豚鼠气道对异丙肾上腺素的耐受性及药物的影响

豚鼠反复气雾吸入或肌内注射异丙肾上腺素(简称异丙)5小时,可使该药对抗组胺性哮喘的作用减弱,形成快速耐受性。腹腔注射阿的平或消炎痛,连续3天,有预防作用。反复吸入气雾7天,异丙松弛离体气管的作用减弱。离体气管接触1 μM异丙25分钟,异丙的松弛气管作用、对抗组胺的收缩作用及抑制过敏性收缩作用可产生快速耐受性;阿的平、异搏定、地塞米松和α-萜品烯醇可预防对抗组胺收缩作用的快速耐受性;花生四烯酸可阻断阿的平的预防作用。耐受性主要表现为β受体对激动剂的亲和力降低,其形成与磷脂酶A₂及花生四烯酸有关。     

豚鼠气道对异丙肾上腺素的耐受性及药物的影响

豚鼠反复气雾吸入或肌内注射异丙肾上腺素(简称异丙)5小时,可使该药对抗组胺性哮喘的作用减弱,形成快速耐受性。腹腔注射阿的平或消炎痛,连续3天,有预防作用。反复吸入气雾7天,异丙松弛离体气管的作用减弱。离体气管接触1 μM异丙25分钟,异丙的松弛气管作用、对抗组胺的收缩作用及抑制过敏性收缩作用可产生快速耐受性;阿的平、异搏定、地塞米松和α-萜品烯醇可预防对抗组胺收缩作用的快速耐受性;花生四烯酸可阻断阿的平的预防作用。耐受性主要表现为β受体对激动剂的亲和力降低,其形成与磷脂酶A_2及花生四烯酸有关。     

蛇床子素对豚鼠离体回肠和结肠带的作用

以豚鼠离体回肠和结肠带为标本,观察蛇床子素(Ost)的作用与Ca²⁺)的关系。结果表明:Ost和钙拮抗剂Ver产生剂量依赖性抑制乙酰胆碱(ACh)、组胺及KCl所致回肠条或结肠带的收缩;非竞争性拮抗CaCl₂累积量—效曲线,pD₂分别为4.41±0.15,7.0±0.2。Ost 100μmol/L和Ver 1μmol/L均能对抗小剂量Ca²⁺所致结肠带收缩,但被加入较大量Ca²⁺所取消。Ost和Ver均能抑制ACh诱导的依内钙性收缩,不影响依外钙性收缩。结果提示Ost具有钙拮抗作用,其作用方式与Ver类似。     

汉防己甲素对气管平滑肌45Ca内流的影响

本文应用国产⁴⁵CaCl₂研究汉防已甲素(以下简称为汉甲)对气管平滑肌钙内流的影响。汉甲对犬与豚鼠气管平滑肌基础的⁴⁵Ca内流量无明显的影响;60μg/ml汉甲对犬气管平滑肌组胺兴奋与高钾打开电位操纵通道(POC)的5 min⁴⁵Ca内流量的抑制率,分别为11.1%与38.3%;60μg/ml汉甲对豚鼠气管平滑肌组胺与高钾兴奋的5min⁴⁵Ca内流量的抑制率分别为48.7%与33.3%,10μg/ml或20μg/ml汉甲虽对犬或豚鼠气管平滑肌组胺兴奋的、高钾兴奋和/或打开POC的⁴⁵Ca内流量具有一定的抑制作用,但无统计学意义。说明汉甲对气管平滑肌POC与受体操纵通道(ROC)均有阻断作用,由于对高钾兴奋和/或打开POC的⁴⁵Ca内流阻断是完全的,而对组胺兴奋和打开RCC的⁴⁵Ca内流阻断是部分的,提示汉甲优先阻断气管平滑肌的POC,60μg/ml汉甲对气管平滑肌POC的阻断强度与50μg/ml异搏定相当。汉甲的钙通道阻断作用可能与其拮抗过敏介质收缩气管的作用有关。     

钾通道开放剂的抗过敏作用及其机制

用多种抗变态反应实验方法,研究钾通道开放剂米诺地尔(Min)与二氮嗪(Dia)的抗过敏作用,并探讨其作用机制。结果表明,Min能抑制大鼠同种被动皮肤过敏反应,拮抗5-HT引起的大鼠皮肤血管通透性增高。Dia和Min均能抑制豚鼠离体回肠平滑肌的过敏性收缩,Dia并能抑制A₂₃₁₈₇和化合物48/80诱发的肥大细胞释放组胺。因此钾通道开放剂Min与Dia具有抗过敏作用,作用的主要机理是抑制肥大细胞外Ca²⁺内流和细胞内贮存钙的释放,从而抑制组胺的释放,此可能与药物开放钾通道的作用有关。     

利多卡因对离体兔胸主动脉环收缩的影响

以维拉帕米(verapamil,Ver)作对照,在离体兔胸主动脉环上对利多卡因(lidocaine,Lid)松弛血管平滑肌的机理进行了探讨。Lid对高K+去极化主动脉环收缩和Ver一样有明显的松弛作用。对去甲肾上腺素(NA)引起主动脉环收缩的试验中,Lid和Ver都能抑制细胞内Ca²⁺的释放,但不抑制外Ca²⁺内流。Lid对KCl,NA量-效曲线产生非平行右移,最大反应压低,且对KCl的抑制作用大于NA,说明Lid对PDC通道有选择性阻滞作用,而对ROC通道相对不敏感。对CaCl₂量-效曲线也产生非平行右移且最大反应压低,呈非竞争性拮抗。初步提示Lid在一定浓度下有拮抗Ca²⁺的作用,这种作用为非特异性,是松弛血管平滑肌机理之一。     

毒毛旋花子苷元对豚鼠心室肌细胞内钙浓度的影响

观察毒毛旋花子苷元(strophanthidin, Str)对分离豚鼠心室肌细胞内游离钙浓度(［Ca²⁺］_i)的影响。酶解分离豚鼠心室肌细胞, 用Fluo 3-AM负载, 激光共聚焦显微镜法测定单个豚鼠心室肌细胞［Ca²⁺］_i的荧光密度。Str可浓度依赖性地升高［Ca²⁺］_i, Str (10 μmol·L^-1)在［Ca²⁺］_i升高达峰值时, 可使细胞挛缩, 而Str (1和10 nmol·L^-1)对细胞形态无影响。TTX、 尼索地平或升高细胞外钙可影响Str (1和100 nmol·L^-1)对［Ca²⁺］_i的升高作用,而对Str (10 μmol·L^-1)无明显影响。在外液中加入ryanodine或去除细胞外钙, 则3个检测浓度的Str升高［Ca²⁺］_i作用均被明显抑制。在无K⁺、 无Na⁺液中, 10 μmol·L^-1 Str升高［Ca²⁺］_i的作用减弱, 而Str (1和100 nmol·L^-1)升高［Ca²⁺］_i的作用无明显影响。加入TTX、 尼索地平或增加细胞外的钙离子浓度, 则3个检测浓度Str的作用均受到影响。提示低浓度Str对［Ca²⁺］_i的升高作用与抑制Na⁺、K⁺-ATP酶活性无关, 而与促进L-型钙通道和TTX敏感性钠通道的“slip-mode”钙电导有关; 高浓度Str升高［Ca²⁺］_i的作用则是抑制Na⁺、K⁺-ATP酶的结果。此外, Str对［Ca²⁺］_i的升高作用还与直接作用于ryanodine受体促进内钙释放有关。     

神经肽DGAVP和Org2766对神经细胞内游离Ca2+的影响

运用Ca²⁺指示剂Fura-2作为细胞内钙离子的荧光探针,利用AR—CM—MIC阳离子测定系统,检测了分离的神经细胞内游离钙及其变化,并观测了DGAVP和Org2766对蛋白质合成抑制剂茴香霉素(ANI)引起细胞内钙离子浓度([Ca²⁺]_i)变化的影响。结果表明茴香霉素可使[Ca²⁺]_i显著升高,且有量效关系;DGAVP本身并不引起[Ca²⁺]_i发生显著变化,但适当剂量的DGAVP可显著对抗一定剂量范围内ANI升高[Ca²⁺]_i的作用,提示DGAVP对抗ANI的蛋白质合成抑制效应可能是通过拮抗ANI升高[Ca²⁺]_i这一途径实现的,另一神经肽Org2766则可能不是通过这一机制发生作用。从细胞内Ca²⁺的角度看,这两种肽的作用机理显然是不同的。     

四肽FMRFa对大鼠心室肌Na+/Ca2+交换的抑制

目的　研究四肽FMRFa对大鼠单个心室肌细胞Na⁺/Ca²⁺交换的作用。方法　用膜片钳全细胞记录法测定成年大鼠心室肌细胞Na⁺/Ca²⁺交换电流(I_Na⁺/Ca²⁺)和其他离子通道电流。结果　FMRFa对大鼠心室肌细胞I_Na⁺/Ca²⁺呈浓度依赖性抑制,100μmol·L^-1浓度时抑制内向和外向I_Na⁺/Ca²⁺密度分别达60.1%和56.5%,对内向电流及外向电流的IC₅₀分别为20μmol·L^-1和34μmol·L^-1。FMRFa5μmol·L^-1抑制I_Na⁺/Ca²⁺内向和外向电流密度分别为38.7%和34.9%,但FMRFa5μmol·L^-1及20μmol·L^-1对L型钙电流、钠电流、瞬时外向电流和内向整流钾电流均无显著抑制作用。结论　FMRFa对大鼠心室肌细胞是一个特异性Na⁺/Ca²⁺交换抑制剂。     

4-氨基吡啶诱发组胺释放及某些药物的拮抗作用

4-氨基吡啶(4-AP)有组胺释放作用。小鼠ip4-AP5mg·kg^-1后,肺中组胺含量明显减低,血中组胺含量显著增高。钙拮抗剂硝苯啶、TMB-8及钾通道开放剂米诺地尔均能明显抑制4-AP诱发的小鼠PMC释放组胺。结果提示,MC可能存在钾通道,4-AP诱发MC释放组胺可能与它阻滞钾通道,从而使钙通道开放,增加Ca²⁺内流有关。     

In vitro Evaluation of Acute Effects of Mitoxantrone (Novantrone®) in Rat and Guinea Pig Atria

Abstract: Since guinea pig and rat atria have been used as models to study acute anthracycline-induced cardiotoxicity, experiments were carried out in these preparations to evaluate possible acute cardiac effects mediated by mitoxantrone (MTX). After a latency period of approximately 90 min, MTX (10^-5—10^-4 M) promoted a concentration-related and time-dependent decrease of spontaneous rate in guinea pig atria. A similar but less intense effect after a longer latency interval was observed in rat atria. In this preparation, MTX (10^-5—10^-4 M) incubated up to 150 min., induced a gradual competitive β-adrenergic blocking effect on the positive chronotropic action of isoproterenol. This was characterized by a progressive decline of pD₂ values without altering E_max. A similar and stronger effect was found in isolated guinea pig atria incubated under same conditions with MTX, except that 10^-4 M exposed for 150 min. was able to depress the E_max to isoproterenol by 21.2%. In addition, MTX (10^-4 M) in this model promoted a non-competitive antagonistic effect on the chonotropic action of histamine. These data are compatible with the idea that MTX could induce cardiac acute effects qualitatively similar to but of lower potency than those produced by doxorubicin in these two models. In addition, guinea pig atria seemed to display higher sensitivity to MTX compared to rat atrial preparations.     

A pharmacological study of bronchodilator properties of NKH477, forskolin,and β‐agonists on guinea pig and ovine isolated bronchioles

In this study we assessed the relaxant responses of two direct adenylate cyclase activators, NKH477 and forskolin, in comparison with two β‐adrenoceptor agonists, salbutamol and isoprenaline. The possible potentiation effect of NKH477 and forskolin on β‐agonist‐induced bronchodilatation was examined. The effectiveness of NKH477 and forskolin in reversing tachyphylaxis development to salbutamol or isoprenaline was also investigated. We tested the in vitro bronchodilator effect of salbutamol, NKH477, and forskolin (10^–9–10^–4 M) on isolated guinea pig bronchiolar ring segments precontracted with carbachol (3 μM). Salbutamol, NKH477, and forskolin produced a concentration‐dependent relaxation. Potency values (pD₂) were determined from cumulative concentration–response curves. The rank order for their potencies was salbutamol > NKH477 > forskolin (7.3 ± 0.3, 6.4 ± 0.3, and 5.4 ± 0.1, respectively). The bronchodilator effects of salbutamol, isoprenaline, NKH477, and forskolin (10^–9–10^–4 M) were examined on isolated ovine bronchioles precontracted with carbachol (0.3 μM). Isoprenaline, NKH477, and forskolin produced a concentration‐dependent relaxation with pD₂ values of 6.1 ± 0.2, 5.4 ± 0.2, and 5.3 ± 0.2, respectively. Tachyphylaxis to the relaxant effects of salbutamol on guinea pig isolated bronchioles was experimentally induced and the potency of salbutamol was reduced to 5.9 ± 0.2 after 24 h incubation with salbutamol (10^–5M). NKH477 and forskolin (10^–6 M) produced a partial reversal of tachyphylaxis to salbutamol‐induced relaxation using salbutamol pretreated tissues. The potency of salbutamol was increased to 6.6 ± 0.2 and 5.9 ± 0.2 after incubation with NKH477 or forskolin (10^–6 M), respectively. Tachyphylaxis to the relaxant effects of isoprenaline resulted in a reduced potency of 5.7 ± 0.2. Forskolin (10^–6 M) produced a partial reversal of tachyphylaxis, while NKH477 (10^–6 M) produced a complete reversal of tachyphylaxis to isoprenaline‐induced relaxation with an pD₂ value of 6.3 ± 0.1. In conclusion, the guinea pig and sheep isolated bronchioles serve as good models to study the relaxant effects of the bronchodilator agents salbutamol, isoprenaline, NKH477, and forskolin. The β‐agonists examined had higher potencies than NKH477 or forskolin. However, the two adenylate cyclase activators, with greater effectiveness of NKH477, when used in combination with the β‐agonists, could produce an increase in the potency of the β‐agonists. Furthermore, the effectiveness of NKH477 and forskolin in reversing tachyphylaxis to the bronchodilator effects of the β‐agonists, particularly salbutamol, may provide an advantage in long‐term use of β‐agonists in bronchial asthma therapy. Drug Dev. Res. 51:169–176, 2000. © 2001 Wiley‐Liss, Inc.     

阿托品对兔胸主动脉平滑肌收缩和细胞增殖的影响

用兔胸主动脉条研究Atr,Ver对CaCl₂,Atr对KCI量—效反应的影响。观察到Atr和Ver能抑制2种激动剂所致兔主动脉条的收缩,量一效曲线右移,最大反应降低,其pD₂值分别为4.4和5.8。两药也能明显抑制NE依内Ca²⁺性收缩,Atr对NE依外Ca²⁺性收缩影响较小,说明Atr主要对细胞外Ca²⁺经PDC所致的收缩有抑制作用。在兔ASMC培养中,有Ca²⁺时,Atr抑制ASMC增殖,无Ca²⁺时,Atr 20.6～185.2 μmol/L表现刺激增殖,555.7～1666.7 μmol/L则抑制MSMC增殖,说明Atr对ASMC作用也与Ca(2+)有关。     

The effect of acteoside on intracellular Ca2+ mobilization and phospholipase C activity in RBL-2H3 cells stimulated by melittin

This study was performed to investigate the effects of acteoside on various cellular functions such as, intracellular Ca²⁺ mobilization, phospholipase C activity, and exocytosis induced by melittin. Melittin (0.1–1 μM) dose-dependently increased intracellular Ca²⁺ mobilization in the presence of extracellular Ca²⁺, but was not affected by 1 μM U73122, a specific PLC inhibitor. In the absence of extracellular Ca²⁺, melittin (1 μM) did not induce a change in intracellular Ca²⁺ mobilization, which suggests that melittin-induced intracellular Ca²⁺ mobilization may be dependent on the influx of extracellular Ca²⁺ rather than on the release of intracellular Ca²⁺ storage. Acteoside (10 μM) significantly inhibited 1 μM melittin-induced Ca²⁺ mobilization by 33 %. In [³H]inositol-labeled cells, 1 μM melittin did not increase inositol phosphate formation, but more than 5 μM melittin significantly increased inositol phosphate formation, which was significantly inhibited by acteoside. Melittin (1 μM) significantly increased histamine release from RBL 2H3 cells in the presence or absence of extracellular Ca²⁺. Acteoside significantly inhibited 1-μM-melittin-induced histamine release by 74 % in the presence of extracellular Ca²⁺ and by 71 % in the absence of extracellular Ca²⁺. These data suggest that the inhibitory effect of acteoside on 1 μM-melittin-induced histamine release may be related to blockage of the calcium-independent pathway. Taken together, these data suggest that melittin has an influence on cellular functions such as intracellular Ca²⁺ mobilization, the PLC pathway, and exocytosis via various independent signalling pathways in RBL-2H3 cells, and was significantly inhibited by acteoside.     

Effects of S 9977-2 on the guinea pig isolated trachea and the human isolated bronchus

The effects of S 9977-2, a new compound which belongs to the trimethylxanthine family and has shown in vivo promnesic activity and in vitro acetylcholinesterase activities inhibition, were studied on the guinea pig isolated trachea and on human isolated bronchi. On the guinea pig isolated trachea, S 9977-2 in concentrations of 10^?7–10^?4 M potentiated the contractile effect of acetylcholine. The potency of acetylcholine was increased 3.39, 4.26, 9.54, and 13.18 fold with concentrations of 10^?7, 10^?6, 10^?5, and 10^?4M, respectively. The maximum effect of acetylcholine was not modified. S 9977-2 did not potentiate the effects of carbachol or pilocarpine. Under similar conditions, eserine (10^?8 and 10^?6M) and tacrine (10^?8–10^?6M) also potentiated the effects of acetylcholine. The potentiating effect of these two substances was stronger than that of S 9977-2, with a 44.7 fold increase for eserine (10^?7M) and a 64.6 fold increase for tacrine (10^?6M). However, both eserine and tacrine had a contractile effect of their own on the guinea pig isolated trachea, whereas S 9977-2 had no such effect. On the human isolated bronchus, S 9977-2 at a concentration of 10^?5M produced a 19.1 fold increase of acetylcholine effects. On the guinea pig isolated trachea, the effects of S 9977-2 vs. acetylcholine were not modified by epithelium removal. They were increased by pretreatment with indomethacin 10^?6M. In very high concentrations (10^?4 and/or 10^?3M), S 9977-2 reduced the effects of histamine and those of serotonin on the guinea pig isolated trachea. S 9977-2 had no effect on the contractile action of potassium chloride or on the relaxant action of adenosine. The results suggest that in the airway smooth muscle S 9977-2 partially inhibits acetylcholinesterase and/or pseudocholinesterase activity. © 1992 Wiley-Liss, Inc.     

葛缕酮的气道扩张作用和呼吸道抗过敏作用

目的观察留兰香油中葛缕酮的气道扩张作用和对呼吸道介质的影响。方法用豚鼠药物引喘法、豚鼠离体气管片法、致敏豚鼠肺组织ＳＲＳ Ａ释放和拮抗ＳＲＳ Ａ、致敏豚鼠离体气管Ｓｃｈｕｌｔｚ Ｄａｌｅ反应法检测。结果葛缕酮对豚鼠药物性哮喘具有保护作用,灌胃给药延长５０％剂量为７６ｍｇ·ｋｇ－１,气雾给药为６３ｇ·Ｌ－１;对豚鼠离体气管有直接松弛作用,ｐＤ２值为４２７±００８,并有抗氨甲酰胆碱作用;能抑制致敏豚鼠肺组织ＳＲＳ Ａ的释放,ＩＣ５０为１８ｍｇ·Ｌ－１,拮抗ＳＲＳ Ａ收缩回肠的ＩＣ５０为２７ｍｇ·Ｌ－１,并能抑制致敏豚鼠离体气管的Ｓｃｈｕｌｔｚ Ｄａｌｅ反应。结论葛缕酮具有气道扩张作用和呼吸道抗过敏作用。     

Role of potassium channels in the relaxant effect of levosimendan in guinea pig tracheal preparations

We investigated both the effect of levosimendan and the role of various potassium channels in carbachol-precontracted tracheal preparations samples obtained from guinea pig. The tracheas were cut into 0.5 cm wide rings and suspended in a 20 ml organ bath. Isometric tension was continuously measured with an isometric force transducer connected to a computer-based data acquisition system. Levosimendan or cromakalim produced concentration-dependent relaxation responses in guinea pig tracheal rings precontracted by carbachol. Incubation of guinea pig tracheal rings with the ATP-dependent potassium channel (K_ATP) blocker glibenclamide for 30 min significantly inhibited the relaxant responses to both levosimendan and cromakalim. The large conductance Ca²⁺-activated potassium channel (BK_Ca) blocker iberiotoxin also caused a significant inhibition on relaxant responses to levosimendan. However, incubation of the tracheal rings with the voltage-dependent potassium channel blocker 4-aminopyridine for 10 min did not cause significant alterations on relaxant responses to levosimendan. The present findings suggested that the relaxant effect induced by levosimendan might be partially due to K_ATP and BKCa in isolated guinea pig tracheal rings.     

Studies on the Mechanism of Spasmolytic Activity of (O-Methyl-)-N-(2,6-dihydroxybenzoyl)tyramine,a Constituent of Aniba riparia (Nees) Mez. (Lauraceae), in Rat Uterus,Rabbit Aorta and Guinea-pig Alveolar Leucocytes

Abstract— The mechanism of action of a nonspecific smooth muscle relaxant, (O-methyl-)-N-(2,6-dihydroxybenzoyl)tyramine (riparin), a constituent of Aniba riparia (Nees) Mez. (Lauraceae) was studied in relation to Ca²⁺ metabolism in smooth muscle tissues and in guinea-pig alveolar leucocytes. In rat depolarized uterus, riparin inhibited in a reversible and noncompetitive manner CaCl₂-induced contraction, a response mediated through voltage-dependent Ca²⁺ channels. The pD₂ value (mean±s.e.m.) for riparin was 4·98±006. When compared with sodium nitroprusside (IC50 2·5 μm ), an antagonist of receptor-operated Ca²⁺ channels, riparin was ineffective in suppressing noradrenaline-induced sustained contractions of rabbit aortic strips. However, in the aorta, the compound inhibited intracellular calcium-dependent transient contractions of noradrenaline and riparin (IC50 10·1 μm ), was approximately two and a half times more potent than procaine (IC50 25·5 μm ), a known inhibitor. In guinea-pig alveolar leucocytes, riparin (IC50 3·2 μm ), inhibited intracellular Ca²⁺ accumulation induced by the calcium ionophore A23187. The results suggest that the inhibition of Ca²⁺ influx and of Ca²⁺ release from intracellular stores contribute to the spasmolytic effects of riparin, which may not involve cyclic AMP generation as the levels of this nucleotide were not increased in alveolar macrophages treated with riparin (10–100 μm ).     

间硝苯吡啶与硝苯吡啶对离体心脏、血管钙拮抗作用的比较性研究

M-Nif对离体豚鼠左心房的钙拮抗作用PD₂′=7.05较Nif PD₂′=7.19弱,抑制心肌的IC₅₀=7.5×10^-8M亦较Nif IC₅₀=2.9×10^-6M弱2.6倍。在离体猪冠脉条实验中M-Nif PD₂′=7.06,Nif PD₂′=6.88,前者稍强,前者抑制血管的作用IC₅₀=6.166×10^-7M亦强于后者IC₅₀=7.02×10^-7M 114倍,Nif扩张血管作用较抑制心肌作用强10倍,提示M-Nif扩张血管与抑制心肌的宽度更大,对治疗心力衰竭、降压将更有利。