Yen P T, Herman P, Van den Abbeele T, Tan C T, Bordure P, Marianowski R, Friedlander G, Tran Ba Huy P
Laboratoire d'Otologie Expérimentale, Faculté Lariboisière-St-Louis, Paris, France.
ORL J Otorhinolaryngol Relat Spec. 1997 May-Jun;59(3):170-5. doi: 10.1159/000276932.
Mucus and cellular debris are eliminated from the middle-ear cavity through the E-tube by the mucociliary system. Depth of the periciliary fluid layer is thought to be regulated by epithelial ion transport activity. Since impairment of the mucociliary system is a key step in the development of otitis media with effusion, we investigated the ion transport mechanisms of the middle-ear epithelium using the middle-ear MESV cell line. ATP has been shown to modulate ion transport as well as various cellular functions in several cell types via purinoceptors. In order to investigate a possible modulation of the transport activity of MESV cells, we evaluated short-circuit current (Isc) changes in response to specific stimulation of putative purinoceptors by ATP and its various analogs. ATP dramatically increased Isc, while adenosine had no effect, thus demonstrating the presence of P2 receptors according to the original classification by Burnstock. The rank order of potency of purinoceptor agonists for stimulation of Isc on the apical side (ATP > UTP > gamma-SATP >> beta-SADP > 2-methylthio-ATP, 2MeSATP > beta, gamma-methylene-ATP, beta,gamma-MeATP) and on the basolateral side (ATP > gamma-SATP > UTP >> beta-SADP > 2 MeSATP > beta,gamma-MeATP), along with studies using selective antagonists and intracellular calcium measurements are consistent with a P2Y receptor subtype. The ATP-induced increase in Isc was related to sodium transport. This modulation might be of importance in stress conditions such as inflammation.
黏液和细胞碎片通过黏液纤毛系统经咽鼓管从中耳腔排出。人们认为纤毛周围液层的深度受上皮离子转运活性调节。由于黏液纤毛系统受损是分泌性中耳炎发病的关键步骤，我们使用中耳MESV细胞系研究了中耳上皮的离子转运机制。在几种细胞类型中，ATP已被证明可通过嘌呤受体调节离子转运以及各种细胞功能。为了研究MESV细胞转运活性的可能调节作用，我们评估了ATP及其各种类似物对假定嘌呤受体的特异性刺激所引起的短路电流（Isc）变化。ATP显著增加Isc，而腺苷无作用，因此根据Burnstock的原始分类证明存在P2受体。嘌呤受体激动剂在顶端侧（ATP > UTP > γ-SATP >> β-SADP > 2-甲硫基-ATP，2MeSATP > β,γ-亚甲基-ATP，β,γ-MeATP）和基底外侧侧（ATP > γ-SATP > UTP >> β-SADP > 2 MeSATP > β,γ-MeATP）刺激Isc的效力排序，以及使用选择性拮抗剂和细胞内钙测量的研究结果与P2Y受体亚型一致。ATP诱导的Isc增加与钠转运有关。这种调节在炎症等应激条件下可能很重要。
