Kukkonen J P, Lund P E, Akerman K E
Department of Physiology, Division of Cell Physiology, Uppsala University, Uppsala, Sweden.
Cell Calcium. 2001 Aug;30(2):117-29. doi: 10.1054/ceca.2001.0219.
We have investigated Ca(2+) release and receptor- and store-operated Ca(2+) influxes in Chinese hamster ovary-K1 (CHO) cells, SH-SY5Y human neuroblastoma cells and RBL-1 rat basophilic leukemia cells using Fura-2 and patch-clamp measurements. Ca(2+) release and subsequent Ni(2+)-sensitive, store-operated influx were induced by thapsigargin and stimulation of G protein-coupled receptors. The alleged noncompetitive IP3 receptor inhibitor,2-aminoethoxydiphenyl borate (2-APB) rapidly blocked a major part of the secondary influx response in CHO cells in a reversible manner. It also reduced Mn(2+) influx in response to thapsigargin. Inhibition of Ca(2+) release was also seen but this was less complete, slower in onset, less reversible, and required higher concentration of 2-APB. In RBL-1 cells, I(CRAC) activity was rapidly blocked by extracellular 2-APB whereas intracellular 2-APB was less effective. Store-operated Ca(2+) influxes were only partially blocked by 2-APB. In SH-SY5Y cells, Ca(2+) influxes were insensitive to 2-APB. Ca(2+) release in RBL-1 cells was partially sensitive but in SH-SY5Y cells the release was totally resistant to 2-APB. The results suggest, that 2-APB (1) may inhibit distinct subtypes of IP3 receptors with different sensitivity, and (2) that independently of this, it also inhibits some store-operated Ca(2+) channels via a direct, extracellular action.
我们使用Fura-2和膜片钳测量技术，研究了中国仓鼠卵巢-K1（CHO）细胞、SH-SY5Y人神经母细胞瘤细胞和RBL-1大鼠嗜碱性白血病细胞中的Ca(2+)释放以及受体介导和储存操纵的Ca(2+)内流。毒胡萝卜素和G蛋白偶联受体的刺激可诱导Ca(2+)释放以及随后对镍敏感的储存操纵内流。所谓的非竞争性IP3受体抑制剂2-氨基乙氧基二苯硼酸盐（2-APB）以可逆方式迅速阻断了CHO细胞中大部分的继发性内流反应。它还减少了毒胡萝卜素引起的Mn(2+)内流。Ca(2+)释放的抑制也有观察到，但这种抑制不太完全，起效较慢，不太可逆，并且需要更高浓度的2-APB。在RBL-1细胞中，细胞外2-APB可迅速阻断I(CRAC)活性，而细胞内2-APB的效果较差。储存操纵的Ca(2+)内流仅被2-APB部分阻断。在SH-SY5Y细胞中，Ca(2+)内流对2-APB不敏感。RBL-1细胞中的Ca(2+)释放部分敏感，但在SH-SY5Y细胞中，释放对2-APB完全耐药。结果表明，2-APB（1）可能以不同的敏感性抑制不同亚型的IP3受体，（2）除此之外，它还通过直接的细胞外作用抑制一些储存操纵的Ca(2+)通道。
