棕色脂肪细胞中钠离子依赖的α-肾上腺素能介导的细胞内（线粒体）钙离子动员

Na+-dependent, alpha-adrenergic mobilization of intracellular (mitochondrial) Ca2+ in brown adipocytes.

作者信息

Connolly E, Nånberg E, Nedergaard J

出版信息

Eur J Biochem. 1984 May 15;141(1):187-93. doi: 10.1111/j.1432-1033.1984.tb08173.x.

DOI:10.1111/j.1432-1033.1984.tb08173.x

Abstract

The existence and significance of a hormone-sensitive, rapidly mobilizable intracellular pool of Ca2+ in hamster brown-fat cells was investigated with 45Ca2+-labelling techniques. It was shown that such a pool existed and was probably located within the abundant mitochondria. It was rapidly mobilized by norepinephrine (median effective concentration 50 nM) through alpha-adrenergic mechanisms. The mobilization of Ca2+ from the intracellular stores (mitochondria) required the presence of extracellular Na+, but not of Ca2+, K+ or Mg2+. It is concluded that the experiments are in agreement with a hypothesis linking the mobilization of intracellular Ca2+ pools with an alpha-adrenergically-induced increase in plasma membrane Na+ permeability (observed as a membrane depolarization), and a subsequent activation of the mitochondrial Na+/Ca2+ exchange, leading to mobilization of mitochondrial Ca2+ and the mediation of alpha-adrenergic effects as a result of an elevated cytosolic Ca2+ level.

摘要

采用⁴⁵Ca²⁺标记技术，研究了仓鼠棕色脂肪细胞中对激素敏感、可快速动员的细胞内Ca²⁺池的存在及其意义。结果表明，这样一个池是存在的，并且可能位于丰富的线粒体中。去甲肾上腺素（半数有效浓度50 nM）通过α-肾上腺素能机制可使其快速动员。从细胞内储存部位（线粒体）动员Ca²⁺需要细胞外Na⁺的存在，但不需要Ca²⁺、K⁺或Mg²⁺。得出的结论是，这些实验与一个假说相符，该假说将细胞内Ca²⁺池的动员与α-肾上腺素能诱导的质膜Na⁺通透性增加（表现为膜去极化）以及随后线粒体Na⁺/Ca²⁺交换的激活联系起来，导致线粒体Ca²⁺的动员，并由于胞质Ca²⁺水平升高而介导α-肾上腺素能效应。