Tepel M, Heidenreich S, Schlüter H, Beinlich A, Nofer J R, Walter M, Assmann G, Zidek W
Marienhospital Herne, Ruhr-Universität-Bochum, Germany.
Eur J Clin Invest. 1996 Dec;26(12):1077-84. doi: 10.1046/j.1365-2362.1996.400592.x.
The effects of diadenosine tetraphosphate (AP4A) diadenosine pentaphosphate (AP5A) and diadenosine hexaphosphate (AP6A) on the cytosolic-free calcium concentration ([Ca2+]i) were evaluated in cultured rat glomerular mesangial cells (MCs) using the fluorescent dye technique. The addition of 10 mumol L-1 AP4A, AP5A or AP6A significantly increased [Ca2+]i in MCs by 57 +/- 9 nmol L-1 n = 17; P < 0.01), 76 +/- 27 nmol L-1 (n = 9; P < 0.01) or 65 +/- 12 nmol L-1 (n = 18; P < 0.01) respectively. In the absence of extracellular calcium, there was no significant change in [Ca2+]i in MCs after administration of diadenosine polyphosphates, indicating that these agents induce transplasma membrane Ca2+ influx. AP6A significantly enhanced the angiotensin II-induced changes in [Ca2+]i in MCs. The AP5A-induced transplasma membrane Ca2+ influx was inhibited by the P2 purinoceptor blockers suramin and pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid (PPADS), but was not affected by the adenosine A1 receptor blocker 8-cyclopentyl-1.3-dipro-pylzanthine (CPDPX). Adenosine triphosphate (ATP) and adenosine 5'-O-(3-thio)triphosphate (ATP-gamma S) increased [Ca2+]i in MCs, whereas alpha, beta-methylene ATP had no effect on [Ca2+]i in MCs. Measurements of diacylglycerol and phosphatidic acid showed that AP5A and AP6A also stimulated phospholipase C, but had no effect on phospholipase D. The inhibition of phosphatidylcholine-specific phospholipase C significantly reduced the AP5A-induced [Ca2+]i increase. In summary, diadenosine polyphosphates induce Ca2+ influx through P2 purinoceptors and may be involved in the local regulation of vascular resistance evoked by the Ca(2+)-dependent contractile response of mesangial cells.
利用荧光染料技术，在培养的大鼠肾小球系膜细胞（MCs）中评估了四磷酸二腺苷（AP4A）、五磷酸二腺苷（AP5A）和六磷酸二腺苷（AP6A）对细胞内游离钙浓度（[Ca2+]i）的影响。添加10 μmol/L的AP4A、AP5A或AP6A可使MCs中的[Ca2+]i分别显著升高57±9 nmol/L（n = 17；P < 0.01）、76±27 nmol/L（n = 9；P < 0.01）或65±12 nmol/L（n = 18；P < 0.01）。在无细胞外钙的情况下，给予多磷酸二腺苷后MCs中的[Ca2+]i无显著变化，表明这些试剂可诱导跨质膜Ca2+内流。AP6A显著增强了血管紧张素II诱导的MCs中[Ca2+]i的变化。P2嘌呤受体阻滞剂苏拉明和磷酸吡哆醛 - 6 - 偶氮苯 - 2',4'-二磺酸（PPADS）可抑制AP5A诱导的跨质膜Ca2+内流，但腺苷A1受体阻滞剂8 - 环戊基 - 1,3 - 二丙基黄嘌呤（CPDPX）对其无影响。三磷酸腺苷（ATP）和5'-O-(3 - 硫代)三磷酸腺苷（ATP-γS）可使MCs中的[Ca2+]i升高，而α,β-亚甲基ATP对MCs中的[Ca2+]i无影响。二酰甘油和磷脂酸的测量结果表明，AP5A和AP6A也可刺激磷脂酶C，但对磷脂酶D无影响。抑制磷脂酰胆碱特异性磷脂酶C可显著降低AP5A诱导的[Ca2+]i升高。总之，多磷酸二腺苷通过P2嘌呤受体诱导Ca2+内流，可能参与由系膜细胞Ca(2+)依赖性收缩反应引起的血管阻力的局部调节。
