Distinct mechanisms of [Ca2+]i oscillations in HSY and HSG cells:: Role of Ca2+ influx and internal Ca2+ store recycling
Distinct mechanisms of [Ca2+]i oscillations in HSY and HSG cells:: Role of Ca2+ influx and internal Ca2+ store recycling
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DOI：
10.1007/s00232-001-0020-6
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发表时间：
2001-06-01
影响因子：
2.4
通讯作者：
Ambudkar, IS
中科院分区：
文献类型：
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作者：
Liu, X;Liao, D;Ambudkar, IS
本研究检测了人涎腺细胞系HSY和HSG中的[Ca2+](i)振荡。在两种细胞类型中，相对低浓度的碳二醇（CCh）诱导振荡，高浓度的碳二醇（CCh）诱导[Ca2+](i)和K-Ca电流持续、稳定地增加。在两种细胞类型中，低IP3诱导[Ca2+](i)振荡，而Tg阻断cch刺激的[Ca2+](i)振荡。与HSG细胞不同，从HSY细胞中去除细胞外Ca2+ (i)不影响CCh刺激的[Ca2+](i)振荡或内部Ca2+储存重新填充，并且（ii）将[CCh]诱导的高[Ca2+](i)稳态增加转化为振荡。与HSG细胞相比，HSY细胞中CCh-或thapsigarin诱导的Ca2+内流更高。重要的是，与HSG细胞相比，HSY细胞显示出相对较高水平的肌内质网Ca2+泵（SERCA）和肌醇三磷酸受体（IP(3)Rs）。这些数据表明，HSY和HSG细胞中的[Ca2+](i)振荡主要是由SERCA和IP3R活性分别从细胞质中摄取Ca2+和释放Ca2+决定的。在HSY细胞中，尽管Ca2+内流决定了[Ca2+]的稳态增加，但Ca2+内流并没有剧烈地促进这一过程(i)。在HSG细胞中，[Ca2+](i)振荡直接依赖于Ca2+内流；进入细胞的Ca2+被迅速吸收到储存中，然后释放到细胞质中。我们认为HSY和HSG细胞[Ca2+](i)振荡机制的差异与它们各自回收内部Ca2+储存的能力有关。
This study examined [Ca2+](i) oscillations in the human salivary gland cell lines, HSY and HSG. Relatively low concentrations of carbachol (CCh) induced oscillatory, and higher [CCh] induced sustained, steady state increases in [Ca2+](i) and K-Ca currents in both cell types. Low IP3 but not thapsigargin (Tg), induced [Ca2+](i) oscillations, whereas Tg blocked CCh-stimulated [Ca2+](i) oscillations in both cell types. Unlike in HSG cells, removal of extracellular Ca2+ from HSY cells (i) did not affect CCh-stimulated [Ca2+](i) oscillations or intemal Ca2+ store refill, and (ii) converted high [CCh]-induced steady-state increase in [Ca2+](i) into oscillations. CCh- or thapsigargin-induced Ca2+ influx was higher in HSY, than in HSG, cells. Importantly, HSY cells displayed relatively higher levels of sarcoendoplasmic reticulum Ca2+ pump (SERCA) and inositoltrisphosphate receptors (IP(3)Rs) than HSG cells.These data demonstrate that [Ca2+](i) oscillations in both HSY and HSG cells are priInarily determined by the uptake of Ca2+ from, and release of Ca2+ into, the cytosol by the SERCA and IP3R activities, respectively. In HSY cells, Ca2+ influx does not acutely contribute to this process, although it determines the steady-state increase in [Ca2+](i). In HSG cells, [Ca2+](i) oscillations directly depend on Ca2+ influx; Ca2+ coming into the cell is rapidly taken up into the store and then released into the cytosol. We suggest that the differences in the mechanism of [Ca2+](i) oscillations HSY and HSG cells is related to their respective abilities to recycle internal Ca2+ stores.