Real-time measurement in living cells of insulin-like growth factor activity using bioluminescence resonance energy transfer

Insulin-like growth factor (IGF)-I and -II function in normal physiology to control growth, development, and differentiation, but are also important in pathophysiological conditions, particularly in cancer. The biological effects of the IGFs are mediated by the IGF-I receptor (IGFR), a covalent homodimer composed of two alpha and two beta chains, similar in structure to the insulin receptor (IR). To allow measurement of the stimulation of IGFR in living cells, we developed an assay based on bioluminescence resonance energy transfer (BRET) between a donor molecule, Renilla luciferase, and an acceptor fluorophore, enhanced yellow fluorescent protein (EYFP). Initial attempts based on fusion of the luciferase to IGFR, and EYFP to IGFR, or to downstream signaling molecules, insulin receptor substrate-1 (IRS1) or protein tyrosine phosphatases-1B (PTP-1B), failed. However, similar experiments with IR, carried our in parallel, proved successful. We therefore, constructed assays based on chimeric IGFR/IR proteins, in which the ligand binding site was derived from IGFR. With the most efficient assay, in which the luciferase is fused to a chimeric receptor with the entire intracellular portion derived from IR, and EYFP fused to PTP-1B, IGF activity was measured specifically with sensitivity similar to the corresponding assay for insulin, based on IR. The established system allows efficient evaluation of candidate ligand- or receptor-directed molecules for the modulation of IGF activities. Furthermore, we demonstrate that a set of inhibitory IGF binding proteins (IGFBPs) or activating IGFBP-specific proteinases, unique to the IGF system, may serve as potential targets. In addition to screening, real-time measurement of IGFR stimulation may be important in efforts to understand the kinetics of receptor stimulation, in particular differences between IGFR and IR.     

IGF-1及其受体在乙型病毒性肝炎组织中表达的临床意义

目的 探讨胰岛素样生长因子-1(IGF-1)及其受体在乙型病毒性肝炎活检组织中的表达及临床意义。方法 采用免疫组化技术，对105例肝炎组织及10例正常肝组织中的IGF-1及其受体的表达情况进行检测分析。结果 半定量分析结果显示，正常肝组织中IGF-1及其受体的表达与急性肝炎、慢性轻度至中度肝炎组织间存在显著性差异；急性、慢性轻度、慢性中度肝炎与慢性重度肝炎间存在显著性差异；而正常肝组织与慢性重度肝炎间无显著性差异。结论 IGF-1及其受体的表达强度可以作为判断肝炎发展过程中不良转化的重要指标。     

Comparative pharmacokinetics and pharmacodynamics of the novel rapid-acting insulin analogue, insulin aspart, in healthy volunteers

Objective: The pharmacokinetics of a new insulin analogue, insulin aspart, were compared with unmodified human insulin in a double-blind crossover study of 25 fasting healthy men following a single subcutaneous dose. Methods: Either insulin aspart or human insulin, 0.1 U · kg-body-weight⁻¹, was injected subcutaneously and followed by determination of 8-h profiles of serum insulin and plasma glucose concentrations. Results: The absorption of insulin aspart was, on average, more than twice as fast and reached levels more than twice as high compared with human insulin [t_max(ins) of 52 (23) vs 145 (93) min, P < 0.0001; and C_max(ins) of 41 (11) vs 18 (4) mU · l⁻¹, P < 0.0001; mean with (SD)]. However, total bioavailability did not differ between the insulins, and thus the mean residence time was significantly shorter for insulin aspart [MRT_(ins) of 149 (26) vs 217 (30) min, P < 0.0001]. Plasma glucose (PG) fell more than twice as rapidly [t_min(PG) of 94 (45) vs 226 (120) min, P < 0.0001], to a greater extent [C_min(PG) 2.1 (0.6) vs 1.4 (0.4) mmol · l⁻¹, P < 0.0001], and for a shorter duration with insulin aspart than with human insulin. Conclusion: With improved subcutaneous absorption characteristics, the insulin aspart concentration–time profile resembles physiological meal-stimulated insulin release more closely than that of unmodified human insulin. This significantly alters the pharmacodynamic response in an advantageous manner in the meal-related treatment of diabetes mellitus. Received: 26 October 1998 / Accepted in revised form: 23 January 1999     

西妥昔单抗联合顺铂对鼻咽癌荷瘤裸鼠移植瘤生长作用的影响

目的：探讨靶向表皮生长因子受体（EGFR）特异性单抗西妥昔单抗单药及与顺铂联合应用对鼻咽癌荷瘤裸鼠移植瘤生长的影响及其可能的作用机制。方法：将鼻咽癌细胞HONE1制成细胞悬液后接种于裸鼠皮下,待成瘤后将裸鼠随机分入4个处理组：生理盐水组、西妥昔单抗组、顺铂组及两药联合组。定期测量每只裸鼠肿瘤最大径和最小径,计算肿瘤体积。用药结束后,处死裸鼠,取出肿瘤组织,称重,计算抑瘤率。用免疫组化方法检测肿瘤组织中磷酸化蛋白激酶B（p-AKT）和人磷酸化细胞外信号调节激酶（p-ERK）表达。结果：与生理盐水组相比,西妥昔单抗单药组肿瘤体积变化及治疗后平均瘤重差异均无统计学意义,顺铂单药组及两药联合组均有抑瘤效应,以两药联合组抑瘤效果尤为显著。免疫组化显示肿瘤组织AKT和ERK磷酸化水平在顺铂处理组上调,而在西妥昔单抗单药及联用组则较低。结论：西妥昔单抗单药对HONE1鼻咽癌荷瘤裸鼠移植瘤的生长无明显影响,但其与顺铂联用可增加顺铂的抑瘤作用。     

乳铁蛋白对原代大鼠成骨细胞IGFBP-3、IGFBP-4、IGFBP-5mRNA表达的影响

目的研究乳铁蛋白对原代大鼠成骨细胞胰岛素生长因子结合蛋白-3(IGFBP-3)、胰岛素生长因子结合蛋白-4(IGFBP-4)、胰岛素生长因子结合蛋白-5(IGFBP-5)m RNA表达的影响。方法用混合酶消化法分离大鼠颅骨成骨细胞,进行原代培养。细胞以6×103/cm2接种于六孔板内,用不同浓度乳铁蛋白即0μg/ml(对照组)、0.1μg/ml(乳铁蛋白1组)、1μg/ml(乳铁蛋白2组)、10μg/ml(乳铁蛋白3组)、100μg/ml(乳铁蛋白4组)、1000μg/ml(乳铁蛋白5组)干预原代大鼠成骨细胞1、3、5、7 d后提取总RNA,采用荧光定量PCR技术分析IGFBP-3、IGFBP-4、IGFBP-5 m RNA的表达。结果与对照组比较,各浓度组及时间段对IGFBP-3 m RNA表达的影响不稳定,时高时低。与对照组比较,除了乳铁蛋白1组外,其他浓度对IGFBP-4 m RNA的表达呈浓度梯度的抑制(P<0.01)。与对照组比较,实验干预第1天,呈浓度梯度抑制IGFBP-5 m RNA的表达(P<0.01),乳铁蛋白4、5组在第5、7天表现为继续抑制(P<0.01),而其他时间及浓度对IGFBP-5 m RNA的表达调控不稳定。结论乳铁蛋白影响原代大鼠成骨细胞IGFBP-3、IGFBP-4、IGFBP-5 m RNA的表达,其中乳铁蛋白对IGFBP-3、IGFBP-5 m RNA表达的调控不稳定,而乳铁蛋白抑制IGFBP-4 m RNA的表达呈浓度依赖性,浓度越高抑制作用越强。     

Prenatal stress affects insulin-like growth factor-1 (IGF-1) level and IGF-1 receptor phosphorylation in the brain of adult rats

It has been shown that stressful events occurring in early life have a powerful influence on the development of the central nervous system. Insulin-like growth factor-1 (IGF-1) promotes the growth, differentiation and survival of both neurons and glial cells and is thought to exert antidepressant-like activity. Thus, it is possible that disturbances in the function of the IGF-1 system may be responsible for disturbances observed over the course of depression. Prenatal stress was used as a valid model of depression. Adult male offspring of control and stressed rat dams were subjected to behavioural testing (forced swim test). The level of IGF-1 in the blood and the expression of IGF-1, IGF-1R, and IRS-1/2 in the hippocampus and frontal cortex using RT-PCR, ELISA and western blotting were measured. In addition the effect of intracerebroventricularly administered IGF-1 and/or the IGF-1R receptor antagonist JB1 in the forced swim test was studied. Prenatally stressed rats showed depressive like behaviour, including increased immobility time as well as decreased mobility and climbing. Intracerebroventricular administration of IGF-1 reversed these effects in stressed animals, whereas concomitant administration of the IGF-1R antagonist JB1 completely blocked the effects. Biochemical analysis of homogenates from the hippocampus and frontal cortex revealed decreases in IGF-1 level and IGF-1R phosphorylation along with disturbances in IRS-1 phosphorylation. These findings reveal that prenatal stress alters IGF-1 signalling, which may contribute to the behavioural changes observed in depression.     

Dehydro-enkephalins. III. Synthesis and biological activity of [ΔAla2, Leu5]-enkephalin

[ΔAla², Leu⁵]-enkephalin has been prepared and shown to be more active than the parent saturated enkephalin in a binding assay using rat brain membranes and [³H] dihydromorphine as a tracer. In a comparison of potencies against [³H] dihydromorphine and [³H]-[d -Ala², d -Leu⁵]-enkephalin as tracers, [ΔAla², Leu⁵]-enkephalin showed preference for μ opiate receptors, possibly due to the hydrophobicity of the ΔAla² residue. A synthetic tetrapeptide enkephalin [ΔAla²]-desLeu⁵-enkephalin had weak activity and high selectivity for the μ receptors. O-Acylation of a serine residue in the peptide was achieved by coupling between the peptide and a carboxylic acid using DCC and a catalytic amount of 4-dimethylaminopyridine.     

Anti-diabetic effects of puerarin,isolated from Pueraria lobata (Willd.), on streptozotocin-diabetogenic mice through promoting insulin expression and ameliorating metabolic function

Diabetes is a chronic disease characterized by the metabolic disorder in specific tissues. Our present study was designed to assess the potential benefits of puerarin (PR) on hypoglycemic and hypolipemic effects in diabetic mice induced by streptozotocin (STZ). The results achieved from these experiments showed that glycemia in STZ-diabetogenic mice were significantly reduced following the PR administration, while serum insulin concentration was increased. In addition, PR contributed to improving the dyslipidemia conditions. Histopathological examination indicated that the STZ-lesioned pancreas tissue in PR-administrated mice was effectively alleviated. Meanwhile, intrapancreatic protein levels of insulin receptor substrate-1 (IRS-1) and insulin-like growth factor-1 (IGF-1) were up-regulated, respectively. On the other hand, endogenous mRNA levels of skeletal muscle insulin receptor (InsR) and peroxisome proliferators-activated receptor α (PPARα) were increased after administration of PR. Taken together, these findings reveal that puerarin effectively exerts the hypoglycemic and hypolipemic roles, which its potential anti-diabetic activity is associated with elevating insulin expression and maintaining metabolic homoeostasis in STZ-diabetogenic mice.     

Pharmacological characterization of the inhibitory activity of beta h-endorphin (beta h-EP), [Arg9,19,24,28,29]-beta h-EP, [Gln8,Gly31]-beta h-EP-Gly-Gly-NH2, in the neuroeffector junction of the mouse vas deferens.

The inhibitory opioid activities of beta h-endorphin (beta h-EP), its structurally related peptide analogues [Gln8,Gly31]-beta h-EP-Gly-Gly-NH2 (Gly-Gly-beta h-EP), [Arg9,19,24,28,29]-beta h-EP (Arg-beta h-EP) and methionine enkephalin have been examined in the electrically stimulated mouse vas deferens bioassay. All four peptides behaved as full agonists; methionine enkephalin was the most potent followed by Arg-beta h-EP, beta h-EP and Gly-Gly-beta h-EP. Neither Gly-Gly-beta h-EP nor Arg-beta h-EP antagonized the inhibitory action of beta h-EP or methionine enkephalin. An hour of tissue exposure to 30 nM beta-funaltrexamine followed by thorough washing, displaced to the right, in a parallel fashion, the concentration-response curves of beta h-EP and analogues. Whereas the displacement of the concentration response curves was 8 to 10-fold for beta h-EP and Arg-beta h-EP, it was only about 3-fold for Gly-Gly-beta h-EP and methionine enkephalin. Naltrindole was the most potent antagonist of methionine enkephalin with an apparent pA2 of 9.4; its potency as an antagonist of beta h-EP and related analogues was approximately one-tenth of this with pA2 values approximately 8.5. Norbinaltorphimine also antagonized the action of the opioid peptides with pA2 values close to 7.8.     

Andrographolide regulates epidermal growth factor receptor and transferrin receptor trafficking in epidermoid carcinoma (A-431) cells

Background and purpose:

Andrographolide is the active component of Andrographis paniculata, a plant used in both Indian and Chinese traditional medicine, and it has been demonstrated to induce apoptosis in different cancer cell lines. However, not much is known about how it may affect the key receptors implicated in cancer. Knowledge of how andrographolide affects receptor trafficking will allow us to better understand new mechanisms by which andrographolide may cause death in cancer cells.

Experimental approach:

We utilized the well-characterized epidermal growth factor receptor (EGFR) and transferrin receptor (TfR) expressed in epidermoid carcinoma (A-431) cells as a model to study the effect of andrographolide on receptor trafficking. Receptor distribution, the total number of receptors and surface receptors were analysed by immunofluorescence, Western blot as well as flow-cytometry respectively.

Key results:

Andrographolide treatment inhibited cell growth, down-regulated EGFRs on the cell surface and affected the degradation of EGFRs and TfRs. The EGFR was internalized into the cell at an increased rate, and accumulated in a compartment that co-localizes with the lysosomal-associated membrane protein in the late endosomes.

Conclusion and implications:

This study sheds light on how andrographolide may affect receptor trafficking by inhibiting receptor movement from the late endosomes to lysosomes. The down-regulation of EGFR from the cell surface also indicates a new mechanism by which andrographolide may induce cancer cell death.     

Proteasomal degradation of IRS-2, but not IRS-1 by calcineurin inhibition: attenuation of insulin-like growth factor-I-induced GSK-3beta and ERK pathways in adrenal chromaffin cells

The ability of calcineurin to regulate IRS-1 and IRS-2 levels has not been examined in any given cells, although calcineurin inhibition by therapeutic immunosuppressants produced cytoprotective and cytotoxic effects (e.g., new-onset of diabetes mellitus, seizure). Chronic (>or=3h) treatment of cultured bovine adrenal chromaffin cells with cyclosporin A or FK506 decreased IRS-2 protein level by approximately 50% (IC(50)=200 or 10nM), without changing IRS-2 mRNA level, and insulin receptor, insulin-like growth factor-I (IGF-I) receptor, IRS-1, PI3K/PDK-1/Akt/GSK-3beta and ERK1/ERK2 protein levels. When the cells were washed to remove the test drug, the decreased IRS-2 level restored to the control level. Cyclosporin A or FK506 treatment inhibited calcineurin activity (IC(50)=500 or 40 nM, in vitro assay). Rapamycin, an FK506-binding protein ligand unable to inhibit calcineurin, failed to decrease IRS-2, but reversed FK506-induced decreases of calcineurin activity and IRS-2 level. Pulse-label followed by polyacrylamide gel electrophoresis revealed that cyclosporin A or FK506 accelerated IRS-2 degradation rate (t(1/2)) from >24 to approximately 4.2h, without altering IRS-2 synthesis. IRS-2 reduction by cyclosporin A or FK506 was prevented by lactacystin (proteasome inhibitor), but not by calpeptin (calpain inhibitor) or leupeptin (lysosome inhibitor). Cyclosporin A or FK506 increased serine-phosphorylation and ubiquitination of IRS-2. Cell surface (125)I-IGF-I binding capacity was not changed in cyclosporin A- or FK506-treated cells; however, IGF-I-induced phosphorylations of GSK-3beta and ERK1/ERK2 were attenuated by approximately 50%, which were prevented by rapamycin or lactacystin. Thus, calcineurin inhibition decreased IRS-2 level via proteasomal IRS-2 degradation, attenuating IGF-I-induced GSK-3beta and ERK pathways.     

Signal transduction of the protective effect of insulin like growth factor-1 on adriamycin-lnduced apoptosis in cardiac muscle cells

To determine whether Insulin-like growth factor (IGF-I) treatment represents a potential means of enhancing the survival of cardiac muscle cells from adriamycin (ADR)-induced cell death, the present study examined the ability of IGF-I to prevent cell death. The study was performed utilising the embryonic, rat, cardiac muscle cell line, H9C2. Incubating cardiac muscle cells in the presence of adriamycin increased cell death, as determined by MTT assay and annexin V-positive cell number. The addition of 100 ng/mL IGF-I, in the presence of adriamycin, decreased apoptosis. The effect of IGF-I on phosphorylation of PI, a substrate of phosphatidylinositol 3-kinase (PI 3-kinase) or protein kinase B (AKT), was also examined in H9C2 cardiac muscle cells. IGF-I increased the phosphorylation of ERK 1 and 2 and PKC zeta kinase. The use of inhibitors of PI 3-kinase (LY 294002), in the cell death assay, demonstrated partial abrogation of the protective effect of IGF-I. The MEK1 inhibitor-PD098059 and the PKC inhibitor-chelerythrine exhibited no effect on IGF-1-induced cell protection. In the regulatory subunit of PI3K-p85- dominant, negative plasmid-transfected cells, the IGF-1-induced protective effect was reversed. This data demonstrates that IGF-I protects cardiac muscle cells from ADR-induced cell death. Although IGF-I activates several signaling pathways that contribute to its protective effect in other cell types, only activation of PI 3-kinase contributes to this effect in H9C2 cardiac muscle cells.     

Calphostin C as a rapid and strong inducer of apoptosis in human coronary artery smooth muscle cells

Vascular smooth muscle cells (VSMCs) play a major role in the development of atherosclerotic and restenotic lesions. The apoptotic process has been implicated in the development of this pathology. In this study, we characterized the induction of apoptosis by calphostin C (CC), a protein kinase C (PKC) inhibitor, in primary human coronary artery smooth muscle cells in the presence and absence of insulin-like growth factor-I (IGF-I). Additionally, we investigated the signal transduction pathways important for IGF-I mediated protection. Calphostin C induced apoptosis, as measured by terminal deoxy-UTP nick-end labeling (TUNEL), in a time- and dose-dependent manner, approaching 20% within 6 h of 50 nM calphostin C treatment. The amount of apoptosis increased to 44.58+/-8.08%, 47.54+/-1.66% and 78.1+/-11.9% after 8, 10 and 12 h of treatment, respectively (p<0.01 vs. control). IGF-I offered significant protection (p<0.05) at 8 and 10 h of treatment (60.6% and 52.5% protection, respectively). DNA ELISA confirmed the apoptotic effect of calphostin C and the protective effect of IGF-I. After 6 h of calphostin C treatment, DNA ELISA revealed 11.20+/-1.53 fold greater apoptosis as compared to baseline values. IGF-I treatment offered a level of protection of 46.6% as measured by DNA ELISA (p=0.06). Apoptosis was further qualitatively confirmed by time-lapse video microscopy and scanning electron microscopy. Interestingly, inhibitors of phosphatidylinositol-3-kinase (PI-3-K), p38 and extracellular regulated kinase (ERK) activation significantly (p<0.05 vs. calphostin C only treatment) increased apoptosis when used in conjunction with calphostin C. Inhibitors of phospatidylinositol-3-kinase and ERK activation reversed IGF-I protection. However, the p38 inhibitor SB203580 failed to reverse IGF-I protection. This study characterized an apoptotic system for human coronary artery smooth muscle cells offering a rapid and strong induction of programmed cell death (PCD) that remains responsive to the survival effects of IGF-I. Studies utilizing this system may prove useful in understanding the apoptotic response of VSMCs in the arterial wall.     

Design and cloning of the gene for a novel insulin analogue, (B30-homoserine) human insulin

In order to prepare a novel human insulin analogue substituted with homoserine at B³⁰ position, (B³⁰-homoserine) human insulin, a synthetic gene was designed by linking directly a gene for B chain with that for A chain. This gene was constructed by enzymatic joining of 10 different synthetic oligonucleotides, and then inserted at the polylinker region of pUC19 plasmid. To achieve a high level of gene expression, the gene fusion technique was employed using amino terminal regions oflacZ gene up toClal orHpal, and either of them has been located under tac promoter. The chemical induction of these fused genes by isopropyl-β-D-thiogalactopyranoside (IPTG) gave a satisfactory level of expression inEscherichia coli harboring the constructed plasmids. It was observed that the fused gene product as a single chain insulin precursor was produced more than 305 of total cell protein ofE. coli as a form of inclusion body.     

The role of insulin and insulin-like growth factor I in the molecular and cellular mechanisms underlying the pathology of Alzheimer's disease

Cellular and molecular processes leading to abnormal accumulation of β amyloid in the brain are slowly being uncovered. A potential involvement of insulin and insulin-like growth factor I (IGF-I) in this plausible pathogenic process in Alzheimer's disease has recently been proposed. Evidence favoring this idea stems from the ability of both hormones to stimulate β amyloid release from neurons as well as by the stimulatory effect that IGF-I exerts on brain amyloid clearance. In addition, insulin and IGF-I levels are altered in Alzheimer's patients and, probably in close association to these changes, cell sensitivity towards insulin—and possibly also IGF-I—is decreased in these patients. We now review evidence that disturbed insulin/IGF-I signaling to brain cells, initiated at the level of the blood–brain barriers is probably instrumental in development of brain amyloidosis. Furthermore, insulin and IGF-I are potent neuroprotective factors and can regulate levels of phosphorylated tau, a major component of neurofibrillary tangles found in Alzheimer's brains. Therefore, a decrease in trophic support to neurons together with increased tau phosphorylation will follow loss of sensitivity towards insulin and IGF-I. Altogether, this supports the notion that a single pathogenic event, i.e., brain resistance to insulin/IGF-I, accounts for neuronal atrophy/death, tangle formation and brain amyloidosis typical of Alzheimer's pathology.     

人甲状旁腺素活性片段前体物Pro-Pro-hPTH(1-34)的制备及活性研究

目的制备出具有生物活性的人甲状旁腺素活性片段类似物,并对其活性进行考察。方法采用基因工程方法:大肠杆菌BL 21为宿主菌,pET 28a为表达载体,天门冬酰胺酶Ⅱ切除信号肽的C末端片段为融合伙伴,在融合伙伴和目的肽结合处引入Asp Pro酸敏感位点及二肽酶Ⅳ识别的N端Pro Pro位点,之后经诱导表达,酸水解使融合伙伴和目的肽分离。结果成功构建了hPTH(1 34)的融合表达体系,它能高效表达含hPTH(1 34)的融合蛋白,经纯化,得到多肽纯品,经鉴定,该多肽的分子量、氨基酸组成均与设计的分子相符,工程菌中用于编码该多肽的DNA片段其测序结果也与原设计相符,是表达该多肽的正确模板。该多肽在Parsons雏鸡分析及卵巢摘除大鼠模型试验中均显示显著活性。结论用基因工程方法成功地制备出人甲状旁腺素活性片段类似物,该产物具有显著生物活性及潜在的药用价值。     

血管内皮生长因子受体-1抗体对人喉鳞癌细胞裸鼠移植瘤生长的影响

目的研究血管内皮生长因子受体-1(VEGFR-1)抗体对人喉鳞癌细胞(Hep-2)裸鼠移植瘤模型的影响。方法利用Hep-2细胞建立裸鼠喉癌模型。20只裸鼠成瘤后分别皮下注射VEGFR-1抗体和生理盐水0.2ml,用药15d后观察肿瘤体积及质量,计算抑瘤率;光镜观察移植瘤的形态学变化;进行肿瘤微血管计数;流式细胞仪检测瘤细胞凋亡情况。结果治疗组与生理盐水组移植瘤体积和质量差异有统计学意义(t体积=-5.058,P<0.001;t′重量=-3.4,P=0.003)。VEGFR-1抗体抑瘤率为49.88%,微血管密度(MVD)治疗组为6±4,对照组为13±8(t=2.486,P=0.023)。治疗组与对照组瘤细胞凋亡率分别为(23±4)%,(10±4)%。两组比较差异有统计学意义(t=8.222,P<0.001)。结论VEGFR-1抗体可以导致肿瘤血管生成减少,并抑制裸鼠Hep-2移植瘤的生长,其作用机制可能与VEGFR-1作用位点的封闭和瘤细胞的凋亡增加有关。     

中华眼镜蛇(Naja Naja Atra)毒神经生长因子对PC_(12)细胞κ阿片受体mRNA表达的影响

目的研究眼镜蛇毒神经生长因子(nNGF)对PC12细胞κ阿片受体mRNA表达的影响,探讨nNGF诱导PC12细胞分化的分子机制。方法用RT-PCR方法半定量地考察nNGF及κ阿片受体的一些拮抗剂和激动剂对PC12细胞κ阿片受体mRNA表达的影响。结果(1)在25,50和100 ng/mL 3个nNGF剂量组中,50和100 ng/mL nNGF显著下调PC12细胞κ阿片受体mRNA的表达。(2)50 ng/mL nNGF分别处理PC12细胞1,3,5,7,10 d后,结果显示κ阿片受体mRNA表达随时间有降低的趋势,7 d时显著下调(P<0.05),10 d时特别显著(P<0.01)。(3)10μmol/L吗啡上调PC12细胞κ阿片受体mRNA表达,并能逆转nNGF对该κ阿片受体mRNA表达的下调效应。10μmol/L纳络酮对PC12细胞κ阿片受体的表达无显著影响,也能逆转nNGF对该κ阿片受体mRNA表达的下调效应。但吗啡和纳络酮共存时不能逆转NGF对该κ阿片受体mRNA表达的下调效应。结论nNGF诱导PC12细胞分化时,能下调其κ阿片受体mRNA表达,这种下调能分别被吗啡或纳络酮逆转,但不能被吗啡和纳络酮共存时逆转。     

Evidence that [Phe1 ψ(CH2-NH)Gly2]nociceptin-(1-13)-NH2, a peripheral ORL-1 receptor antagonist,acts as an agonist in the rat spinal cord

[Phe¹ ψ(CH₂-NH)Gly²]nociceptin-(1-13)-NH₂, a pseudopeptide analogue of nociceptin is an antagonist in peripheral assays. Here, using in vivo electrophysiological recordings of dorsal horn neurones, [Phe¹ ψ(CH₂-NH)Gly²]nociceptin-(1-13)-NH₂ appears to have agonist activity after spinal administration. The noxious evoked activity of the neurones was inhibited by [Phe¹ ψ(CH₂-NH)Gly²]nociceptin-(1-13)-NH₂, which was as potent as nociceptin itself.     

7-[(1S,5R)-2-苄基-2,6二氮杂环(3.2.1)辛烷-6-基]喹诺酮类化合物的合成与抗菌作用

以 ( 4R) 羟基 L 脯氨酸为原料 ,经十三步反应得 ( 1S ,5R) 2 苄基 2 ,6 二氮杂二环 ( 3.2 .1)辛烷二氢溴酸盐 ,以此化合物作为 7位侧链 ,合成了四个喹诺酮类化合物 ,并测定了它们对 10株革兰氏阳性菌和 6株革兰氏阴性菌的MIC值 ,结果表明 ,它们的体外抗菌作用均低于对照药加替沙星和环丙沙星。本文共合成了 2 0个化合物 ,除 2、3、4外 ,其余均为文献未见报道的新化合物 ,其结构经NMR和MS所确证。