Rustenbeck I, Eggers G, Münster W, Lenzen S
Institute of Pharmacology and Toxicology, University of Göttingen, Germany.
Biochem Biophys Res Commun. 1993 Aug 16;194(3):1261-8. doi: 10.1006/bbrc.1993.1959.
The mechanism of spermine-induced enhancement of mitochondrial Ca2+ uptake was explored using the fluorescent Ca2+ indicator Fluo-3/AM to measure the free matrix Ca2+ concentration. Simultaneously, the extramitochondrial Ca2+ concentration was registered by a Ca(2+)-ion selective electrode. Spermine lowered the extramitochondrial steady state Ca2+ concentration and at the same time induced a decrease of the intramitochondrial Ca2+ concentration. However, there is a concentration-dependent reversal of the stimulatory action of spermine, which may be explained by the existence of a second, low-affinity binding site for spermine which mediates an inhibition of uptake in spite of the existence of an inwardly directed Ca2+ gradient.
利用荧光钙指示剂Fluo-3/AM测量游离基质钙浓度，探究了精胺诱导线粒体钙摄取增强的机制。同时，通过钙离子选择性电极记录线粒体外钙浓度。精胺降低了线粒体外稳态钙浓度，同时导致线粒体内钙浓度降低。然而，精胺的刺激作用存在浓度依赖性逆转，这可能是由于存在第二个低亲和力精胺结合位点，尽管存在内向的钙离子梯度，但该位点介导了摄取抑制。
