Chinet T, Fouassier L, Dray-Charier N, Imam-Ghali M, Morel H, Mergey M, Dousset B, Parc R, Paul A, Housset C
Laboratoire de Biologie et Pharmacologie des Epithéliums Respiratoires, Université Paris V René Descartes, Hôpital Ambroise Paré, Boulogne,
Hepatology. 1999 Jan;29(1):5-13. doi: 10.1002/hep.510290142.
Fluid and ion transport across biliary epithelium contributes to bile flow. Alterations of this function may explain hepatobiliary complications in cystic fibrosis (CF). We investigated electrogenic anion transport across intact non-CF and CF human gallbladder mucosa in Ussing-type chambers. In non-CF tissues, baseline transmural potential difference (PD), short-circuit current (Isc), and resistance (R) were -2.2 +/- 0.3 mV (lumen negative), 40.7 +/- 7.8 microA/cm2, and 66.5 +/- 9.6 Omega. cm2, respectively (n = 14). The addition of forskolin (10(-5) mol/L) to the apical and basolateral baths and that of adenosine 5'-triphosphate (ATP) (10(-4) mol/L) to the apical bath induced significant increases in Isc by 8.0 +/- 1.4 and 10.3 +/- 1.8 microA/cm2, respectively. Depletion of bathing solutions in Cl- and HCO3- significantly reduced baseline Isc and the forskolin- and ATP-induced increases in Isc. Anion secretion was stimulated by extracellular ATP via P2Y2 purinoceptors, as indicated by the effects of different nucleotides on Isc and on 36Cl efflux in cultured gallbladder epithelial cells. This effect was mediated by cytosolic calcium increase and Ca2+/calmodulin-dependent protein kinase II, as ascertained by using inhibitors. In CF preparations, basal PD and Isc were lower than in non-CF, and the response to forskolin was abolished, whereas the response to ATP was enhanced (P <.05 for all). We conclude that electrogenic anion secretion occurs in human gallbladder mucosa under basal state and is stimulated by an adenosine 3',5'-cyclic monophosphate (cAMP)-dependent pathway mediated by cystic fibrosis transmembrane conductance regulator (CFTR), and by exogenous ATP via a CFTR-independent pathway that is up-regulated in CF and involves P2Y2 purinoceptors and a calcium-dependent pathway.
液体和离子跨胆管上皮的转运有助于胆汁流动。该功能的改变可能解释囊性纤维化（CF）中的肝胆并发症。我们在Ussing型小室中研究了完整的非CF和CF人胆囊黏膜上的电生性阴离子转运。在非CF组织中，基线跨膜电位差（PD）、短路电流（Isc）和电阻（R）分别为-2.2±0.3 mV（管腔为负）、40.7±7.8 μA/cm²和66.5±9.6 Ω·cm²（n = 14）。向顶端和基底浴中添加福斯高林（10⁻⁵ mol/L）以及向顶端浴中添加腺苷5'-三磷酸（ATP）（10⁻⁴ mol/L）分别使Isc显著增加8.0±1.4和10.3±1.8 μA/cm²。Cl⁻和HCO₃⁻中的浴液耗尽显著降低了基线Isc以及福斯高林和ATP诱导的Isc增加。细胞外ATP通过P2Y2嘌呤受体刺激阴离子分泌，这由不同核苷酸对培养的胆囊上皮细胞中Isc和³⁶Cl外流的影响表明。如使用抑制剂所确定的，该效应由胞质钙增加和Ca²⁺/钙调蛋白依赖性蛋白激酶II介导。在CF制剂中，基础PD和Isc低于非CF，对福斯高林的反应消失，而对ATP的反应增强（所有P < 0.05）。我们得出结论，电生性阴离子分泌在基础状态下发生于人胆囊黏膜中，并且由囊性纤维化跨膜传导调节因子（CFTR）介导的腺苷3',5'-环磷酸（cAMP）依赖性途径以及通过CFTR非依赖性途径的外源性ATP刺激，该途径在CF中上调且涉及P2Y2嘌呤受体和钙依赖性途径。
