Effects of Olea europaea L. extract on the rat isolated ileum and trachea

The effects of an Olea europaea L. dried leaf extract containing 3.2% of oleuropein were investigated on the rat isolated ileum and trachea. On basal tone rat isolated ileum, Olea europaea L. extract was shown to produce a dual effect characterized by a contraction at low doses (10^?7-10^?4g/mL) and a relaxation at high doses (3.10^?4-10^?3g/mL). The extract induced contractile effect was found to involve at least histamine, 5-hydroxytryptamine and thromboxane A₂. On precontracted rat isolated ileum, the extract only induced a relaxation that was not modified by nifedipine, diltiazem, dipyridamone, verapamil or papaverine (10^?6 M). The effects of the extract were also studied on the rat isolated trachea. On basal tone organs, Olea europaea L. extract did not produce any effect, whereas, when basal tone was raised by acetylcholine (ACh 10^?3 M), the drug caused a relaxation (maximal effect 39.01% ± 5.40%) of the response to theophylline; (3.10 ± 10^?3M n = 15). It is suggested that the induced relaxation is consecutive to an increase of intracellular 3′5′ cAMP.     

Bisnordihydrotoxiferine and vellosimine from Strychnos divaricans root: Spasmolytic properties of bisnordihydrotoxiferine

Bisnordihydrotoxiferine and vellosimine, two tertiary indole alkaloids have been isolated from the root of Strychnos divaricans. Bisnordihydrotoxiferine antagonized in a nonspecific manner, oxytocin and acetylcholine induced contractions in the rat uterus and acetylcholine and histamine responses in the guinea-pig ileum. Bisnordihydrotoxiferine, like verapamil, produced effects on voltage dependent Ca²⁺ channels. For example in guinea-pig ileum, bisnordihydrotoxiferine (pD'₂ 3.92±0.09) and verapamil (pD'₂ 6.00±0.11) inhibited KCl induced contractions. Furthermore, bisnordihydrotoxiferine (pD'₂ 4.37±0.02) and verapamil (pD'₂ 6.83±0.10) also antagonized CaCl₂ induced contractions of K⁺-depolarized rat uterus. When compared with sodium nitroprusside, an antagonist of receptor operated Ca²⁺ channels, bisnordihydrotoxiferine had no effect. However, in the aorta, the alkaloid (IC₅₀, 6.10 × 10^?6M) antagonized the intracellular calcium dependent transient contractions of noradrenaline and it was about four times more potent than procaine (IC₅₀, 2.30 × 10^?5M), a known inhibitor of the release of Ca²⁺ from intracellular stores. Bisnordihydrotoxiferine may produce nonspecific spasmolytic actions mainly by inhibiting intracellular calcium mobilization and to a lesser extent by inhibiting voltage dependent calcium channels in smooth muscles.     

Uterotonic properties of the methanol extract of Monechma ciliatum

The oxytocic activity of the hot methanol extract (HME) of the leaves of Monechma ciliatum was compared with other uterine stimulants like ergometrine, oxytocin, 5-hydroxytryptamine (5-HT), acetylcholine (ACh) and prostaglandins (PGs) E₂ and F₂α (PGE₂ and PGF₂α) in the presence of some antagonists in an attempt to explain the mechanism of action of the extract. The effects of the reference drugs on uteri isolated from rats pretreated with HME for 2 weeks were also observed. Atropine blocked the effect of ACh and partially blocked those of HME while L-366-948 blocked only the effect of oxytocin. Indomethacin inhibited the effects of HME as well as all the other drugs, except the PGs and ACh. D-600 blocked the effect of all the drugs including HME. Methysergide antagonised only the effect of 5-HT and partially blocked ergometrine. Prolonged treatment altered the uterine musculature and the activity profile of the reference drugs. These results suggest that the HME may be acting by more than one mechanism to contract the uterus and explains the mechanism of the anti-implantation activity of the plant.     

Involvement of calcium in the cardiac depressant actions of a garlic dialysate

In order to elucidate a possible role for calcium on the negative cardiotropic effects of a garlic (Allium sativum L., Liliaceae) dialysate in rat atria we studied: (a) the effects of our extract 15 min after preincubation with high and low concentrations of extracellular calcium ([Ca²⁺]_o) on left and right activity of rat atria. The negative inotropism of garlic dialysate increased with calcium 0.75 mM; in contrast, high level of calcium (4.5 mM) induced a significant reduction of this depressant effect. None of these treatments modified the negative chronotropism of garlic; (b) nifedipine (10⁻⁹ to 10⁻⁷ M), verapamil (10⁻⁹ to 10⁻⁷ M) and diltiazem (10⁻⁹ to 10⁻⁷ M) induced a concentration-depe synergism of the log concentration-effect curve of garlic dialysate on left atria. Verapamil and diltiazem (10⁻⁷ M), but not nifedipine increased the inhibitory chronotropism of garlic in right atria; (c) negative inotropic and chronotropic effects demonstrated by nifedipine (1 × 10⁻¹⁰ to 1.1 × 10⁻⁶ M) were antagonized as expected by preincubation with Bay K-8644. Depressant actions of garlic were not modified with this pretreatment. These results suggest that the negative inotropic effect of our garlic dialysate is related to [Ca²⁺]_o availability. It is possible that a restriction of intracellular calcium contributes to this effect. However, the negative chronotropic effect of garlic is scarcely affected by these modifications.     

The source of ca2+ for the spasmolytic actions of longicaudatine,a bisindole alkaloid isolated from Strychnos trinervis (Vell.) Mart. (Loganiaceae)

Longicaudatine, a tertiary bisindole alkaloid isolated from the root bark of Strychnos trinervis (Vell.) Mart. (Loganiaceae), antagonized in a noncompetitive manner, carbachol and histamine induced contractions of the guinea-pig ileum and bradykinin responses in the rat uterus. The respective pD₂' values (mean ± SE) were 4.61 ± 0.21, 4.98 ± 0.04 and 4.49 ± 0.01. Longicaudatine, unlike verapamil, had no effect on voltage dependent Ca²⁺ channels, as it failed to inhibit KCI or CaCl₂ induced contractions of guinea-pig ileum and depolarized rat uterus respectively. When compared with sodium nitroprusside, an antagonist of receptor operated Ca²⁺ channels, longicaudatine produced a slower and weaker inhibition of noradrenaline induced sustained contractions of rabbit aortic strips. However, in the aorta, the alkaloid antagonized the intracellular calcium dependent transient contractions of noradrenaline and longicaudatine (IC₅₀, 5.01 × 10^?7 M) was approximately 133 times more potent that procaine (IC₅₀, 6.68 × 10^?5 M), a known inhibitor of the release of Ca²⁺ from intracellular stores. Longicaudatine may exert nonspecific spasmolytic effects by acting on intracellular Ca²⁺ stores, rather than on depolarization dependent or receptor operated Ca²⁺ channels.     

Reduction of agonist-induced contractions of guinea-pig isolated ileum by flavonoids

The effect of 13 flavonoids on the contraction of guinea-pig isolated ileum induced by prostaglandin E₂ (PGE₂) and leukotriene D₄ (LTD₄) have been investigated. Apigenin, quercetin and kaempferol at a concentration of 10 μM significantly (p<0.001) reduced the contraction to either agonist. Crysin and flavone antagonized only PGE₂ (p<0.01). The other flavonoids were inactive. The blocking effect of apigenin, quercetin and kaempferol against PGE₂ was also concentration- and time-dependent, and was augmented by the calcium channel blocker verapamil or by lowering the extracellular calcium to 25%, consistent with a calcium-mediated mechanism of protection which these flavonoids, at the same concentration, also showed against barium chloride (BaCl₂)- or acetylcholine (ACh)-induced contraction (p<0.05–0.001).     

γ-Mangostin increases serotonin 2A/2C, muscarinic, histamine and bradykinin receptor mRNA expression

Aim of the study

γ-Mangostin is a xanthone found in the fruit hulls of Garcinia mangostana L., which have long been used in Southeast Asia as a traditional medicine for the treatment of abdominal pain, dysentery, wound infections, fever and convulsions. Recent studies have revealed that γ-mangostin exhibits a variety of pharmacological activities, including serotonin 2 (5-HT₂) receptor antagonism, anti-inflammatory effects and analgesic effects. To explore the mechanism of γ-mangostin responsible for these pharmacological activities, especially its effects on some related receptors, we investigated the effects of γ-mangostin on 5-HT₂, histamine (H₁) and bradykinin (BK₂) receptor gene expression in neuroblastoma (NG 108-15) cells in vitro. Additionally, to extend the study of the pharmacological properties, we examined the effect of γ-mangostin on the muscarinic (M₄) receptor.

Materials and methods

NG 108-15 cells were cultured in vitro and treated with γ-mangostin or a 5-HT₂ receptor antagonist (either imipramine or ketanserin). Then, the levels of mRNA for 5-HT_2A/2C receptors were evaluated by semi-quantitative RT-PCR. The preventive effect of serotonin on the enhancement effects was also revealed. Additionally, the effects of γ-mangostin on the muscarinic, histamine and bradykinin receptors were determined.

Results

Chronic application of γ-mangostin at a concentration of 0.1 μM induced a significant increase in the level of 5-HT_2A/2C receptor mRNA. These effects were prevented by serotonin. Moreover, γ-mangostin up-regulated the M₄, H₁ and BK₂ receptors.

Conclusion

The ability of γ-mangostin to enhance the expression of 5-HT_2A/2C, muscarinic, histamine and bradykinin receptor mRNA suggests that this compound has antagonistic effects. These pharmacological properties may partly account for the benefits of using mangosteen in the treatment of inflammation, pain and neuropsychiatric symptoms.     

大黄对豚鼠胃窦环行肌条的影响

 目的研究大黄对豚鼠离体胃平滑肌条收缩活动的影响及其可能的机制。方法将豚鼠胃窦环形肌条置于盛有Krebs液的灌流肌槽中,并记录其等长收缩活动。观察不同浓度(1%,3%,10%,30%,100%)的大黄对胃窦环形肌条收缩活动的影响以及阿托品、维拉帕米和六烃季胺对大黄引起的胃窦环形肌条收缩活动的影响。结果大黄剂量依赖性增大胃窦环行肌条的收缩波平均振幅和增高胃窦环行肌条张力,每1mL含1g生药的大黄加快胃窦环行肌条的收缩频率。阿托品、维拉帕米和六烃季胺部分阻断大黄对豚鼠胃窦环行肌条的兴奋作用。结论大黄对豚鼠胃窦环行肌条的收缩活动有兴奋作用。大黄的这一兴奋作用部分经由胆碱能M受体、胆碱能N受体和L-型钙通道介导。     

莲心碱对家兔主动脉条收缩性能的影响

 目的　观察莲心碱 (liensinine,Lien)对氯化钾(KCl),去甲肾上腺素(NE)和组织胺(Hist)所致家兔主动脉条收缩的作用。并研究其对血管条依内钙性收缩和依外钙性收缩的影响。方法　离体平滑肌实验方法。结果　不同剂量Lien及维拉帕米(Ver)对KCl,NE,Hist诱导的主动脉条均呈抑制作用,并可非竞争性拮抗组胺的量效曲线,PD₂′值分别为4.31,6.89。Lien和Ver均能抑制组胺诱导的依内钙收缩,而对依外钙收缩作用较弱。结论　Lien可舒张兔主动脉条,该作用与钙离子拮抗有关,且对主动脉依内钙性收缩的敏感性大于依外钙性收缩。     

Pharmacological screening of the methanol and dichloromethanol extracts of Genista patens

The pharmacological effects of the dichloromethanol and methanol extracts obtained from leaves and stems of Genista patens DC were analysed in in vitro and in vivo models. Both extracts showed low acute toxicity (LD₅₀ > 3 g/kg), CNS depressor and antiinflammatory activity, and similar analgesic effect in models of chemical and thermal stimulation. Furthermore, the dichloromethanol extract (1–20 mg/kg) induced a pronounced dose-dependent decrease on blood pressure. On isolated organs, the dichloromethanol extract (1, 10, 100 μg/mL) shifted the concentration-effect curve to the right for ACh and reduced the E_max induced by histamine without modifying responses induced by noradrenaline and serotonin.     

Effects of the essential oil of Croton zehntneri,and its constituent estragole on intestinal smooth muscle

The effects on isolated guinea-pig ileum of the essential oil of Croton zehntneri (CZEO) and of its main constituent estragole (57% of CZEO by weight) were studied. CZEO and estragole (0.1–100 μg/mL) decreased the tonus in 56% and 61.5%, respectively, of the muscles. At concentrations above 10 μg/mL, they induced spontaneous rhythmic movements of small amplitude (less than 11% of the potassium contraction peak to peak). At concentrations from 1 to 100 μg/mL and with similar potencies, these agents blocked the contractions induced by acetylcholine, histamine and 50 mM K⁺ and caused relaxation of already established potassium contractures. Tested separately, CZEO, estragole and anethole (28% of CZEO by weight) blocked the contraction induced by Ca⁺⁺ in the presence of 50 mM K⁺, but CZEO was more potent than estragole or anethole in blocking the Ca⁺⁺-induced contractions than those induced by K⁺. With large increases in the agonist concentration, the action of the oils on the contractions induced by Ca⁺⁺ was reversible; however, their effect on contractions induced by histamine or ACh was not. The data show that the essential oil of Croton zehntneri has an effect on intestinal smooth muscle that is predominantly antispasmodic, and attributable in part to the effect of estragole, a major constituent. © 1997 John Wiley & Sons, Ltd.     

Actions of Artemisia vulgaris extracts and isolated sesquiterpene lactones against receptors mediating contraction of guinea pig ileum and trachea

Aim of the study

The present study evaluates the Philippine medicinal plant Artemisia vulgaris for antagonistic activity at selected biogenic amine receptors on smooth muscle of the airways and gastrointestinal tract in order to explain its traditional use in asthma and hyperactive gut.

Materials and methods

The antagonistic activity of chloroform crude extract (AV-CHCl₃) and methanol crude extract (AV-MeOH) of Artemisia vulgaris was studied against concentration-response curves for contractions of the guinea pig ileum and trachea to 5-hydroxytrptamine (5-HT₂ receptors), methacholine (M₃ muscarinic receptors), histamine (H₁ receptors) and β-phenylethylamine (trace amine-associated receptors, TAAR1).

Results and discussion

The Artemisia vulgaris chloroform (AV-CHCl₃) and methanol (AV-MeOH) extract showed histamine H1 antagonism in the ileum and trachea. Further analysis of AV-CHCl₃ isolated two major components, yomogin and 1,2,3,4-diepoxy-11(13)-eudesmen-12,8-olide. Yomogin, a sesquiterpene lactone, exhibited a novel histamine H1 receptor antagonism in the ileum.

Conclusion

The presence of a specific, competitive histamine receptor antagonist and smooth muscle relaxant activity in Artemisia vulgaris extracts on the smooth muscle in ileum and trachea explains its traditional use in the treatment of asthma and hyperactive gut.     

吴茱萸汤醇提各组分止呕活性的研究

目的 :对吴茱萸汤醇提各组分止呕活性的研究和机制初步探讨。方法 :采用硫酸铜诱导家鸽呕吐实验 ,小鼠胃排空实验 ,ACh和 5-HT作用的离体大鼠胃条实验来确定其中具有止呕活性的组分 ,并观察有效组分对ACh ,5-HT ,组胺累积浓度 效应曲线的影响。结果 :50%醇洗脱液和 70%醇洗脱液有十分显著性的止呕效应 ,且副作用较小 ,对ACh ,5-HT ,组胺累积浓度 效应曲线均有一定的作用。结论 :50%醇洗脱液和 70%醇洗脱液含有的止呕活性成分较多 ,50%和 70%醇可以从吴茱萸汤中提取较多止呕活性成分 ,止呕作用可能与拮抗ACh ,5-HT ,组胺受体有关。     

丹红注射液对大鼠离体肠系膜动脉血管环作用及机制

目的:探讨丹红注射液对离体大鼠肠系膜动脉血管环的作用及作用机制.方法:采用离体血管环实验方法,经生物信号采集与分析系统测定血管环张力的变化.结果:丹红注射液对血管基础张力无影响;能明显舒张去甲肾上腺素(norepinephrine,NE)预收缩的完整内皮血管,去内皮后对该作用无明显影响;能明显舒张高钾预收缩的血管;对咖啡因预收缩血管作用无明显影响;能抑制NE诱导的内钙释放及外钙内流;钾通道阻滞剂对丹红注射液的舒张作用无影响.结论:丹红注射液有明显的扩血管作用,主要通过血管平滑肌起作用,其机制可能为抑制受体、电压依赖的外钙内流和IP3受体介导的内钙释放而舒张血管.     

Spasmolytic activity of Rosmarinus officinalis L. involves calcium channels in the guinea pig ileum

Ethnopharmacological relevance

Rosmarinus officinalis L. is a plant used around the world for its properties to cure pain in several conditions, such as arthritic and abdominal pain or as an antispasmodic; however, there are no scientific studies demonstrating its spasmolytic activity. Therefore, the aim of the present study was to investigate the effect of an ethanol extract from Rosmarinus officinalis aerial parts and the possible mechanism involved by using rings from the isolated guinea pig ileum (IGPI).

Materials and methods

The IGPI rings were pre-contracted with potassium chloride (KCl; 60 mM), acetylcholine (ACh; 1 × 10⁻⁹ to 1 × 10⁻⁵ M) or electrical field stimulation (EFS; 0.3 Hz of frequency, 3.0 ms of duration and 14 V intensity) and tested in the presence of the Rosmarinus officinalis ethanol extract (150, 300, 600 and 1 200 μg/mL) or a referenced smooth muscle relaxant (papaverine, 30 μM). In addition, the possible mechanism of action was analyzed in the presence of hexametonium (a ganglionic blocker), indomethacine (an inhibitor of prostaglandins), l-NAME (a selective inhibitor of the nitric oxide synthase) and nifedipine (a calcium channel blocker).

Results

Rosmarinus officinalis ethanol extract exhibited a significant and concentration-dependent spasmolytic activity on the contractions induced by KCl (CI₅₀ = 661.06 ± 155.91 μg/mL); ACh (CI₅₀ = 464.05 ± 16.85 μg/mL) and EFS (CI₅₀ = 513.72 ± 34.13 μg/mL). Spasmolytic response of Rosmarinus officinalis (600 μg/mL) was reverted in the presence of nifedipine 1 μM, but not in the presence of hexamethonium 0.5 mM, indomethacine 1 μM or l-NAME 100 μM.

Conclusion

The present results reinforce the use of Rosmarinus officinalis as antispasmodic in folk medicine. Moreover, it is demonstrated the involvement of calcium channels in this activity, but not the participation of nicotinic receptors, prostaglandins or nitric oxide.     

Pharmacological studies on hypotensive and spasmolytic activities of pure compounds from Moringa oleifera

Bioassay directed fractionation of an ethanolic extract of Moringa oleifera (MO) leaves resulted in the isolation of four pure compounds, niazinin A (1), niazinin B (2), niazimicin (3) and niaziminin A + B (4 + 5). Intravenous administration of either one of the compounds (1–10 mg/kg) produced hypotensive and bradycardiac effects in anaesthetized rats. Pretreatment of the animals with atropine (1 mg/kg) completely abolished the hypotensive and bradycardiac effects of acetylcholine (ACh), whereas cardiovascular responses to the test compounds remained unaltered, ruling out the possible involvement of muscarinic receptor activation. In isolated guinea-pig atria all the compounds (50–150 μg/mL) produced negative inotropic and chronotropic effects. Each compound inhibited K⁺ -induced contractions in rabbit aorta as well as ileal contractions induced by ACh or histamine at similar concentrations. Spontaneous contractions of rat uterus were also inhibited equally by all compounds. These data indicate that the direct depressant action of these compounds exhibited on all the isolated preparations tested is probably responsible for its hypotensive and bradycardiac effects observed in vivo. Moreover, spasmolytic activity exhibited by the constituents of the plant provides a scientific basis for the traditional uses of the plant in gastrointestinal motility disorders.     

苦丁茶对豚鼠离体气管平滑肌收缩功能的影响

目的 :研究苦丁茶对豚鼠离体气管平滑肌的影响。方法 :以累积技术建立CaCl₂ 和组织胺 (His)的量效曲线 ,研究了苦丁茶对CaCl₂ ,His和乙酰胆碱 (Ach)等致喘介质对豚鼠离体气管平滑肌收缩功能的影响。结果 :CaCl₂ 和His引起气管条明显的收缩 ,pD₂ 分别为 3.59和 5 .34。苦丁茶能明显压低CaCl₂ 和His的量效曲线 ,并使曲线右移。苦丁茶对Ach和His 3×10^-6mmol·L^-1引起的气管平滑肌收缩有明显的逆转作用 ,IC₅₀ 分别为 0.16mg·ml^-1和 0.2 1mg·ml^-1。结论 :提示苦丁茶有明显的舒张豚鼠离体气管平滑肌的作用。     

重组人组织型纤溶酶原激活剂缺失变体的溶栓作用及对血小板聚集和胞浆游离钙离子浓度的影响

 目的 研究重组人组织型纤溶酶原激活剂缺失变体(reteplase,Ret)的溶栓作用以及对离体家兔血小板聚集功能和对血小板静息状态胞浆内游离钙浓度的影响。方法 家兔血栓模型采用动-静脉旁路法,血小板聚集实验采用比浊法,血小板静息状态胞浆内游离钙浓度采用Fura-2荧光测定法。结果Ret(3.75×10⁵,7.50×10⁵,15.0×10⁵U·kg^-1)对家兔动-静脉旁路所形成的血栓有明显溶栓作用,可明显减轻血栓干湿重量,并呈一定的剂量依赖性。Ret(1 000,3 000,10 000 U·mL^-1)对ADP诱导的血小板聚集可产生浓度依赖性的抑制作用,并可明显降低血小板静息状态的[Ca²⁺]_i,并呈一定的浓度依赖性。结论Ret具有明显的血栓溶解作用,可明显抑制ADP诱导的血小板聚集,并明显降低血小板静息状态的[Ca²⁺]_i。     

Cardiovascular effects of plant secondary metabolites norarmepavine,coclaurine and norcoclaurine

The cardiovascular effects of (±)-norarmepavine, a benzylisoquinoline alkaloid of natural origin, have been determined on anaesthetized rats in vivo, on spontaneously beating atria and on aortic smooth muscle. In aorta, the effects of (±)-coclaurine and (±)-norcoclaurine, benzylisoquinolines with a related structure, were also compared. (±)-Norarmepavine (10 mg/kg i.v.) decreased the mean arterial pressure and heart rate by 45% and 21%, respectively. (±)-Norarmepavine (10⁻⁵–10⁻³ M ) showed a negative chronotropic effect on rat-isolated atria, decreasing the spontaneous frequency by about 54%. Aortic rings contracted with KCl 70 mM were relaxed in a concentration-dependent manner by (±)-norarmepavine, (±)-coclaurine and (±)-norcoclaurine (10⁻⁶–10⁻³ M ). The two earlier alkaloids exhibited an efficacy similar to verapamil, relaxing the aortic rings by 100%. (±)-Norcoclaurine exhibited a lower efficacy. These results point to the importance of methylation of these compounds. The rank order of potency was: (±)-verapamil > (±)-norarmepavine > (±)-norcoclaurine > (±)-coclaurine. The alkaloids shifted to the right the calcium-dependent contraction curves, denoting a calcium antagonist-like effect; however, only a 10-fold increment of (±)-norcoclaurine concentration produced an equivalent effect. Our results demonstrate the hypotensive and bradycardic properties of (±)-norarmepavine. It is proposed that this alkaloid could somehow modulate calcium entry, its intracellular release or the calcium sensitivity of the cell contractile-machinery, previously postulated for coclaurine. (±)-Norcoclaurine effects reported here are not in agreement with the proposal of (±)-norcoclaurine as a calcium channel activator or β₁-adrenoceptor agonist. © 1998 John Wiley & Sons, Ltd.     

Participation of the serotonergic system in the memory effects of Ginkgo biloba L. and Panax ginseng C. A. Mey

The 7-day oral administration of the extracts from Ginkgo biloba (GK501) and Panax ginseng (G115) as well as their combination PHL-00701 (Gincosan®) produced changes in rat behaviour suggesting memory-enhancing effects. Single doses of agonists and antagonists of different serotonin receptor subtypes influenced the rat's capability for retention of learned behaviour and the behavioural effects of the drugs tested. GK501 decreased the density (B_max) of 5-HT₁ receptors in the frontal cerebral cortex and hippocampus. Data concerning the effects of the drugs tested suggest the participation of the serotonergic transmitter system as an important neurochemical correlate of rat behaviour and of the memory effects of the drugs studied. This participation is modulated by the differences in the functions of the serotonin receptor subtypes.