Evidence for a sodium/calcium exchanger and voltage‐dependent calcium channels in adipocytes

FEBS Letters

Lee, L.-Y.¹  Snowdowne, Kenneth W.¹  Pershadsingh, Harrihar A.² 

[1] Departmentof Biochemistry, University of the Pacific School of Dentistry, 2155 Webster Street, San Francisco, CA 94115, USA;Department of Laboratory Medicine, University of California, San Francisco, CA 94143-0808 USA

关键词: Na+-Ca2+ exchange;    Ca2+;    intracellular;    Ca2+ channel;    Aequorin;    (Adipocyte);   

DOI  :  10.1016/0014-5793(89)81169-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The objective of these studies is to identify and characterize Ca²⁺-transport systems that may be of potential importance in the action of Ca²⁺-mobilizing hormones in the adipocyte. Using the Ca²⁺-sensitive photoprotein, aequorin, [Ca²⁺]_i was estimated to be 0.15 μM, assuming an intracellular [Mg²⁺] of 1 mM. Substitution of Na⁺ with choline⁺ caused a transient increase in [Ca²⁺]_i which was inversely related to extracellular [Na⁺], consistent with operation of a mediated Na⁺-Ca²⁺ exchange system. The stoichiometry was 3Na⁺:Ca²⁺. Elevation of extracellular K⁺ caused an increase in [Ca²⁺]_i that was blocked by the Ca²⁺ channel antagonist, diltiazem, by omitting extracellular Ca²⁺, or by substituting Sr²⁺ for Ca²⁺. These findings indicate the presence of an Na⁺-Ca²⁺ exchanger and voltage-sensitive Ca²⁺ channels in adipocytes.

【 授权许可】

Unknown