Bouchelouche P N, Hainau B, Frederiksen O
Department of Clinical Chemistry, Herlev Hospital, Copenhagen, Denmark.
Cell Calcium. 1989 Jan;10(1):37-46. doi: 10.1016/0143-4160(89)90042-0.
Rabbit gall-bladder epithelial cells were isolated by a combination of Ca2+ omission, enzymatic treatment, and mechanical detachment and had a viability of 96-98% and well preserved morphology. Measurements of cytosolic free Ca2+ concentration ([Ca2+]i) in these cells with the Ca2+-fluorescent indicator fura-2 demonstrated a resting [Ca2+]i level of 115 +/- 12 nM. When used in concentrations which inhibit rabbit gall-bladder isosmotic NaCl absorption (1-100 microM), the Ca2+-channel activator BAY K 8644 caused a dose-dependent increase in the epithelial [Ca2+]i to a maximal value of 850 nM. The effect was dependent on extracellular Ca2+, and was not altered by 1 microM L-verapamil. Depolarization of the epithelial cells with KCl had no effect on [Ca2+]i. The results suggest that BAY K 8644 activates a Ca2+ influx which is not dependent on voltage-gated channels. Cytosolic Ca2+ may be involved in the regulation of isosmotic NaCl absorption in the mammalian gall-bladder.
通过结合省略钙离子、酶处理和机械分离的方法分离出兔胆囊上皮细胞,其活力为96%-98%,形态保存良好。用钙离子荧光指示剂fura-2测量这些细胞的胞质游离钙离子浓度([Ca2+]i),结果显示静息[Ca2+]i水平为115±12 nM。当以抑制兔胆囊等渗氯化钠吸收的浓度(1-100 microM)使用时,钙离子通道激活剂BAY K 8644导致上皮细胞[Ca2+]i呈剂量依赖性增加,最大值达到850 nM。该效应依赖于细胞外钙离子,且不受1 microM L-维拉帕米的影响。用氯化钾使上皮细胞去极化对[Ca2+]i没有影响。结果表明,BAY K 8644激活了一种不依赖于电压门控通道的钙离子内流。胞质钙离子可能参与了哺乳动物胆囊中等渗氯化钠吸收的调节。