Effect of procaterol on the isolated airway smooth muscle and the release of anaphylactic chemical mediators from the isolated lung fragments.

The effects of an orally active and selective beta 2-stimulant, procaterol (OPC-2009) on the isolated pulmonary smooth muscle and the release of chemical mediators from the passively sensitized lung fragments were studied and compared with those of isoprenaline (isoproterenol) and salbutamol. Procaterol potently relaxed the isolated guinea pig trachea and lung parenchyma in a concentration-dependent fashion. The drug at a similar range of concentrations antagonized the contraction of the isolated guinea pig trachea and lung parenchyma or human bronchus induced by leukotriene (LT) D4. Salbutamol and isoprenaline also showed similar effects to those of procaterol on the above experiments, but the potencies were consistently weaker than that of procaterol. The release of either histamine or LTs from the passively sensitized human lung fragments was markedly and dose-dependently inhibited by both the 5 min and 15 h treatment with procaterol (10(-10)-10(-7) mol/l) before antigen challenge. Isoprenaline and salbutamol in 5 min treatment experiments showed similar potency as and less potency than procaterol, respectively, on the release of these mediators, but the inhibition potencies of these drugs, particularly isoprenaline, were remarkably reduced by 15 h treatment. From these results, procaterol, besides the existing use as a bronchodilator, is expected to be a potentially prophylactic drug for allergic asthma because of the strong inhibition of the anaphylactic mediator release.     

Anticholinergic properties of oxitropium bromide (Ba 253) and its metabolites

Anticholinergic properties of oxitropium bromide (Ba 253) were compared with those of atropine and ipratropium bromide (Sch 1000). The metabolites of Ba 253 (Ba 941, BEA 1125), the decomposition product (Ba 250), and the impurity (Ad 187) were also studied. In rat salivary activity, gastric secretion and rabbit gastric-motility, the anticholinergic activities of parenterally administered Ba 253 were 2.3 to 11.8 times and 1 to 2 times stronger than that of atropine and Sch 1000, respectively. The mydriatic and antisecretory actions of Ba 253 (p.o. or i.d.) were 1/7 and 1/47 those of atropine, respectively. In isolated rat stomach, guinea pig gallbladder and ileum, the anticholinergic activity of Ba 253 is similar to that of atropine. Inhalation of Ba 253 aerosol prevented ACh- and histamine-induced cough in guinea pigs, and its potency was 1/5 that of atropine or as the same as that of Sch 1000. In the isolated guinea pig trachea and ileum, the potencies of the anticholinergic activities of Ba 250 and Ad 187 were the same as that of Ba 253, but those of the other metabolites were very weak. These results suggest that the anticholinergic activity of Ba 253 is stronger than that of atropine when parenterally administered, and it cannot distinguish between the subtypes of muscarinic receptors.     

General pharmacological studies on a bronchodilator, oxitropium bromide (Ba 253)

The effects of oxitropium bromide (Ba 253) on respiratory, cardiovascular, digestive and urogenital systems were studied. Ba 253 increased heart rate in anesthetized cats at low doses (0.1-0.3 mg/kg, i.v.) and decreased blood pressure in dogs and cats at high dose (3 mg/kg, i.v.). Aerosol inhalation of a high concentration of Ba 253, however, did not influence the heart rate. Ba 253 enhanced the isoproterenol-induced inotropic action and vasodilation. Intestinal transport of mice were inhibited by Ba 253 (s.c.), but not inhibited by oral administration. Ba 253 (1-30 mg/kg, i.v.) enhanced the motility of rat uterus in vivo, but inhalation of the Ba 253 aerosol did not have any affect. Ba 253 had no effects on vasoconstriction, spontaneous motility of the ileum, bile secretion, urinary excretion and spontaneous motility of the urinary bladder. These results indicate that intravenous or subcutaneous administration of Ba 253 decreased blood pressure, enhanced uterus motility and inhibited intestinal transport, but the inhalation or oral administration, even at high doses, has no effects on the cardiovascular system and uterine motility.     

Effect of AS-35 on agonist-induced contractions and the resting tonus of airway smooth muscles and the in vitro release of chemical mediators from passively sensitized lung fragments from humans and guinea pigs.

Effects of 9-[(4-acetyl-3-hydroxy-2-n-propylphenoxy)methyl]-3-(1H-tetrazol -5-yl)-4H-pyrido[1,2-alpha]pyrimidin-4-one (AS-35) on the resting tonus or contractions induced by agonists, such as leukotriene (LT) D4 and specific antigen of isolated guinea pig tracheas or human bronchi, and the in vitro anaphylactic release of histamine and LTs from human lung fragments were investigated and compared with the effects of FPL 55712 and disodium cromoglycate. AS-35 as well as FPL 55712 did not affect the contractions induced by acetylcholine and histamine of the isolated guinea pig trachea. However, the compound at relatively low concentrations obviously inhibited contractions induced by LTD4, and the antagonistic activity was stronger than that of FPL 55712. Treatment of the isolated human bronchus with AS-35 tended to induce the inhibition of both LTD4- and antigen-induced contractions and the relaxation of the resting tonus in a concentration-dependent manner. The inhibitory potency at 10(-6) g/ml was slightly stronger than that of FPL 55712, but this was not statistically significant. The anaphylactic release of histamine and LTs from the lung fragments appeared to be inhibited by the treatment with AS-35 5 min prior to the antigen challenge. From these results, it is suggested that AS-35 is effective against allergic asthma through antagonism towards peptide-LTs released anaphylactically in addition to inhibition of the chemical mediator release.     

Effect of oxitropium bromide (Ba253) on increased airway resistance induced by various agonists and antigen in the guinea pig

Effects of oxitropium bromide (Ba253), which was administered by inhalation, on the resting and stimulus-induced airway resistance were examined in the artificially ventilated guinea pig and compared with those of ipratropium bromide (Sch1000), atropine and isoproterenol. Results obtained were as follows: 1) Ba253 as well as other reference compounds hardly affected the resting resistance. 2) Ba253 strongly and persistently inhibited the acetylcholine (ACh)-induced resistance. Sch1000 caused a similar but relatively weaker inhibition than Ba253. Either atropine or isoproterenol caused only a transient inhibition. 3) The increase in resistance induced by histamine, serotonin, leukotriene D4 or antigen was prevented by Ba253. Atropine, Sch1000 and isoproterenol also inhibited these reactions, but the effects and the duration were generally weaker and shorter than those of Ba253. 4) Repeated inhalations of Ba253 for 7 days did not influence the inhibition of the ACh-induced increase in airway resistance by this drug. However, isoproterenol tended to attenuate the suppression of the resistance by the drug. From these results, it is suggested that Ba253 is a useful inhalant drug for asthma.     

Adenosine-induced bronchoconstriction of isolated lung and trachea from sensitized guinea-pigs.

1. The bronchoconstriction of airway-perfused lungs and contraction of superfused tracheal spirals from guinea-pigs in response to adenosine were examined. 2. In lungs from untreated animals, adenosine had little effect unless the perfusion pressure was raised with carbachol (1.1 microM), when it caused a fall in perfusion pressure. However, if removed from guinea-pigs sensitized with ovalbumin (5 mg and 10 mg i.p. 14 and 12 days before use), adenosine was bronchoconstrictor, exerting bronchodilator effects only at high (1 mg) doses. The constrictor response to adenosine (300 micrograms) was significantly greater than that in lungs from untreated or sham-injected animals. 3. In superfused trachea from untreated animals, adenosine exerted only relaxant responses. In tissues from ovalbumin-sensitized guinea-pigs adenosine produced contractile responses, with relaxation appearing only at high (1 mg) doses. 4. Thus sensitization by antigen challenge revealed a bronchoconstrictor response of isolated airway preparations to adenosine. This is related to the clinical situation where only asthmatic subjects respond to adenosine by bronchoconstriction and suggests that the sensitization may destabilize inflammatory cells for mediator release by adenosine. 5. The response to a second exposure to adenosine was consistently reduced (lungs) or converted to a relaxation (trachea) indicating tachyphylaxis and consistent with a mediator release mechanism. 6. The P1-purinoceptor antagonist, 8-phenyltheophylline (3.9 microM), antagonized the relaxant responses to higher doses of adenosine. However, it did not affect the contractile responses to lower doses of adenosine.(ABSTRACT TRUNCATED AT 250 WORDS)     

Scutellarin induced Ca(2+ ) release and blocked KCl-induced Ca(2+ ) influx in smooth muscle cells isolated from rat thoracic artery

This study was designed to investigate the effect of scutellarin (1) on the modulation of intracellular Ca(2+ ) concentration in thoracic smooth muscle cells of rat. Single smooth muscle cells were obtained enzymatically. Fluo-3 AM was used to determine the alteration of intracellular-free Ca(2+ )([Ca(2+ )](i)) and the changes in fluorescence intensity under different agonists were recorded. Compound 1 induced Ca(2+ ) transients in the medium with and/or without Ca(2+ ). In the Ca(2+ )-free medium, after pretreatment of 1, thapsigargin failed to cause the elevation of [Ca(2+ )](i). However, 1 still caused the elevation of [Ca(2+ )](i) after pretreatment of thapsigargin. The infusion of 1 blocked KCl-induced Ca(2+ ) entry and this effect was hardly reversible. The results of present study suggested that 1 increased [Ca(2+ )](i) by blocking sarcoplasmic reticulum Ca(2+ )/ATPase and blocked voltage-dependent Ca(2+ ) channels in smooth muscle cells of the rat thoracic aortic artery.     

Pharmacological studies on oxatomide: (4) Effect on the histamine release from isolated rat peritoneal exudate cells (PEC) and lung slices

The present study was carried out to evaluate the inhibitory effect of oxatomide and disodium cromoglycate (DSCG) on the histamine release from rat PEC and lung slices induced by antigen-antibody reaction, concanavalin A, compound 48/80 and A-23187. Oxatomide in the range of 1 microM to 10 microM inhibited the allergic histamine release from rat PEC and lung slices induced by antigen-antibody reaction in the presence of phosphatidyl-L-serine (PS). Although the inhibitory action of oxatomide was significant even at a concentration of 1 microM, the action did not increase with an increase in concentration of the drug. DSCG showed a concentration-dependent inhibition on the allergic histamine release from rat PEC and lung slices in the range of 10 microM to 100 microM. The histamine release from rat PEC induced by the combined treatment of concanavalin A and PS was inhibited by oxatomide (0.1 to 10 microM) and DSCG (10 to 100 microM). Oxatomide (up to 10 microM) showed no effect on the histamine release induced by compound 48/80, while DSCG in the range of 10 microM to 100 microM showed a concentration dependent inhibition of the release. Oxatomide at a concentration of 10 microM showed a significant inhibition on the histamine release induced by the calcium ionophore A-23187. On the other hand, DSCG had no effect on this reaction. Oxatomide at high concentrations did not stimulate the histamine release by itself.     

Comparison of the release of various mediators from atrial and ventricular tissues of sensitized guinea-pig hearts

By comparison with ventricular tissues, collagenase-dispersed cell suspensions obtained from atrial tissues of sensitized guinea-pigs showed a higher histamine content, a higher proportion of mast cells, and a higher release with antigen or antisera to IgG, IgG1 and IgG2 of the following mediators: histamine, thromboxane B2 and leukotriene C4.     

Effect of variation in endogenous levels of ascorbic acid on the in vitro immunological release of histamine and slow reacting substance of anaphylaxis from actively sensitized guinea-pig lung fragments

1. The in vitro immunological release of histamine and slow reacting substance of anaphylaxis (SRS-A) from actively sensitized guinea-pig lung fragments was greatly reduced when the animals were maintained on an ascorbic acid-deficient diet. Excessive dietary levels of ascorbic acid did not increase mediator release above normal levels. 2. Restoration of ascorbic acid in the diet of scorbutic guinea-pigs restored in vitro immunological histamine to normal levels. 3. Variation in dietary levels of ascorbic acid had no effect on lung histamine content. 4. The lung ascorbic acid content was proportional to the dietary intake. Approximately 60% of the total lung ascorbic acid was removed by the process of chopping and washing of the tissue. This relationship was independent of dietary intake. 5. The results indicate that the immunological release of mediators of inflammation from guinea-pig lung is dependent on adequate endogenous levels of ascorbic acid.     

DDPH对多种介质所致豚鼠离体气管平滑肌收缩的影响

目的：研究ＤＤＰＨ对多种介质引起的豚鼠离体气管平滑肌收缩的影响。方法：离体器官平滑肌实验法。结果：不同剂量的ＤＤＰＨ可非竞争性抑制Ｈｉｓｔ，ＡＣｈ及Ｃａ＾２＋的作用，使它们的量效曲线非平行右移，最大反应变低，其ｐＤ’２值分别为４．０９，３．９５，３．９５。ＤＤＰＨ还抑制Ｋ＾＋所致气管平滑肌收缩，但作用较维拉帕米弱，它们的ＩＣ５０值分别为１１．７５和１．５８μｍｏｌ／Ｌ。结论：ＤＤＰＨ通过非竞争性Ｃ     

Effect of clenbuterol, a new beta 2 selective adrenoceptor stimulant, on the release of histamine and SRS-A from passively sensitized guinea-pig chopped lungs

Effect of clenbuterol on the release of histamine and SRS-A from passively sensitized guinea-pig lungs was studied in a superfused-cascade bioassay system, and compared with isoproterenol and salbutamol. One-week-old guinea-pig lungs were used, since histamine and SRS-A were released more in these than in 6- or 12-week old lungs during anaphylaxis. Clenbuterol, isoproterenol and salbutamol (10(-8) - 10(-7) M) were found to inhibit the releases of histamine and SRS-A. These actions were inhibited by propranolol. These results suggest that clenbuterol inhibits the releases of histamine and SRS-A via the beta-adrenoceptor.     

Effect of ethanol on GABA uptake and release from hypothalamic fragments

A study was performed on the effect of ethanol on the basal and K⁺-evoked efflux of endogenous GABA from rat hypothalamic fragments. The amount of GABA present in the medium and in the tissue was measured by radioreceptor assay. In vitro addition of ethanol (50 and 100 mM) enhanced the K⁺-evoked efflux of GABA in a Ca⁺⁺-dependent manner, and increased tissue GABA content. Since K⁺-evoked outflow induced by ethanol was not affected by the presence of nipecotic acid, ethanol appears to alter the uptake of endogenous GABA. An inhibitory effect of ethanol on ³H-GABA uptake was observed under K⁺ depolarization. On the other hand, acute ethanol administration produced a decrease in basal and K⁺-evoked efflux from hypothalamic fragments and in tissue GABA concentration. Changes in GABA efflux may lie behind some of the neuropharmacological effects of ethanol.     

Effect of tranilast on the release of slow reacting substance of anaphylaxis (SRS-A) and contraction of the smooth muscle

Slow reacting substance of anaphylaxis (SRS-A) and slow reacting substance (SRS) were released from actively sensitized guinea-pig lung with bovine serum albumin and from rat peritoneal exudate cells with ionophore A23187, respectively. FPL55712 markedly inhibited the contraction induced by SRS-A and SRS in guinea-pig ileum which was treated with atropine (10(-7) g/ml), mepyramine (10(-6) g/ml), and cyproheptadine (10(-7) g/ml). Tranilast and isoproterenol markedly suppressed the release of SRS-A in a dose-dependent manner; the concentrations of these drugs that gave 50% inhibition (IC50) were 1.1 X 10(-4)M and 8.3 X 10(-9)M, respectively. Although the inhibitory effect of tranilast (10(-3)M) was not affected in the presence of propranolol (3 X 10(-6)M), the inhibitory effect of isoproterenol was greatly diminished by propranolol. Also, tranilast markedly suppressed the release of SRS in a dose-dependent manner, its IC50 being 6.4 X 10(-5)M. However isoproterenol slightly inhibited the release of SRS. Disodium cromoglycate did not suppressed the release of SRS-A at all, and it suppressed SRS release a little. Tranilast inhibited the contraction induced by leukotriene C4 (0.5 ng/ml) and D4 (1 ng/ml) in guinea-pig trachea in a dose-dependent manner; the IC50 values were 2.2 X 10(-4)M and 2.0 X 10(-4)M, respectively, for these inhibitions. These results suggest that the inhibition of SRS-A release and SRS-A-induced contraction of smooth muscle by tranilast participates in the anti-asthmatic effect of tranilast, and its inhibitory mechanism is different from that of isoproterenol.     

Effect of calmidazolium (R24571) on histamine release from isolated rat mast cells

The effects of selected calmodulin-antagonists, i.e. calmidazolium (R24571), trifluoperazine, cis- and transflupenthixol, chlorpromazine, and imipramine, on rat mast cells and on mast cell histamine release were investigated. The drugs induced histamine release, apparently by cytotoxic effects, with a rank order of potency in accordance with their lipid solubility and with maximal release at calmidazolium (5 mumol/l), trifluoperazine (40 mumol/l), cis- and trans-flupenthixol (50 mumol/l), chlorpromazine (100 mumol/l), and imipramine (500 mumol/l). Inhibition of the histamine release induced by antigen, compound 48/80, and the ionophore A23187 was only observed with some of the drugs tested, with maximal inhibition at calmidazolium (2 mumol/l), chlorpromazine (25-50 mumol/l), and imipramine (100-250 mumol/l). The concentration-response curve for histamine release induced by calmidazolium was significantly shifted to the right by antigen (i.e. horse serum) in the medium and the addition of antigen was capable of immediately stopping the release induced by calmidazolium, indicating binding of calmidazolium by antigen. Similar effects on the actions of calmidazolium were observed with phosphatidylserine. The inhibition by calmidazolium of the histamine release induced by antigen, compound 48/80, and the ionophore A23187 was significantly counteracted by glucose in the medium. The findings do not confirm an involvement of calmodulin in the histamine release process in rat mast cells. The ability of calmidazolium to bind to proteins and phospholipids in the medium indicates multiple cellular targets for calmidazolium, and the observations with glucose suggest an impaired mitochondrial function to be of major significance.(ABSTRACT TRUNCATED AT 250 WORDS)     

益母草水提物对子宫收缩活动的影响

目的:益母草水提物对大鼠离体子宫平滑肌收缩功能的影响。方法:实验前两日雌性未孕大鼠每日肌肉注射苯甲酸雌二醇1 mg.kg-1,于第3日颈椎脱臼处死动物,迅速剖取子宫,用BL-420E生物机能系统记录子宫收缩曲线;加入水提物药液20、20、40μL,采用累加给药方式,每次给药后记录10 min收缩曲线,比较给药前后收缩张力、频率和活动力的变化。结果:益母草水提物对未孕大鼠子宫均具有促进收缩作用,使子宫活动力、收缩张力均值和最小值均明显增加(P0.05或P0.01),且呈一定量效关系;同时,水提物可抑制缩宫素对子宫的收缩作用,使子宫活动力、收缩张力的均值和最大值均显著降低(P0.05或P0.01)。结论:益母草水提物对子宫活动具有双向调节作用,对未孕大鼠正常子宫具有兴奋作用,对痉挛子宫具有舒张作用。