Selective protection of cells against X-irradiation. Isoproterenol protects only those cells that possesβ-adrenoreceptors

Summary In mixed culture of Chinese hamster fibroblatst, clone 431, and transformed murine L fibroblasts, clone B-82, isoproterenol was found to protect only 431 cells against ionizing radiation. It was shown that 431 cells, in contrast to B-82 cells, possess-adrenoreceptors, and the radioprotective effect of isoproterenol can be realized only if this agent interacts with-adrenoreceptors coupled with the cAMP system. Since malignization often causes the disappearance of-adrenergic and other hormone receptors, the combined culturing and irradiation of the cells studied can be regarded as a model of the growth of malignant cells (B-82) among normal tissue cells (431 cells) under conditions of radiation therapy. A possibility of selective protection against radiation damage of normal tissue cells, with retention of the former radiosensitivity of tumor cells, is discussed.     

Differential effects of prostaglandins and isoproterenol on cAMP content and Na,K pump activity in rat submandibular acini

Summary The -adrenergic agonist isoproterenol and prostaglandins E₁ and E₂ (but not F₂) increased the cAMP content of rat submandibular acini in vitro, but only isoproterenol enhanced ouabain-sensitive⁸⁶Rb (K) uptake. These findings suggest that cAMP is not involved in the activation of the Na, K pump in salivary cells.     

Effect of high doses of somatostatin on adenylate cyclase activity in peripheral mononuclear leukocytes from normal subjects and from acute leukemia patients

Summary In normal lymphocytes somatostatin non-competitively inhibited basal (ID₅₀ 5×10^–4 M) and isoproterenol- and forskolin-stimulated adenylate cyclase activity (Ac). In acute leukemia blasts, non-responsive to isoproterenol, forskolin, which activates the catalytic subunit, stimulated and somatostatin inhibited Ac, thus indicating the leukemic enzyme, though defective, retains the inhibitory pathway and catalyst function.     

Hormone and forskolin-stimulated cyclic AMP accumulation in human lymphocytes: reliability of longitudinal time measurements

Summary Reliability of measurement of lymphocyte cyclic AMP synthesis in intact cells was estimated by taking 3 successive blood samples during a one-month period from 11 healthy volunteers. Isoproterenol and prostaglandin E₁-stimulated cyclic AMP accumulation were used to evaluate the activity of these two receptor activities in human lymphocytes. Forskolin-stimulated cyclic AMP accumulation was used to evaluate the activity of the Ns/catalytic subunit. Only for forskolin was significant reliability observed. For isoproterenol and prostaglandin E₁ significant reliability was observed only for male subjects.Acknowledgment. This work was supported in part by the following organizations: Chief Scientist's Office, Israel Ministry of Health; Herman Goldman Foundation, New York; United Jewish Endowment Fund of Greater Washington-Pollinger Foundation.     

大豆异黄酮对异丙肾上腺素诱导大鼠心肌纤维化的保护作用

目的观察大豆异黄酮(Soybean isoflavone,SI)对异丙肾上腺素(Isoproterenol,ISO)诱导的心肌纤维化(Myocardial fibrosis,MF)的保护作用.方法异丙肾上腺素皮下注射诱导心肌纤维化模型,经SI低、中、高(30,60,120 mg/kg)3个剂量组和阳性对照卡托普利组(50 mg/kg)治疗后,观察其对心肌细胞直径(MD)、心室重量指数(HW/BW)、左心室重量指数(LVI)、羟脯氨酸(Hyp)含量及心肌组织中钙调神经磷酸酶(Calcineurin,Ca N)活性的影响.结果 SI不同剂量组均能够降低HW/BW和LVI(P0.05或P0.01),减少羟脯氨酸含量(P0.05或P0.01)),减小心肌细胞直径(P0.05或P0.01),降低心肌组织中Ca N的活性(P0.01),减轻ISO诱导的心肌纤维化.结论 SI对心肌纤维化的保护作用可能与降低心肌组织中钙调神经磷酸酶活性有关.     

异丙肾上腺素致大鼠心肌缺血型慢性心力衰竭的实验研究

目的:建立异丙肾上腺素(ISO)缺血型慢性心力衰竭(CHF)大鼠模型,为研究慢性心衰的发病机制和有效治疗措施提供理想的动物模型。方法:模型组大鼠首次按3.0 mg/(kg.d)腹腔注射ISO连续3 d,观察4周,第5周按2.0 mg/(kg.d)继续给药2 d,观察1周,第6周再按3.0 mg/(kg.d)给药2 d,1周后进行血流动力学指标、血清心肌肌钙蛋白-Ⅰ(cTn-Ⅰ)、血管紧张素Ⅱ(AngII)水平等测定和肺组织病理学观察。结果:模型组大鼠较正常对照组左室收缩最大速率降低25.2%,左室舒张最大速率绝对值降低了33.7%,肺组织病理改变明显,血清cTn-Ⅰ和AngII水平明显增加(P<0.01)。结论:采用大鼠间断性腹腔反复注射一定剂量ISO制备慢性心衰模型方法稳定、可靠、容易控制。     

三味檀香散对实验性心肌缺血大鼠的保护作用研究

目的：研究三味檀香散对异丙肾上腺素（Isoproterenol,Iso）致大鼠实验性心肌缺血的保护作用．方法：采用ip Iso诱导大鼠造成急性心肌缺血的动物模型,实验大鼠随机分为正常对照组,Iso模型组,阳性对照组,三味檀香散大、小剂量组,测定各组大鼠心电图T波变化、血流动力学指标：平均动脉压（MBP）、左心室收缩压（LVSP）、左心室舒张末压（LVEDP）和心率（HR）,大鼠颈动脉取血,测定血清乳酸脱氢酶（LDH）和肌酸激酶（CK）．结果：大小剂量的三味檀香散组大鼠心电图T波改变和心率（HR）明显低于模型组（P〈0．01）,而血流动力学指标：LVSP、-LVEDP明显高于模型组（P〈0．05或P〈0．01）,但对大鼠平均动脉压（MBP）无影响．三味檀香散组血清LDH和CK活性明显低于模型对照组．结论：藏药三味檀香散对Iso所致大鼠心肌缺血损伤具有一定的保护作用．     

Potentiating effect of phenylephrine on isoproterenol activation of thyroxine type II deiodinase in the pineal gland of adult rats

In the present study we show, for the first time, that phenylephrine (PHE), an -adrenergic receptor agonist, potentiates the effect of isoproterenol (ISO), a -adrenergic agonist, in activating pineal type II5-deiodinase (5-D) activity. The potentiating effect of PHE was observed only at doses of ISO which induce submaximal activation of the enzyme. However, at doses which lead to maximal activation of the enzyme, PHE was ineffective. The results suggest that not only -, but also -adrenergic receptors, are involved in the sympathetic noradrenergic regulation of pineal 5-D activity in the adult rat.     

异丙肾上腺素荧光猝灭法测定水中痕量锰

报道了异丙肾上腺素与MnO4^-的反应,结果表明，在pH=9．91的伯瑞坦-罗比森缓冲溶液中，异丙肾上腺素可被高锰酸根氧化，导致其荧光强度显著减弱；最大激发及发射波长为278nm和616nm；MnO4^-质量浓度在0．1～6．4mg／L范围内，与荧光猝灭程度成正比．常见的共存离子不干扰其测定．本方法用于环境水样中痕量锰的测定，回收率为97．2％～104．0％，结果令人满意．     

Acute effects of adrenergic agents on post-defibrillation arrest time in a cultured heart model

Possible drug interactions with electrical defibrillation were examined. We tested the hypothesis that adrenergic agents (epinephrine, norepinephrine, isoproterenol) and a calcium channel blocker (verapamil), when applied acutely, alter the duration of arrest following a defibrillator shock. A secondary hypothesis (based on observations) was that the drugs alter the occurrence of changes to normal rhythms following the shock. Dissociated heart cells from 10-day chicken embryos were cultured to form spherical aggregates and plated in petri dishes. In the experiments, the spheres were paced at 0.75 V/cm above contraction threshold, and a biphasic defibrillator shock was applied for 1 ms at 46 V/cm. The arrest time and occurrence of rhythm changes were recorded. The adrenergic agents shortened the duration of arrest following a defibrillator shock, while the calcium channel blocker lengthened the arrest time. Comparisons with the control proportion of double beats showed no significant change with the adrenergic agents and a decrease with verapamil.Received 19 August 2004; received after revision 8 October 2004; accepted 18 October 2004