کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10926433 | 1091844 | 2008 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Steady-state coupling of plasma membrane calcium entry to extrusion revealed by novel L-type calcium channel block
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
بیولوژی سلول
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![عکس صفحه اول مقاله: Steady-state coupling of plasma membrane calcium entry to extrusion revealed by novel L-type calcium channel block Steady-state coupling of plasma membrane calcium entry to extrusion revealed by novel L-type calcium channel block](/preview/png/10926433.png)
چکیده انگلیسی
The L-type Ca2+ channel (CaV1.2) is the main pathway for trans-sarcolemmal (SL) Ca2+ influx in cardiac myocytes. To maintain Ca2+ homeostasis, chronic SL Ca2+-influx must be matched by chronic SL efflux. In this study we tested the hypothesis that chronic down-regulation of SL Ca2+ entry regulates SL extrusion. We studied mRNA and Ca2+ handling responses to chronic down-regulation of Ca2+ channel current induced by over-expression of the small GTPase Rem. Rem lowered net SL diastolic Ca2+ entry, and reduced the twitch Ca2+ amplitude. Rem also significantly slowed Ca2+ transient decay kinetics (p < 10â3). Rem reduced NCX1.1 protein level and function. To measure Na-Ca2+ exchange (NCX) function and sarcoplasmic reticulum (SR) store load we perfused Ca2+-free bath for 25 s followed by rapid application of 50 mM caffeine. In control, caffeine transient relaxations were described by a bi-exponential decay with a fast phase that was 10 mM Ni2+-senstive. Rem significantly slowed caffeine-induced relaxation time course (Rem versus control, p < 10â6). To test whether extrusion slowing was mediated by insufficient basal Ca2+ for allosteric NCX activation we measured the effect of increasing bath Ca2+ from 1.8 to 6 mM on caffeine-induced relaxation kinetics. 6 mM Ca2+ did not alter kinetics of control cells, but in Rem-over-expressed cells 6 mM Ca2+ sped kinetics. We conclude that chronic block of CaV1.2 channel-mediated SL entry alters NCX expression, and coincidentally controls SR Ca loading and SL Ca2+ efflux.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Cell Calcium - Volume 44, Issue 4, October 2008, Pages 353-362
Journal: Cell Calcium - Volume 44, Issue 4, October 2008, Pages 353-362
نویسندگان
William C. Lester, Elizabeth A. Schroder, Don E. Burgess, Doug Yozwiak, Douglas A. Andres, Jonathan Satin,