Tsunoda Y, Mizuno T
Biochim Biophys Acta. 1985 Nov 7;820(2):189-98. doi: 10.1016/0005-2736(85)90112-9.
Biphasic responses of amino[14C]pyrine accumulation and oxygen consumption were registered by gastrin stimulation in dispersed parietal cells from guinea pig gastric mucosa, and this was mimicked with the calcium ionophore A23187. The characteristics of these phases (first phase and second phase) were distinguished by the differences in the requirements of extracellular Ca2+. The first phase evoked by gastrin or ionophore A23187 was independent of extracellular Ca2+, whereas the second phase was not. In the first phase, fluorescence of a cytosolic Ca2+ indicator (quin2-AM) increased with the stimulation of ionophore A23187 and carbamylcholine chloride in the presence of extracellular Ca2+. In addition, an increase in cytosolic Ca2+ induced by ionophore A23187, but not by carbamylcholine chloride was also observed in the absence of extracellular Ca2+, suggesting that Ca2+ pool(s) in parietal cells might be present in the intracellular organelle. Cytochalasin B and colchicine, but not oligomycin, could eliminate this cytosolic Ca2+ increase induced by A23187 in a Ca2+-free medium. On the other hand, in a Ca2+-free medium, addition of ATP after pretreatment with digitonin could diminish the cytosolic Ca2+ increase brought about by A23187. This was also observed with oligomycin-treated cells, but not with cytochalasin B-treated cells. Similarly, subcellular fractionation of a parietal cell which had been pretreated with cytochalasin B or colchicine in an intact cell system reduced the rate of ATP-dependent Ca2+ uptake. These observations indicate that intracellular Ca2+ transport in dispersed parietal cells may be regulated by the microtubular-microfilamentous system. In conclusion, this study demonstrates the possibility of the existence of intracellular Ca2+ transport mediated by gastrin or ionophore A23187 and regulated by the microtubular-microfilamentous system in parietal cells.
在豚鼠胃黏膜分散的壁细胞中，胃泌素刺激可使氨基[¹⁴C]吡啶积累和氧消耗出现双相反应，钙离子载体A23187也能模拟这种反应。这些阶段（第一阶段和第二阶段）的特征通过细胞外Ca²⁺需求的差异来区分。胃泌素或离子载体A23187诱发的第一阶段与细胞外Ca²⁺无关，而第二阶段则依赖于细胞外Ca²⁺。在第一阶段，在细胞外Ca²⁺存在的情况下，离子载体A23187和氯化氨甲酰胆碱刺激可使胞质Ca²⁺指示剂（quin2-AM）的荧光增强。此外，在无细胞外Ca²⁺的情况下，也观察到离子载体A23187诱导的胞质Ca²⁺增加，但氯化氨甲酰胆碱未诱导这种增加，这表明壁细胞中的Ca²⁺池可能存在于细胞内细胞器中。细胞松弛素B和秋水仙碱，而非寡霉素，可消除无Ca²⁺培养基中A23187诱导的这种胞质Ca²⁺增加。另一方面，在无Ca²⁺培养基中，用洋地黄皂苷预处理后添加ATP可减少A23187引起的胞质Ca²⁺增加。寡霉素处理的细胞也观察到这种情况，但细胞松弛素B处理的细胞未观察到。同样，在完整细胞系统中用细胞松弛素B或秋水仙碱预处理的壁细胞亚细胞分级分离降低了ATP依赖性Ca²⁺摄取率。这些观察结果表明，分散壁细胞中的细胞内Ca²⁺转运可能受微管-微丝系统调节。总之，本研究证明了壁细胞中存在由胃泌素或离子载体A23187介导并受微管-微丝系统调节的细胞内Ca²⁺转运的可能性。
