Involvement of mitogen-activated protein kinases and protein kinase C in cadmium-induced prostaglandin E2 production in primary mouse osteoblastic cells

We previously reported that cadmium (Cd) induced prostaglandin E₂ (PGE₂) biosynthesis through the activation of cytosolic phospholipase A₂ (cPLA₂) and induction of cyclooxygenase 2 (COX-2) in primary mouse osteoblastic cells. In the present study, we further investigated the mechanism of PGE₂ production by Cd focusing on the main mitogen-activated protein kinase (MAPK) subfamilies that mediate prostaglandin synthesis, extracellular signal-regulated kinase (ERK1/2 MAPK), c-jun-amino-terminal kinase (JNK MAPK) and p38 MAPK, and protein kinase C (PKC) which is activated by Cd in several kinds of cells. Cd at 2 μM and above stimulated PGE₂ production in osteoblastic cells and its production was inhibited by the kinase-specific inhibitors PD98059, SB203580, curcumin, and calphostin C. Calphostin C also inhibited the production of PGE₂ by phorbol 12-myristate 13-acetate (PMA), which is a potent activator of PKC. PD98059 inhibited PGE₂ production stimulated by PMA as well as Cd, indicating that activation of PKC by ERK1/2 MAPK was necessary for Cd-stimulated PGE₂ production. Moreover, Cd stimulated the phosphorylation of these three MAPKs, and inhibition of the phosphorylation of ERK1/2 MAPK by calphostin C was also observed. On the other hand, Cd was found to phosphorylate cPLA₂ and the phosphorylation was inhibited by PD98059, indicating that cPLA₂ was activated by Cd through ERK1/2 MAPK and released arachidonic acid (AA), a substrate of COX-2, from membranous phospholipids. From these results, it was suggested that activation of each of the ERK1/2, p38, and JNK MAPK cascades in addition to that of PKC and cPLA₂ played an important role in the Cd-stimulated biosynthesis of PGE₂ in mouse osteoblastic cells.     

Involvement of reactive oxygen species, protein kinase C, and tyrosine kinase in prostaglandin E2 production in Balb/c 3T3 mouse fibroblast cells by quinolone phototoxicity

We examined the effect of an antioxidant and protein kinase inhibitors on prostaglandin E₂ (PGE₂) release from Balb/c 3T3 mouse fibroblast cells induced by quinolone phototoxicity. Simultaneous administration of sparfloxacin (SPFX) or lomefloxacin (LFLX) at 12.5 to 100 μ M and ultraviolet-A (UVA) irradiation for 10 min markedly elevated PGE₂ concentration in the incubation medium, whereas levofloxacin (LVFX) at concentrations up to 100 μ M and UVA irradiation did not increase PGE₂ concentration. Pretreatment with 100 μ M pyrrolidine dithiocarbamate (PDTC), an antioxidant, or 1 μ M calphostin C, a selective inhibitor of protein kinase C (PKC), completely inhibited the elevation of PGE₂ in the 24-h incubation medium; pre-treatment with 10 μ M H7, a cyclic nucleotide-dependent protein kinase, and PKC or 1 μ M herbimycin A, a tyrosine kinase inhibitor, inhibited the PGE₂ elevation by 29 to 39%. Conversely, 25 nM staurosporine significantly augmented the PGE₂ elevation by quinolones plus UVA. Interleukin-1β (IL-1β ) and tumor necrosis factor α (TNFα ) were not detected in the incubation medium of 3T3 cells after quinolone plus UVA, corresponding to the lack of effect of antibodies against IL-1α , IL-1β , and TNFα on PGE₂ release from 3T3 cells. These results suggest that PGE₂ production in 3T3 cells by quinolone phototoxicity is modulated by reactive oxygen species, PKC, and tyrosine kinase, but not by IL-1 or TNFα . Received: 23 September 1997 / Accepted: 1 December 1997     

前列腺癌组织中泛素偶联酶E2C、蛋白激酶B表达及其与预后相关性

目的 探讨前列腺癌组织中泛素偶联酶E2C(UBE2C)、蛋白激酶B(AKT1)表达及其预后相关性。方法 选取2014年1月至2016年12月四川大学华西医院泌尿外科研究所收集的92例前列腺癌组织（前列腺癌组）、70例良性前列腺增生组织（良性前列腺增生组）进行研究,根据随访结果将前列腺癌组分为两组,预后良好组（68例）、预后不良组（24例）。采用免疫组织化学法检测不同组织中UBE2C、AKT1表达情况进行比较,并分析其与病人临床病理特征关系;采用COX回归模型分析前列腺癌病人预后影响因素。结果 与良性前列腺增生组相比,前列腺癌组UBE2C[84.78%(78/92)比22.86%(16/70)]、AKT1[78.26%(72/92)比28.57%(20/70)]阳性表达率均较高（P<0.05）;前列腺癌组UBE2C表达与年龄、TNM分期、术前前列腺特异抗原（PSA）水平均无关（P>0.05）,与Gleason评分、淋巴结转移均有关（P<0.05）,AKT1表达与年龄、淋巴结转移无关（P>0.05）,与Gleason评分、TNM分期、术前PSA水平均有关（P<...     

前列腺素E2栓促宫颈成熟引产的临床观察与护理

目的探讨前列腺素E2栓（普贝生）促宫颈成熟引产的临床效果与护理方法。方法需引产产妇130例随机分为观察组和对照组,各65例。观察组给予普贝生阴道后穹窿内放置,对照组给予缩宫素静脉滴注,观察2组产妇用药后不同时间的宫颈评分,记录产妇分娩方式、剖宫产率、羊水污染及胎心异常、新生儿出生窒息情况。结果观察组促宫颈成熟总有效率为90.8%高于对照组的46.2%,用药后各时期宫颈Bishop评分均高于对照组,差异均有统计学意义（P〈0.05）。2组胎心变化、羊水异常、新生儿窒息及宫缩过频发生率比较差异无统计学意义（P〉0.05）;观察组剖宫产率低于对照组,阴道分娩率高于对照组,差异有统计学意义（P〈0.05）。结论普贝生促宫颈成熟引产安全有效,值得临床推广应用。     

不同剂量前列腺素E2对H9c2心肌细胞肥大的影响

目的:研究前列腺素E2(PGE2)对H9c2心肌细胞的肥大作用,并分析其量效关系,为寻找抗心肌肥大的潜在靶点提供理论依据.方法:将H9c2心肌细胞分为空白对照组(C组)和PGE2处理组,PGE2处理组又分为小剂量PGE2组(D1组)、中剂量PGE2组(D2组)和大剂量PGE2组(D3组).各组细胞培养液中PGE2终浓度分别为0、0.1、1及10 μmol/L.给药孵育48 h后,利用荧光显微镜观察大鼠H9c2心肌细胞形态及体积;通过测量细胞直径大小、BCA法测定细胞总蛋白含量来确定心肌细胞是否肥大;RT-PCR技术测量心钠肽(Atrial natriuretic peptide,ANP)、脑钠肽(Brain natriuretic peptide,BNP)mRNA的表达水平,以此判断是否发生病理性肥大.结果:与C组比较,免疫荧光显示D1组、D2组及D3组细胞形态改变、体积增大;细胞直径及总蛋白含量显著增加(P＜0.05),不同剂量PGE2组间亦具有统计学差异(P＜0.05);D2组及D3组较C组细胞内ANP、BNP mRNA表达水平显著增高(P＜0.05).结论:PGE2可剂量依赖地诱导H9c2心肌细胞肥大,较大剂量PGE2引发心肌细胞病理性肥大.抑制PGE2合成有望为抑制心肌肥大提供靶点.     

Frequency-dependent effects of activation and inhibition of protein kinase C on neurohypophysial release of oxytocin and vasopressin

Summary Isolated rat neurohypophyses were superfused in vitro and the release of vasopressin and oxytocin into the medium was determined by specific radioimmunoassays. Hormone secretion was increased by electrical stimulation of the pituitary stalk at different frequencies. The effects of several phorbol esters, known to activate (phorbol 12,13-dibutyrate, PDB) or not to affect (4a-phorbol 12,13-dideconate and phorbol 12-monoacetate) protein kinase C, and of the direct protein kinase C inhibitor 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7) were tested.Electrical stimulation with 450 pulses caused the release of about 45 U vasopressin and 55 U oxytocin, when a frequency of 3 Hz was applied, and of about 500 U vasopressin and oxytocin, when a frequency of 15 Hz was used.PDB (1 gmol/l) increased the release of vasopressin evoked by 15 Hz stimulation maximally by about 40–50% and that evoked by 3 Hz stimulation by about 150%. The release of oxytocin evoked by 15 Hz stimulation was increased by about 150% and that evoked by 3 Hz stimulation by about 400–500% in the presence of PDB. Both inactive phorbol esters had no effects on the evoked release of vasopressin or oxytocin. The effect of PDB on the release of vasopressin and oxytocin was blocked by H7 (10–30mol/1). H7 (30 ol/1) alone reduced the release of vasopressin evoked by stimulation at 15 Hz by 50%. The release of oxytocin was not significantly affected by H7. In the presence of naloxone (1 ol/1) the release of oxytocin evoked by 3 and 15 Hz stimulation was increased by about 175 and 105%, respectively. In the presence of naloxone, H7 (30 mol/1) had no effect on the release of oxytocin evoked by stimulation at 15 Hz, but PDB caused an increase of the release of oxytocin similar to that in the absence of naloxone. Inactivation of protein kinase C by prolonged exposure of isolated neurohypophyses to PDB (1 mol/1) for 4 h reduced the release of vasopressin evoked by stimulation at 15 Hz by about 45%.In conclusion, activation of protein kinase C can facilitate impulse-induced hormone secretion from neurosecretory nerve endings. Under the present in vitro conditions, an endogenous activation of protein kinase C appears to be involved, in part, in the frequency-dependent facilitation of vasopressin, but not of oxytocin secretion. In addition, the inhibition of oxytocin release by endogenous opioids appears not to be associated with effects on protein kinase C.Abbreviations DMSO dimethylsulphoxide - H7 1-(5-isoquinolinylsulfonyl)-2-methyl-piperazine - PDB phorbol 12,13-dibutyrate Send offprint requests to K. Rack at the above address     

Nicotine-induced release of noradrenaline and neuropeptide Y in guinea-pig heart: role of calcium channels and protein kinase C

Summary The role of calcium, calcium influx through calcium channels, and activation of protein kinase C for the nicotine-induced release of noradrenaline and of the sympathetic co-transmitter neuropeptide Y (NPY) was investigated in the guinea-pig isolated perfused heart. In the coronary venous overflow noradrenaline and NPY were determined by high-pressure liquid chromatography and radioimmunoassay, respectively. In the presence of extracellular calcium (1.85 mmol/l) nicotine (1–100 mol/l) evoked a concentration-dependent overflow of both transmitters with a molar ratio of approximately 1500 (noradrenaline):1 (NPY). The nicotine-induced (100 mol/l) overflow of noradrenaline and NPY was in a linear manner related (r = 0.79 and 0.90, respectively; p < 0.05) to the extracellular calcium concentration (0–1.85 mmol/l), and it was prevented by calcium-free perfusion. The L-type calcium channel blocker felodipine (100 nmol/l) did not affect the nicotine-induced (100 mol/l) transmitter overflow. On the other hand, the neuronal (N-type) calcium channel blockers -conotoxin (100 nmol/l) and cadmium chloride (50 mol/l) reduced the nicotine-induced (100 pmol/l) transmitter overflow to 20% of the control value, suggesting a role of N-type calcium channels in mediating the calcium influx for the nicotine-induced transmitter release. The nicotine-induced (30 mol/l) overflow of both transmitters was two- to three-fold increased by activation of protein kinase C (phorbol 12-myristate 13-acetate; 100 nmol/l). The transmitter overflow was unaffected by 4-phorbol 12,13-didecanoate (100 nmol/l), a phorbol ester which does not stimulate protein kinase C. Further supporting a modulatory role of protein kinase C, inhibition of the enzyme by either polymyxin B (100 gmol/I) or by cremophor RH-30 (1mol/l) almost completely suppressed the overflow of noradrenaline and NPY. The results of the present study indicate that nicotine evokes a concentration-dependent exocytotic co-release of noradrenaline and NPY in the guinea-pig isolated perfused heart which is characterized by its dependence on extracellular calcium, calcium influx through N-type calcium channels and activation of protein kinase C.This work was supported by a grant from the Forschungsrat Rauchen und Gesundheit Send of fprint requests to M. Haass at the above address     

海马胞外钙不依赖去甲肾上腺素释放及蛋白激酶C的调制作用(英文)

在细胞外无钙时,佛波醇基酯能加强3,4-二氨基吡啶、藜芦定或哇巴因所诱发的去甲上腺素(NE)释放,但对莫能星(Mon)诱发的NE释放无作用。河豚毒素能阻断前3种物质诱发的NE释放,但对Mon诱发的释放无作用。钙整合剂BAPTA-AM能抑制这4种物质诱发的NE释放。结果提示蛋白激酶c仅调制由膜去极化因素诱发的NE释放。     

Chronic inhibition of intracellular Ca release or protein kinase C activation significantly reduces the development of morphine dependence

We have previously shown that chronic antagonism of metabotropic glutamate receptors in the brain attenuates naloxone-precipitated withdrawal symptoms in rats treated chronically with subcutaneous (s.c.) morphine. Several subtypes of metabotropic glutamate receptors are directly linked, through a guanine nucleotide regulatory protein, to the phosphatidylinositol (PI) second messenger system. In the present investigation, we assessed the effect of inhibiting the products of PI hydrolysis on the development of opioid dependence. Thus, concurrently with subcutaneous morphine, we infused intracerebroventricularly (i.c.v.) in rats, various doses of chelerythrine, which selectively inhibits the activation of protein kinase C, and thapsigargin, which inhibits the release of intracellular Ca²⁺ when given chronically. Both chelerythrine and thapsigargin reduced the severity of naloxone-precipitated abstinence symptoms when infused i.c.v. at a dose of 10 nmol/day. A single injection of either chelerythrine or thapsigargin immediately prior to the precipitation of withdrawal failed to decrease the severity of abstinence symptoms. Our results suggest that by chronically inhibiting activity of the phosphatidyl-inositol system, the development of morphine dependence can be attenuated.     

The role of protein kinase C activation and the vascular complications of diabetes

Diabetes mellitus is a chronic disease caused by inherited and/or acquired deficiency in production of insulin by the pancreas, and by resistance to insulin's effects. Such a deficiency results in increased concentrations of glucose and other metabolites in the blood, which in turn damages many of the body's systems, in particular the eyes, kidneys, nerves, heart and blood vessels. There are two major types of diabetes mellitus: Type 1 diabetes (insulin-dependent diabetes, IDDM or juvenile onset diabetes) and Type 2 diabetes (non-insulin-dependent diabetes, NIDDM or adult-onset). Chronic hyperglycemia is a major initiator of diabetic micro- and cardiovascular complications, such as retinopathy, neuropathy and nephropathy. Several hyperglycemia-induced mechanisms may induce vascular dysfunctions, which include increased polyol pathway flux, altered cellular redox state, increased formation of diacylglycerol (DAG) and the subsequent activation of protein kinase C (PKC) isoforms and accelerated non-enzymatic formation of advanced glycated end products. It is likely that each of these mechanisms may contribute to the known pathophysiologic features of diabetic complications. Others and we have shown that activation of the DAG-PKC pathway is associated with many vascular abnormalities in the retinal, renal, neural and cardiovascular tissues in diabetes mellitus. DAG-PKC pathway affects cardiovascular function in many ways, such as the regulation of endothelial permeability, vasoconstriction, extracellular matrix (ECM) synthesis/turnover, cell growth, angiogenesis, cytokine activation and leucocyte adhesion, to name a few. Increased DAG levels and PKC activity, especially alpha, beta1/2 and delta isoforms in retina, aorta, heart, renal glomeruli and circulating macrophages have been reported in diabetes. Increased PKC activation have been associated with changes in blood flow, basement membrane thickening, extracellular matrix expansion, increases in vascular permeability, abnormal angiogenesis, excessive apoptosis and changes in enzymatic activity alterations such as Na(+)-K(+)-ATPase, cPLA(2), PI3Kinase and MAP kinase. Inhibition of PKC, especially the beta1/2 isoform has been reported to prevent or normalize many vascular abnormalities in the tissues described above. Clinical studies have shown that ruboxistaurin, a PKCbeta isoform selective inhibitor, normalize endothelial dysfunction, renal glomerular filtration rate and prevented loss of visual acuity in diabetic patients. Thus, PKC activation involving several isoforms is likely to be responsible for some of the pathologies in diabetic retinopathy, nephropathy and cardiovascular disease. PKC isoform selective inhibitors are likely new therapeutics, which can delay the onset or stop the progression of diabetic vascular disease with very little side effects.     

Styrylquinazolines: a new class of inhibitors on prostaglandin E2 production in lipopolysaccharide-activated macrophage cells

A series of styrylquinazoline derivatives (2a-k) were prepared and evaluated for their inhibiton of prostaglandin E(2) (PGE(2)) production by cyclooxygenase-2 (COX-2). The latter was induced by lipopolysaccharide-stimulated macrophage cells RAW264.7. 3', 4'-Dihydroxylated styrylquinazolines (2a-c), 3'-hydroxylated styrylquinazolines (2h, 2i), and 3'-acetoxy-styrylquinazolines (2j, 2k) exhibited good inhibitory effects of PGE(2) production by COX-2 with a range of IC(50) values of 1.19 approximately 3.56 microM. The potencies were comparable or better than that of the representative stilbene resveratrol (IC(50) = 3.07 microM). These results indicate that styrylquinazolines can be considered as potential resveratrol analogues in the modulation of prostaglandin production by COX-2.     

米索前列醇、欣普贝生及COOK宫颈扩张双球囊在足月妊娠引产中的对比研究

目的分析米索前列醇、欣普贝生及COOK宫颈扩张双球囊促宫颈成熟的特点,探讨足月妊娠适宜的引产措施。方法将91例有引产指征、宫颈Bishop评分〈6分的足月妊娠初产妇随机分为米索前列醇组（31例）、COOK球囊组（28例）、欣普贝生组（32例）,观察各组孕妇宫颈Bishop评分、宫缩情况、产程时间、分娩方式及母胎并发症。结果欣普贝生组及COOK球囊组促宫颈成熟显效率分别为78．6％、75．O％,明显优于米索前列醇组（22．6％）,但欣普贝生组强直性宫缩、胎盘早剥的发生率高于COOK球囊组（P〈0．05）。欣普贝生组与COOK球囊组剖宫产率比较差异无统计学意义（P〉0．05）,但均低于米索前列醇组（P〈0．05）。三组病例新生儿Apgar评分、脐动脉pH值比较差异无统计学意义（P〉0．05）。结论小剂量米索前列醇口服给药促宫颈成熟作用较弱,但给药途径方便,价格便宜,对于经济状况低下人群可考虑使用。欣普贝生诱导宫颈成熟效果明显,但可出现强直性宫缩、第二产程过快、胎盘早剥等不良反应。COOK球囊促宫颈成熟作用温和、不良反应少,是除米索前列醇及欣普贝生外另一种可供选择的促宫颈成熟方法。     

Differential expression of protein kinase C subtypes during ginsenoside Rh2-induced apoptosis in SK-N-BE(2) and C6Bu-1 cells

We examined the modulation of protein kinase C (PKC) subtypes during apoptosis induced by ginsenoside Rh2 (G-Rh2) in human neuroblastoma SK-N-BE(2) and rat glioma C6Bu-1 cells. Apoptosis induced by G-Rh2 in both cell lines was confirmed, as indicated by DNA fragmentation and in situ strand breaks, and characteristic morphological changes. During apoptosis induced by G-Rh2 in SK-N-BE(2) cells, PKC subtypes alpha, beta and gamma were progressively increased with prolonged treatment, whereas PKC delta increased transiently at 3 and 6 h and PKC epsilon was gradually down-regulated after 6 h following the treatment. On the other hand, PKC subtype zeta markedly increased at 24 h when maximal apoptosis was achieved. In C6Bu-1 cells, no significant changes in PKC subtypes alpha, gamma, delta, epsilon and zeta were observed during apoptosis induced by G-Rh2. These results suggest the evidence for a possible role of PKC subtype in apoptosis induced by G-Rh2 in SK-N-BE(2) cells but not in C6Bu-1 cells, and raise the possibility that G-Rh2 may induce apoptosis via different pathways interacting with or without PKC in different cell types.     

Comparison of human α1-adrenoceptor subtype coupling to protein kinase C activation and related signalling pathways

The coupling of human α₁-adrenoceptor subtypes to protein kinase C (PKC) and PKC-related signalling events were investigated in rat-1 fibroblasts stably expressing α_1A-, α_1B- or α_1D-adrenoceptors at densities of 1328 ± 200, 5030 ± 703 and 150 ± 14 fmol/mg protein respectively. In functional assays the α₁-adrenoceptor agonist phenylephrine significantly stimulated PKC (assessed as increased activity in the membrane fraction) in cells expressing α_1A- or α_1B- but not α_1D-adrenoceptors. In immunoblot assays phorbol ester treatment enhanced membrane-associated immunoreactivity of PKCα, PKCδ and PKCɛ to a similar extent in all three cell lines. Stimulation of α_1A- and α_1B-adrenoceptors also increased immunoreactivity of PKCα, PKCδ and PKCɛ in the membrane fraction, while α_1D-adrenoceptor stimulation yielded only very small and inconsistent alterations. Immunoreactivity of PKCζ was not consistently affected by phorbol ester or phenylephrine in any of the cell lines. Stimulation of all three α₁-adrenoceptors time- and concentration-dependently increased inositol phosphate formation. Maximum activation occurred with the order α_1A≈α_1B > α_1D. Phenylephrine also concentration dependently elevated free intracellular [Ca²⁺] in all three cell lines with the order of efficacy α_1A > α_1B > α_1D. In the presence of ethanol, phenylephrine stimulated phosphatidylethanol formation in α_1A- and α_1B-adrenoceptor-expressing cells time and concentration dependently but only weakly and inconsistently in α_1D-adrenoceptor-expressing cells. The efficacy of phenylephrine (100 μM) relative to that of noradrenaline (100 μM) for stimulation of phosphatidylethanol formation was similar (≥ 75%) for all three subtypes. The alkylating agent phenoxybenzamine concentration dependently reduced α_1A-adrenoceptor density and phenylephrine-stimulated Ca²⁺ elevations to levels seen with α_1D-adrenoceptors but reductions of phenylephrine-stimulated phosphatidylethanol formation were weaker. We conclude that human α_1A- and α_1B-adrenoceptors expressed in rat-1 cells couple to activation of PKCα, PKCδ and PKCɛ but not PKCζ; this may involve stimulation of phospholipases C and D and intracellular Ca²⁺ elevations. Activation of these pathways by α_1D-adrenoceptors appears to be much weaker and was not detected consistently; this was not fully explained by weak partial agonism of phenylephrine at this subtype or by lower receptor densities. Overall the α_1A-adrenoceptor may have the highest efficiency of stimulus-response coupling among human α₁-adrenoceptor subtypes. Received: 25 July 1997 / Accepted: 29 September 1997     

Effect of bolesatine on phospholipid/calcium dependent protein kinase in vero cells and in rat thymus

 Bolesatine, a glycoprotein from Boletus satanas Lenz, has previously been shown to be mitogenic to rat and human lymphocytes at very low concentrations, whereas higher concentrations inhibit protein synthesis in vitro and in several in vivo systems. The mechanism whereby this mitogenic activity occurs was previously unknown. To elucidate this mechanism, the effects of bolesatine have been studied in a cell-free system, VERO cells in culture, and in rat thymus. Bolesatine was found to activate PKC, in vitro (cell free system), in VERO cells, and in vivo in rat thymus. In a cell-free system, bolesatine appears to be a direct effector of PKC. The activation is concentration dependent for 1 – 10 ng/ml. At the same time, VERO cells significantly proliferate when incubated with bolesatine (3, 5 and 10 ng/ml), since the DNA synthesis increases by 27, 48 and 59%, for respectively, 3, 5 and 10 ng/ml compared with control. Moreover, Bolesatine (5 and 10 ng/ml) induces InsP₃ release in a concentration-dependent manner (114 and 142%) as compared to control. In vivo, 24 h after oral administration of bolesatine to rats (20, 100 and 200 μg/kg), PKC activity is significantly increased in thymus. The most effective doses (100 and 200 μg/kg) give 590 – 620% increase in cytosolic PKC activity and 85 – 91% increase in total PKC activity as compared to control. This PKC activation by bolesatine in rat thymus is directly linked to the mitogenic activity observed in vivo. Bolesatine is thus capable of activating the PKC directly and/or indirectly (via InsP₃ release) during its mitogenic process. Received: 6 February 1995 / Accepted: 20 March 1995     

体外柴胡皂苷元d对C_6大鼠神经胶质瘤细胞前列腺素E_2生成的影响

目的　观察柴胡皂苷元d(saikogenind ,SGD)对C6大鼠神经胶质瘤细胞体外前列腺素E2 (PGE2 )生成的影响。方法　用放射性免疫法测定细胞产生的PGE2 ,液体闪烁测量法测定14 C花生四烯酸 (AA)标记细胞释放14 C AA。结果　SGD在 1～ 2 0 μmol·L-1范围内 ,抑制由钙离子载体A2 3187诱发C6大鼠神经胶质瘤细胞前列腺素E2 (prostaglandinE2 ,PGE2 )释放 ,其IC50 为 3μmol·L-1,但对花生四烯酸 (arachi donicacid ,AA)释放无影响。SGD不影响细胞微粒体组分将AA转化为PGE2 。结论　SGD抑制由钙离子载体A2 3187诱发体外C6大鼠神经胶质瘤细胞PGE2 产生 ,但不抑制AA释放和直接抑制环氧脂酶 (cyclooxygenase ,COX)活性。     

The involvement of protein kinase C and tyrosine kinase in vanadate-induced contraction

Gastric smooth muscle of cats was used to investigate the involvement of protein kinase in vanadate-induced contraction. Vanadate caused a contraction of cat gastric smooth muscle in a dose-dependent manner. Vanadate-induced contraction was totally inhibited by 2 mM EGTA and 1.5 mM LaCl₃ and significantly inhibited by 10 μM verapamil and 1 μM nifedipine, suggesting that vanadate-induced contraction is dependent on the extracellular Ca²⁺ concentration, and the influx of extracellular Ca²⁺ was mediated through voltage-dependent Ca²⁺ channel. Both protein kinase C inhibitor and tyrosine kinase inhibitor significantly inhibited the vanadate-induced contraction and the combined inhibitory effect of two protein kinase inhibitors was greater than that of each one. But calmodulin antagonists did not have any influence on the vanadate-induced contraction. On the other hand, both forskolin (1 μM) and sodium nitroprusside (1 μM) significantly inhibited vanadate-induced contraction. Therefore, these results suggest that both protein kinase C and tyrosine kinase are involved in the vanadate-induced contraction which required the influx of extracellular Ca²⁺ in cat gastric smooth muscle, and that the contractile mechanism of vanadate may be different from that of agonist binding to its specific receptor.     

Cyclo-oxygenase-2 expression and prostaglandin E2 production in experimental chronic gastric ulcer healing

Prostaglandin, a key molecule that stimulates the complex array of ulcer healing mechanism, gets synthesized in the mucosal cells by cyclooxygenase (COX) enzymes: COX-1 and COX-2. High expression level of COX-2 protein at healing ulcer margins highlights its role in ulcer healing and hypothesized to be an important contributing factor in healing mechanism of anti-ulcer drugs. In the present study we have compared the expression profile of COX-2 protein, prostaglandin E2 (PGE2) levels and myeloperoxidase activity in acetic acid induced chronic gastric ulcer model in rats treated with omeprazole, misoprostol and COX-2 selective nonsteroidal anti-inflammatory drug (NSAID) celecoxib. Both COX-2 expression and PGE2 level have shown differential pattern in different treated groups parallel to the differential effects of these drugs on ulcer healing. Omeprazole has significantly elevated the expression level of COX-2 protein, PGE2 level (19.37%), and decreased myeloperoxidase activity (81.92%), thereby causing the most effective ulcer healing (89.74%). Similar trend was observed with misoprostol, but with relatively less pronounced ulcer healing and COX-2 expression. Celecoxib has retarded COX-2 expression and delayed ulcer healing. Therefore, induction of COX-2 expression leading to higher level of prostaglandin appears to be an important contributing factor in drug mediated ulcer healing apart from the respective mechanisms of different drugs.     

前列腺素E2栓与缩宫素用于妊娠期糖尿病引产的对比分析

目的探讨妊娠期糖尿病采用前列腺素E2栓与缩宫素引产的效果对比。方法本次研究选择的对象共80例,均为本院2010年6月-2012年8月收治的妊娠期糖尿病行引产术者,随机按观察组和对照组各40例划分,对照组采用缩宫素治疗,观察组采用前列腺素E2栓治疗,回顾两组临床资料。结果两组用药前Bishop评分差异无统计学意义（P〉0．05）,用药后12h观察组显著高于对照组,差异有统计学意义（P〈0．05）。观察组临产时间短于对照组,阴道顺产率高于对照组,产后出血量及出生5min新生儿Apgar评分无明显差异（P〉0．05）。结论妊娠糖尿病患者引产中应用前列腺素E2栓药物,可缩短临产时间、促进宫颈成熟和引产,降低剖宫产率,为母婴安全提供了保障。     

Comparison of the involvement of protein kinase C in agonist-induced contractions in mouse aorta and corpus cavernosum

Protein kinase C (PKC) is involved in the regulation of vascular smooth muscle contraction. However, the role of PKC in erectile function is poorly understood. This study investigated whether PKC mediates agonist-induced contractions in mouse penile tissue (corpora cavernosa). We also compared the effects of PKC activators and inhibitors on contractile responses in mouse corpus cavernosum with those in mouse aorta. Aortic rings and corpus cavernosal strips from C57BL/6J mice were mounted in the organ bath for isometric tension recording. Our data showed that a PKC(alpha/beta) selective inhibitor, G(?)6976 (10 microM), inhibited phenylephrine and 9,11-dideoxy-11alpha,9alpha-epoxymethanoprostaglandin F(2alpha) (U46619, a thromboxane mimetic)-induced contractions in mouse aorta, reducing the maximum contraction by 94% and 17%, respectively. A non-selective PKC inhibitor, chelerythrine (30 microM), also significantly reduced phenylephrine- and U46619-induced maximum contractions in mouse aorta. However, G(?)6976 and chelerythrine had no significant effects on phenylephrine- and U46619-induced contractions in corpus cavernosum. Furthermore, a PKC activator, phorbol-12,13-dibutyrate (0.1 microM), significantly increased contractions in aorta (208+/-14% of KCl-induced maximum contraction) but failed to cause contractions in corpus cavernosum at 1 and 10 microM. Western blot analysis data suggested that protein expression of PKC was similar in aorta and corpus cavernosum. Taken together, our data indicate that PKC does not have a significant role in agonist-induced contractions in mouse corpus cavernosum, whereas it mediates the contractile response to agonists in the aorta.