Endoh Takayuki, Kobayashi Hiroshi, Nobushima Hiromi, Shibukawa Yoshiyuki, Tazaki Masakazu, Sueishi Kenji
Department of Physiology, Tokyo Dental College, Chiba, Japan.
Bull Tokyo Dent Coll. 2012;53(1):33-6. doi: 10.2209/tdcpublication.53.33.
Osteoblasts play a major role in bone formation. Osteoblasts employ intracellular Ca(2+) as a second messenger modulating hormonal responses and a cofactor for bone mineralization. Voltage-dependent Ca(2+) channels (VDCCs) are most commonly present in excitable cell membranes. They are also present at lower levels even in most nonexcitable cells too. In both types of cell, they mediate the influx of Ca(2+) in response to membrane depolarization. Prepulse facilitation is a phenomenon in which a long and strong depolarizing pulse induces a form of VDCC that exhibits an increased opening probability. We believe this to be the first study to demonstrate that strong depolarization prepulses both increase and decrease VDCCs in osteoblasts.
成骨细胞在骨形成过程中发挥着主要作用。成骨细胞利用细胞内钙离子作为第二信使来调节激素反应，并作为骨矿化的辅助因子。电压依赖性钙通道（VDCCs）最常见于可兴奋细胞膜中。即使在大多数非可兴奋细胞中，它们也以较低水平存在。在这两种类型的细胞中，它们介导钙离子响应膜去极化而内流。预脉冲易化是一种现象，即长时间且强烈的去极化脉冲会诱导一种VDCC形式，其表现出增加的开放概率。我们认为这是第一项证明强去极化预脉冲既能增加又能减少成骨细胞中VDCCs的研究。
