The spasmogenic effects of vanadate in human isolated bronchus
The spasmogenic effects of vanadate in human isolated bronchus
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DOI：
10.1038/sj.bjp.0701277
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发表时间：
1997-08-01
影响因子：
7.3
通讯作者：
Small, RC
中科院分区：
文献类型：
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作者：
Cortijo, J;Villagrasa, V;Small, RC
吸入钒化合物，特别是钒酸盐，是职业性支气管哮喘的一个原因。我们研究了钒酸盐对人离体支气管的作用。钒酸盐（0.1 μ M-3 mM）产生浓度依赖性，持续良好的收缩。其-logEC（50）为3.74 +/- 0.05（平均值+/- s.e.）其最大效应相当于对乙酰胆碱反应的97.5 +/-4.2（ACh，1 mM）。2钒酸盐（200 μ M）诱导的人支气管收缩不依赖于上皮细胞，不受吲哚美辛抑制（2.8 μ M），齐留通（10 μ M），阿托品、美托洛尔和酚妥拉明的混合物（每种1 μ M），或用化合物48/80.3钒酸盐通过肥大细胞脱粒（200 μ M）诱导的收缩不受维拉帕米或硝苯地平组织暴露的影响（各1 μ M）或加入到无Ca 2+、含EGTA（0.1mM）的生理盐溶液（PSS）中。然而，组织孵育与ryanodine（10 μ M）中的Ca 2+自由，EGTA（0.1 mM）含有PSS减少钒酸盐诱导的收缩。在暴露于无Ca 2+的含EGTA（0.1 mM）的PSS的组织中进行一系列钒酸盐挑战，目的是耗尽细胞内Ca 2+储存。在这些组织中，环匹阿尼酸（CPA; 10 μ M）阻止了钙离子诱导的钒酸盐诱导的收缩恢复。4在富含K+（80 mM）的PSS、无K+ PSS或含有哇巴因（10 μ M）的PSS中孵育的组织没有改变钒酸盐（200 μ M）诱导的收缩。哇巴因（10 μ M）取消了K+诱导的人支气管松弛沐浴在K+无PSS。钒酸盐（200 μ M）不具有这种作用。哇巴因（10 μ M）使Na+的组织含量增加，K+的组织含量降低。相反，钒酸盐（200 μ M）没有改变这些离子的组织含量。在Na+缺乏（25 mM）PSS或PSS中含有阿米洛利（0.1 mM）的组织孵育显著抑制钒酸盐（200 μ M）的痉挛作用。5用蛋白激酶C（PKC）抑制剂H-7（10 μ M）、staurosporine（1 μ M）和calphostin C（1 μ M）中的每一种进行组织处理显著降低钒酸盐（200 μ M）诱导的收缩。染料木黄酮（100 μ M），蛋白酪氨酸激酶的抑制剂，也减少了对钒酸盐的反应。6钒酸盐（0.1-3 mM）和乙酰胆碱（1 μ M-3 mM）各自增加支气管中磷酸肌醇的积累。这种反应不受单独或与ryanodine（10 μ M）组合的无Ca 2+培养基的影响。7在人培养的气管平滑肌细胞中，组胺（100 μ M）和钒酸盐（200 μ M）均引起细胞内Ca 2+浓度的瞬时增加（[Ca 2 +]（i））.8细胞内微电极记录显示钒酸盐的收缩作用（200 μ M）与细胞去极化有关。9可以得出结论，钒酸盐直接作用于人支气管平滑肌，促进Ca 2+从细胞内储存中释放。Ca ~（2+）释放机制包括磷酸肌醇第二信使的产生和Ca-ATP酶的抑制。PKC的激活在介导钒酸盐诱导的收缩中起重要作用，[Ca 2 +]（i）值接近于基础。
1 Inhalation of vanadium compounds, particularly vanadate, is a cause of occupational bronchial asthma. We have now studied the action of vanadate on human isolated bronchus. Vanadate (0.1 mu M-3 mM) produced concentration-dependent, well-sustained contraction. Its -logEC(50) was 3.74 +/- 0.05 (mean +/- s.e. mean) and its maximal effect was equivalent to 97.5 +/- 4.2% of the response to acetylcholine (ACh, 1 mM).2 Vanadate (200 mu M)-induced contraction of human bronchus was epithelium-independent and was not inhibited by indomethacin (2.8 mu M), zileuton (10 mu M), a mixture of atropine, mepyramine and phentolamine (each at 1 mu M), or by mast cell degranulation with compound 48/80.3 Vanadate (200 mu M)-induced contraction was unaltered by tissue exposure to verapamil or nifedipine (each 1 mu M) or to a Ca2+-free, EGTA (0.1 mM)-containing physiological salt solution (PSS). However, tissue incubation with ryanodine (10 mu M) in Ca2+-free, EGTA (0.1 mM)-containing PSS reduced vanadate-induced contraction. A series of vanadate challenges was made in tissues exposed to Ca2+-free EGTA (0.1 mM)-containing PSS with the object of depleting intracellular Ca2+ stores. In such tissues cyclopiazonic acid (CPA; 10 mu M) prevented Ca2+-induced recovery of vanadate-induced contraction.4 Tissue incubation in K+-rich (80 mM) PSS, K+-free PSS, or PSS containing ouabain (10 mu M) did not alter vanadate (200 mu M)-induced contraction. Ouabain (10 mu M) abolished the K+-induced relaxation of human bronchus bathed in K+-free PSS. This action was not shared by vanadate (200 mu M). The tissue content of Na+ was increased and the tissue content of K+ was decreased by ouabain (10 mu M). In contrast, vanadate (200 mu M) did not alter the tissue content of these ions. Tissue incubation in a Na+-deficient (25 mM) PSS or in PSS containing amiloride (0.1 mM) markedly inhibited the spasmogenic effect of vanadate (200 mu M).5 Vanadate (200 mu M)-induced contractions were markedly reduced by tissue treatment with each of the protein kinase C (PKC) inhibitors H-7 (10 mu M), staurosporine (1 mu M) and calphostin C (1 mu M). Genistein (100 mu M), an inhibitor of protein tyrosine kinase, also reduced the response to vanadate.6 Vanadate (0.1-3 mM) and ACh (1 mu M-3 mM) each increased inositol phosphate accumulation in bronchus. Such responses were unaffected by a Ca2+-free medium either alone or in combination with ryanodine (10 mu M).7 In human cultured tracheal smooth muscle cells, histamine (100 mu M) and vanadate (200 mu M) each produced a transient increase in intracellular Ca2+ concentration ([Ca2+](i)).8 Intracellular microelectrode recording showed that the contractile effect of vanadate (200 mu M) in human bronchus was associated with cellular depolarization.9 It is concluded that vanadate acts directly on human bronchial smooth muscle, promoting the release of Ca2+ from an intracellular store. The Ca2+ release mechanism involves both the production of inositol phosphate second messengers and inhibition of Ca-ATPase. The activation of PKC plays an important role in mediating vanadate-induced contraction at values of [Ca2+](i) that are close to basal.