Zanello L P, Norman A W
Department of Biochemistry, University of California, Riverside 92521, USA.
Biochem Biophys Res Commun. 1996 Aug 14;225(2):551-6. doi: 10.1006/bbrc.1996.1210.
1 alpha,25-dihydroxyvitamin-D3 [1 alpha,25(OH)2D3] is known to potentiate in osteoblast-like rat osteosarcoma cells (ROS 17/2.8) the influx of Ca2+ through voltage-activated L-type Ca2+ channels. In the present study, by means of the whole-cell patch-clamp technique, we found that physiological concentrations of 1 alpha,25(OH)2D3 (5-5000 x 10(-11) M) also stimulate, in a dose-dependent manner, outwardly rectifying anionic currents over the course of 1-5 minutes. These currents, recorded in the presence of 130 mM glutamate or approximately 140 mM C1- in the external solution, were blocked by 200 microM DIDS, a stilbene derivative selective for C1- channels. We conclude that, in addition to the already known effects of 1 alpha,25(OH)2D3 on Ca2+ channels, the hormone also enhances in ROS 17/2.8 cells an outward anion conductance. This is the first report concerning activation of anion channels by 1 alpha,25(OH)2D3.
已知1α,25 - 二羟基维生素D3 [1α,25(OH)2D3]可增强大鼠成骨样骨肉瘤细胞（ROS 17/2.8）中通过电压激活的L型Ca2+通道的Ca2+内流。在本研究中，通过全细胞膜片钳技术，我们发现生理浓度的1α,25(OH)2D3（5 - 5000×10(-11) M）在1 - 5分钟内也以剂量依赖的方式刺激外向整流阴离子电流。在外部溶液中存在130 mM谷氨酸或约140 mM Cl-的情况下记录的这些电流，被200 μM DIDS（一种对Cl-通道有选择性的芪衍生物）阻断。我们得出结论，除了1α,25(OH)2D3对Ca2+通道的已知作用外，该激素还增强了ROS 17/2.8细胞中的外向阴离子电导。这是关于1α,25(OH)2D3激活阴离子通道 的首次报道。
