Tse F W, Tse A, Hille B
Department of Physiology and Biophysics, University of Washington, Seattle 98195.
Proc Natl Acad Sci U S A. 1994 Oct 11;91(21):9750-4. doi: 10.1073/pnas.91.21.9750.
Gonadotropin-releasing hormone induces oscillatory release of Ca2+ from inositol trisphosphate-sensitive stores of gonadotropes. Simultaneously with electrophysiological measures of cytoplasmic [Ca2+], corresponding changes in [Ca2+] within intracellular stores were monitored with a fluorescent dye, mag-indo-1. Each cycle of oscillation released only 10% of the detectable stored Ca2+. Some Ca2+ was recovered by the stores using a mechanism sensitive to inhibitors of intracellular Ca2+ ATPases, and much of the remainder was temporarily and rapidly pumped into other intracellular compartments or out of the cell. The dynamics of Ca2+ oscillations are thus more complex than a repeated emptying and refilling of a single compartment. The free concentrations measured show that intracellular Ca2+ store compartments contain strong Ca2+ buffers.
促性腺激素释放激素诱导促性腺激素细胞中对肌醇三磷酸敏感的储存库释放Ca2+振荡。在对细胞质[Ca2+]进行电生理测量的同时，用荧光染料mag-indo-1监测细胞内储存库中[Ca2+]的相应变化。每个振荡周期仅释放可检测到的储存Ca2+的10%。一些Ca2+通过对细胞内Ca2+ATP酶抑制剂敏感的机制被储存库回收，其余大部分则被暂时快速泵入其他细胞内隔室或细胞外。因此，Ca2+振荡的动力学比单个隔室的反复排空和重新填充更为复杂。所测得的游离浓度表明，细胞内Ca2+储存隔室含有强大的Ca2+缓冲剂。
