Interaction between injected Ca2+ and intracellular Ca2+ stores in Xenopus oocytes

FEBS Letters

Dascal, Nathan¹  Boton, Rony¹ 

[1] Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel

关键词: Oocyte;    Chloride channel;    Calcium;    Calcium store;    Xenopus laevis;   

DOI  :  10.1016/0014-5793(90)80278-Q

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Upon two repetitive deep injections of Ca²⁺ into Xenopus oocyte (200–300 μn under the membrane), the amplitude of the transient Cl⁻ current induced by the second injection is several-fold higher than that of the first one. This ‘potentiation’ persists even at 60–90 min intervals between injections. However, in oocytes permeabilized to Ca²⁺ by the ionophore A23187 in a Ca²⁺-free solution, the potentiation completely disappears after 30 min. It is proposed that the injected Ca²⁺ is largely taken up by the stores, whereas following the second injection, a higher proportion of Ca²⁺ reaches the membrane, since the stores are already loaded. In ionophore-treated oocytes, the stores lose the accumulated Ca²⁺ over several minutes and are then ready to take up Ca²⁺ again, hindering its arrival at the membrane.

【 授权许可】

Unknown