SECRETORY RESPONSES OF RAT PERITONEAL MAST-CELLS TO HIGH INTRACELLULAR CALCIUM
SECRETORY RESPONSES OF RAT PERITONEAL MAST-CELLS TO HIGH INTRACELLULAR CALCIUM
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DOI：
10.1016/0014-5793(88)81445-5
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发表时间：
1988-01-04
期刊：
影响因子：
3.5
通讯作者：
NEHER, E
中科院分区：
文献类型：
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作者：
PENNER, R;NEHER, E
采用膜片钳技术研究不同细胞内钙浓度([Ca~(2+)]i)对大鼠腹膜肥大细胞分泌的影响。当细胞内钙离子以吸管负载的二溴巴比妥钠加入细胞内时，[Ca~(2+)]_i升高到1-10μM引起的膜电容增加，表明胞吐作用呈浓度依赖性。在较高的浓度下，可以观察到反应的降低。暴露于微摩尔[Ca~(2+)]的细胞发生了形态变化，导致肿胀，这表明细胞骨架发生了变化。二溴BAPTA(4 MM)强烈抑制GTP-γ-S诱导的细胞分泌，从而抑制G蛋白介导的刺激作用。应用钙离子载体离子霉素后，细胞内[Ca~(2+)]i一过性升高，这种升高与钙离子依赖性分泌的作用是平行的。当细胞内钙离子浓度低于1μM时，细胞内钙离子的有效缓冲作用消失。我们的结果表明，[Ca~(2+)]的增加可以触发分泌，但前提是这种分泌是高的和持续的。然而，在生理刺激下，肥大细胞的分泌是在[Ca~(2+)]i低于1μM的情况下进行的。因此，我们得出结论，在生理条件下肥大细胞脱颗粒不仅仅是[Ca~(2+)]i升高的结果，而是其他第二信使系统与钙一起协同作用，以确保快速有效的分泌。
The patch-clamp technique was used to investigate the secretory responses of rat peritoneal mast cells at various intracellular calcium concentrations ([Ca2+]i). When Calcium was introduced into the cell with pipette-loaded dibromo-BAPTA, elevation of [Ca2+]iinto the range 1–10 μM induced membrane capacitance increases indicative of exocytosis in a concentration-dependent manner. At higher concentrations a decrease of the response was observed. Cells that were exposed to micromolar [Ca2+]iunderwent morphological alterations resulting in swelling, which is indicative of cytoskeletal alterations. The presence of dibromo-BAPTA (4 mM) strongly inhibited secretion induced by GTP-γ-S, thus hampering the contribution of G-protein-mediated stimulation. Application of the Ca2+ionophore ionomycin resulted in transient increases in [Ca2+]iwhich were parallelled by Ca2+-dependent secretion. Effective buffering of the cytosolic calcium level below 1 μM abolished the secretory response. Our results show that an increase in [Ca2+]ican trigger secretion, but only if it is high and sustained. During physiological stimulation, however, secretion proceeds at [Ca2+]ibelow 1 μM. It is, therefore, concluded that mast cell degranulation under physiological conditions is not simply a result of an increase in [Ca2+]i, but that other second messenger systems in conjunction with calcium act synergistically in order to ensure fast and efficient secretion.