Role of calcium and phosphoinositides in the actions of certain hormones and neurotransmitters.
Role of calcium and phosphoinositides in the actions of certain hormones and neurotransmitters.
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钙和磷酸肌醇在某些激素和神经递质的作用中的作用。
DOI：
10.1172/jci111886
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Exton,JH
中科院分区：
文献类型：
--
作者：
Exton,JH
无花果。I显示了哺乳动物细胞中钙离子的调节机制。钙离子通过膜电位依赖或非依赖的选择性质膜通道进入细胞。此外，Ca~(2+)可通过Na~‘通道或通过Na~+/Ca~(2+)交换器(1)进入。为了防止钙的病理性堆积，细胞具有质膜上的钙-三磷酸腺苷酶泵，将胞内钙维持在0.1-0.2的水平，M(1)。Na+/Ca~(2+)交换器也主要作用是挤出Ca~(2+)(1)。Ca~(2+)泵作为低容量系统对Ca~(2+)具有高亲和力，而交换器则相反。除质膜系统外，细胞内机制控制胞浆Ca~(2+)(图1)。这些机制主要涉及内质网和线粒体，它们吸收或释放Ca~(2+)。某些膜和其他细胞成分也结合和缓冲胞浆Ca~(2+)“。内质网的钙摄取是通过一个ATPase进行的，而有丝分裂的摄取则涉及一个特定的载体，并由质子M7力驱动(2)。对这两种细胞器的钙外流途径知之甚少。最近的证据表明，内质网是
Fig. I shows the mechanisms involved in the regulation of Ca2" in mammalian cells. Ca2" enters cells through selective plasma membrane channels that are either membrane potentialdependent or-independent (1). In addition, Ca2+ may enter through the Na'channel or by a Na+/Ca2+ exchanger (1). To prevent the pathological accumulation of Ca2, cells possess a plasma membrane Ca2'ATPase pump that maintains cytosolic Ca2+ at aresting level of 0.1-0.2, M (1). The Na+/Ca2" exchanger also acts mainly to extrude Ca2+(1). The Ca2+ pump acts as a low capacity system with high affinity for Ca2+, whereas the reverse is true for the exchanger. In addition to plasma membrane systems, intracellular mechanisms control cytosolic Ca2+(Fig. 1). These mainly involve the endoplasmic (sarcoplasmic) reticulum and mito-chondria, which take up or release Ca2+(2). Certain membranes and other cellular constituents also bind and buffer cytosolic Ca2". Ca2+ uptake by endoplasmic reticulum occurs by an ATPase, whereas that by mitocheNndria involvesa specific carrier and is driven by the proton m7-force (2). Less is known about the Ca2'efflux pathways of either organelle. Recent evidence suggests that the endoplasmic reticulum is