BONE CELL CALCIUM REGULATION

这项研究的长期目标是了解这些因素 调节成骨细胞钙。它正变得越来越多 显然，这种离子的变化与作用机制有关 几种吸收剂，以及对各种 钙调节系统将有助于开发潜在的方法 控制全身骨代谢的病理变化 或者是当地的。具体地说，它是在分离的成骨细胞中提出的 取自新生大鼠的头盖骨和成骨细胞人的头盖骨 骨肉瘤细胞系SAOS-2和G292，以：1.进一步研究 细胞内钙离子动员调节的本质 池子，特别强调鸟嘌呤三磷酸和 它可能与肌醇磷酸盐如1(1，4，5)p3相互作用； 阐明磷脂酰肌醇代谢调节的本质和作用 骨吸收因子和有丝分裂原对细胞内钙的影响， 表皮生长因子(EGF)，以便更好地进行对比和对比 与其他骨吸收药如凝血酶的作用； 阐明肌醇磷脂代谢调节的本质 通过钙通道拮抗剂的实验，以及 离子载体和细胞外钙水平；4.研究 这些细胞的电生理特性，重点是膜 电位和钾、钠、钙电流；5.研究 表皮生长因子和凝血酶对上述电生理特性的影响； 肌醇磷酸盐对电生理的影响 在AIMS 4和5中定义的性质；7.研究酪氨酸激酶的作用 成骨细胞钙-肌醇磷脂调节活性的研究 EGF对新陈代谢和增殖的影响。胞质 钙调节将用荧光染料Fura-2和 氚-肌醇标记细胞中磷脂酰肌醇的代谢 高效液相色谱方法。细胞增殖将会 通过掺入氚胸苷进行评估。这个 电生理特性将用膜片钳进行研究 技巧。总体而言，这里提出的研究应该会在 细胞内和质膜调节的深度信息 成骨细胞钙调控机制的研究进展 重点是。关于这些途径的可能的多样性 由EGF和凝血酶等潜在不同的介质激活。

The long-term objective of this study Is to understand the factors regulating osteoblastic cell calcium. It is becoming increasingly evident that changes In this ion are involved in the mechanism of action of several resorptive agents and that an understanding of the various calcium regulatory systems will aid in the development of potential ways to control pathological changes in bone metabolism occurring systemically or locally. Specifically, it is proposed in osteoblastic cells isolated from the calvaria of newborn rats and In the osteoblastic human osteosarcomal cell lines, SaOS-2 and G292, to: 1. to further study the nature of the regulation of mobilization of calcium from intracellular pools with particular emphasis on the role of guanine trisphosphate and Its possible interaction with inositol phosphates such as 1(1,4,5)p3; 2. to delineate the nature of regulation of phosphoinositide metabolism and cytosolic calcium levels by the bone resorptive agent and mitogen, epidermal growth factor (EGF), in order to better compare and contrast its effects with other bone resorptive agents such as thrombin; 3. to delineate the nature of regulation of phosphoinositide metabolism by calcium via experimentation with calcium channel antagonists, an ionophore and extracellular calcium levels; 4. to study the electrophysiological properties of these cells with emphasis on membrane potential and potassium, sodium and calcium currents; 5. to study the effects of EGF and thrombin on these electrophysiological properties; 6. to study the effects of inositol phosphates on the electrophysiological properties defined in aims 4 & 5; 7. to study the role of tyrosine kinase activity in the regulation of osteoblastic cell calcium, phosphoinositide metabolism as well as proliferation In response to EGF. Cytosolic calcium regulation will be studied with the fluorescent dye, Fura-2, and phosphoinositide metabolism in tritiated -inositol labelled cells by means of high performance liquid chromatography. Cell proliferation will be assessed by incorporation of tritiated thymidine. The electrophysiological properties will be studied with patch-clamp techniques. In general, the studies proposed here should provide more In depth information on the intracellular and plasma membrane regulatory mechanisms involved in the control of osteoblastic cell calcium with emphasis. on the possible diversities of these pathways involved upon activation by agents as potentially different as EGF and thrombin.