Finch E A, Turner T J, Goldin S M
Department of Neurobiology, Harvard Medical School, Boston, MA 02115.
Science. 1991 Apr 19;252(5004):443-6. doi: 10.1126/science.2017683.
Inositol 1,4,5-trisphosphate (IP3)-induced calcium release from intracellular stores is a regulator of cytosolic-free calcium levels. The subsecond kinetics and regulation of IP3-induced calcium-45 release from synaptosome-derived microsomal vesicles were resolved by rapid superfusion. Extravesicular calcium acted as a coagonist, potentiating the transient IP3-induced release of calcium-45. Thus, rapid elevation of cytosolic calcium levels may trigger IP3-induced calcium release in vivo. Extravesicular calcium also produced a more slowly developing, reversible inhibition of IP3-induced calcium-45 release. Sequential positive and negative feedback regulation by calcium of IP3-induced calcium release may contribute to transients and oscillations of cytosolic-free calcium in vivo.
肌醇1,4,5 -三磷酸（IP3）诱导的细胞内钙库钙释放是细胞溶质游离钙水平的调节因子。通过快速灌注解析了IP3诱导的突触体衍生微粒体囊泡中钙-45释放的亚秒级动力学和调节机制。囊泡外钙作为协同激动剂，增强了IP3诱导的钙-45瞬时释放。因此，细胞溶质钙水平的快速升高可能在体内触发IP3诱导的钙释放。囊泡外钙还产生了一种发展较慢、可逆的对IP3诱导的钙-45释放的抑制作用。钙对IP3诱导的钙释放的顺序性正反馈和负反馈调节可能有助于体内细胞溶质游离钙的瞬变和振荡。
