of excitatory but not inhibitory transmitter release. The mechanism of this effect is unclear. It is, in contrast to the former, not sensitive to pertussis toxin. When the adenosine elicited potassium currents at the postsynaptic site are blocked, slow inward currents, normally carried by calcium, are unaffected by adenosine. A2 receptor mediated actions have not been found in the hippocampus. While the precise analysis of these effects has been done largely on rats they were all found in human hippocampal slices as well. © 1993 Wiley-Liss, Inc.     

Action in vitro and in vivo of chlorpromazine and haloperidol on cyclic nucleotide systems in mouse cerebral cortex and cerebellum.

Three different procedures were utilized to study the action of chlorpromazine (CPZ) and haloperidol on adenylate cyclase-cyclic nucleotide systems in the mouse cerebral cortex and cerebellum. Using incubated tissue slices which in both tissues demonstrate an activation of adenylate cyclase by norepinephrine (NE), CPZ was found to be more effective than haloperidol in reducing this response. With the second method it was shown that adenylate cyclase in homogenates was stimulated in both tissues by NE while dopamine (DA) was active in only the cerebral cortex. With this broken cellular preparation, CPZ exerted greater antagonism than haloperidol on both the NE- and DA-sensitive enzymes. Moreover, the DA-responsive enzymes were blocked by both agents to a greater extent than was observed with the NE-induced stimulation. In the third experiment haloperidol and three doses of CPZ were injected into mice in vivo, at specified intervals; thereafter the tissues were rapidly inactivated by focused microwave irradiation (0.5 sec), and cyclic AMP and cyclic GMP levels were subsequently determined. In general, the acute injections ($\text{1}\text{2}$–8 hr) of CPZ and haloperidol diminished the steady-state levels of the two nucleotides. Subchronic administration (24–48 hr) usually resulted in elevated cyclic AMP amounts. The data indicate that under both in vitro and in vivo conditions, neuroleptics inhibit neurohumorally-induced activation of adenylate cyclase. Subchronic injections, however, suggest other factors become prominent i.e. inhibition of phosphodiesterase or enhanced receptor sensitivity.     

雷公藤内酯醇诱导兔血小板聚集作用

雷公藤内酯醇 (Ｔｒｉｐｔｏｌｉｄｅ ,Ｔｒｉ)具有抗肿瘤、免疫抑制、抗炎等生物活性 ;临床上用于治疗银屑病 ,类风湿性关节炎及白血病[1] 。但在动物实验和临床应用中发现其静脉注射会引起严重的血栓性浅静脉炎 ;为探讨其引起血栓性浅静脉炎的机制 ,我们观察了Ｔｒｉ对兔血小板功能的影响。1　材料与方法1.1　材料　Ｔｒｉ由本所提取 ,纯度 99 9% ,使用时以 2 %丙二醇配成所需浓度。ＡＤＰ美国Ｓｉｇｍａ生产 ;5 ＨＴ瑞士Ｆｌｕ ｋａ生产 ;ＴＸＢ2 放免药盒 ,中国医学科学院基础所提供 ;ｃＡＭＰ和ｃＧＭＰ放免药盒 ,中国原子能研究所提…     

The stimulation of human neutrophil migration by angiotensin II: its dependence on Ca2+ and the involvement of cyclic GMP

1. Angiotensin II had a bimodal effect on human neutrophil migration. Low concentrations of angiotensin II stimulated random migration. At a concentration of 10⁻¹⁰ M it caused a maximal increase of migration; migration increased from 47.2±2.1 μm in the absence of angiotensin II, to 73.1±2.2 μm with 10⁻¹⁰ M angiotensin II present in the lower compartment of the Boyden chamber (n=5, P<0.001). Stimulation of migration by angiotensin II was partly chemotactic and partly chemokinetic. Angiotensin II concentrations of 10⁻⁸ M and higher inhibited chemotactic peptide-stimulated chemotaxis.
2. The stimulant effect of angiotensin II on migration was completely dependent on extracellular Ca²⁺. In the presence of 1 mM Ca²⁺, angiotensin II stimulated migration to 76.1±1.7 μm, while migration in the absence of Ca²⁺ was 42.2±1.9 μm (n=4, P<0.001). Different types of calcium channel blockers either moderately or strongly inhibited angiotensin II-activated migration. Stimulation of migration by angiotensin II in intact cells required higher concentrations of Ca²⁺ than in electroporated cells. This supports the view that there is an influx of Ca²⁺ through the plasma membrane, and a requirement of calcium for an intracellular target.
3. Angiotensin II-stimulated migration was inhibited by pertussis toxin; from 71.6±2.0 μm in the absence, to 43.6±1.5 μm in the presence of pertussis toxin (n=4, P<0.001). Migration of electroporated neutrophils stimulated by angiotensin II was synergistically enhanced by GTPγS. This suggests that one or more G-proteins are involved in the activating effect of angiotensin II.
4. Inhibitors of soluble guanylate cyclase and antagonists of cyclic GMP-dependent kinase strongly inhibited the activating effect of angiotensin II. The results suggest that the activating effect of angiotensin II is mediated by cyclic GMP and by cyclic GMP-dependent kinase.

     

Antioxidative effect of schisanhenol on human low density lipoprotein and its quantum chemical calculation

AIM: To investigate the effect of schisanhenol (Sal) on copper ion-induced oxidative modulation of human low density lipoprotein (LDL). METHODS: The antioxidative activity of eight schisandrins (DCL) on microsome lipid peroxidation induced by Vit C/NADPH system was first observed, and then, the effect of Sal on Cu^2 -induced human LDL oxidation was studied. The generation of malondialdehyde (MDA), lipofuscin, reactive oxygen species (ROS), consumption of α-tocopherol as well as electrophoretic mobility of LDL were determined as criteria of LDL oxidation. Finally, the quantum chemical method was used to calculate the theoretical parameters of eight DCL for elucidating the difference of their antioxidant ability. RESULTS: Sal was shown to be the most active one among eight schizandrins in inhibiting microsome lipid oxidation induced by Vit C/NADPH. Sal 100, 50, and 10 μmol/L inhibited production of MDA, lipofuscin and ROS as well as the consumption of α-tocopherol in Cu^2 -induced oxidation of human LDL in a dose-dependent manner. Sal also reduced electrophoretic mobility of the oxidized human LDL. Further study of quantum chemistry found that Sal was the strongest one among eight DCL to scavenge O^-.2, R‘, RO‘, and ROO radicals. CONCLUSION: Sal has antioxidative effect on human LDL oxidation. The mechanism of Sal against LDL oxidation may be through scavenging free radicals.