Effects of GABAA receptor ligands on noradrenaline concentration and β-adrenoceptor binding in mouse cerebral cortex

The present experiments investigated changes in -adrenoceptor binding and noradrenaline stores in mouse cerebral cortex after single treatments with drugs which bind to the GABA_A receptor but which attenuate the actions of GABA. Neither the GABA antagonist, securinine, nor the picrotoxin/Cl^– channel ligand, picrotoxin, affected noradrenaline levels or -adrenoceptor binding. However, both the benzodiazepine inverse agonist, DMCM, and pentylenetetrazole increased noradrenaline levels 24 h after injection. Only pentylenetetrazol modified -adrenoceptor binding: there was a significant increase in receptor number 4 days after injection, but a significant decrease after 7 days. The anxiogenic, proconvulsant drug, yohimbine, was without effect. The changes induced by DMCM and pentylenetetrazole do not seem to be related to the behavioural effects of these drugs or to their affinity for binding to benzodiazepine receptors. The possibility that these compounds have actions in addition to those at the GABA_A receptor is discussed.     

Conformational features responsible for the binding of cyclic analogues of enkephalin to opioid receptors

Models of μ- and δ-receptor-bound backbone conformations of enkephalin cyclic analogues containing Phe⁴ were determined by comparing geometrical similarity among the previously found low-energy, backbone structures of -enkephalinamide, -enkephalinamide, -enkephalin and -enkephalin. The present μ-receptor-bound conformation resembles a β-I bend in the peptide backbone centred on the Gly³-Phe⁴ region. Two slightly different models were found for the δ-receptor-bound conformation; both of them are more extended than the μ-receptor-bound conformation and include a γ-turn (or a γ-like turn) on the Gly³ residue. Energetically favourable rotamers of Tyr and Phc side chains were also determined for the μ- and δ-conformations. The present models of μ- and δ-conformations share geometrical similarity with the low-energy structures of Leu-enkephalin and the analogue.     

Plasma membrane-mediated nuclear uptake and chromatin binding of insulin in tumor cell lines

Analysis of different cellular fractions after incubation of SW 948 and SW 707 colorectal carcinoma cells or WM 266-4 melanoma cells with 125I-insulin revealed the nondegraded hormone in the chromatin of these cells. Nuclear 125I-insulin was bound to specific fragments of EcoRI-, HaeIII-, and HincII-digested chromatin. A 45-kDa chromatin protein species that binds 125I-insulin was identified. Actinomycin D and cycloheximide inhibited the insulin-stimulated expression of chromatin receptors. Uptake of 125I-insulin by isolated nuclei occurred only in the presence of plasma membranes. Thus, at least some effects of insulin on target cells can be explained by direct gene regulation instead of "second messenger" action.     

Cyclical use of tamoxifen and high-dose medroxyprogesterone acetate in advanced estrogen receptor positive breast cancer

Summary One-hundred and seventy patients with estrogen receptor positive (10 pmol/g protein) advanced breast cancer have been treated in a prospective randomized study either with continuous tamoxifen 30 mg × 1 daily (TAM), or with TAM 30 mg × 1 daily for 8 weeks alternating with medroxyprogesterone acetate 500 mg × 2 daily for 8 weeks (TAM/HD-MPA). The response rate was 62% in the group treated with cyclic TAM/HD-MPA versus 41% in the TAM alone group (p = 0.02). There was no significant difference in duration of remissions or survival.     

Expression and function of c-kit receptor in bone marrow mononuclear cells of patients with myelodysplastic syndromes

目的　了解骨髓增生异常综合征 (MDS)骨髓单个核细胞c kit受体的表达与功能。方法　采用免疫荧光方法测定c kit受体蛋白 (CD117)的表达 ;逆转录 聚合酶链反应方法测定c kitmRNA的表达 ;细胞培养检测c kit受体的功能。结果　CD117表达率正常人为 3 0 4 %± 1 4 9% ,MDS患者为 8 58%± 5 2 8% ,两者差异有显著性 (P <0 0 5) ;RA患者为 5 12 %± 2 13% ) ,RAEB RAEB t患者为 10 0 1%± 5 0 7% ,两者差异有显著性 (P <0 0 5) ;MDS继发白血病患者为 32 4 3%± 18 16 %。MDS患者c kit基因mRNA表达与CD117表达相一致。正常骨髓单个核细胞体外半固体培养 ,在加入造血干细胞因子、白细胞介素 3、红细胞生成素 (SCF IL 3 Epo)后形成的粒 巨噬细胞集落 (CFU GM)较仅加入IL 3 Epo显著增多 (P <0 0 5) ,红系爆式集落 (BFU E)数量极显著增多 ,且BFU E体积显著增大(P <0 0 1)。MDS患者在上述相同条件下CFU GM数量无明显变化 (P >0 0 5) ,与正常对照比较 ,CFU GM和BFU E数量均显著减少 (P <0 0 5)。结论　MDS患者骨髓单个核细胞CD117表达明显高于正常对照 ,且与病情进展相关 ;c kitmRNA表达与CD117表达相一致 ;MDS患者骨髓单个核细胞体外培养时 ,SCF协同IL 3、Epo促进造血干 祖细胞增殖分化能力较正常对照明     

不同方法使用东莨菪碱脱毒效果的比较

目的：观察东莨菪碱（scopolamine,Spm)和氯丙嗪（chloprmazine,Clo)对吗啡戒断反应的影响。方法：采用吗啡依赖大鼠模型,不同剂量单多次皮下注射（sc)东莨菪碱及合并使用氯丙嗪处理动物后,腹腔注射（ip)纳洛酮5mg/kg诱发戒断反应,观察戒断症状。结果：单次sc东莨菪碱1.0mg/kg及多次sc东莨菪碱0.5mg/kg可明显抑制吗啡依赖大鼠的身体戒断反应,合并注射氯丙嗪20.0mg/kg时的效果更好.结论:东莨菪碱通过Ach受体可以抑制吗啡戒断反应,氯丙嗪则可能通过作用于蓝斑墙 枢部位α2受体与东莨菪碱起到协同作用.     

Effect of ipratropium bromide on airway and pulmonary muscarinic receptors in a rat model of chronic obstructive pulmonary disease

Objective　To observe the level of muscarinic receptors in airway and lung tissues, and the effect of inhaled ipratropium bromide on these receptors in a rat model of chronic obstructive pulmonary disease (COPD). Methods　This model was developed by exposure of rats to 250 ppm SO2 gas, 5?h/d, 5d/wk, for a period of 7 wk. The COPD rats inhaled 0.025% aerosolized iratropium bromide for 20 min, 2 times daily, in an airtight chamber. Muscarinic receptors in airway and lung tissues of normal rats, ipratropium bromide-treated COPD rats and the recovering COPD rats were measured by the radio-ligand binding assay. Results　Airway/lung pathology and pulmonary function tests showed that chronic SO2 exposure caused pathophysiologic changes similar to those observed in human COPD. The density (0.038±0.011, pmol/mg protein) and affinity (Kd, 23±11 pmol/L) of muscarinic receptors in airway and lung tissues of COPD rats were not changed compared with those of normal control rats (0.030±0.008 and 29±19, respectively, P&gt;0.05). Densities of the muscarinic receptors were not changed after inhalation of ipratropium bromide for 5 days, but increased significantly after inhalation for 30 days, as compared with those of the untreated COPD rats. The muscarinic receptors returned the normal levels at day 6 after cessation of ipratropium bromide treatment. There were no differences among different groups of rats in equilibrium dissociation constants (Kd). Conclusion　A rat model of COPD with pathophysiologic changes similar to the human counterpart was developed using chronic SO2 exposure. There was no significant change in the number and function of muscarinic receptors in airway and lung tissues of the COPD rats, but upregulation of the muscarinic receptors was observed after long-term inhalation of ipratropium bromide.     

豚鼠视网膜组织M4受体的表达

目的 检测M4受体在豚鼠视网膜组织的表达及分布.方法 4周龄三色豚鼠21只,其中7只动物眼球制备石蜡切片,免疫组织化学染色法检测后极部视网膜组织M4受体表达与分布;其余动物分别提取眼视网膜组织RNA和蛋白质,逆转录聚和酶链反应(RT-PER)、蛋白质免疫印迹(Western blot)法检测M4受体mRNA和蛋白质表达.结果 免疫组织化学染色显示,M4受体分布于豚鼠视网膜RPE细胞层,光感受器细胞层、外核层、内核层,大多数神经节细胞,以及内从状层和内核层交界区;豚鼠视网膜组织表达M4受体mRNA,扩增产物约为221 bp,阴性对照未见扩增产物.免疫印迹显示,豚鼠视网膜组织表达明显的M4受体免疫反应活性,分子量约为38 000.阴性对照组无阳性表达条带.结论 豚鼠视网膜组织有M4受体蛋白表达.     

大鼠脾虚证与血清甲状腺激素及下丘脑、胸腺细胞核T3受体关系

目的：探讨脾虚证与血清甲状腺激素及下丘脑、胸腺细胞核T3受体的关系。方法：成年SD大鼠32只了随机分为4组（每组8只）：A组（正常组）、B组（脾虚组）、C组（治疗组）、D组（自复组）。采用放射配基分析法,测定各组大鼠血清T3、T4、FT3、FT4、 γ－T3 及下丘脑、胸腺细胞核T3受体的含量。结果：B、D组大鼠血清T3、T4、FT3、FT4含量均较A、C组低,有显差异（P＜0.05或P＜0.01）;各且间血清γ－T3 含量无显性差异;B、D组下丘脑、胸腺细胞T3受体含量较A、C组低,有显差异（P＜0.01）。结论：血清甲状腺激素及下丘脑、胸腺细胞核T3受体的水平降低,可导致甲状腺激素生物效应低下,经由神经内分泌免疫调节环路,削弱免疫功能,这可能是脾虚证的一种重要病机。     

电针对大鼠胃粘膜胃泌素和EGFR表达及AgNOR的影响

目的 观察电针足三里穴对胃粘膜细胞受体表达及核增殖的影响。探讨针灸作用机制。方法 75只SD大鼠随机分段分为5线,在清醒状态下针刺实验,SABC法免疫组化染色观察胃粘膜细胞胃泌素（Gas)、表皮生长因子受体（EGFR）表达程度,AgNOR特染观察胃腺细胞增殖情况。结果 电针足三里穴胃粘膜EGFR阳性表达率73.3%,Gas表达率66.7%;电针三阴交对EGFR表达远景as表达率为46.7%;联合穴位组Gas,EGFR表达均达60.0%,AgNOR特染各组核内嗜银颗粒无明显差异。结论 电针足三里可提高胃粘膜细胞Gas和EGFR表达率。改变细胞分子结构。影响细胞功能,电针对胃粘膜细胞核增殖无影响。